A two-stage planetary reducer and joint module

Abstract

This application relates to the field of robotics technology and proposes a two-stage planetary reducer and joint module. The reducer includes a housing and a first-stage reduction assembly and a second-stage reduction assembly disposed therein, with the second-stage reduction assembly radially located outside the first-stage assembly. The first-stage reduction assembly includes a first-stage sun gear, first-stage planet gears meshing with it, a first-stage planet carrier mounting the planet gears, and a first-stage internal gear ring fixed to the housing. The second-stage reduction assembly includes a second-stage sun gear, second-stage planet gears meshing with it, a second-stage planet carrier mounting the planet gears, and a second-stage internal gear ring fixed to the housing. The second-stage sun gear is fixedly connected to the first-stage planet carrier and outputs power from the second-stage planet carrier. This application compresses the axial dimension through a radially nested layout and utilizes a transmission method with two independently fixed internal gear rings and planet carriers, achieving a compact and flat structure while obtaining a higher transmission ratio and transmission efficiency, significantly improving the torque density and overall manufacturability of the reducer.

Description

Technical Field

[0001] This application relates to the field of robotics technology, and in particular to a two-stage planetary reducer and joint module. Background Technology

[0002] With the development of robotics technology, higher requirements have been placed on the planetary reducer, the core transmission component of the joint module. It is expected to achieve a larger reduction ratio and output torque in a smaller space, that is, to have high torque density, so as to improve the overall performance of the joint module.

[0003] Currently, common joint modules typically employ a configuration where the motor and planetary reducer are directly axially connected. However, when using large-diameter flat motors, this configuration struggles to achieve a good structural fit, easily resulting in a stepped shape between the large-diameter motor and the small-diameter reducer. This not only fails to effectively utilize radial space for a compact, flat design but also wastes space, creating difficulties for the overall robot layout.

[0004] In pursuit of a compact structure, a nested two-stage planetary reducer employing double-sided gears has emerged in existing technology. This design integrates the internal ring gear of the first-stage planetary reducer and the sun gear of the second-stage planetary reducer into a single integral part, achieving axial parallel nesting of the two stages of transmission. While this design reduces the axial dimension, its structure itself has inherent drawbacks: First, this integrated design forces the first-stage transmission to adopt a ring-driven operation with the internal ring gear as the output. According to the principles of planetary gear transmission, the transmission ratio and efficiency of this operation are lower than those of a carrier-driven operation with the planetary carrier as the output, thus limiting further performance improvements of the reducer and even the entire joint module. Second, double-sided gears, as a special composite part integrating internal and external gears, have complex processing techniques and require high manufacturing and assembly precision, increasing production costs and reducing the manufacturability and versatility of the part.

[0005] Therefore, how to design a planetary reducer that can be adapted to large-diameter flat motors to achieve a flat layout of joint modules, while structurally avoiding the performance loss of circular drive and the machining difficulties of double-sided gears, thereby improving transmission performance while ensuring good manufacturability, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of this, this application proposes a two-stage planetary reducer and joint module, aiming to solve the technical problems of low transmission efficiency and difficulty in achieving high-performance adaptation with large-diameter flat motors in existing nested planetary reducers using double-sided gears.

[0007] The technical solution of this application is implemented as follows: In a first aspect, this application provides a two-stage planetary reducer, including a housing and a first-stage reduction assembly and a second-stage reduction assembly disposed within the housing, wherein the second-stage reduction assembly is located radially outside the first-stage reduction assembly of the housing; The first-stage reduction assembly includes a first-stage sun gear, a first-stage planet gear meshing with the first-stage sun gear, a first-stage planet carrier for mounting the first-stage planet gear, and a first-stage internal gear ring. The first-stage planet gear meshes with the first-stage internal gear ring, the first-stage internal gear ring is fixed to the housing, and the first-stage sun gear is used to receive input power. The secondary reduction assembly includes a secondary sun gear, secondary planet gears meshing with the secondary sun gear, a secondary planet carrier for mounting the secondary planet gears, and a secondary internal gear ring. The secondary planet gears mesh with the secondary internal gear ring, the secondary internal gear ring is fixed to the housing, the secondary sun gear is fixedly connected to the primary planet carrier, and the secondary planet carrier serves as the power output end of the secondary planetary reducer.

[0008] Based on the above technical solution, preferably, one end of the housing is formed with a reducer mounting cavity, and the first-stage reduction assembly and the second-stage reduction assembly are housed in the reducer mounting cavity; The other end of the housing is provided with a mounting hole that communicates with the reducer mounting cavity; The first-stage internal gear ring includes a gear ring portion and a fixing portion arranged coaxially. The gear ring portion passes through the mounting hole and is located in the reducer mounting cavity. The fixing portion is fixedly connected to the outer end face of the housing. The secondary internal gear ring is fixed to the inner circumferential wall of the reducer mounting cavity.

[0009] Based on the above technical solution, preferably, the secondary sun gear is supported on the outer periphery of the gear ring portion of the primary internal gear ring by a first bearing and is fixedly connected to the primary planetary carrier.

[0010] Based on the above technical solution, preferably, the first-stage planetary carrier includes a first-stage plate and a first-stage baffle. The first-stage plate is located on the side of the gear ring portion of the first-stage internal gear ring away from the fixed portion and is fixedly connected to the second-stage sun gear. The first-stage plate is provided with a plurality of first rotating members distributed circumferentially. The first-stage planetary gear is movably sleeved on the first rotating members. The first-stage baffle is located on the side of the first-stage planetary gear away from the first-stage plate and is fixedly connected to the first rotating members.

[0011] Based on the above technical solution, preferably, the secondary planetary carrier includes a secondary plate and a secondary baffle. The secondary plate is located on the side of the secondary planetary gear facing away from the mounting hole. The secondary plate is provided with a plurality of second rotating members distributed circumferentially. The secondary planetary gear is movably sleeved on the second rotating members. The secondary baffle is located on the side of the secondary planetary gear away from the secondary plate and is fixedly connected to the second rotating members.

[0012] Based on the above technical solution, preferably, a first end cover is fixedly provided at the opening end of the reducer mounting cavity, the secondary plate is supported on the first end cover by a second bearing, and an output flange is fixedly connected to the outside of the secondary plate.

[0013] In a second aspect, this application discloses a joint module, including the two-stage planetary reducer and the motor described in the first aspect. The housing has a receiving cavity at one end away from the reducer mounting cavity. The motor includes a stator, a rotor ring sleeved inside the stator, and a rotor shaft. The stator is fixed to the receiving cavity, one end of the rotor shaft is connected to the rotor ring, and the other end passes through the mounting hole and is fixedly connected to the first-stage sun gear; The receiving cavity, the mounting hole, and the reducer mounting cavity are sequentially connected to form a continuous air duct.

[0014] Based on the above technical solution, preferably, a blade structure is connected between the rotor shaft and the rotor ring to drive airflow within the air duct.

[0015] Based on the above technical solution, preferably, it also includes a second end cover and an encoding detection mechanism. The second end cover is fixed to the housing and closes the receiving cavity; the encoding detection mechanism is disposed on the second end cover and is used to detect the rotational speed of the rotor shaft.

[0016] Based on the above technical solution, preferably, the encoding detection mechanism includes an output gear, a detection gear, an encoder, and a protective cover; The output gear is fixedly mounted on the end of the rotor shaft away from the first-stage sun gear; The detection gear is rotatably mounted on the second end cover and meshes with the output gear; The encoder is used to acquire the rotation signal of the detection gear; The protective cover is fixed to the end of the second end cover away from the housing, and the detection gear and encoder are encapsulated in the space formed by the protective cover and the second end cover.

[0017] This application has the following advantages over the prior art: 1) The two-stage planetary reducer disclosed in this application, by radially arranging the two-stage reduction components outside the first-stage reduction components, allows the two stages of transmission to overlap axially, greatly compressing the overall axial dimension and forming a flattened structure. This allows for natural physical docking with large-diameter flat motors, avoiding a stepped shape and achieving efficient utilization of radial space. Simultaneously, it abandons the double-sided gear structure that leads to difficult processing and low efficiency of the first-stage transmission, employing two easily manufactured and independently fixed internal gear rings, and ensuring that both stages of transmission use a frame-driven working mode with superior transmission ratio and efficiency. This design achieves structural compactness while significantly improving the overall reduction ratio and mechanical efficiency of the transmission system, thereby fundamentally solving the performance loss problem commonly encountered when adapting to large-diameter motors, ultimately achieving the core goal of high torque density in the joint module.

[0018] 2) By supporting the second-stage sun gear on the outer circumference of the fixed first-stage internal gear ring via the first bearing, the two-stage transmission components are precisely nested and aligned in the radial direction, which greatly improves the compactness and overall rigidity of the structure. At the same time, the fixed connection between the second-stage sun gear and the first-stage planetary carrier ensures that the power output of the first-stage reduction gear can be directly and without backlash transmitted to the second-stage input. Thus, based on achieving high transmission efficiency and smooth power, it lays a key structural foundation for the flat design and high-performance output of the entire reducer.

[0019] 3) Due to the radial nested layout and the output from the outermost secondary planetary carrier, the output flange can have a larger design diameter, which not only facilitates connection with large loads, but also significantly improves the torque output and load-bearing capacity of the joint, making it particularly suitable for high torque load scenarios such as the waist and knee joints of robots.

[0020] 4) The joint module provided in this embodiment integrates the motor and the two-stage planetary reducer into a housing with a continuous ventilation channel. This not only achieves a high degree of integration and structural flattening of the power unit, but also cleverly utilizes the motor operation itself to promote internal air circulation, providing an efficient integrated heat dissipation solution for the motor and reducer. This significantly improves the thermal stability and overall reliability of the joint module under continuous high load operation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1This is a three-dimensional structural diagram of the joint module disclosed in the embodiments of this application; Figure 2 This is a schematic diagram of the two-stage planetary reducer disclosed in the embodiments of this application; Figure 3 This is an exploded view of the first-stage deceleration component disclosed in the embodiments of this application; Figure 4 This is an exploded view of the two-stage deceleration assembly disclosed in the embodiments of this application; Figure 5 This is an exploded view of the motor and coding detection mechanism disclosed in the embodiments of this application; Figure 6 This is a schematic diagram of the planar structure of the joint module disclosed in the embodiments of this application; Figure 7 for Figure 6 Planar sectional view at point AA; Figure label: 1. Housing; 11. Reducer mounting cavity; 12. Mounting hole; 13. Receiving cavity; 2. First-stage reduction gear assembly; 21. First-stage sun gear; 22. First-stage planetary gears; 23. First-stage planetary carrier; 24. First-stage internal gear ring; 241. Gear ring section; 242. Fixing section; Z1. First bearing; 231. First-stage plate; 232. First-stage baffle; 233. First rotating component; 3. Secondary reduction gear assembly; 31. Secondary sun gear; 32. Secondary planetary gears; 33. Secondary planetary carrier; 34. Secondary internal gear ring; 331. Secondary plate; 332. Secondary baffle; 333. Secondary rotating component; 4. First end cover; Z2. Second bearing; 5. Output flange; 6. Motor; 61. Stator; 62. Rotor ring; 63. Rotor shaft; 64. Blade structure; 7. Second end cover; 8. Encoding detection mechanism; 81. Output gear; 82. Detection gear; 83. Encoder; 84. Protective cover. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0025] In the description of the embodiments of this application, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0028] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0029] like Figure 2 As shown, combined with Figure 3 , 46, 7, This application discloses a two-stage planetary reducer, including a housing 1 and a first-stage reduction assembly 2 and a second-stage reduction assembly 3 installed in the housing 1.

[0030] The housing 1 provides structural support and a mounting base for the entire reducer, and its internal space is used to accommodate and position all transmission components. The primary reduction assembly 2 and the secondary reduction assembly 3 are the core parts of the reduction transmission, working together to achieve a high overall reduction ratio. In particular, the secondary reduction assembly 3 is arranged radially outside the primary reduction assembly 2 in the housing 1. This radially nested layout allows the two transmission components to partially or completely overlap axially, thereby significantly reducing the overall axial dimension of the reducer and facilitating a flattened structure.

[0031] In this embodiment, the first-stage reduction assembly 2 includes a first-stage sun gear 21, first-stage planetary gears 22, a first-stage planetary carrier 23, and a first-stage internal gear ring 24. The first-stage sun gear 21 serves as the input component of this stage of transmission, receiving external power input. Multiple first-stage planetary gears 22 simultaneously mesh with the first-stage sun gear 21, distributing and transmitting power. These first-stage planetary gears 22 are mounted on the first-stage planetary carrier 23 via bearings or other support structures. The first-stage planetary carrier 23 maintains the relative positions of the planetary gears and serves as the motion output component of this stage of transmission. The first-stage internal gear ring 24 is a ring gear whose internal teeth simultaneously mesh with all the first-stage planetary gears 22. The first-stage internal gear ring 24 is fixedly mounted on the housing 1 and does not rotate during operation. This arrangement ensures that when power is input from the first-stage sun gear 21, driving the first-stage planetary gears 22 to rotate, the first-stage planetary gears 22 are forced to revolve around the first-stage sun gear 21 while rotating on their own axes, thereby driving the first-stage planetary carrier 23 to output rotation with reduced speed and increased torque.

[0032] The secondary reduction gear 3 includes a secondary sun gear 31, secondary planet gears 32, a secondary planet carrier 33, and a secondary internal gear ring 34. The secondary sun gear 31 is fixedly connected to the primary planet carrier 23, thus directly receiving the power output from the primary reduction gear 2 as the input for the secondary transmission. Multiple secondary planet gears 32 mesh with the secondary sun gear 31 simultaneously. Similar to the primary structure, the secondary planet gears 32 are mounted on the secondary planet carrier 33 via bearings; the secondary planet carrier 33 is the output component of the secondary transmission. The secondary internal gear ring 34 is also a ring gear, its internal teeth meshing with all the secondary planet gears 32, and this secondary internal gear ring 34 is also independently and fixedly mounted on the housing 1.

[0033] It should be noted that the secondary internal gear ring 34 here is a completely separate and independent component from the aforementioned primary internal gear ring 24. When the secondary sun gear 31 rotates and drives the secondary planetary gears 32, the fixed secondary internal gear ring 34 forces the secondary planetary gears 32 to revolve, thereby driving the secondary planetary carrier 33 to rotate, achieving a second reduction and torque increase. Finally, the power after two stages of reduction is output from the secondary planetary carrier 33.

[0034] The two-stage planetary reducer provided in this application has a higher transmission ratio because the magnitude of the transmission ratio is determined by which planetary gear is fixed. In this application embodiment, both the first-stage and second-stage internal gear rings are independently fixed to the housing, forming a classic carrier-driven planetary transmission. In this mode, the transmission ratio calculation formula is "1 + number of teeth on the internal gear ring / number of teeth on the sun gear". The "1" ensures that the transmission ratio is always greater than 1 and is the maximum value among all transmission forms under the condition of the same number of gear teeth. Therefore, by ensuring that both stages of transmission adopt this carrier-driven type with fixed internal gear rings and planetary carrier output, this application enables each stage to obtain the theoretically maximum single-stage reduction ratio. The final total transmission ratio after multiplying the two stages is maximized, thus providing a theoretical basis for achieving higher output torque.

[0035] The higher transmission efficiency of this application's embodiments lies in the superior force flow path and gear meshing state of the carrier-driven transmission. When the internal gear ring is fixed, the input power is distributed from the sun gear through multiple planet gears and collaboratively drives the planet carrier to rotate and output power. During this process, the fixed internal gear ring provides a stable and rigid force fulcrum for the entire gear system, the power transmission path is direct, and the force on each gear pair is uniform. At the same time, the relative sliding speed at the gear meshing point is small, resulting in lower frictional losses. In contrast, if a ring-driven transmission (i.e., planet carrier fixed, internal gear ring output) is forced, the mechanical conditions and relative motion relationship at the meshing point will change, usually leading to greater sliding friction and thus reducing transmission efficiency. Therefore, this application optimizes the meshing conditions from the perspective of transmission principle through a two-stage carrier-driven design, achieving higher mechanical efficiency.

[0036] The two-stage planetary reducer disclosed in this application significantly reduces the overall axial dimension by radially arranging the second-stage reduction component outside the first-stage reduction component, allowing the two stages of transmission to overlap axially. This results in a flattened structure, enabling natural physical docking with large-diameter flat motors and avoiding a stepped shape, thus achieving efficient utilization of radial space. Simultaneously, it abandons the double-sided gear structure that leads to manufacturing difficulties and low efficiency in the first-stage transmission, employing two easily manufactured and independently fixed internal gear rings, and ensuring that both stages of transmission use a frame-driven operating mode with superior transmission ratio and efficiency. This design achieves structural compactness while significantly improving the overall reduction ratio and mechanical efficiency of the transmission system, thereby fundamentally solving the performance loss problem commonly encountered when adapting to large-diameter motors, ultimately achieving the core goal of high torque density in the joint module.

[0037] In some embodiments, a reducer mounting cavity 11 is formed at one end of the housing 1, and the primary reduction assembly 2 and the secondary reduction assembly 3 are housed and mounted in the cavity as a whole, which provides an integrated and protected mounting environment for all transmission components.

[0038] On the opposite end of the housing 1, opposite the reducer mounting cavity 11, a mounting hole 12 is provided. This mounting hole 12 communicates with the reducer mounting cavity 11, forming a channel from the outside of the housing 1 to the internal transmission components. The design of this hole is crucial for the subsequent installation and positioning of components, especially since the primary internal gear ring 24 and the rotor shaft 63 of the motor 6 (described below) need to pass through the mounting hole 12.

[0039] In this embodiment, the first-stage internal gear ring 24 includes a gear ring portion 241 and a fixing portion 242 coaxially arranged. The gear ring portion 241 is a cylindrical part with an internal gear. During assembly, it passes through the mounting hole 12 on the housing 1, allowing its working section to extend into the reducer mounting cavity 11 for normal meshing with the first-stage planetary gear 22. The fixing portion 242 is a flange or flange structure with a large radial dimension, located at one end of the gear ring portion 241. After assembly, this fixing portion 242 is fastened to the outer end face of the housing 1 on the side with the mounting hole 12 by screws or other means.

[0040] This design allows the primary internal gear ring 24 to be installed and fixed from one end of the housing 1, with the fixing point located on the outer end face of the housing 1, rather than the inner wall of the cavity.

[0041] The installation method for the secondary internal gear ring 34 differs from that of the primary internal gear ring 24. The secondary internal gear ring 34, as an independent annular component, is directly fixed to the inner circumferential wall of the reducer mounting cavity 11. This fixing method means that the axial and radial positions of the secondary internal gear ring 34 are entirely defined and supported by the inner wall structure of the mounting cavity, with its fixing point located inside the cavity.

[0042] This embodiment specifies the overall configuration of the reducer by defining the specific cavity and hole structure of the housing 1 and clarifying the distinct installation positions and fixing methods of the two-stage internal gear rings. This design allows for a partially staggered arrangement of the two-stage internal gear rings in the axial direction, freeing up space for the rational layout of internal planetary gears and planet carriers, while ensuring the stability and reliability of their respective fixing. It is a specific and preferred implementation method for achieving a radially compact nested structure.

[0043] In some embodiments, the secondary sun gear 31 is supported by a first bearing Z1 on the outer peripheral surface of the gear ring portion 241 of the primary internal gear ring 24. This means that while the gear ring portion 241 of the primary internal gear ring 24 performs its meshing transmission function as a fixed gear ring, its outer cylindrical surface also serves as a rotational support reference for the secondary sun gear 31. The first bearing Z1 is mounted between these two components, enabling the secondary sun gear 31 to achieve smooth and concentric rotational motion relative to the fixed gear ring portion 241. This support method tightly links the two stages of transmission radially, allowing the secondary sun gear 31 to be arranged around and supported by the core fixing member of the primary transmission assembly, thereby forming a radially nested structure.

[0044] Meanwhile, the second-stage sun gear 31 is also fixedly connected to the first-stage planetary carrier 23. As the output component of the first-stage reduction gear 2, the first-stage planetary carrier 23 directly and rigidly transmits its rotational motion to the fixed second-stage sun gear 31. Therefore, the second-stage sun gear 31 plays a dual role: for the second-stage reduction gear 3, it is the sun gear for power input; for the entire transmission chain, it is the direct receiver of the power output from the first-stage reduction gear 2. This fixed connection ensures a simple and efficient power transmission path from the first stage to the second stage, avoiding energy loss, hysteresis, or structural instability that might result from floating or flexible connections.

[0045] By adopting the above scheme, the second-stage sun gear 31 is supported on the outer periphery of the fixed first-stage internal gear ring 24 via the first bearing Z1, achieving precise radial nesting and alignment of the two-stage transmission components, which greatly improves the compactness and overall rigidity of the structure. At the same time, the fixed connection between the second-stage sun gear 31 and the first-stage planetary carrier 23 ensures that the power output from the first-stage reduction gear is directly and without backlash transmitted to the second-stage input. Thus, based on achieving high transmission efficiency and smooth power, it lays a key structural foundation for the flattened design and high-performance output of the entire reducer.

[0046] In some embodiments, the first-stage planetary carrier 23 adopts a split frame structure, specifically composed of a first-stage plate 231 and a first-stage baffle 232. The first-stage plate 231 is the main load-bearing and connecting component, and its entirety is located on the side of the gear ring portion 241 of the first-stage internal gear ring 24 away from its fixed portion 242. This positioning arrangement places the first-stage plate 231 at the opening end of the reducer mounting cavity 11. The first-stage plate 231 is fixedly connected to the second-stage sun gear 31, which allows the first-stage plate 231 to directly and without loss transmit the power from the movement of its own components to the second-stage sun gear 31, thereby achieving power coupling between the two stages of reduction.

[0047] On the primary plate 231, a plurality of first rotating members 233 are arranged along its circumference. These first rotating members 233 are preferably planetary pins, which are fixed to the primary plate 231 and extend outward. Each primary planetary gear 22 is movably mounted on a corresponding first rotating member 233 via a bearing. This movable mounting means that the planetary gear can rotate freely and smoothly around the first rotating member 233, which is the key to the planetary gear's rotational motion.

[0048] The first-stage baffle 232 is the cover plate on the other side of the frame structure. It is arranged on the side where all the first-stage planetary gears 22 face away from the first-stage plate 231, that is, the first-stage planetary gears 22 are installed in the space between the first-stage plate 231 and the first-stage baffle 232. The first-stage baffle 232 is fixedly connected to the ends of each of the first rotating components 233. Through this connection, the first-stage baffle 232 and the first-stage plate 231 work together to firmly lock both ends of all the first rotating components 233, thereby axially limiting all the first-stage planetary gears 22 to a precise and stable installation space and preventing them from axially moving during operation.

[0049] In some embodiments, the secondary planetary carrier 33 also adopts a split frame structure, specifically composed of a secondary plate 331 and a secondary baffle 332. The secondary plate 331 is the main load-bearing and connecting base, and its entirety is located on the side of all secondary planetary gears 32 facing away from the mounting holes 12 on the housing 1. This arrangement means that the secondary plate 331 is located on the side of the reducer mounting cavity 11 away from the motor 6 mounting end, making the layout of the secondary transmission components more concentrated and leaving space for the final output interface.

[0050] On the secondary plate 331, a plurality of second rotating members 333 are arranged along its circumference. These second rotating members 333 are preferably planetary pins, which are fixedly connected to the secondary plate 331 and extend toward the mounting hole 12. Each secondary planetary gear 32 is movably sleeved on a corresponding second rotating member 333 via a bearing. This movable sleeve arrangement allows the secondary planetary gear 32 to rotate freely and smoothly around the second rotating member 333, which is the mechanical basis for its rotational motion.

[0051] The secondary baffle 332 serves as the other side cover of the frame structure. It is positioned on the side of all secondary planetary gears 32 away from the secondary plate 331, opposite to the secondary plate 331. All secondary planetary gears 32 are thus installed and housed within the axial space between the secondary plate 331 and the secondary baffle 332. The secondary baffle 332 is fixedly connected to the ends of each of the second rotating members 333. Through this connection, the secondary baffle 332 and the secondary plate 331 work together to firmly fix both ends of all the second rotating members 333, thereby precisely axially limiting all the secondary planetary gears 32 within a closed and stable mounting frame, effectively preventing axial displacement during transmission and ensuring meshing stability.

[0052] In some embodiments, a first end cap 4 is fixedly provided at the opening end of the reducer mounting cavity 11. The first end cap 4 closes the opening of the reducer mounting cavity 11, forming a complete and sealed internal space together with the housing 1, thereby protecting the internal transmission components from the influence of external dust and impurities.

[0053] The secondary plate 331 is supported on the first end cover 4 by a second bearing Z2. Specifically, the outer ring of the second bearing Z2 is press-fitted or fixed in a pre-set bearing seat hole inside the first end cover 4, while the inner ring of the second bearing Z2 is engaged and fixed with the corresponding journal or mounting part on the secondary plate 331. This support method allows the secondary plate 331 and the entire secondary planetary carrier 33 assembly it supports to achieve smooth and concentric rotational movement relative to the fixed housing 1 (via the first end cover 4).

[0054] An output flange 5 is fixedly connected to the outer side of the secondary plate 331, that is, the side facing away from the internal space of the reducer mounting cavity 11. The output flange 5 is a disc-shaped connector that is rigidly connected to the secondary plate 331 by screws or other means. As the final mechanical interface of the entire two-stage planetary reducer, the output flange 5 outputs the rotational power after two stages of reduction and torque amplification to the outside, so as to make a direct and reliable connection with the next stage linkage, hub or other external load of the robot.

[0055] Due to the radial nested layout and the output from the outermost secondary planetary carrier 33, the output flange 5 can achieve a larger design diameter, which not only facilitates connection with large loads, but also significantly improves the torque output and load-bearing capacity of the joint, making it particularly suitable for high torque load scenarios such as the waist and knee joints of robots.

[0056] This application also discloses a joint module, as shown in the attached document. Figure 1 , 5 As shown in Figures 6 and 7, this joint module structurally integrates the aforementioned two-stage planetary reducer and drive motor 6, with both achieving an integrated configuration through a unified housing 1. Specifically, a receiving cavity 13 is specially provided at the other end of the housing 1 away from the reducer mounting cavity 11. This receiving cavity 13 provides dedicated mounting and housing space for the motor 6 component, allowing the motor 6 to be compactly integrated into one end of the reducer, together forming a structurally complete power unit.

[0057] The motor 6 comprises a stator 61, a rotor ring 62, and a rotor shaft 63. The stator 61 is fixedly mounted on the inner wall of the receiving cavity 13, remaining stationary. The rotor ring 62 is fitted inside the stator 61 and can rotate relative to the stator 61, thus forming an external rotor type motor 6 structure. The rotor shaft 63 is a key transmission component connecting the motor 6 and the reducer. One end of the shaft is connected to the rotating rotor ring 62, thereby obtaining the output power of the motor 6; the other end passes through the existing mounting hole 12 on the housing 1, extends into the reducer mounting cavity 11, and forms a fixed connection with the first-stage sun gear 21 of the reducer. Thus, the rotational power generated by the motor 6 is directly and rigidly input into the first-stage transmission of the reducer through the rotor shaft 63.

[0058] In this embodiment, the accommodating cavity 13, the mounting hole 12 on the housing 1, and the reducer mounting cavity 11 are connected in sequence to form a continuous internal air duct from the motor 6 end to the inside of the reducer.

[0059] When the motor 6 is running, the rotation of the rotor ring 62 and rotor shaft 63 disturbs the surrounding air. This through-flow duct provides a clear path for airflow, allowing air to flow from the receiving cavity 13, through the mounting hole 12, and finally through the reducer mounting cavity 11, or to form a reverse flow. This active air circulation effectively removes the heat generated by the motor 6 during operation and the heat generated by the meshing of the gears inside the reducer, achieving synergistic forced air cooling for both.

[0060] The joint module provided in this embodiment integrates the motor 6 and the two-stage planetary reducer into a housing 1 with a continuous ventilation channel. This not only achieves a high degree of integration and structural flattening of the power unit, but also cleverly utilizes the operation of the motor 6 itself to promote internal air circulation, providing an efficient integrated heat dissipation solution for the motor 6 and the reducer. This significantly improves the thermal stability and overall reliability of the joint module under continuous high load operation.

[0061] In some embodiments, a blade structure 64 is connected between the rotor shaft 63 and the rotor ring 62 to drive airflow within the duct.

[0062] When the motor 6 starts, the rotor ring 62 drives the rotor shaft 63 to rotate at high speed, and the blade structure 64 fixed on the rotor shaft 63 also rotates at high speed. The rotating blades do work on the surrounding air, like a built-in centrifugal fan, which can effectively drive the air to generate directional flow. This driven airflow will move along the through-flow channel formed by the receiving cavity 13, the mounting hole 12 and the reducer mounting cavity 11 connected in sequence.

[0063] In this embodiment, the airflow generated by the blade rotation can originate from the receiving cavity 13, pass through the relatively narrow mounting hole 12, and be forced or drawn into the reducer mounting cavity 11 on the other side. Conversely, the airflow may also circulate within the cavity. Regardless of the flow direction, the flowing air will pass over the surface of the heating area of ​​the motor 6 stator and rotor assembly, as well as the area of ​​gear meshing transmission inside the reducer. The continuous flow of air can continuously carry away the heat generated in these critical parts and dissipate it to the external environment through the surface of the housing 1 or structural gaps.

[0064] This embodiment cleverly utilizes the motor 6 itself as a power source by integrating a simple blade structure 64 inside the rotor of the motor 6, achieving forced convection cooling within the sealed integrated housing 1. This design eliminates the need for additional fans or complex cooling pipes, effectively improving the heat dissipation capacity of the joint module under high load and long-term operation conditions with extremely low additional cost and structural complexity, thereby ensuring the operating temperature stability and overall operational reliability of both the motor 6 and the reducer.

[0065] In some embodiments, the joint module is further provided with a second end cap 7 at the opening end of the receiving cavity 13. The second end cap 7 is fixedly installed on the housing 1 by means of screws or other connections, and its function is to close the opening of the receiving cavity 13. By installing the second end cap 7, the receiving cavity 13 is isolated from the external environment, forming a relatively sealed space. This not only protects the internal motor 6 and reducer components from external dust, impurities and accidental impacts, but also provides a stable and clean installation platform for the coding detection mechanism 8.

[0066] An integrated coding detection mechanism 8 is mounted on the second end cover 7. The core function of this mechanism is to detect the rotational speed of the rotor shaft 63 in real time. Since the rotor shaft 63 is directly connected to the rotor ring 62, its rotational speed directly reflects the real-time output speed of the motor 6. The coding detection mechanism 8 uses a non-contact sensing principle to capture the motion signals of specific markers rotating on or synchronously with the rotor shaft 63, and converts these signals into electrical signals, thereby accurately calculating the angular velocity and rotational position of the rotor shaft 63.

[0067] As some specific implementations, the coding detection mechanism 8 includes an output gear 81, a detection gear 82, an encoder 83, and a protective cover 84.

[0068] The output gear 81 is fixedly installed at the end of the rotor shaft 63 away from the first-stage sun gear 21, that is, at the end of the rotor shaft 63 that extends out of the motor 6 cavity. Since the rotor shaft 63 rotates synchronously with the rotor ring 62, the output gear 81 fixed at its end can directly and without lag reflect the real-time speed of the motor 6, serving as the original signal source for speed detection.

[0069] The detection gear 82 is rotatably mounted on the second end cover 7 via bearings or bushings, and forms a stable meshing relationship with the output gear 81. When the output gear 81 rotates with the rotor shaft 63, it drives the meshing detection gear 82 to rotate at a certain transmission ratio. This gear pair arrangement can convert the high speed of the rotor shaft 63 into a speed more suitable for measurement by the rear encoder 83, while also providing more flexible space for the arrangement of the encoder 83.

[0070] The encoder 83 serves as a sensing element, with its sensing portion precisely aligned with the detection gear 82. The encoder 83 does not mechanically contact the detection gear 82; instead, it uses non-contact principles such as magnetic induction and photoelectric sensing to capture the rotational motion of the detection gear 82 in real time and convert it into corresponding pulse or digital signals, thereby accurately calculating the rotational speed and angular position of the detection gear 82. Since the rotational speed of the detection gear 82 is proportional to the rotational speed of the rotor shaft 63, the rotational speed information of the input shaft of the motor 6 can be obtained indirectly and accurately.

[0071] The protective cover 84 and the second end cover 7 together form a sealed installation space. The detection gear 82 and the encoder 83 are completely enclosed within this space. This design provides a clean, dust-proof, oil-proof, and physically interference-proof stable working environment for the precision detection gear 82 transmission pair and the sensitive encoder 83 element, greatly improving the long-term reliability and measurement accuracy of the entire speed feedback system.

[0072] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A two-stage planetary reducer, characterized in that, It includes a housing and a primary reduction gear assembly and a secondary reduction gear assembly disposed within the housing, wherein the secondary reduction gear assembly is located radially outside the primary reduction gear assembly. The first-stage reduction assembly includes a first-stage sun gear, a first-stage planet gear meshing with the first-stage sun gear, a first-stage planet carrier for mounting the first-stage planet gear, and a first-stage internal gear ring. The first-stage planet gear meshes with the first-stage internal gear ring, the first-stage internal gear ring is fixed to the housing, and the first-stage sun gear is used to receive input power. The secondary reduction assembly includes a secondary sun gear, secondary planet gears meshing with the secondary sun gear, a secondary planet carrier for mounting the secondary planet gears, and a secondary internal gear ring. The secondary planet gears mesh with the secondary internal gear ring, the secondary internal gear ring is fixed to the housing, the secondary sun gear is fixedly connected to the primary planet carrier, and the secondary planet carrier serves as the power output end of the secondary planetary reducer.

2. The two-stage planetary reducer as described in claim 1, characterized in that: A reducer mounting cavity is formed at one end of the housing, and the first-stage reducer assembly and the second-stage reducer assembly are housed in the reducer mounting cavity; The other end of the housing is provided with a mounting hole that communicates with the reducer mounting cavity; The first-stage internal gear ring includes a gear ring portion and a fixing portion arranged coaxially. The gear ring portion passes through the mounting hole and is located in the reducer mounting cavity. The fixing portion is fixedly connected to the outer end face of the housing. The secondary internal gear ring is fixed to the inner circumferential wall of the reducer mounting cavity.

3. The two-stage planetary reducer as described in claim 2, characterized in that: The secondary sun gear is supported on the outer periphery of the gear ring portion of the primary internal gear ring by a first bearing and is fixedly connected to the primary planetary carrier.

4. The two-stage planetary reducer as described in claim 3, characterized in that: The primary planetary carrier includes a primary plate and a primary baffle. The primary plate is located on the side of the gear ring portion of the primary internal gear ring away from the fixed portion and is fixedly connected to the secondary sun gear. The primary plate is provided with a plurality of first rotating members distributed circumferentially. The primary planetary gear is movably sleeved on the first rotating members. The primary baffle is located on the side of the primary planetary gear away from the primary plate and is fixedly connected to the first rotating members.

5. The two-stage planetary reducer as described in claim 2, characterized in that: The secondary planetary carrier includes a secondary plate and a secondary baffle. The secondary plate is located on the side of the secondary planetary gear facing away from the mounting hole. The secondary plate is provided with a plurality of second rotating members distributed circumferentially. The secondary planetary gear is movably sleeved on the second rotating members. The secondary baffle is located on the side of the secondary planetary gear away from the secondary plate and is fixedly connected to the second rotating members.

6. The two-stage planetary reducer as described in claim 5, characterized in that: A first end cover is fixedly installed at the opening end of the reducer mounting cavity, the secondary plate is supported on the first end cover by a second bearing, and an output flange is fixedly connected to the outside of the secondary plate.

7. A joint module, characterized in that: The device includes a two-stage planetary reducer as described in any one of claims 2-6 and a motor, wherein a receiving cavity is provided at one end of the housing away from the reducer mounting cavity, and the motor includes a stator, a rotor ring sleeved inside the stator, and a rotor shaft; The stator is fixed to the receiving cavity, one end of the rotor shaft is connected to the rotor ring, and the other end passes through the mounting hole and is fixedly connected to the first-stage sun gear; The receiving cavity, the mounting hole, and the reducer mounting cavity are sequentially connected to form a continuous air duct.

8. The joint module as described in claim 7, characterized in that, A blade structure is connected between the rotor shaft and the rotor ring to drive airflow within the duct.

9. The joint module as described in claim 7, characterized in that, It also includes a second end cap and an encoding detection mechanism. The second end cap is fixed to the housing and closes the receiving cavity. The encoding detection mechanism is disposed on the second end cap and is used to detect the rotational speed of the rotor shaft.

10. The joint module as described in claim 9, characterized in that, The encoding detection mechanism includes an output gear, a detection gear, an encoder, and a protective cover; The output gear is fixedly mounted on the end of the rotor shaft away from the first-stage sun gear; The detection gear is rotatably mounted on the second end cover and meshes with the output gear; The encoder is used to acquire the rotation signal of the detection gear; The protective cover is fixed to the end of the second end cover away from the housing, and the detection gear and encoder are encapsulated in the space formed by the protective cover and the second end cover.

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