Low-backlash planetary differential speed reducer
By combining the differential adjustment mechanism and the controller, real-time backlash compensation of the planetary reducer is achieved, which solves the hysteresis and vibration problems caused by backlash, improves the dynamic response and accuracy of the equipment, extends its service life and reduces maintenance costs.
Patent Information
- Application Number
- CN202522603687.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-09
- Publication Date
- 2026-01-23
- Estimated Expiration
- 2035-12-09
AI Technical Summary
The backlash in existing planetary gear reducers causes lag, vibration, and impact in the transmission system during commutation, affecting the high-speed and high-precision performance of the equipment, and it is difficult to perform backlash compensation in real time and dynamically.
A low-backlash planetary differential reducer was designed. The differential gear ring is actively driven to rotate at a micro-angle through a differential adjustment mechanism. Real-time backlash compensation is achieved in combination with a controller. The reducer includes components such as an adjustment motor, an adjustment gear shaft, a gear ring drive gear, and a composite bearing to ensure that the transmission backlash approaches zero or the target preload state.
It achieves improved transmission rigidity, faster dynamic response of equipment, smoother movement, reduced vibration and noise, extended maintenance-free period, reduced cost, and maintains the compact structure and intelligent control capabilities of planetary reducers.
Smart Images
Figure CN223825538U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a speed reducer especially relates to a low gear clearance planetary differential speed reducer. BACKGROUND
[0002] The planetary speed reducer is widely applied in the field needing high precision, high rigidity transmission such as industrial robot, precision machine tool, aerospace, high-end automation equipment with the advantages of compact structure, large transmission ratio, strong carrying capacity, high efficiency, in these application scenarios, the return gap (that is, gear clearance) of transmission system is the key index of influencing positioning accuracy, motion stability and dynamic response performance, and too large gear clearance can lead to hysteresis, vibration and even impact when the system reverses, which seriously restricts the high speed and high precision performance of equipment. SUMMARY
[0003] The utility model discloses a low gear clearance planetary differential speed reducer that can actively and real-time control transmission gear clearance.
[0004] The utility model discloses a low gear clearance planetary differential speed reducer that can actively and real-time control transmission gear clearance.
[0005] Preferably, the differential adjustment mechanism includes an adjustment gear shaft rotatably mounted on the housing. One end of the adjustment gear shaft extends through the housing to the outside and is connected to an adjustment motor. The housing has an adjustment shaft between the adjustment gear shaft and the differential gear ring. A gear ring drive gear is rotatably mounted on the adjustment shaft. The outer wall of the differential gear ring has adjustment external teeth. The gear ring drive gear meshes with the adjustment gear shaft and the adjustment external teeth.
[0006] Preferably, a first needle roller bearing is provided between the gear ring drive gear and the adjusting shaft to support its rotation.
[0007] Preferably, the differential gear ring is supported on the inner side of the drive cavity of the housing by a composite bearing, and at least two composite bearings are provided, with the two composite bearings respectively located on both axial sides of the differential gear ring.
[0008] Preferably, a second needle roller bearing is provided between the input planetary gear and the output planetary gear and the planetary shaft, and a wear-resistant bushing is provided on both axial sides of each first needle roller bearing to limit the axial clearance between the input planetary gear and the output planetary gear.
[0009] Preferably, the input gear ring is fixed to the housing and located on the side wall of the drive cavity near the input shaft, and the differential gear ring is located between the input gear ring and the bearing housing.
[0010] Preferably, the system also includes a controller electrically connected to the regulating motor of the differential regulating mechanism, which controls the regulating motor to dynamically compensate for transmission backlash based on load, temperature, or positioning commands.
[0011] This invention utilizes a differential adjustment mechanism to actively drive the differential gear ring to rotate at a micro-angle, directly and precisely adjusting the meshing phase of the output gear. This allows for real-time adjustment of the transmission backlash to near zero or the target preload state during equipment assembly, operation, or after wear. Transmission rigidity is fundamentally improved, resulting in faster dynamic response, stronger resistance to impact loads, and smoother movement during high-speed start-stop or reversing. It effectively reduces vibration and noise and improves the trajectory tracking accuracy of the end effector. During normal operation, the differential adjustment mechanism can be set to the optimal preload position instead of continuously providing maximum preload, reducing unnecessary wear. When the backlash increases due to natural wear after a period of operation, it can be compensated for again through the adjustment mechanism. The need for immediate replacement of expensive high-precision gears significantly extends the maintenance-free cycle and service life of the entire machine, reducing costs. The differential adjustment mechanism is fully integrated into the housing, maintaining the traditional advantage of a compact planetary gearbox structure. Simultaneously, it connects to the controller, enabling closed-loop intelligent control based on load, temperature, or positioning error feedback. The wear-resistant bushing design not only improves the wear resistance of the planetary shafts but, more importantly, precisely limits the axial positions of the input and output planetary gears, providing a stable and reliable reference for differential adjustment and preventing adjustment misalignment caused by axial movement. The composite bearing's support for the differential gear ring ensures smooth, unhindered rotation during adjustment, guaranteeing the accuracy of the adjustment action and the long-term operational stability of the entire system. Attached Figure Description
[0012] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;
[0013] Figure 2 This is a utility model Figure 1 Enlarged view of point A.
[0014] In the diagram: 1. Housing; 2. Bearing housing; 3. Input shaft; 4. Output shaft; 5. Planetary carrier; 6. Planetary shaft; 7. Input planetary gear; 8. Output planetary gear; 9. Input gear; 10. Input gear ring; 11. Output gear; 12. Differential gear ring; 13. Adjusting gear shaft; 14. Adjusting shaft; 15. Gear ring drive gear; 16. Adjusting external gear; 17. First needle roller bearing; 18. Composite bearing; 19. Second needle roller bearing; 20. Wear-resistant bushing. Detailed Implementation
[0015] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.
[0016] Example: Figures 1 to 2The low backlash planetary differential reducer shown includes a housing 1, a controller, and a differential adjustment mechanism. The output end of the housing 1 is provided with a bearing seat 2, and a drive cavity is formed between the bearing seat 2 and the housing 1. An input shaft 3 is rotatably provided on the housing 1, with its inner end extending into the drive cavity. An output shaft 4 is rotatably provided on the bearing seat 2, with its inner end extending into the drive cavity. The input shaft 3 and the output shaft 4 are coaxially arranged.
[0017] A planetary carrier 5 is rotatably mounted within the drive cavity. The planetary carrier 5 is sleeved on the outer side of the inner ends of the input shaft 3 and the output shaft 4. At least one planetary shaft 6 is mounted on the planetary carrier 5. Each planetary shaft 6 has an input planetary gear 7 and an output planetary gear 8 rotatably mounted in parallel. A second needle roller bearing 19 is provided between each input planetary gear 7 and the output planetary gear 8 and the planetary shaft 6. Wear-resistant bushings 20 are provided on both axial sides of each first needle roller bearing 17 on the planetary shaft 6 to limit the axial clearance between the input planetary gear 7 and the output planetary gear 8. The design of the wear-resistant bushings 20 not only improves the wear resistance of the planetary shaft 6, but more importantly, precisely limits the axial position of the input planetary gear 7 and the output planetary gear 8, providing a stable and reliable reference for differential adjustment and preventing adjustment misalignment caused by axial movement. The inner end of the input shaft 3 is sleeved with a material that meshes with the input planetary gear 7. The input gear 9 is fixed on the housing 1, and the input gear ring 10 meshes with the input planetary gear 7. The inner end of the output shaft 4 is fitted with an output gear 11 meshing with the output planetary gear 8. The differential gear ring 12 meshes with the output planetary gear 8 and is rotatably disposed in the drive cavity. The differential gear ring 12 is supported on the inner side of the drive cavity of the housing 1 by a composite bearing 18. At least two composite bearings 18 are provided, and the two composite bearings 18 are respectively disposed on the two axial sides of the differential gear ring 12. The support of the composite bearings 18 on the differential gear ring 12 ensures that it rotates smoothly and without jamming during the adjustment process, ensuring the accuracy of the adjustment action and the long-term operational stability of the entire system. The input gear ring 10 is fixed on the housing 1 and located on the side wall of the drive cavity near the input shaft 3. The differential gear ring 12 is located between the input gear ring 10 and the bearing seat 2.
[0018] A differential adjustment mechanism is provided on one side of the housing 1, which is connected to the differential gear ring 12 for driving the differential gear ring 12 to rotate at a small angle relative to the housing 1. By actively driving the differential gear ring 12 to rotate at a small angle through the differential adjustment mechanism, the meshing phase of the output gear 11 can be directly and accurately adjusted. Thus, during equipment assembly, operation, or after wear, the transmission backlash can be adjusted to near zero or the target preload state in real time, fundamentally improving the transmission rigidity, making the equipment's dynamic response faster, its impact load resistance stronger, and its movement smoother during high-speed start-stop or reversing, effectively reducing vibration and noise, and improving the trajectory tracking accuracy of the end effector. The differential adjustment mechanism includes an adjustment gear shaft 13 rotatably mounted on the housing 1. One end of the adjustment gear shaft 13 extends through the housing 1 to the outside and is connected to an adjustment motor. An adjustment shaft 14 is provided between the adjustment gear shaft 13 and the differential gear ring 12 in the housing 1. A gear ring drive gear is rotatably mounted on the adjustment shaft 14. The differential gear ring 12 has an adjusting external tooth 16 on its outer wall. The gear ring drive gear 15 meshes with the adjusting gear shaft 13 and the adjusting external tooth 16. A first needle roller bearing 17 is provided between the gear ring drive gear 15 and the adjusting shaft 14 to support its rotation. During normal operation, the differential adjustment mechanism can be set to the optimal preload position instead of continuously providing the maximum preload force, reducing unnecessary wear. When the backlash increases due to natural wear after a period of operation, it can be recompensated by the adjustment mechanism without immediately replacing the expensive high-precision gear, greatly extending the maintenance-free cycle and service life of the whole machine and reducing costs. The controller is electrically connected to the adjusting motor of the differential adjustment mechanism. It controls the adjusting motor to dynamically compensate for the transmission backlash according to the load, temperature or positioning command. The differential adjustment mechanism is fully integrated into the housing 1, maintaining the traditional advantage of the compact structure of the planetary reducer. At the same time, it is connected to the controller to realize closed-loop intelligent control based on load, temperature or positioning error feedback.
[0019] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.
Claims
1. A low-backlash planetary differential reducer, comprising a housing (1), wherein a bearing seat (2) is provided at the output end of the housing (1), and a drive cavity is formed between the bearing seat (2) and the housing (1), characterized in that: An input shaft (3) extending into the drive cavity is rotatably mounted on the housing (1), and an output shaft (4) extending into the drive cavity is rotatably mounted on the bearing housing (2). The input shaft (3) and the output shaft (4) are coaxially aligned. A planetary carrier (5) is rotatably mounted inside the drive cavity. The planetary carrier (5) is sleeved on the outer side of the inner ends of the input shaft (3) and the output shaft (4). At least one planetary shaft (6) is mounted on the planetary carrier (5). An input planetary gear (7) and an output planetary gear (8) are rotatably mounted side by side on each planetary shaft (6). The inner end of the input shaft (3) is sleeved with a gear that meshes with the input planetary gear (7). An input gear (9) is provided. An input gear ring (10) that meshes with the input planetary gear (7) is fixed on the housing (1). An output gear (11) that meshes with the output planetary gear (8) is sleeved on the inner end of the output shaft (4). A differential gear ring (12) that meshes with the output planetary gear (8) is rotatably provided in the drive cavity. A differential adjustment mechanism that is connected to the differential gear ring (12) is provided on one side of the housing (1) to drive the differential gear ring (12) to rotate at a small angle relative to the housing (1) in order to adjust the meshing backlash between the output planetary gear (8), the output gear (11), and the differential gear ring (12).
2. The low backlash planetary differential reducer according to claim 1, characterized in that: The differential adjustment mechanism includes an adjustment gear shaft (13) rotatably mounted on the housing (1). One end of the adjustment gear shaft (13) extends through the housing (1) to the outside and is connected to an adjustment motor. The housing (1) has an adjustment shaft (14) between the adjustment gear shaft (13) and the differential gear ring (12). A gear ring drive gear (15) is rotatably mounted on the adjustment shaft (14). An adjustment external tooth (16) is provided on the outer wall of the differential gear ring (12). The gear ring drive gear (15) meshes with the adjustment gear shaft (13) and the adjustment external tooth (16).
3. The low backlash planetary differential reducer according to claim 2, characterized in that: A first needle roller bearing (17) is provided between the gear ring drive gear (15) and the adjusting shaft (14) to support its rotation.
4. The low backlash planetary differential reducer according to claim 1, characterized in that: The differential gear ring (12) is supported on the inner side of the drive cavity of the housing (1) by a composite bearing (18). At least two composite bearings (18) are provided, and the two composite bearings (18) are respectively provided on both sides of the axial direction of the differential gear ring (12).
5. The low backlash planetary differential reducer according to claim 3, characterized in that: A second needle roller bearing (19) is provided between the input planetary gear (7) and the output planetary gear (8) and the planetary shaft (6). The planetary shaft (6) is provided with wear-resistant bushings (20) on both sides of each first needle roller bearing (17) to limit the axial clearance between the input planetary gear (7) and the output planetary gear (8).
6. The low backlash planetary differential reducer according to claim 1, characterized in that: The input gear ring (10) is fixed on the housing (1) and located on the side wall of the drive cavity near the input shaft (3). The differential gear ring (12) is located between the input gear ring (10) and the bearing seat (2).
7. The low-backlash planetary differential reducer according to any one of claims 1-6, characterized in that: It also includes a controller, which is electrically connected to the regulating motor of the differential regulating mechanism, and controls the regulating motor to dynamically compensate for the transmission backlash according to the load, temperature or positioning command.