A uniform load type high-efficiency large speed ratio speed change mechanism

Abstract

The utility model discloses a kind of high-efficiency large speed ratio speed change mechanism of uniform load type, it is related to mechanical transmission technical field, by symmetrical layout of double transmission wheel and eccentric drive module, eccentric motion of complementary phase is provided, eliminate asymmetric bending moment;Power conversion frame is decoupled as pure rotation output by power output stem and transmission rod with the annular swing of transmission wheel Motion;Dynamic uniform load module combines eccentric compensation unit and gap adaptive structure, realize the load balance of multiple kinematic pair;Motion constraint component limits transmission wheel trajectory, output shaft and shell are connected to form two kinds of speed change mode.The utility model core technology is not limited to: whether involute, cycloid, or arbitrary curve's concave-convex tooth shape, whether sliding engagement or rolling engagement, as long as tooth shape is regularly distributed, annular swing driving output rotation can be realized, to meet the speed needs of various rotating machinery equipment, applicable to various large speed ratio transmission scene.Solve the problem of traditional mechanism eccentric load, interference and low efficiency.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission technology, specifically to a load-sharing type high-efficiency high-ratio speed change mechanism. Background Technology

[0002] Planetary transmission mechanisms with small tooth difference and cycloidal pinwheel planetary transmission mechanisms are typical high-ratio speed change devices, and have important applications in equipment fields such as industrial robots and precision machine tools. Existing technology CN101280824A discloses a precision cycloidal pinwheel planetary transmission device, which reduces tooth backlash by symmetrically arranging cycloidal wheels and pinwheels and employing reverse tooth profile meshing. However, its core output mechanism still relies on a single set of pin-hole pairs to transmit power.

[0003] This type of mechanism is based on the principle of simultaneous meshing of multiple teeth in planetary gear trains. It achieves a large speed ratio transmission through the phase misalignment motion of asymmetric involute or cycloidal tooth profiles. The core transmission component for motion conversion typically adopts an output mechanism with a pin-hole fit. Although this mechanism effectively converts the complex planar motion of the planetary gears into the pure rotational motion of the output shaft, it generally suffers from prominent problems such as low efficiency, poor load-bearing capacity, and short service life in practical engineering applications.

[0004] Theoretical analysis and experimental research show that the root cause of the aforementioned technical defects lies in the asymmetric load-bearing characteristics of the traditional pin-hole output mechanism. The specific problems with this structure are as follows:

[0005] Asymmetric load concentration: During power transmission, the load distribution of each pin-hole pair exhibits significant non-uniformity. The load distribution of the pin-hole pair is uneven, and under actual working conditions, only 1-2 sets of pin holes bear the main load, resulting in excessive local stress, which accelerates contact fatigue and bending failure.

[0006] Furthermore, the load line deviates from the ideal axis of symmetry. This off-center loading effect leads to two key technical defects: overload of the central bearing and risk of motion interference.

[0007] Firstly, the central bearing of the eccentric shaft system needs to withstand an alternating radial load several times greater than the theoretical value. The theoretical value is significantly amplified, which significantly accelerates the bearing fatigue failure process and shortens the bearing life.

[0008] Secondly, the pin components are prone to contact fatigue damage and bending fracture under the combined action of periodic shear force and bending moment, making it difficult to effectively improve the load-bearing capacity of the whole machine.

[0009] Furthermore, the prior art CN213479118U discloses a device for improving the load-bearing capacity of a transmission output mechanism with a small tooth difference. This technology shortens the fulcrum span by adding an intermediate plate and segmented bushings, but it has the following limitations:

[0010] Insufficient dynamic load distribution: The reaction forces of the left and right planetary gear pins are in opposite directions, causing the bushings to bear bending loads, making it impossible to achieve dynamic load distribution among multiple kinematic pairs.

[0011] Symmetry defect: The output shaft is located on one side of the double external gears, resulting in uneven force on the gears on both sides, and the off-center load effect cannot be completely eliminated.

[0012] To address the shortcomings of existing technologies, current improvement solutions mainly focus on increasing the number of pin holes (typically 6-10 sets of pin hole pairs) or adopting a symmetrical double-eccentric structure. However, practical applications show that increasing the number of pin holes fails to fundamentally improve load distribution characteristics: due to the phase motion characteristics of planetary gear trains and the objective existence of pin hole clearances, multiple pin hole pairs cannot achieve true load-equalizing fit; instead, overload of individual pin holes may exacerbate the risk of system failure. Although the symmetrical double-eccentric structure of the transmission device balances some of the additional load, the output shaft is located on one side of the two external gears, so the forces on the two external gears are not completely consistent. Therefore, the pin shaft, pin holes, bearings, and external gears do not achieve symmetrical load-equalizing. Thus, how to achieve symmetrical and balanced load-bearing of the pin shaft-pin hole pair through structural innovation has become a key technical bottleneck for improving the overall performance of this type of transmission mechanism. Utility Model Content

[0013] The problem this invention aims to solve is the technical issues of asymmetric load concentration, central bearing overload, and motion interference risk in existing technologies. It provides a symmetrical planetary gear train and phase complementary drive that completely eliminates the off-center load effect, achieves dynamic load sharing and clearance self-adaptation, realizes load balance of multiple kinematic pairs, optimizes geometric constraints, and eliminates the risk of motion interference. This is a load-sharing type high-efficiency high-speed ratio transmission mechanism.

[0014] To address the aforementioned problems, this utility model provides a load-sharing, high-efficiency, high-ratio speed change mechanism, comprising:

[0015] The power input unit is an input shaft used to receive input power;

[0016] A symmetrical planetary gear train assembly includes two symmetrically arranged drive wheels, which are connected to the power input unit via an eccentric drive module. The eccentric drive module is configured to provide phase-complementary eccentric motion to the drive wheels to eliminate asymmetric bending moments.

[0017] A power conversion frame is located between the two drive wheels, and the power conversion frame is equipped with:

[0018] The power output rod passes through the through-hole structure of the transmission wheel and is fixedly connected to the external components, and is used to convert the circumferential oscillating motion of the transmission wheel into pure rotational output;

[0019] The dynamic load sharing module includes a motion transmission component and an eccentricity compensation unit that works in conjunction with the motion transmission component. The motion transmission component is embedded in the motion transmission channel of the transmission wheel. The eccentricity compensation unit is configured to synchronize the periodic oscillation of the transmission wheel and decouple it into the pure rotational motion of the power conversion frame. At the same time, it achieves load balancing distribution among multiple motion pairs through phase synchronization and clearance self-adaptation.

[0020] A motion constraint component engages with the transmission wheel to limit the motion trajectory of the transmission wheel;

[0021] The power output unit is an output shaft, rotatably connected to the housing, and selectively fixed to the power output rod or the motion constraint assembly to form two speed change modes:

[0022] First mode: When the motion constraint component is fixedly connected to the housing and the power output rod is connected to the power output unit, the power conversion frame serves as the output end, forming a load-sharing type high-efficiency high-speed ratio transmission mechanism with a fixed motion constraint component and a power conversion frame output.

[0023] Second mode: When the power conversion frame is fixedly connected to the housing and the motion constraint component is connected to the power output unit, the motion constraint component serves as the output end, forming a load-sharing type high-efficiency high-speed ratio transmission mechanism with a fixed power conversion frame and an output motion constraint component.

[0024] Geometric constraints, based on the oscillation trajectory envelope characteristics of the transmission wheel, ensure that the size of the motion transmission channel and the eccentricity of the eccentricity compensation unit satisfy a non-interference relationship, thus ensuring the geometric compatibility of the power transmission path.

[0025] Preferably, the eccentric drive module includes an eccentric sleeve fixedly connected to the power input unit. The eccentric sleeve is provided with two symmetrically eccentric shafts, and the eccentricity of the eccentric shafts is consistent with the eccentricity of the eccentric compensation unit.

[0026] Preferably, the eccentricity compensation unit of the dynamic load sharing module is a small eccentric sleeve fitted on the motion transmission component, the outer circle of which is rotatably connected to the motion transmission channel, and its eccentricity direction is synchronized with the eccentricity drive module.

[0027] Preferably, the power conversion frame is a star wheel frame located between two external gears. Several external connecting rods and transmission rods are evenly distributed on the star wheel frame. The power output rod and motion transmission component are several external connecting rods and transmission rods evenly distributed on the star wheel frame.

[0028] Preferably, the power output rod body and the through hole structure are fitted with a clearance fit, and the extension direction of the power output rod body is either unidirectionally penetrating one side of the transmission wheel or bidirectionally penetrating both sides of the transmission wheel.

[0029] Preferably, the motion constraint component is a gear or pin structure, which is shared with or separately arranged from the transmission wheel, and each transmission wheel corresponds to one motion constraint component.

[0030] Preferably, the tooth profile of the transmission wheel is an involute, cycloid, circular arc, or pin tooth structure, and the teeth are evenly distributed to achieve regular driving of periodic oscillation.

[0031] Preferably, the transmission wheel is an external gear, and the through-hole structure and motion transmission channel are formed by a number of through holes and transmission holes evenly distributed on the external gear.

[0032] Preferably, the motion constraint component is a gear or pin structure corresponding to the transmission wheel, and one motion constraint component corresponds to one or two of the transmission wheels.

[0033] Preferably, the power input unit and the eccentric drive module are integrated into an eccentric crankshaft or are separate connection structures.

[0034] Preferably, the power conversion frame is a floating structure or is rotatably connected to the eccentric drive module.

[0035] Preferably, all rotating joints are equipped with bearings or wear-resistant rings to reduce frictional loss.

[0036] Preferably, the geometric constraint condition satisfies the relationship: R≥r+e, where R is the radius of the motion transmission channel, r is the radius of the motion transmission component, and e is the eccentricity of the eccentric drive module.

[0037] Compared with the prior art, the present invention achieves the following beneficial technical effects:

[0038] This invention places the power conversion frame between two transmission wheels, adopts a symmetrical layout of dual transmission wheels, and utilizes symmetrically distributed involute transmission wheels and an eccentric drive module to achieve a 180° phase difference in meshing torque balance. This fundamentally eliminates the asymmetrical bending moment load of traditional single-sided planetary gear systems, achieving completely symmetrical force distribution on the two transmission wheels. This forms a symmetrical planetary gear system with complementary phase drive, ensuring that the load is evenly distributed on both sides of the transmission wheels. Compared with the single-sided pin shaft output of existing technologies, the symmetrical meshing structure of this invention with double external gears reduces tooth surface contact stress by more than 40%, and the unit area load of the pin hole pair is reduced to 1 / 3 of that of the traditional structure. The multi-eccentric shaft parallel mechanism increases the system torque capacity by 2-3 times, while eliminating local stress concentration caused by eccentric load.

[0039] This invention employs a multi-set eccentric shaft output mechanism with phase synchronization characteristics to decouple the planar circumferential oscillation motion of the external gear into the pure rotational motion output of the star wheel carrier. Through the equal phase angle arrangement of each eccentric shaft set and the pin hole pair clearance compensation structure, the dynamic load sharing module synchronizes the oscillation of the external gear through the eccentric compensation unit. Combined with the clearance adaptive structure of the transmission rod and the motion transmission channel, dynamic load balance distribution among multiple kinematic pairs is achieved. Compared with the prior art, the symmetrical force of the planetary gear system reduces the equivalent dynamic load of the central bearing by more than 60%. With the load sharing effect of the multi-pin hole pair, the overall transmission efficiency is increased to more than 95%. The fatigue life of key kinematic pairs is extended to several times that of traditional structures.

[0040] This invention ingeniously utilizes the envelope characteristics of the oscillating motion of the external gears to establish geometric constraints. Through parametric design, it ensures no motion interference between the external gears and the output mechanism within the extreme swing angle range, achieving geometric optimization of the power transmission path. This perfectly transmits the power from the star wheel carrier between the two external gears to the outside. By employing a non-interference motion conversion mechanism, the axial installation space is compressed, significantly reducing the overall size compared to traditional double-eccentric structures. The geometric compatibility of the power transmission path is optimized, and transmission stability is improved, making it suitable for high-speed, high-precision applications.

[0041] The core technology of this utility model is not limited to: whether it is an involute, a cycloid, or an arbitrary curve with concave and convex tooth profiles, whether it is sliding meshing or rolling meshing, as long as the tooth profiles are regularly and evenly distributed, they can achieve circumferential oscillating drive output rotational motion to meet the speed requirements of various rotating mechanical equipment. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of Embodiment 1 of the load-sharing type high-efficiency high-ratio speed change mechanism of this utility model.

[0043] Schematic diagram of internal gear fixed / star wheel frame output mechanism.

[0044] Figure 2 yes Figure 1 Sectional view of AA.

[0045] Figure 3 This is a schematic diagram of Embodiment 2 of the load-sharing type high-efficiency high-ratio speed change mechanism of this utility model.

[0046] Schematic diagram of the star wheel frame fixing / internal gear output mechanism of this utility model.

[0047] In the diagram: 1-Power input unit, 2-Eccentric drive module, 2.1-Eccentric shaft, 2.2-Eccentric sleeve, 3-Transmission wheel, 3.1-Through hole structure, 3.2-Motion transmission channel, 4-Power conversion frame, 4.1-Power output rod, 4.2-Motion transmission component, 5-Eccentric compensation unit, 6-Motion constraint assembly, 7-Power output unit, 8-Housing. Detailed Implementation

[0048] The present invention will be further explained below with reference to the accompanying drawings and embodiments.

[0049] Example 1: As Figure 1 , Figure 2 The diagram illustrates a load-sharing, high-efficiency, high-ratio transmission mechanism with a fixed internal gear and a star wheel frame output. It mainly comprises: an eccentric sleeve 2.2 of an eccentric drive module 2 fixedly connected to a power input unit 1 (i.e., input shaft), the eccentric sleeve 2.2 having two symmetrically eccentric eccentric shafts 2.1; two transmission wheels 3 (i.e., external gears) rotatably connected to the eccentric shafts 2.1 respectively, the transmission wheels 3 having a plurality of through-hole structures 3.1 (i.e., through holes) and motion transmission channels 3.2 (i.e., transmission holes) evenly distributed on them; and a power conversion frame 4 (i.e., star wheel frame) located between the two transmission wheels 3, the power conversion frame 4 having a plurality of power output rods 4.1 (i.e., external connecting rods) and motion transmission components 4.2 (i.e., transmission rods) evenly distributed on it. The rod body 4.1 is fixedly connected to the motion transmission component 4.2 and passes through the through hole structure 3.1 on the transmission wheel 3 to be fixedly connected to the external component. The motion transmission component 4.2 is rotatably connected to the power conversion frame 4, and its two ends are respectively embedded in the motion transmission channel 3.2 of the transmission wheel 3. Several eccentric compensation units 5 (i.e., small eccentric sleeves) are located between the motion transmission component 4.2 and the motion transmission channel 3.2. The eccentricity of the inner hole and the outer circle of the eccentric compensation unit 5 is consistent with the eccentricity of the eccentric shaft 2.1 on the eccentric sleeve 2.2, and its outer circle is rotatably connected to the motion transmission channel 3.2 on the transmission wheel 3. The motion constraint component 6 (i.e., internal gear) meshes with the transmission wheel 3. The power output unit 7 (i.e., output shaft) is rotatably connected to the housing 8.

[0050] Figure 1 The motion constraint component 6 is fixedly connected to the housing 8, and the power output rod 4.1 extends to both ends, passing through the transmission wheels 3 on both sides and being fixedly connected to the power output unit 7, forming a load-sharing type high-efficiency high-speed ratio transmission mechanism with fixed internal gear and star wheel frame output.

[0051] As a preferred embodiment, the power input unit 1 and the eccentric sleeve 2.2 are either separate structures or combined into an eccentric crankshaft. Figure 1 , Figure 2 The diagram shows a split structure.

[0052] As a preferred embodiment, the power conversion frame 4 is a floating structure or is rotatably connected to the eccentric sleeve. Figure 1 , Figure 2 The power conversion frame 4 shown is a floating structure, and there is no contact between the power conversion frame 4 and the eccentric sleeve 2.2.

[0053] As a preferred embodiment, the inner hole of the eccentric compensation unit 5 and the motion transmission component 4.2 are rotatably connected, fixedly connected, or combined into an eccentric crankshaft. Figure 1 The inner hole of the eccentric compensation unit 5 is rotatably connected to the motion transmission component 4.2.

[0054] As a preferred embodiment, the cross-sectional shape of the power output rod 4.1 and the through hole structure 3.1 is circular, square or other geometric shape, and the two are fitted with a clearance. Figure 2 The cross-sectional shape of the power output rod 4.1 and the through hole structure 3.1 is elliptical, and there is a gap between them so that there is no interference in any motion state.

[0055] As a preferred embodiment, the power output rod 4.1 extends outward in one direction, penetrates one side of the external gear and is fixedly connected to the external component, or extends outward in both directions, penetrates both sides of the external gear and is fixedly connected to the external component. Figure 1 The power output rod 4.1 extends outwards in both directions.

[0056] As a preferred embodiment, the transmission wheel 3 is an involute gear, a circular arc gear, a point-line meshing gear, a pin gear, or a cycloidal wheel. Figure 1 , Figure 2 The intermediate transmission wheel 3 is a modified involute gear.

[0057] As a preferred embodiment, the motion constraint component 6 is a gear or pin that meshes with the transmission wheel 3, and can be shared with two external gears or be separate, with each external gear corresponding to one internal gear. Figure 1 The motion constraint component 6 is a gear that meshes with the two transmission wheels 3.

[0058] As a preferred option, all rotating joints are fitted with bearings or wear-resistant rings. Figure 1 In the middle, bearings are provided for the rotational connections between the eccentric sleeve 2.2 and the transmission wheel 3, between the power input unit 1 and the power output unit 7, and between the power output unit 7 and the housing 8.

[0059] As a preferred embodiment, based on the oscillation trajectory envelope characteristics of the transmission wheel 3, the dimensions of the motion transmission channel 3.2 and the eccentricity of the eccentric compensation unit 5 satisfy a non-interference relationship, ensuring the geometric compatibility of the power transmission path. The geometric constraint condition satisfies the relationship: R≥r+e, where R is the radius of the motion transmission channel 3.2, r is the radius of the motion transmission component 4.2, and e is the eccentricity of the eccentric drive module 2. This utility model cleverly utilizes the envelope characteristics of the oscillating motion of the external gear to establish geometric constraint conditions. Through parametric design, it ensures that there is no motion interference between the external gear and the output mechanism within the limit oscillation angle range, achieving geometric optimization of the power transmission path, thereby perfectly transmitting the power of the star wheel frame between the two external gears to the outside. Through a non-interference motion conversion mechanism, the axial installation space is compressed, the overall volume is greatly reduced compared to the traditional double eccentric structure, the geometric compatibility of the power transmission path is optimized, and the transmission stability is improved, making it suitable for high-speed and high-precision working conditions.

[0060] Example 2: Figure 3 The diagram illustrates a high-efficiency, high-ratio speed change mechanism with a fixed star wheel frame and internal gear output, designed for load sharing. The power output rod 4.1 extends to the left, passes through the left-hand transmission wheel 3, and is fixedly connected to the housing 8. The motion constraint component 6 is fixedly connected to the power output unit 7, forming the high-efficiency, high-ratio speed change mechanism with a fixed star wheel frame and internal gear output. The eccentric compensation unit 5 and the motion transmission component 4.2 are combined into an eccentric crankshaft. A spherical sliding bearing is provided between the middle section of the eccentric crankshaft and the power conversion frame 4, and self-aligning bearings are provided between both ends and the transmission wheel 3. This design better adapts to machining errors and achieves better load sharing. The remaining technical solutions are the same as in the embodiment.

[0061] This utility model's load-sharing type high-efficiency high-ratio transmission mechanism achieves efficient power transmission in two transmission modes through a symmetrical planetary gear train layout, dynamic load-sharing compensation, and geometric optimization design. The working process is described in detail below with reference to Embodiment 1 (fixed internal gear / star gear carrier output) and Embodiment 2 (fixed star gear carrier / internal gear output):

[0062] Example 1: Internal gear fixed / star wheel frame output mode

[0063] 1. Power Input and Eccentric Drive: Power is transmitted to the eccentric sleeve 2.2 of the eccentric drive module 2 through the power input unit 1. The two symmetrically eccentric shafts 2.1 on the eccentric sleeve 2.2 drive two symmetrically arranged transmission wheels 3, causing them to produce eccentric motion with a phase difference of 180°, thereby eliminating asymmetric bending moment.

[0064] 2. Circumferential Swing Motion and Dynamic Load Sharing: The eccentric motion of the transmission wheel 3 is converted into circumferential swing motion, and its swing trajectory is transmitted to the power conversion frame 4 through the motion transmission channel 3.2. The eccentricity compensation unit 5 of the dynamic load sharing module is mounted on the motion transmission component 4.2, and its eccentricity direction is synchronized with the eccentric shaft 2.1. The load of each motion pair is evenly distributed through the clearance adaptive design.

[0065] 3. Motion Conversion and Power Output: The power conversion frame 4 decouples the circumferential oscillating motion of the transmission wheel 3 into pure rotational motion by passing the power output rod 4.1 through the through hole structure 3.1 of the transmission wheel 3. The power output rod 4.1 is fixedly connected to the power output unit 7, and the motion constraint component 6, i.e., the internal gear, is fixed to the housing 8, forming the star wheel frame 4 as the transmission path of the output end.

[0066] The geometric constraint condition satisfies the relationship: R≥r+e, where R is the radius of the motion transmission channel 3.2, r is the radius of the motion transmission component 4.2, and e is the eccentricity of the eccentric drive module 2, ensuring no motion interference during the swing process and geometric compatibility of the power transmission path.

[0067] Example 2: Fixed Star Gear Frame / Internal Gear Output Mode

[0068] 1. Switching between power input and constraint conditions: The power input unit 1 drives the eccentric shaft 2.1 of the eccentric sleeve 2.2, which in turn drives the transmission wheel 3 to swing. The power conversion frame 4 is fixed to the housing 8 via the power output rod 4.1, restricting its rotational freedom.

[0069] 2. Internal gear output and motion transmission: The oscillating motion of the transmission wheel 3 is transmitted to the motion constraint component 6 through meshing. The internal gear 6 is fixedly connected to the power output unit 7, becoming the power output end.

[0070] 3. Dynamic load sharing and adaptive compensation: The eccentric compensation unit 5 works in conjunction with the self-aligning bearing to adapt to machining errors and achieve dynamic load balancing of multiple kinematic pairs.

[0071] This invention efficiently converts the complex oscillating motion of the transmission wheel 3 into the pure rotational motion of the power output unit 7 through a symmetrical planetary gear train, dynamic load sharing compensation, and geometric parameter optimization. It solves the problems of asymmetrical load concentration and excessive local stress in traditional mechanisms, significantly improving load-bearing capacity, transmission efficiency, and reliability. It is suitable for high-speed ratio transmission scenarios such as industrial robots and precision machine tools.

[0072] In the description of this utility model, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model. Unless otherwise expressly specified and limited, the terms "installed," "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; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0073] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0074] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A load-sharing type high-efficiency high-ratio transmission mechanism, comprising: Power input unit (1), used to receive input power; characterized in that, A symmetrical planetary gear train assembly includes two symmetrically arranged drive wheels (3), which are connected to the power input unit (1) via an eccentric drive module (2). The eccentric drive module (2) is configured to provide phase-complementary eccentric motion to the drive wheels (3) to eliminate asymmetric bending moments. A power conversion frame (4) is located between the two drive wheels (3), and the power conversion frame (4) is provided with: The power output rod (4.1) passes through the through hole structure (3.1) of the transmission wheel (3) and is fixedly connected to the external component, for converting the circumferential oscillating motion of the transmission wheel (3) into pure rotational output; The dynamic load sharing module includes a motion transmission component (4.2) and an eccentric compensation unit (5) that works in conjunction with the motion transmission component (4.2). The motion transmission component (4.2) is embedded in the motion transmission channel (3.2) of the transmission wheel (3). The eccentric compensation unit (5) is configured to synchronize the periodic oscillation of the transmission wheel (3) and decouple it to the pure rotational motion of the power conversion frame (4). At the same time, it achieves load balancing distribution of multiple kinematic pairs through phase synchronization and gap adaptation. The motion constraint component (6) engages with the transmission wheel (3) to limit the motion trajectory of the transmission wheel (3); The power output unit (7) is rotatably connected to the housing (8) and selectively fixed to the power output rod (4.1) or the motion constraint assembly (6) to form two speed change modes: First mode: When the motion constraint component (6) is fixedly connected to the housing (8) and the power output rod (4.1) is connected to the power output unit (7), the power conversion frame (4) serves as the output end; Second mode: When the power conversion frame (4) is fixedly connected to the housing (8) and the motion constraint component (6) is connected to the power output unit (7), the motion constraint component (6) serves as the output end; Geometric constraints, based on the oscillation trajectory envelope characteristics of the transmission wheel (3), ensure that the size of the motion transmission channel (3.2) and the eccentricity of the eccentricity compensation unit (5) satisfy a non-interference relationship, thereby ensuring the geometric compatibility of the power transmission path.

2. The uniform-load type high-efficiency large-speed-ratio shift mechanism according to claim 1, characterized by The eccentric drive module (2) includes an eccentric sleeve (2.2) fixedly connected to the power input unit (1). The eccentric sleeve (2.2) is provided with two symmetrically eccentric shafts (2.1). The eccentricity of the eccentric shafts (2.1) is consistent with the eccentricity of the eccentric compensation unit (5).

3. The load-sharing type high-efficiency high-ratio transmission mechanism according to claim 1, characterized in that, The eccentricity compensation unit (5) of the dynamic load sharing module is a small eccentric sleeve fitted on the motion transmission component (4.2). Its outer circle is rotatably connected to the motion transmission channel (3.2), and its eccentricity direction is synchronized with the eccentricity drive module (2).

4. The load-sharing type high-efficiency high-ratio transmission mechanism according to claim 1, characterized in that, The power output rod (4.1) and the through hole structure (3.1) are fitted with a clearance fit, and the extension direction of the power output rod (4.1) is either unidirectionally penetrating one side of the transmission wheel (3) or bidirectionally penetrating both sides of the transmission wheel (3).

5. The speed-changing mechanism according to claim 1, characterized in that: The motion constraint component (6) is a gear or pin structure corresponding to the transmission wheel (3), and one motion constraint component (6) corresponds to one or two transmission wheels (3).

6. The speed-changing mechanism according to claim 1, characterized in that: The tooth profile of the transmission wheel (3) is an involute, cycloid, circular arc or pin tooth structure, and the tooth profile is evenly distributed to achieve regular driving of periodic oscillation.

7. The speed-changing mechanism according to claim 1, characterized in that: The power input unit (1) and the eccentric drive module (2) are an integrated eccentric crankshaft or a separate connection structure.

8. The speed-changing mechanism according to claim 1, characterized in that: The power conversion frame (4) is a floating structure or is rotatably connected to the eccentric drive module (2).

9. The speed-changing mechanism according to claim 1, characterized in that: All rotating joints are equipped with bearings or wear-resistant rings to reduce frictional losses.

10. The speed-changing mechanism according to claim 1, characterized in that: The geometric constraint condition satisfies the relationship: R≥r+e, where R is the radius of the motion transmission channel (3.2), r is the radius of the motion transmission component (4.2), and e is the eccentricity of the eccentric drive module (2).

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