Planetary reduction gear capable of bearing impact load

Abstract

This utility model relates to the field of planetary gear reducer technology and discloses a planetary gear reducer capable of withstanding impact loads. It includes a housing, a cover, an input shaft, an output shaft, a sun gear body, and planet gear bodies. A first bearing is fixed to the right side of the inner wall of the cover, and the first bearing is slidably connected to the surface of the output shaft. A gear ring is provided on the inner wall of the housing. A front frame is fixed to the surface of the output shaft. A rear frame is detachably connected to one side of the front frame. Four equidistant connecting shafts are fixed to the opposite surfaces of the rear frame and the front frame. A buffer assembly is provided on the surface of the input shaft. A second bearing is fixed to the inner wall of the planet gear bodies, and a mounting shaft is fixed to the inner ring of the second bearing. Multiple stress relief grooves are circumferentially formed on the connecting shafts. This planetary gear reducer capable of withstanding impact loads solves the key technical problem of traditional planetary gear reducers being prone to tooth damage, bearing failure, or structural cracking under impact loads.

Description

Technical Field

[0001] This utility model relates to the field of planetary reducer technology, specifically a planetary reducer capable of withstanding impact loads. Background Technology

[0002] A planetary gear reducer is a versatile precision transmission device. Its core structure includes a central sun gear, planet gears evenly distributed around the sun gear and meshing internally, a fixed internal gear ring meshing externally with the planet gears, and a planet carrier connecting and supporting all the planet gears. Power is transmitted from the input shaft to the sun gear, driving the planet gears to rotate on their own axes and also revolve around the sun gear along the inner wall of the gear ring, thereby driving the planet carrier to output greater torque at a reduced speed. This structure gives it advantages such as high rigidity, high precision, high transmission efficiency, and compact size, and it is widely used in high-precision, heavy-duty fields such as industrial robots, construction machinery, and aerospace.

[0003] However, traditional planetary gearboxes reveal their weaknesses when faced with impact loads generated by frequent starts and stops, sudden jamming, or drastic load changes. Impact torque acts instantaneously on the connection between the planetary gears and their shafts, as well as the input end of the sun gear. This immense stress can easily cause plastic deformation or tearing of the planet carrier shaft bores supporting the planetary gears, and the planetary gear shafts may also bend or break. Simultaneously, the impact is directly transmitted to the sun gear teeth, causing irreversible damage such as pitting and tooth breakage. Current technologies typically address this by simply increasing material strength or structural dimensions, but this leads to increased weight and cost of the gearbox, and the buffering effect is limited, failing to fundamentally solve the problem of impact stress concentration and affecting the reliability and service life of the equipment under harsh operating conditions. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a planetary reducer that can withstand impact loads, so as to solve the key technical problem that traditional planetary reducers are prone to tooth damage, bearing failure or structural cracking under impact loads.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a planetary reducer capable of bearing impact loads, comprising a housing, a cover, an input shaft, an output shaft, a sun gear body, and planet gear bodies. A first bearing is fixed to the right side of the inner wall of the cover, and the first bearing is slidably connected to the surface of the output shaft. A gear ring is provided on the inner wall of the housing. A front frame is fixed to the surface of the output shaft. A rear frame is detachably connected to one side of the front frame. Four equidistant connecting shafts are fixed to the opposite surfaces of the rear frame and the front frame. A buffer assembly is provided on the surface of the input shaft. A second bearing is fixed to the inner wall of the planet gear bodies, and an mounting shaft is fixed to the inner ring of the second bearing. Multiple stress relief grooves are circumferentially formed on the connecting shafts. A third bearing is fixed to the left side of the inner wall of the housing, and the inner ring of the third bearing is slidably connected to the surface of the input shaft. The sun gear body meshes with the planet gear bodies, and the planet gear bodies mesh with the gear ring.

[0006] Preferably, the output end of the input shaft is provided with an external spline, and the input end of the sun gear body is provided with an internal spline hole that matches it. The sun gear body is slidably connected to the input shaft through a spline pair, and its axial movement is restricted between the inner wall of the front frame and the buffer assembly.

[0007] Preferably, the mounting shaft surface is provided with external splines on both the left and right sides, and the inner wall of the connecting shaft is provided with an internal spline hole that matches it.

[0008] Preferably, the stress relief groove has a U-shaped cross-section.

[0009] Preferably, the input shaft surface buffer assembly is a disc spring assembly sleeved on its surface, a blind hole is provided on the left side surface of the sun gear body, the blind hole is arranged in a ring, one side surface of the disc spring assembly is located inside the blind hole, and a preload adjustment structure is provided on the input shaft surface.

[0010] Preferably, the input shaft surface preload adjustment structure includes a threaded section formed on its surface, and an adjusting nut is threadedly connected to the threaded end surface of the input shaft, with the end face of the adjusting nut abutting against a disc spring assembly.

[0011] Preferably, elastic washers are provided on both the left and right sides of the mounting shaft, with one surface of the elastic washer in contact with the surface of the second bearing and the other surface of the elastic washer in contact with the end face of the connecting shaft.

[0012] Preferably, the rear frame and the front frame are each provided with four through holes, and long bolts are slidably connected to the inner walls of the through holes. The long bolts are threaded with mounting nuts, and the mounting nuts are located on the right side surface of the front frame.

[0013] Compared with the prior art, the beneficial effects achieved by this utility model are:

[0014] First, this invention integrates the spline connection of the input shaft with the disc spring assembly, the U-shaped stress relief groove on the planetary carrier connecting shaft, and the elastic washers on both sides of the planetary gears to construct a comprehensive, multi-stage buffer system from input to transmission to load bearing. This system can efficiently absorb and dissipate instantaneous impact energy from different directions, converting destructive rigid impacts into controllable elastic deformation and heat. This significantly reduces the peak dynamic load on key transmission components, fundamentally avoiding severe failures such as tooth breakage, pitting, and bearing sintering caused by impact overload, and greatly extending the service life and maintenance cycle of the reducer.

[0015] Secondly, the adjustable preload of the disc spring at the input end of this utility model allows users to precisely set the trigger threshold of the buffer system according to the load characteristics and impact intensity in actual applications, thus achieving functional customization. The planetary carrier adopts a split-type bolt connection, which not only ensures structural strength but also greatly facilitates assembly and maintenance, allowing for quick replacement of internal parts. Structural innovations such as stress relief grooves achieve a leap in performance without significantly increasing weight and cost, making this reducer a promising candidate for applications in fields with stringent requirements for reliability and impact resistance, such as heavy-duty industrial robots, construction machinery, and mining equipment. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0017] Figure 2 This is a three-dimensional structural schematic diagram of the present invention from another perspective;

[0018] Figure 3 This is a cross-sectional structural diagram of the present invention;

[0019] Figure 4 This is a schematic diagram of the exploded structure of this utility model;

[0020] Figure 5 This is a partial disassembled structural diagram of the present invention;

[0021] Figure 6 This is a schematic diagram of the input shaft in this utility model.

[0022] The components are as follows: 1. Outer shell; 2. Shell cover; 3. Input shaft; 4. Output shaft; 5. First bearing; 6. Gear ring; 7. Rear frame; 8. Front frame; 9. Connecting shaft; 10. Sun gear body; 11. Stress relief groove; 12. Mounting shaft; 13. Planetary gear body; 14. Second bearing; 15. Elastic washer; 16. Adjusting nut; 17. Disc spring assembly; 18. Long bolt; 19. Mounting nut; 20. Third bearing. Detailed Implementation

[0023] The specific embodiments of this utility model will now be described in further detail with reference to the accompanying drawings.

[0024] Please see Figures 1-6 A planetary gear reducer capable of bearing impact loads includes a housing 1, a cover 2, an input shaft 3, an output shaft 4, a sun gear body 10, and planet gear bodies 13. A first bearing 5 is fixed to the right side of the inner wall of the cover 2, and the first bearing 5 is slidably connected to the surface of the output shaft 4. A gear ring 6 is provided on the inner wall of the housing 1. A front frame 8 is fixed to the surface of the output shaft 4. A rear frame 7 is detachably connected to one side of the front frame 8. Four equidistant connecting shafts 9 are fixed to the opposite surfaces of the rear frame 7 and the front frame 8. A buffer assembly is provided on the surface of the input shaft 3. A second bearing 14 is fixed to the inner wall of the planet gear body 13. An mounting shaft 12 is fixed to the inner ring of the second bearing 14. Multiple stress relief grooves 11 are circumferentially provided on the connecting shafts 9. A third bearing 20 is fixed to the left side of the inner wall of the housing 1, and the inner ring of the third bearing 20 is slidably connected to the surface of the input shaft 3. The sun gear body 10 meshes with the planet gear body 13, and the planet gear body 13 meshes with the gear ring 6.

[0025] Through the above technical solution, power is input through the input shaft 3, driving the sun gear body 10 to rotate. The sun gear body 10 then drives the planetary gear body 13, which meshes with it, to rotate. Since the planetary gear body 13 simultaneously meshes with the fixed gear ring 6, it is forced to rotate around its own mounting shaft 12, while also driving the planetary carrier structure, composed of the front carrier body 8 and the rear carrier body 7 connected by the connecting shaft 9, to revolve around the center of the reducer. Finally, the power is output through the output shaft 4, which is fixed to the planetary carrier, achieving speed reduction and torque increase. In this process, the buffer component is used to absorb the torque impact at the input end, while the stress relief groove 11 on the connecting shaft 9 is used to disperse the impact stress transmitted to the planetary carrier. As a pre-set flexible link, the stress relief groove 11 can change the distribution of impact stress on the rigid connecting shaft 9, guiding the stress to be evenly distributed in the groove area, thereby avoiding irreversible plastic deformation or fracture caused by sharp stress concentration in a local area. This lays a solid structural foundation for the long-term stable operation of the entire reducer under high load conditions.

[0026] The output end of the input shaft 3 is provided with an external spline, and the input end of the sun gear body 10 is provided with an internal spline hole that matches it. The sun gear body 10 is slidably connected to the input shaft 3 through a spline pair, and its axial movement is restricted between the inner wall of the front frame 8 and the buffer assembly.

[0027] Through the above technical solution, this splined connection ensures the reliability of torque transmission between the input shaft 3 and the sun gear body 10, while allowing the sun gear body 10 to make a small axial sliding on the input shaft 3. When the front buffer assembly provides preload, the sun gear body 10 is pressed against the inner wall of the rear planetary carrier front frame 8, forming a stable initial working position. When a sudden impact load acts in the opposite direction on the sun gear body 10, it can compress the front buffer assembly and generate axial displacement. This process can convert a part of the impact energy into the elastic potential energy of the buffer assembly, thereby achieving buffering. This design makes the sun gear body 10 no longer a rigid body when subjected to impact, but a moving part that can dissipate force through small movements. This greatly alleviates the direct rigid damage of impact torque to the spline tooth surface, sun gear teeth, and subsequent transmission links, and significantly improves the adaptability and durability of the transmission system to harsh working conditions.

[0028] External splines are provided on both the left and right sides of the surface of the mounting shaft 12, and internal spline holes that mate with it are provided on the inner wall of the connecting shaft 9.

[0029] Through the above technical solution, the mounting shaft 12 is tightly connected to the internal spline holes on the front and rear carriers of the planetary carrier via splines at both ends. This spline connection provides torsional resistance far exceeding that of ordinary optical shaft connections, ensuring that the enormous torque borne by the planetary gear body 13 is smoothly transmitted to the planetary carrier. Meanwhile, the stress relief groove 11 on the connecting shaft 9 surrounds the spline holes. Its flexible design can compensate for minor deformations that may occur in the spline pair under extreme stress, preventing failure at the connection due to excessive stress concentration.

[0030] The stress relief groove 11 has a U-shaped cross-section, and the depth of the stress relief groove 11 is 30% to 50% of the diameter of the connecting shaft 9.

[0031] Through the above technical solution, the stress relief groove 11 with its smooth arc transition avoids the crack initiation problem that may be caused by the sharp bottom of the groove, as is the case with the V-shaped groove. When the connecting shaft 9 is subjected to a huge radial force or bending moment from the planetary gear body 13, the stress will preferentially concentrate in the relatively weak area at the bottom of the groove. However, the smooth contour of the U-shape allows the stress to be smoothly redistributed along the groove wall, causing the material to undergo controllable, large-scale elastic deformation rather than local yielding, thereby converting the impact energy into the local deformation energy of the connecting shaft 9 for absorption.

[0032] The input shaft 3 surface buffer assembly is a disc spring assembly 17 sleeved on its surface. A blind hole is opened on the left side surface of the sun gear body 10. The blind hole is arranged in a ring shape. The right side surface of the disc spring assembly 17 is located inside the blind hole. A preload adjustment structure is provided on the surface of the input shaft 3.

[0033] Through the above technical solution, the disc spring assembly 17, with its high stroke and small deformation characteristics, is pre-tensioned between the blind hole of the sun gear body 10 and the preload adjustment structure. During normal operation, the preload keeps the sun gear body 10 tightly against the inner wall of the planet carrier. When an impact load is transmitted, forcing the sun gear body 10 to move axially, it must overcome the preload of the disc spring assembly 17 and further compress it. This process transforms the sudden, destructive torque impact into stable compression work on the spring assembly, instantaneously absorbing and storing a large amount of energy, and greatly smoothing the torque peak.

[0034] The preload adjustment structure on the surface of the input shaft 3 includes a threaded section on its surface. An adjusting nut 16 is threadedly connected to the threaded end of the input shaft 3, and the end face of the adjusting nut 16 abuts against the disc spring assembly 17.

[0035] Through the above technical solution, the adjusting nut 16, by screwing it onto the threaded section of the input shaft 3, can precisely adjust its position relative to the end face of the sun gear body 10. Tightening the adjusting nut 16 directly increases the compression of the disc spring assembly 17, thereby increasing its initial preload on the sun gear body 10. This means that a larger impact torque is required to drive the sun gear body 10 to begin axial movement and activate the buffer function, allowing the buffer threshold of the reducer to be flexibly set according to actual working conditions.

[0036] Elastic washers 15 are provided on both the left and right sides of the mounting shaft 12. One side of the elastic washer 15 is in contact with the surface of the second bearing 14, and the other side of the elastic washer 15 is in contact with the end face of the connecting shaft 9.

[0037] Through the above technical solution, the elastic washer 15 is pre-compressed between the bearing of the planetary gear and the end face of the connecting shaft 9 of the planetary carrier. They form an axial buffer interface. When the planetary gear body 13 has an axial tendency to move or is subjected to axial impact components during transmission, the elastic washer 15 will be further compressed or released, absorbing the axial impact energy through its elastic deformation, and allowing the planetary gear body 13 assembly to make a small amount of axial floating, avoiding hard collisions between the bearing and the rigid carrier, and also helping to eliminate axial clearance, making the transmission smoother.

[0038] Both the rear frame 7 and the front frame 8 have four through holes on their surfaces. Long bolts 18 are slidably connected to the inner walls of the through holes. Installing nuts 19 are threaded onto the surface of the long bolts 18. The installing nuts 19 are located on the right side surface of the front frame 8.

[0039] Through the above technical solution, the long bolt 18 passes through the corresponding through holes on the front and rear frames and is locked to the outside of the front frame 8 by the mounting nut 19. This connection method firmly clamps the rear frame 7 and the front frame 8 together, forming an integral, high-rigidity planetary carrier structure. The sliding fit between the through holes and the long bolt 18 ensures positioning accuracy, while the preload of the bolt connection ensures that the mating surfaces will not separate or undergo relative displacement under complex alternating loads, thereby ensuring the stability of the planetary gear mounting shaft 12 position and guaranteeing transmission accuracy.

[0040] Working principle: Power is input through the input shaft 3, which transmits torque to the sun gear body 10 via a splined connection at its front end. This splined connection allows the sun gear body 10 to slide slightly axially when subjected to impact. The sun gear body 10 then drives multiple planetary gear bodies 13 to rotate. The planetary gear bodies 13 simultaneously mesh with the gear ring 6 fixed to the inner wall of the outer casing 1, thereby forcing the planetary gear bodies 13 to rotate around their own mounting shaft 12 while also driving the planetary carrier, which is assembled from the front carrier body 8 and the rear carrier body 7 via a connecting shaft 9 and long bolts 18, to revolve around the center line of the reducer. Finally, the power is output through the output shaft 4, which is fixed to the planetary carrier, realizing the core transmission functions of deceleration and torque amplification. Throughout the transmission process, the protection system against impact loads works in concert: when a sudden strong impact is transmitted from the load end to the planetary gears or from the input end, firstly, the elastic washers 15 on both sides of the planetary gears absorb the axial impact component; secondly, the huge radial and bending stresses are transmitted to the connecting shaft 9 of the planetary carrier through the mounting shaft 12. At this time, the U-shaped stress relief groove 11 opened on the connecting shaft 9 disperses and absorbs these stress peaks through its own controllable elastic deformation, preventing plastic damage to the structure; at the same time, if the impact comes from the input end, the huge torque will cause the sun gear body 10 to compress the buffer assembly composed of disc spring group 17 at its front end. The disc spring group 17 converts the impact kinetic energy into elastic potential energy through compression, stores it, and slowly releases it. The adjusting nut 16 allows the starting force threshold of this buffer system to be preset according to actual needs. The entire system, through the disc spring assembly 17 at the input end, the stress relief groove 11 on the transmission path, and the elastic washers 15 on the planetary gear side, forms a three-dimensional, multi-layered impact protection network. This allows the reducer to maintain efficient transmission while easily handling various complex impact load conditions. It significantly improves the equipment's reliability, durability, and adaptability to harsh working conditions, effectively solving the key technical problem of traditional planetary reducers being prone to tooth damage, bearing failure, or structural cracking under impact loads.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used only 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 process, method, article, or apparatus.

[0042] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A planetary reduction machine capable of carrying impact load, comprising a housing (1), a cover (2), an input shaft (3), an output shaft (4), a sun gear body (10) and a planetary gear body (13), characterized in that: The right side of the inner wall of the shell cover (2) is fixed with a first bearing (5), which is slidably connected to the surface of the output shaft (4). The inner wall of the outer shell (1) is provided with a gear ring (6). The surface of the output shaft (4) is fixed with a front frame (8). The front frame (8) is detachably connected to a rear frame (7). The rear frame (7) and the front frame (8) are fixed with four equidistant connecting shafts (9) on opposite sides. The surface of the input shaft (3) is provided with a buffer assembly. The inner wall of the planetary gear body (13) is fixed with a second bearing (14). The inner ring of the second bearing (14) is fixed with an installation shaft (12). The connecting shaft (9) is provided with multiple stress relief grooves (11) in the circumferential direction. The left side of the inner wall of the outer shell (1) is fixed with a third bearing (20). The inner ring of the third bearing (20) is slidably connected to the surface of the input shaft (3). The sun gear body (10) meshes with the planetary gear body (13). The planetary gear body (13) meshes with the gear ring (6).

2. A planetary speed reducer capable of bearing impact load according to claim 1, characterized in that: The output end of the input shaft (3) is provided with an external spline, and the input end of the sun gear body (10) is provided with an internal spline hole that matches it. The sun gear body (10) is slidably connected to the input shaft (3) through a spline pair, and its axial movement is restricted between the inner wall of the front frame (8) and the buffer assembly.

3. A planetary speed reducer capable of carrying impact load according to claim 1, characterized in that: The mounting shaft (12) has external splines on both the left and right sides of its surface, and the connecting shaft (9) has an internal spline hole that matches it.

4. A planetary speed reducer capable of carrying impact load according to claim 1, characterized in that: The stress relief groove (11) has a U-shaped cross-section.

5. A planetary speed reducer capable of carrying impact load according to claim 1, characterized in that: The input shaft (3) surface buffer assembly is a disc spring assembly (17) sleeved on its surface. The sun gear body (10) has a blind hole on its left side surface. The blind hole is arranged in a ring shape. One side surface of the disc spring assembly (17) is located inside the blind hole. The input shaft (3) surface is provided with a preload adjustment structure.

6. A planetary speed reducer capable of carrying impact load according to claim 1, characterized in that: The preload adjustment structure on the surface of the input shaft (3) includes a threaded section on its surface, and an adjusting nut (16) is threadedly connected to the threaded end surface of the input shaft (3), with the end face of the adjusting nut (16) abutting against a disc spring assembly (17).

7. A planetary speed reducer capable of carrying impact load according to claim 1, characterized in that: Elastic washers (15) are provided on both the left and right sides of the mounting shaft (12). One side surface of the elastic washer (15) is in contact with the surface of the second bearing (14), and the other side surface of the elastic washer (15) is in contact with the end face of the connecting shaft (9).

8. A planetary speed reducer capable of carrying impact load according to claim 1, characterized in that: The rear frame (7) and the front frame (8) are each provided with four through holes. Long bolts (18) are slidably connected to the inner walls of the through holes. The long bolts (18) are threaded with mounting nuts (19). The mounting nuts (19) are located on the right side surface of the front frame (8).

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