Planetary transmission mechanism and driving device thereof

Abstract

This application provides a planetary transmission mechanism, including a lead screw drive assembly and a sleeve assembly. The lead screw drive assembly is at least partially located within the inner cavity of the sleeve assembly, and the lead screw drive assembly meshes with the sleeve assembly. The sleeve assembly is a split structure, comprising a cylindrical body, a first gear ring, and a second gear ring. The cylindrical body is at least partially located between the first gear ring and the second gear ring. The planetary transmission mechanism includes a limiting assembly, comprising a first limiting part and a second limiting part. One end of the first gear ring and the cylindrical body are limited by the first limiting part, and the other end of the second gear ring and the cylindrical body are limited by the second limiting part, thereby reducing the risk of displacement of the cylindrical body and the first gear ring, as well as reducing the risk of displacement of the cylindrical body and the second gear ring.

Description

Technical Field

[0001] This application relates to the field of mechanical transmission components, and in particular to a planetary transmission mechanism and its driving device. Background Technology

[0002] In the related planetary transmission mechanism, a sleeve and rollers are included. The sleeve includes a cylindrical body and two internal toothed parts. The cylindrical body is located between the two internal toothed parts. The internal toothed parts mesh with the corresponding teeth of the rollers. The teeth of the two internal toothed parts correspond to each other in the axial direction of the sleeve, which means that the two internal toothed parts and the teeth at both ends of the rollers simultaneously enter or disengage. However, in general, when the precision is not high, there will be a certain gap when one tooth of the internal toothed part meshes with one end of the roller teeth and enters the next tooth meshing with the roller teeth. Especially at high speed, there is a possibility of impact during gear meshing, and the rollers are prone to axial movement, which affects the transmission stability. Summary of the Invention

[0003] This application provides a planetary transmission mechanism that improves transmission stability.

[0004] This application provides a planetary transmission mechanism, including a lead screw drive assembly and a sleeve assembly. The lead screw drive assembly is at least partially located within the inner cavity of the sleeve assembly, and the lead screw drive assembly meshes with the sleeve assembly. The sleeve assembly includes a cylindrical body portion, a first gear ring portion, and a second gear ring portion. The cylindrical body portion is located between the first gear ring portion and the second gear ring portion. The first gear ring portion includes a first tooth, and a plurality of the first teeth are distributed circumferentially along the first gear ring portion. The second gear ring portion includes a second tooth, and a plurality of the second teeth are distributed circumferentially along the second gear ring portion. Along the circumference of the sleeve assembly, the first tooth and the second tooth are staggered.

[0005] This application provides a planetary transmission mechanism in which the first tooth and the second tooth are staggered along the circumferential direction of the sleeve assembly to ensure that when the tooth at one end of the sleeve assembly disengages, the tooth at the other end engages, which can improve the smooth operation of the roller, reduce the possibility of roller slippage, and improve the transmission stability of the planetary transmission mechanism.

[0006] This application provides a driving device, which includes a motor and a planetary transmission mechanism. The planetary transmission mechanism includes a lead screw drive assembly and a sleeve assembly. The lead screw drive assembly is at least partially located in the inner cavity of the sleeve assembly and meshes with the sleeve assembly. The sleeve assembly includes a cylindrical body, a first gear ring, and a second gear ring. The cylindrical body is at least partially located between the first gear ring and the second gear ring. The first gear ring includes a plurality of first teeth distributed circumferentially along the first gear ring. The second gear ring includes a plurality of second teeth distributed circumferentially along the second gear ring. Along the circumferential direction of the sleeve assembly, the first teeth and second teeth are staggered. The lead screw drive assembly includes a lead screw and a roller. The motor is connected to the lead screw, and the roller is threadedly connected to the lead screw. The roller part is threadedly meshed with the sleeve assembly. One end of the roller meshes with the first gear ring and the other end meshes with the second gear ring.

[0007] Applying a planetary transmission mechanism with a first and second tooth misalignment to a drive device ensures that when one end of the tooth disengages, the other end of the tooth engages, which can significantly improve the smooth operation of the drive device and enhance its transmission stability. Attached Figure Description

[0008] Figure 1 This is a three-dimensional structural diagram of a driving device according to this application;

[0009] Figure 2 Is it like this? Figure 1 A schematic diagram of the planar structure of the drive device shown;

[0010] Figure 3 This is an axial cross-sectional view of a planetary transmission mechanism according to this application;

[0011] Figure 4 Is it like this? Figure 3 A three-dimensional structural schematic diagram of the sleeve assembly shown;

[0012] Figure 5 Is it like this? Figure 4 The exploded structural diagram of the sleeve assembly shown is shown.

[0013] Figure 6 Is it like this? Figure 4 A schematic diagram of the axial cross-sectional structure of the sleeve assembly shown;

[0014] Figure 7 Is it like this? Figure 4 Another planar structural schematic diagram of the sleeve assembly shown;

[0015] Figure 8 Is it like this? Figure 7A schematic projection of the first gear section and the second gear section shown.

[0016] Figure 9 Is it like this? Figure 5 A three-dimensional structural schematic diagram of the first gear section shown;

[0017] Figure 10 Is it like this? Figure 9 A schematic diagram of the planar structure of the first gear ring from another perspective;

[0018] Figure 11 Is it like this? Figure 9 A schematic projection of the first gear section shown;

[0019] Figure 12 Is it like this? Figure 9 A schematic diagram of the planar structure of the first gear ring from another perspective;

[0020] Figure 13 Is it like this? Figure 5 A three-dimensional structural schematic diagram of the second gear section is shown;

[0021] Figure 14 Is it like this? Figure 13 A schematic projection of the second gear section shown;

[0022] Figure 15 Is it like this? Figure 13 A schematic diagram of the second gear section from another perspective;

[0023] Figure 16 Is it like this? Figure 5 A schematic diagram of the first and second gear sections from one perspective.

[0024] Figure 17 Is it like this? Figure 5 A three-dimensional sectional view of the cylindrical section shown;

[0025] Figure 18 Is it like this? Figure 5 A three-dimensional sectional view of the cylindrical section shown from another perspective;

[0026] Figure 19 Is it like this? Figure 17 A schematic axial sectional view of the cylindrical section shown. Detailed Implementation

[0027] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0028] It should be understood that the described embodiments are merely some embodiments of this application, and not all embodiments. All other technical solutions obtained by those skilled in the art based on the technical solutions in this application without inventive effort are within the scope of protection of this application.

[0029] The technical solutions described in this application should be understood by those skilled in the art. For example, directional descriptions such as "front," "back," "left," "right," "up," and "down" are only used to describe the relationship between objects and are not substantive limitations. "Multiple" means at least two or more.

[0030] This application provides a planetary transmission mechanism, wherein the sleeve is an important component of the planetary transmission mechanism, which is a crucial component of the drive device and has a wide range of applications. Drive devices can be used in automotive steering motors, actuators, and collaborative equipment. The planetary transmission mechanism provided in this application is a linear transmission mechanism, where the drive device primarily converts rotary motion into linear motion. It can be applied to any equipment requiring motion conversion. The planetary transmission mechanism includes a lead screw drive assembly 1 and a sleeve assembly 2. The lead screw drive assembly 1 is at least partially located within the inner cavity of the sleeve assembly 2, and the lead screw drive assembly 1 meshes with the sleeve assembly 2. The planetary transmission mechanism... A ball screw drive is a mechanical transmission device that can convert rotary motion into linear motion. The ball screw drive assembly includes a ball screw and rollers. Generally, the rotary motion of the ball screw or sleeve assembly 2 is converted into linear motion of the sleeve assembly 2 and the ball screw through the planetary motion of the rollers. The rollers include multiple rollers and a cage to prevent the rollers from deviating from their rotational trajectory. Planetary transmission mechanisms include upright and reverse types. This embodiment uses an upright planetary transmission mechanism as an example. The difference between the upright and reverse types is that when the sleeve is rotated to move the ball screw, it is called a reverse roller ball screw; when the ball screw is rotated to move the sleeve, it is called an upright roller ball screw. In related technologies, the sleeve includes a cylindrical body, with two teeth formed at each end of the inner wall of the cylindrical body. The sleeve has an internal thread that meshes with the external thread of the roller, while the gear ring meshes with the teeth at both ends of the roller, thus enabling transmission. Due to the need to mesh with the roller and considering its operating environment, the sleeve must possess certain rigidity, wear resistance, and heat resistance. Therefore, sleeves in current technologies are made of metal to meet these performance requirements. Manufacturing a complete sleeve from metal requires a series of complex processes, such as forging the gear blank, stress-relief annealing, rough turning, quenching and tempering, gear shaping, high-intensity shot peening, phosphating, and nitriding. The high-intensity shot peening, phosphating, and nitriding steps, in particular, are time-consuming and have relatively low manufacturing efficiency. The complex process described above requires significant time, manpower, and financial resources. Furthermore, while all-metal sleeves offer high strength, they also result in a larger overall mass for the planetary transmission mechanism. Additionally, although all-metal sleeves possess high rigidity, ensuring transmission stability at normal speeds, high-speed rotation or extremely large instantaneous amplitudes can lead to impacts during gear meshing, affecting the transmission stability of the metal sleeve and consequently impacting the transmission performance of the planetary transmission mechanism. Moreover, the direct metal-to-metal collisions during the meshing of the metal sleeve and rollers can generate considerable noise.

[0031] To solve the above problems, the following will refer to Figures 1 to 19 The technical solution of this application may be described in whole or in part by way of the above.

[0032] Please refer to the following first. Figure 3As shown, this application provides a planetary transmission mechanism, including a lead screw transmission assembly 1 and a sleeve assembly 2. The lead screw transmission assembly 1 includes a plurality of rollers 12 and a lead screw 11. The plurality of rollers 12 are distributed circumferentially along the lead screw 11. The rollers 12 are threadedly connected to the lead screw 11. One end of the roller 12 engages with the first gear ring portion 22, and the other end of the roller 12 engages with the second gear ring portion 23. The rollers 12 are threadedly connected to the cylinder portion 21. The lead screw transmission assembly 1 is at least partially located in the inner cavity of the sleeve assembly 2, and the lead screw transmission assembly 1 engages with the sleeve assembly 2.The sleeve assembly 2 includes a cylindrical body 21, a first geared ring 22, and a second geared ring 23. The first geared ring 22 is connected to one end of the cylindrical body 21, and the second geared ring 23 is connected to the other end of the cylindrical body 21. At least one of the cylindrical body 21, the first geared ring 22, and the second geared ring 23 is made of plastic, including three types of solutions. The first type is where one part is made of plastic, and the other two are made of metal. For example, the cylindrical body 21 can be made of plastic, while the first geared ring 22 and the second geared ring 23 can be made of metal; alternatively, the first geared ring 22 can be made of plastic, while the cylindrical body 21 and the second geared ring 23 can be made of metal; alternatively, the second geared ring 23 can be made of... The first type is made of plastic, while the cylindrical body 21 and the first gear ring 22 are made of metal. The second type has two parts made of plastic and the third part made of metal. For example, the cylindrical body 21 could be made of metal, while the first gear ring 22 and the second gear ring 23 are made of plastic; alternatively, the first gear ring 22 could be made of metal, while the cylindrical body 21 and the second gear ring 23 are made of plastic; or the second gear ring 23 could be made of metal, while the cylindrical body 21 and the first gear ring 22 are made of plastic. The third type has all three parts made of plastic, for example, the cylindrical body 21, the first gear ring 22, and the second gear ring 23 are all made of plastic. If two different materials are used in the manufacturing process, it can be achieved using an interlocking molding process. That is, dissimilar materials can be processed using this process. It is worth mentioning that this embodiment mainly takes the third type as an example, where the cylindrical body 21, the first gear ring 22, and the second gear ring 23 are all made of the same material, plastic, and processed using injection molding. Compared to metal material manufacturing processes, injection molding is more efficient. By selecting suitable molds and raw materials, it can produce sleeves with high dimensional accuracy, good surface finish, and that meet requirements. This allows for high-precision and high-efficiency production, suitable for mass production, and can reduce costs. Furthermore, sleeves made of plastic material ensure wear resistance, rigidity, and heat resistance. Based on these requirements, the overall weight of the sleeve can be reduced, thus making the entire planetary transmission mechanism lighter, achieving the goal of weight reduction. Furthermore, and importantly, the use of plastic sleeve components provides a buffering effect when engaging with the lead screw drive assembly, regardless of whether it's under normal operating speeds or under specific conditions such as high-speed rotation or extremely large instantaneous amplitude. This buffers the impact force during engagement and disengagement, thereby improving transmission stability. Additionally, the plastic sleeve components used in this application can buffer the impact of direct metal-to-metal collisions when they mesh with metal rollers, thus reducing noise.

[0033] Furthermore, in the above scheme, the first gear ring portion 22 is connected to one end of the cylindrical body portion 21, and the second gear ring portion 23 is connected to the other end of the cylindrical body portion 21. That is, the cylindrical body portion 21 is located between the first gear ring portion 22 and the second gear ring portion 23. The connection includes assembly connection and integral part connection. That is, the first gear ring portion 22 and the cylindrical body portion 21 can be fixed by assembly connection, or the first gear ring portion 22 and the cylindrical body portion 21 can be an integral part. Similarly, the second gear ring portion 23 and the cylindrical body portion 21 can be fixed by assembly connection, or the second gear ring portion 23 can be an integral part. The ring portion 23 and the cylindrical portion 21 are a single piece. In this embodiment, "single piece" should be understood as a non-assembled connection. The base material can be manufactured through casting, forging, stamping, extrusion, metal injection molding, metal powder metallurgy, etc., and then machined. Alternatively, the single piece can be directly manufactured through molding, casting, forging, stamping, extrusion, metal injection molding, metal powder metallurgy, etc. In some applications, the effect is directly related. For applications using a single extrusion molding method, the explanation of "single piece" can be supplemented as appropriate. In this embodiment, 3D printing can be used to print a one-piece sleeve assembly made of plastic. The first gear ring portion 22 and the cylindrical body portion 21 can be connected indirectly or directly by assembly. Similarly, the second gear ring portion 23 and the cylindrical body portion 21 can be connected indirectly or directly by assembly. This assembly connection is also called a split-type connection, meaning that the first gear ring portion 22, the second gear ring portion 23, and the cylindrical body portion 21 adopt a split structure, and the first gear ring portion 22, the second gear ring portion 23, and the cylindrical body portion 21 are manufactured independently. After preparation, the first gear ring portion 22, the second gear ring portion 23 and the cylindrical portion 21 are assembled and fixed. In this embodiment, the first gear ring portion 22, the second gear ring portion 23 and the cylindrical portion 21 are mainly used as a separate structure. In this application, direct connection refers to the connection between two parts or structures without the help of a third party. Connection by glue or other adhesives is also a direct connection. Indirect connection refers to the connection between two parts or structures through a third party, which will be described in detail below.

[0034] Specifically, in one embodiment, the second gear ring portion 23 is at least partially made of engineering thermoplastic material, wherein the portion of the second gear ring portion 23 that meshes with the roller is made of engineering thermoplastic material, and the remainder is made of metal, which can be manufactured using an insert molding process. Of course, the second gear ring portion 23 may be entirely made of engineering thermoplastic material, while the first gear ring portion 22 and the cylindrical portion 21 may be made of metal. Furthermore, the second gear ring portion 23 is located at the mating end of the cylindrical portion 21, and the mating end should be understood as the end that needs to be mated with an external drive device. The external drive device portion is connected to the external drive device. The second gear ring 23 is at least partially made of engineering thermoplastic material and located at the mating end because it needs to be driven by an external drive device, which requires a large torque. This also means that the second gear ring 23 will be subjected to greater impact during meshing under conditions of high-speed rotation or particularly large instantaneous amplitude. Therefore, the second gear ring 23 is at least partially made of engineering thermoplastic material, which can play a better role in buffering, protecting the second gear ring 23, and improving transmission stability.

[0035] In one embodiment, the cylindrical body 21, the first gear ring 22, and the second gear ring 23 are all made of engineering thermoplastic materials. In this embodiment, PEEK, or polyether ether ketone, is used. This material has high temperature resistance, corrosion resistance, and meets rigidity requirements. It also has self-lubricating properties. Of course, PEEK can also be mixed with other materials in a certain proportion to improve its self-lubricating properties, such as carbon fiber and graphite. Because it has easy processing properties, it can be prepared and processed by injection molding, injection molding, extrusion molding, and compression molding. In this embodiment, injection molding is used.

[0036] Furthermore, since the first gear ring portion 22, the second gear ring portion 23, and the cylindrical portion 21 in this embodiment are all made of engineering thermoplastic material, their assembly process differs slightly from that of metal materials. Engineering thermoplastic materials can be assembled using interference fits, transition fits, and clearance fits. The reason for this slight difference in assembly process compared to metal materials is that metal materials have a certain degree of ductility. The first gear ring portion 22 and the second gear ring portion 23 can be forcibly pressed into the cylindrical portion 21 without damage due to sudden deformation. Alternatively, the cylindrical portion 21 can be heated before inserting the first gear ring portion 22 and the second gear ring portion 23 without damage. However, since all three are made of plastic, the effect of inserting the first gear ring portion 22 and the second gear ring portion 23 by heating the cylindrical portion 21 is not particularly suitable. Moreover, if forced insertion is performed by press fitting, it may... Due to factors such as pressure, all three components may be partially damaged. In this embodiment, a transition fit is first made, and then the components are fixed by sealing with adhesive. That is, the first toothed ring 22 is transitionally fitted to one end of the cylinder 21, and the first toothed ring 22 is fixed to one end of the cylinder 21 with adhesive. The second toothed ring 23 is transitionally fitted to the other end of the cylinder 21, and the second toothed ring 23 is fixed to the other end of the cylinder 21 with adhesive. The advantage of this assembly and fixing method is that it avoids damage to all three components during the assembly process and improves the product qualification rate. Of course, in some other embodiments, the first toothed ring 22 and the second toothed ring 23 can be inserted by slightly heating the cylinder 21, which can also achieve an interference fit between the cylinder 21 and the first toothed ring 22 and the second toothed ring 23. The cylinder 21 and the first toothed ring 22 and the second toothed ring 23 can also be fixed by welding.

[0037] Please see Figure 5 and Figure 6As shown, in this embodiment, the sleeve assembly 2 is a split structure. The cylindrical body 21 includes a cylindrical body 211 with a cylindrical cavity G. The cylindrical body 211 includes a first end 1-1 and a second end 1-2. The first end 1-1 has a first opening 1-11, and the second end 1-2 has a second opening 1-21. A first gear ring 22 is connected to the first end 1-1, and at least part of the first gear ring 22 is located in the first opening 1-11. A second gear ring 23 is connected to the second end 1-2, and at least part of the second gear ring 23 is located in the second opening 1-21. The first opening 1-11, the second opening 1-21, and the cylindrical cavity G are connected. The first gear ring 22 and the second gear ring 23 are annular structures. The outer ring wall of the first gear ring 22 is indirectly or directly connected to the inner wall of the cylindrical body 211, and the outer ring wall of the second gear ring 23 is indirectly or directly connected to the inner wall of the cylindrical body 211. In this application, "direct connection" refers to two-way connection. Direct connection refers to the connection between components or structures without the use of a third-party component or structure, but through glue or other adhesives. Indirect connection refers to the connection between two components or structures through a third-party component or structure. In this embodiment, the outer ring wall of the first gear ring portion 22 is directly connected to the inner wall of the cylinder body 211 by glue, and the outer ring wall of the second gear ring portion 23 is also directly connected to the inner wall of the cylinder body 211 by glue. In addition, the cylinder body portion 21 includes an internal thread 212, which is located in the cylinder cavity G and is connected to the inner wall of the cylinder body 211 that forms the cylinder cavity G. The first gear ring portion 22 includes a first ring body 221 and a first gear ring 222. The first gear ring 222 is located inside the first ring body 221 and extends along the axial direction of the first ring body 221. The first gear ring 222 includes a plurality of first teeth 2-1, which are distributed circumferentially along the first gear ring 222.The second gear ring portion 23 includes a second ring body 231 and a second gear ring 232. The second gear ring 232 is located inside the second ring body 231 and extends axially along the second ring body 231. The second gear ring 232 includes multiple second teeth 2-2, which are distributed circumferentially along the second gear ring 232. In other words, the cylindrical portion 21 has a threaded structure, while the first teeth 2-1 of the first gear ring portion 22 and the second teeth 2-2 of the second gear ring portion 23 are both straight teeth. The two tooth shapes are different. Since the cylindrical portion 21, the first gear ring portion 22, and the second gear ring portion 23 are injection molded, during the demolding process, if the cylindrical portion 21, the first gear ring portion 22, and the second gear ring portion 23 are integrated as one piece... If the cylinder body 21, the first gear ring 22, and the second gear ring 23 are separate parts, they can be molded and demolded separately. The mold inside the cylinder cavity G of the cylinder body 21 is demolded by rotating along the spiral direction of the internal thread design, while the first gear ring 22 and the second gear ring 23 only need to be demolded by moving along their axial direction, which is convenient for demolding. After demolding, the three parts can be assembled and fixed, which is convenient for installation and has high molding efficiency. Of course, in this embodiment, the first tooth 2-1 and the second tooth 2-2 are both straight tooth structures. In some other embodiments, the first tooth 2-1 and the second tooth 2-2 can be helical tooth structures, etc.

[0038] Please see Figure 5 and Figure 6 As shown, the axial dimension of the first gear ring portion 22 is smaller than the axial dimension of the second gear ring portion 23. The second gear ring portion 23 includes a threaded section 233. The second gear ring 232 is located between the internal thread 212 and the threaded section 233. The threaded section 233, the second gear ring 232, and the second ring body 231 are integral parts. As mentioned above, this embodiment takes a positive planetary transmission mechanism as an example. Therefore, when the lead screw moves the sleeve, the sleeve moves axially along the movement path set by the lead screw. The second gear ring portion 23 is provided with a threaded section 233. This threaded section 233 is mainly connected to other external actuator joints to drive the movement of the external actuator joints. Therefore, the axial dimension of the second gear ring portion 23 is larger than the axial dimension of the first gear ring portion 22.

[0039] This application provides a method for manufacturing a planetary transmission mechanism, comprising the following steps: providing a mold, introducing material into the mold cavity, cooling and solidifying the material, demolding to obtain a preliminary blank of the cylindrical body portion 21, a preliminary blank of the first gear ring portion 22, and a preliminary blank of the second gear ring portion 23, respectively, performing precision machining on the preliminary blanks of the cylindrical body portion 21, the first gear ring portion 22, and the second gear ring portion 23, and obtaining the cylindrical body portion 21, the first gear ring portion 22, and the second gear ring portion 23, assembling and fixing the first gear ring portion 22 to one end of the cylindrical body portion 21, and assembling and fixing the second gear ring portion 23 to the other end of the cylindrical body portion 21. The sleeve assembly 2 is obtained, wherein at least one of the cylinder body 21, the first gear ring 22, and the second gear ring 23 is made of plastic; a screw drive assembly 1 is provided, and at least part of the screw drive assembly 1 is installed into the inner cavity of the sleeve assembly 2, so that the screw drive assembly 1 meshes with the sleeve assembly 2. This includes two preparation methods: one is to form three preparation cavities in the same mold, namely, the first cavity for preparing the initial blank of the cylinder body 21, the second cavity for preparing the initial blank of the first gear ring 22, and the third cavity for preparing the initial blank of the second gear ring 23; material is added to the cylinder. The temperature is controlled between 180°C and 210°C. The material melts upon heating, and the injection molding machine injects the material into the mold, which then flows into three preparation cavities. After cooling and solidification, the material is demolded in one step to obtain the preforms of the barrel section 21, the first gear ring section 22, and the second gear ring section 23. After further finishing, the barrel section 21, the first gear ring section 22, and the second gear ring section 23 are obtained. The advantage of this method is that it can reduce costs. Alternatively, three independent molds are required, each with one cavity. The material can be injected into the three independent mold cavities simultaneously by one injection molding machine, or three injection molding machines can be used to inject into the three independent molds separately. In the cavity, after demolding from three independent molds, the initial blanks of the cylindrical part 21, the first gear ring part 22, and the second gear ring part 23 are obtained respectively. After fine processing, the cylindrical part 21, the first gear ring part 22, and the second gear ring part 23 are obtained. The advantage of this production method is that three production lines can be formed, and each production line can produce different parts, thus improving production efficiency. Through the above preparation steps, it is convenient to prepare and process sleeve components with plastic material. After assembling the sleeve components with plastic material with the screw drive components, a planetary transmission mechanism that can improve transmission stability is prepared.

[0040] This embodiment uses the latter method for preparation. Specifically, a first mold is provided, the material is introduced into the cavity of the first mold, and after cooling and shaping, the cylindrical part 21 is obtained by demolding. The cylindrical part 21 is then obtained by fine machining of the cylindrical part 21.

[0041] Material is introduced into the cavity of the second mold, cooled and shaped, and then demolded to obtain the first gear ring part 22 blank. The first gear ring part 22 blank is then finely machined to obtain the first gear ring part 22.

[0042] Material is introduced into the cavity of the third mold, cooled and shaped, and then demolded to obtain the initial blank of the second gear ring 23. The initial blank of the second gear ring 23 is then precision machined to obtain the second gear ring 23, thereby improving production efficiency.

[0043] In addition, the material is an engineering thermoplastic material, specifically PEEK. The cylindrical body 21, the first gear ring 22, and the second gear ring 23 are all made of engineering thermoplastic material. After the first gear ring 22 is transitionally assembled with one end of the cylindrical body 21, the first gear ring 22 and one end of the cylindrical body 21 are then connected and fixed with adhesive. The second gear ring 23 and one end of the cylindrical body 21 are also connected and fixed with adhesive. Its advantages have been explained above and will not be elaborated further here.

[0044] In addition, finishing processes include grinding, polishing, and checking accuracy. If the mold accuracy is sufficient and conditions permit, after obtaining the initial blanks of the cylindrical part 21, the first gear ring part 22, and the second gear ring part 23, the initial blanks of the cylindrical part 21, the first gear ring part 22, and the second gear ring part 23 are ground to obtain the cylindrical part 21, the first gear ring part 22, and the second gear ring part 23.

[0045] In related technologies, the sleeve assembly includes a cylindrical body, with two gear rings formed at both ends of the inner wall of the cylindrical body. The teeth of the two gear rings correspond one-to-one along the axial direction of the sleeve assembly, and the tooth grooves of the two gear rings also correspond one-to-one along the axial direction of the sleeve assembly. This means that the teeth of the two gear rings are not misaligned, and the corresponding teeth of the sleeve generally mesh with the teeth at both ends of the roller. The two teeth without misalignment mean that they simultaneously engage or disengage. However, generally speaking, under conditions of low precision, there will be a gap during the process of one tooth engaging with the tooth body and the next tooth engaging with the tooth body. Especially at high speeds, there is a possibility of impact during gear meshing, which affects the stability of the rotational transmission. To solve the above problems, please refer to [reference needed]. Figures 7 to 8As shown, this application also provides a planetary transmission mechanism including a lead screw drive assembly 1 and a sleeve assembly 2. The lead screw drive assembly 1 is at least partially located in the inner cavity of the sleeve assembly 2, and the lead screw drive assembly 1 meshes with the sleeve assembly 2. The sleeve assembly 2 includes a cylindrical body portion 21, a first gear ring portion 22, and a second gear ring portion 23. The cylindrical body portion 21 is located between the first gear ring portion 22 and the second gear ring portion 23. The first gear ring portion 22 includes first teeth 2-1, and a plurality of first teeth 2-1 are distributed circumferentially along the first gear ring portion 22. The second gear ring portion 23 includes second teeth 2-2, and a plurality of second teeth 2-2 are distributed circumferentially along the second gear ring portion 23. Along the circumferential direction of the sleeve assembly 2, the first teeth 2-1 and the second teeth 2-2 are staggered. A first tooth groove is formed between two adjacent first teeth 2-1, and a second tooth groove is formed between two adjacent second teeth 2-2. The staggered arrangement means that the first teeth 2-1 correspond to the second tooth groove along the axial direction of the sleeve assembly 2, and the second teeth 2-2 correspond to the first tooth groove along the axial direction of the sleeve assembly 2. Its purpose is to… Therefore, when a sleeve with a misaligned setting is applied to a drive device, it can ensure that one end of the tooth disengages while the other end of the tooth engages, thus ensuring the smooth operation of the planetary transmission part and not affecting the operation of the product, thereby improving the stability of the rotational transmission. In addition, in this embodiment, the lead screw transmission assembly 1 includes a lead screw 11 and a roller 12, wherein the two ends of the roller 12 are respectively provided with teeth. The teeth at both ends can be misaligned or misaligned with the first tooth 2-1 and the second tooth 2-2. Of course, in this embodiment, the cylinder part 21, the first gear ring part 22 and the second gear ring part 23 can all be made of metal, or the cylinder part 21, the first gear ring part 22 and the second gear ring part 23 in the above embodiment can all be made of engineering thermoplastic material, or they can be made of two different materials, without limitation. Of course, this embodiment will focus on the example of the cylinder part 21, the first gear ring part 22 and the second gear ring part 23 being made of engineering thermoplastic material.

[0046] Please see Figure 8 As shown, specifically, the plane perpendicular to the central axis of the sleeve assembly 2 is defined as the projection plane Q. The orthographic projection of the first tooth 2-1 on the projection plane Q is the first tooth projection Q1, and the orthographic projection of the second tooth 2-2 on the projection plane Q is the second tooth projection Q2. The first tooth projection Q1 and the second tooth projection Q2 are misaligned. The misalignment of the first tooth 2-1 and the second tooth 2-2 of the first gear ring 22 can ensure that it disengages from one end of the roller and engages with the other end of the roller. This ensures the smooth operation of the planetary gear part, effectively avoids axial movement of the roller, does not affect the operation of the product, and improves the stability of rotational transmission.

[0047] For further information, please refer to [link / reference]. Figure 8As shown, defined on the same projection plane Q, the orthographic projection of the first gear ring 22 on the projection plane Q is the first gear ring projection Q3, and the orthographic projection of the second gear ring 23 on the projection plane Q is the second gear ring projection Q4. The center of the first gear ring projection Q3 and the center of the second gear ring projection Q4 overlap. The line connecting the tooth vertex N1 of the first tooth projection Q3 to the center N2 of the first gear ring projection Q3 is 0. The line connecting the tooth vertex N3 of the second tooth 2-2 projection to the center of the second tooth 2-2 projection is P. There is a misalignment angle ε between 0 and P. The angle 0° < misalignment angle ε < 10°. The angle of misalignment angle ε between 0 and P can be an integer such as 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, etc. For higher precision, it can be 5.25°, etc. Through continuous calculation and experimentation, the ideal misalignment angle is between 4° and 6°, with the optimal value being around 5.6°. A certain degree of error is within a reasonable range and should not be limited by it.

[0048] Furthermore, since the first tooth 2-1 of the first gear ring portion 22 and the second tooth 2-2 of the second gear ring portion 23 need to be positioned at both ends of the cylindrical portion 21 with a certain misalignment angle, and since the cylindrical portion 21, the first gear ring portion 22, and the second gear ring portion 23 are all made of engineering thermoplastic materials, according to the aforementioned embodiment, a transition fit is first adopted, followed by sealing. During the sealing process, if the first gear ring portion 22 or the second gear ring portion 23 shifts, the first tooth 2-1 of the first gear ring portion 22 and the second tooth 2-2 of the second gear ring portion 23 will not be positioned at both ends of the cylindrical portion 21 with a certain misalignment angle, resulting in the final product failing to meet the requirements. To solve this problem, in this embodiment, please refer to... Figure 5 , Figures 9 to 19 As shown, the sleeve assembly 2 has a split structure. The first gear ring portion 22 is connected to one end of the cylinder portion 21, and the second gear ring portion 23 is connected to the other end of the cylinder portion 21. The planetary transmission mechanism 100 includes a limiting assembly 5, which includes a first limiting portion 51 and a second limiting portion 52. The first gear ring portion 22 and one end of the cylinder portion 21 are circumferentially limited by the first limiting portion 51, and the second gear ring portion 23 and the other end of the cylinder portion 21 are circumferentially limited by the second limiting portion 52. That is, the first limiting portion 51 acts on the first gear ring. The first limiting part 51 is positioned at one end of the first gear ring 22 and the cylindrical part 21 to pre-limit the two before installation and fixation, so as to prevent the first limiting part 51 from shifting circumferentially relative to the cylindrical part 21 during the bonding process, so as to achieve the predetermined position installation and fixation of the first gear ring 22. Similarly, the second limiting part 52 acts on the other end of the second gear ring 23 and the cylindrical part 21 to pre-limit the two before installation and fixation, so as to prevent the second limiting part 52 from shifting circumferentially relative to the cylindrical part 21 during the bonding process, so as to achieve the predetermined position installation and fixation of the second gear ring 23.

[0049] Specifically, please refer to Figure 5 , Figure 9 , Figure 10 , Figure 13 As shown, the first limiting portion 51 includes a first protrusion 511 and a first limiting groove 512. The first protrusion 511 is connected to one end of the cylindrical body portion 21 and one end of the first gear ring portion 22. The first limiting groove 512 is located at one end of the cylindrical body portion 21 and connected to the other end of the first gear ring portion 22. The first protrusion 511 is at least partially located in the first limiting groove 512. The second limiting portion 52 includes a second protrusion 521 and a second limiting groove 522. The second protrusion 521 is connected to the other end of the cylindrical body portion 21 and one end of the second gear ring portion 23. The second limiting groove 522 is located at the other end of the cylindrical body portion 21 and one end of the second gear ring portion 23. The second protrusion 521 is at least partially located in the second limiting groove 522, which includes four schemes. The first scheme is that the first protrusion 511 is connected to the inner wall of one end of the cylindrical body 21, and the first limiting groove 512 is located on the outer annular wall of the first gear ring portion 22. The second protrusion 521 is connected to the inner wall of the other end of the cylindrical body 21, and the second limiting groove 522 is located on the outer annular wall of the second gear ring portion 23. The second scheme is that the first protrusion 511 is connected to the outer annular wall of the first gear ring portion 22, and the first limiting groove 512 is located on the inner wall of one end of the cylindrical body 21. The second protrusion 521 and... The second gear ring portion 23 is connected to the outer ring wall, and the second limiting groove 522 is located on the inner wall of the other end of the cylindrical body portion 21. A third option is that the first protrusion 511 is connected to the inner wall of one end of the cylindrical body portion 21, and the first limiting groove 512 is located on the outer ring wall of the first gear ring portion 22. The second protrusion 521 is connected to the outer ring wall of the second gear ring portion 23, and the second limiting groove 522 is located on the inner wall of the other end of the cylindrical body portion 21. A fourth option is that the first protrusion 511 is connected to the outer ring wall of the first gear ring portion 22, and the first limiting groove 512 is located on the inner wall of one end of the cylindrical body portion 21. The second protrusion 521 is connected to the inner wall of the other end of the cylindrical body portion 21. One end is connected to the inner wall, and the second limiting groove 522 is located on the outer ring wall of the second gear ring portion 23. This embodiment focuses on the second scheme as an example. Of course, in this embodiment, the first limiting portion 51 and the second limiting portion 52 are not separate components, but rather parts of each component. In other words, the first protrusion 511 of the first limiting portion 51 is connected to the first gear ring portion 22. The connection can include assembly connection or integral part. For example, in some embodiments, the first protrusion 511 and the first gear ring portion 22 are connected and fixed by snap-fit, glue, tenon and mortise connection, etc. In this embodiment, please refer to Figure 5As shown, the first protrusion 511 and the first gear ring portion 22 are integrally formed. A first limiting groove 512 extending axially along the cylindrical body portion 21 can be milled into the inner wall of one end of the cylindrical cavity G of the cylindrical body portion 21. The first protrusion 511 is aligned with the opening of the first limiting groove 512 and inserted, so that the first gear ring portion 22 is inserted into one end of the cylindrical cavity G of the cylindrical body portion 21. Furthermore, the first protrusion 511 and the first gear ring portion 22 are integrally formed to facilitate the processing and fabrication of the first gear ring portion 22. Similarly, the second protrusion 521 and the second gear ring portion 23 are integrally formed. A second limiting groove 522 extending axially along the cylindrical body portion 21 can be milled into the inner wall of the other end of the cylindrical cavity G of the cylindrical body portion 21. The second protrusion 521 is aligned with the second limiting groove 522. The slot of part 2 is inserted, and the second gear ring part 23 is inserted into the other end of the cylinder cavity G of the cylinder part 21. Specifically, the first protrusion 511 and the first gear ring part 22 are integral parts. The first protrusion 511 is located on the outer peripheral wall of the first gear ring part 22. The first protrusion 511 protrudes radially along the first gear ring part 22 and extends axially along the first gear ring part 22. The first limiting groove 512 is located on the inner side wall of one end of the cylinder part 21. The second protrusion 521 and the second gear ring part 23 are integral parts. The second protrusion 521 is located on the outer peripheral wall of the second gear ring part 23. The second protrusion 521 protrudes radially along the second gear ring part 23 and extends axially along the second gear ring part 23. The second limiting groove 522 is located on the inner side wall of the other end of the cylinder part 21.

[0050] In addition, please see Figure 19 As shown, the first limiting groove 512 is located on the inner wall of one end of the cylindrical part 21, and the second limiting groove 522 is located on the inner wall of the other end of the cylindrical part 21. Along the axial direction of the cylindrical part 21, the first limiting groove 512 and the second limiting groove 522 are offset. The offset angle can be referenced to the aforementioned offset angle ε, so that the first gear ring part 22 and the second gear ring part 23 are installed along the first limiting groove 512 and the second limiting groove 522 respectively, and the first tooth 2-1 and the second tooth 2-2 are immediately offset. Of course, in some other embodiments, the first limiting groove 512 and the second limiting groove 522 may not be offset, but the positions of the first protrusion 511 and the first gear ring part 22 and the second protrusion 521 and the second gear ring part 23 are different, and there is a certain degree of misalignment. In comparison, the offset setting of the first limiting groove 512 and the second limiting groove 522 in this embodiment is more convenient to manufacture and improves the accuracy.

[0051] As mentioned above, this embodiment uses a positive planetary transmission mechanism as an example. Therefore, when the lead screw moves the sleeve, the sleeve moves axially along the movement path set by the lead screw. The second gear ring 23 is provided with a threaded section 233, which mainly connects with other external actuators to drive the movement of the external actuators. Therefore, the structure of the second gear ring 23 is different from that of the first gear ring 22. To prevent the first gear ring 22 and the second gear ring 23 from being installed in reverse, please refer to [link to relevant documentation]. Figure 16 As shown, the width dimension of the first protrusion 511 along the circumference of the first gear ring portion 22 is H, and the width dimension of the second protrusion 521 along the circumference of the second gear ring portion 23 is L, where H > L or H < L. In other words, the dimensions of H and L are not equal. The first protrusion 511 is adapted to the first limiting groove 512, meaning that the width dimension of the first limiting groove 512 is equal to or approximately equal to the dimension of H. The second protrusion 521 is adapted to the second limiting groove 522, meaning that the width dimension of the second limiting groove 522 is equal to or approximately equal to the dimension of L. This indicates that the second protrusion 521 cannot be fitted into the first limiting groove 512, and the first protrusion 511 cannot be fitted into the second limiting groove 522, in order to avoid the first gear ring portion 22 and the second gear ring portion 23 being installed backwards.

[0052] In addition, please refer to again Figure 9 , Figure 13 , Figure 17 and Figure 18 As shown, the limiting component 5 includes a third limiting part 53 and a fourth limiting part 54. The third limiting part 53 includes a third protrusion 531 and a third limiting groove 532. The third protrusion 531 is connected to one end of the cylindrical body part 21 and one end of the first gear ring part 22. The third limiting groove 532 is located at one end of the cylindrical body part 21 and connected to the other end of the first gear ring part 22. The third protrusion 531 is at least partially located in the third limiting groove 532. The fourth limiting part 54 includes a fourth protrusion 541 and a fourth limiting groove 542. The fourth protrusion 541 is connected to the other end of the cylindrical body part 21. The fourth limiting groove 542 is located at the other end of the cylindrical body 21 and connected to the other end of the second gear ring 23. The fourth protrusion 541 is at least partially located in the fourth limiting groove 542. Similarly, there are four schemes. You can refer to the schemes of the first limiting part 51 and the second limiting part 52. They will not be described in detail here. It is worth mentioning that the purpose of setting the third limiting part 53 and the fourth limiting part 54 is to further enable the first gear ring 22 and the second gear ring 23 to be pre-positioned and installed relative to the cylindrical body 21.

[0053] For further information, please refer to [link / reference]. Figure 11 and Figure 14As shown, the plane perpendicular to the central axis of the sleeve assembly 2 is defined as the projection plane Q. Along the axial direction of the sleeve assembly 2, the orthographic projection of the first gear ring portion 22 on the projection plane Q is the first gear ring projection Q3, the orthographic projection of the first protrusion 511 on the projection plane Q is the first protrusion projection Q5, and the orthographic projection of the third protrusion 531 on the projection plane Q is the third protrusion projection Q6. The line connecting the center point of the first protrusion projection Q5 to the center of the first gear ring projection Q3 is A, and the line connecting the center point of the third protrusion projection Q6 to the center of the first gear ring projection Q3 is B. There is an angle θ between A and B, where 0° < angle θ < 180°. The orthographic projection of the second gear ring portion 23 on the projection plane Q is the second gear ring projection Q4, the orthographic projection of the second protrusion 521 on the projection plane Q is the second protrusion projection Q7, and the orthographic projection of the fourth protrusion 541 on the projection plane Q is the fourth protrusion projection Q8. The line connecting the center point of the second protrusion projection Q7 to the center of the first gear ring projection Q3 is A, and the line connecting the center point of the third protrusion projection Q6 to the center of the first gear ring projection Q3 is B. There is an angle θ between A and B, where 0° < angle θ < 180°. The line connecting the centers of the projections of the second gear ring Q4 is C, and the line connecting the center of the projection of the fourth protrusion Q8 to the center of the projection of the second gear ring Q4 is D. There is an angle θ between C and D, where 0° < angle θ < 180°. In this embodiment, the angle θ is 120°. The reason for setting the angle θ between 0° and 180° is that if it were set to 180°, it would be equivalent to setting the first protrusion 511 and the third protrusion 531 radially along the first gear ring portion 22. This would result in the possibility of inserting the first protrusion 511 into the third limiting groove 532 and the third protrusion 531 into the first limiting groove 512, thus potentially leading to incorrect circumferential positioning. Therefore, setting the angle θ between 0° and 180° prevents incorrect circumferential positioning. Similarly, the setting of the second protrusion 521 and the fourth protrusion 541 is also to prevent incorrect circumferential positioning.

[0054] Please see Figure 12 and Figure 15 As shown, along the axial direction of the first gear ring portion 22, the first protrusion 511 includes a first segment 11-1 and a second segment 11-2. The width of the second segment 11-2 along the circumferential direction of the first gear ring portion 22 is smaller than the width of the first segment 11-1 along the circumferential direction of the first gear ring portion 22. Along the axial direction of the second gear ring portion 23, the second protrusion 521 includes a third segment 21-1 and a fourth segment 21-2. The width of the third segment 21-1 along the circumferential direction of the second gear ring portion 23 is smaller than the width of the fourth segment 21-2 along the circumferential direction of the second gear ring portion 23. The reason for this design is to prevent the front and rear ends of the first gear ring portion 22 and the second gear ring portion 23 from being installed in reverse. On the other hand, it can play a guiding role, with the segment with the smaller width playing a guiding role.

[0055] Additionally, please see Figures 1 to 2As shown, this application provides a driving device including a motor 4 and a planetary transmission mechanism 100. The planetary transmission mechanism 100 includes a lead screw drive assembly 1 and a sleeve assembly 2. The lead screw drive assembly 1 is at least partially located in the inner cavity of the sleeve assembly 2, and the lead screw drive assembly 1 meshes with the sleeve assembly 2. The sleeve assembly 2 includes a cylindrical body portion 21, a first gear ring portion 22, and a second gear ring portion 23. The first gear ring portion 22 is connected to one end of the cylindrical body portion 21, and the second gear ring portion 23 is connected to the other end of the cylindrical body portion 21. At least one of the first gear ring portion 22 and the second gear ring portion 23 is made of plastic. The lead screw drive assembly 1 includes a lead screw 11 and a roller 12. The motor 4 is connected to the lead screw 11, and the roller 12 is threadedly connected to the lead screw 11. Part of the roller 12 is threadedly engaged with the sleeve assembly 2, and part of the roller 12 is toothedly engaged with the sleeve assembly 2. The drive device can be applied to fields such as automotive steering motors, actuators, and collaborative equipment. That is, the drive device mainly converts rotary motion into linear motion. It can be applied as long as the equipment requires a motion conversion method, and its application is relatively wide. The cylinder portion 21 is at least partially located between the first gear ring portion 22 and the second gear ring portion 23. The first gear ring portion 22 includes a plurality of first teeth 2-1, which are distributed circumferentially along the first gear ring portion 22. The second gear ring portion 23 includes a plurality of second teeth 2-2, which are distributed circumferentially along the second gear ring portion 23. Along the circumference of the sleeve assembly 2, the first teeth 2-1 and the second teeth 2-2 are misaligned. The lead screw drive assembly 1 includes a lead screw 11 and a roller 12. The motor 4 is connected to the lead screw 11, and the roller 12 is threadedly connected to the lead screw 11. Part of the roller 12 is threadedly engaged with the sleeve assembly 2. One end of the roller 12 engages with the first gear ring portion 22, and the other end engages with the second gear ring portion 23. The teeth at both ends of the roller 12 can be staggered accordingly, either to match the first gear ring portion 22 and the second gear ring portion 23 respectively, or not to be staggered.

[0056] The functions and structural principles of this invention have been demonstrated and explained in the embodiments.

[0057] The above examples illustrate the principles and implementation methods of the present invention. These embodiments are merely illustrative and intended to aid in understanding the method and core concepts of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A planetary transmission mechanism, characterized by, The system includes a lead screw drive assembly (1) and a sleeve assembly (2). The lead screw drive assembly (1) is at least partially located in the inner cavity of the sleeve assembly (2), and the lead screw drive assembly (1) meshes with the sleeve assembly (2). The sleeve assembly (2) is a split structure, and the sleeve assembly (2) includes a cylindrical body (21), a first gear ring (22), and a second gear ring (23). The cylindrical body (21) is at least partially located between the first gear ring (22) and the second gear ring (23). The planetary transmission mechanism (100) includes a limiting assembly (5), which includes a first limiting part (51) and a second limiting part (52). One end of the first gear ring (22) and the cylindrical body (21) are limited and engaged by the first limiting part (51), and the other end of the second gear ring (23) and the cylindrical body (21) are limited and engaged by the second limiting part (52).

2. The planetary transmission mechanism according to claim 1, characterized in that The first gear ring portion (22) is circumferentially limited to one end of the cylindrical portion (21) by the first limiting portion (51), and the second gear ring portion (23) is circumferentially limited to the other end of the cylindrical portion (21) by the second limiting portion (52).

3. A planetary transmission mechanism according to claim 1 or 2, characterised in that, The first limiting part (51) includes a first protrusion (511) and a first limiting groove (512). The first protrusion (511) is connected to one end of the cylindrical part (21) and one end of the first gear ring part (22). The first limiting groove (512) is located at one end of the cylindrical part (21) and connected to the other end of the first gear ring part (22). The first protrusion (511) is at least partially located in the first limiting groove (512). The second limiting part (52) includes a second protrusion (521) and a second limiting groove (522). The second protrusion (521) is connected to the other end of the cylindrical part (21) and one end of the second gear ring part (23). The second limiting groove (522) is located at the other end of the cylindrical part (21) and connected to the other end of the second gear ring part (23). The second protrusion (521) is at least partially located in the second limiting groove (522).

4. A planetary transmission mechanism according to claim 3, characterised in that, The first limiting groove (512) is located on the inner wall of one end of the cylindrical part (21), and the second limiting groove (522) is located on the inner wall of the other end of the cylindrical part (21). Along the axial direction of the cylindrical part (21), the first limiting groove (512) and the second limiting groove (522) are misaligned.

5. The planetary transmission mechanism according to claim 3, characterized in that, The first protrusion (511) and the first gear ring portion (22) are integral parts. The first protrusion (511) is located on the outer peripheral wall of the first gear ring portion (22). The first protrusion (511) protrudes radially along the first gear ring portion (22) and extends axially along the first gear ring portion (22). The first limiting groove (512) is located on the inner sidewall of one end of the cylindrical body portion (21). The second protrusion (521) and the second gear ring portion (23) are integral parts. The second protrusion (521) is located on the outer peripheral wall of the second gear ring portion (23). The second protrusion (521) protrudes radially along the second gear ring portion (23) and extends axially along the second gear ring portion (23). The second limiting groove (522) is located on the inner sidewall of the other end of the cylindrical body portion (21).

6. The planetary transmission mechanism according to claim 3, characterized in that, The width dimension of the first protrusion (511) along the circumference of the first gear portion (22) is H, and the width dimension of the second protrusion (521) along the circumference of the second gear portion (23) is L, wherein H > L or H < L, the first protrusion (511) is adapted to the first limiting groove (512), and the second protrusion (521) is adapted to the second limiting groove (522).

7. The planetary transmission mechanism according to claim 3, characterized in that, The limiting component (5) includes a third limiting part (53) and a fourth limiting part (54). The third limiting part (53) includes a third protrusion (531) and a third limiting groove (532). The third protrusion (531) is connected to one end of the cylindrical part (21) and one end of the first gear ring part (22). The third limiting groove (532) is located at one end of the cylindrical part (21) and connected to the other end of the first gear ring part (22). The third protrusion (531) at least partially Located in the third limiting groove (532); the fourth limiting part (54) includes a fourth protrusion (541) and a fourth limiting groove (542), the fourth protrusion (541) is connected to one end of the cylindrical part (21) and one of the second gear ring part (23), the fourth limiting groove (542) is located at the other end of the cylindrical part (21) and connected to the other of the second gear ring part (23), and the fourth protrusion (541) is at least partially located in the fourth limiting groove (542).

8. The planetary transmission mechanism according to claim 7, characterized in that, Define the plane perpendicular to the central axis of the sleeve assembly (2) as the projection plane (Q). Along the axial direction of the sleeve assembly (2), the orthographic projection of the first gear ring portion (22) on the projection plane (Q) is the first gear ring projection (Q3), the orthographic projection of the first protrusion (511) on the projection plane (Q) is the first protrusion projection (Q5), and the orthographic projection of the third protrusion (531) on the projection plane (Q) is the third protrusion projection (Q6). The line connecting the center point of the first protrusion projection (Q5) to the center of the first gear ring projection (Q3) is A, and the line connecting the center point of the third protrusion projection (Q6) to the center of the first gear ring projection (Q3) is B. A and B... There is an angle θ between them, where 0° < angle θ < 180°; the orthographic projection of the second gear ring (23) on the projection plane (Q) is the second gear ring projection (Q4), the orthographic projection of the second protrusion (521) on the projection plane (Q) is the second protrusion projection (Q7), the orthographic projection of the fourth protrusion (541) on the projection plane (Q) is the fourth protrusion projection (Q8), the line connecting the center point of the second protrusion projection (Q7) to the center of the second gear ring projection (Q4) is C, the line connecting the center point of the fourth protrusion projection (Q8) to the center of the second gear ring projection (Q4) is D, and there is an angle θ between C and D, where 0° < angle θ < 180°.

9. The planetary transmission mechanism according to any one of claims 1 to 8, characterized in that, Along the axial direction of the first gear ring portion (22), the first protrusion (511) includes a first segment (11-1) and a second segment (11-2), wherein the width dimension of the second segment (11-2) along the circumferential direction of the first gear ring portion (22) is smaller than the width dimension of the first segment (11-1) along the circumferential direction of the first gear ring portion (22). Along the axial direction of the second gear ring portion (23), the second protrusion (521) includes a third segment (21-1) and a fourth segment (21-2), wherein the width dimension of the third segment (21-1) along the circumferential direction of the second gear ring portion (23) is smaller than the width dimension of the fourth segment (21-2) along the circumferential direction of the second gear ring portion (23).

10. A driving device, characterized in that, The driving device includes a motor (4) and a planetary transmission mechanism (100). The planetary transmission mechanism (100) includes a lead screw drive assembly (1) and a sleeve assembly (2). The lead screw drive assembly (1) is at least partially located in the inner cavity of the sleeve assembly (2), and the lead screw drive assembly (1) meshes with the sleeve assembly (2). The sleeve assembly (2) is a split structure, including a cylindrical body (21), a first gear ring (22), and a second gear ring (23). The cylindrical body (21) is at least partially located between the first gear ring (22) and the second gear ring (23). The planetary transmission mechanism (100) includes a limiting assembly (5), which includes... The first limiting part (51) and the second limiting part (52) are connected. The first gear ring part (22) and one end of the cylindrical part (21) are limited and engaged by the first limiting part (51), and the second gear ring part (23) and the other end of the cylindrical part (21) are limited and engaged by the second limiting part (52). The lead screw drive assembly (1) includes a lead screw (11) and a roller (12). The motor (4) is connected to the lead screw (11). The roller (12) is threadedly connected to the lead screw (11). The roller (12) is threadedly engaged with the sleeve assembly (2). One end of the roller (12) is engaged with the first gear ring part (22), and the other end is engaged with the second gear ring part (23).

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