A reduction gear integrating multi-stage planetary gears

Abstract

The application relates to the technical field of reducers, in particular to a reducer integrated with multiple-stage planetary gears, which comprises an outer cylinder and multiple-stage planetary gear systems, the axial position of the first-stage planetary gear system is fixed, the axial positions of the rest planetary gear systems are not fixed, a ring-shaped boss is integrally formed on a planet carrier, a sun gear is fixed in the ring-shaped boss and extends to the meshing of the next-stage planetary gear system and a planet gear, the end surface of the sun gear does not contact the inner wall of the next-stage ring-shaped boss, the inner corner and the outer corner of the ring-shaped boss are provided with a round corner transition structure, a containing groove is formed in the side end surface of the planet carrier of the next-stage planetary gear system close to the ring-shaped boss, the ring-shaped boss is partially or completely embedded in the containing groove, and a gap is left between the outer wall of the ring-shaped boss and the inner wall of the containing groove. The application can realize efficient load sharing and coaxial degree maintenance of multiple-stage planetary gears, and improve the comprehensive performance, reliability and service life of the reducer.

Description

Technical Field

[0001] This invention relates to the field of speed reducer technology, and more specifically to a speed reducer integrating multi-stage planetary gears. Background Technology

[0002] Multi-stage planetary gear reducers are widely used in engineering machinery, aerospace, and new energy transmission fields due to their advantages such as large transmission ratio, compact structure, and high load-bearing capacity. Their core performance indicators include transmission efficiency, load-bearing capacity, operational stability, and service life, and the load-sharing performance and coaxiality of the multi-stage planetary gears are key factors that directly determine these indicators.

[0003] In existing multi-stage planetary gear reducers, the sun gears of each stage mostly adopt a rigid connection structure. To achieve uniform load distribution in the planetary gear train, floating structures are usually set in each gear pair. By providing radial or axial floating space for the transmission components, manufacturing and assembly errors are compensated, and load distribution is achieved, avoiding premature wear and failure of the gear teeth caused by uneven loading of the planetary gears. However, the floating structures used in existing technologies to achieve load distribution have low stiffness. When the reducer output is subjected to impact loads, alternating loads, or external vibrations, the floating structure becomes a channel for the vibration and impact loads to be transmitted to the input. The fluctuating load at the output end is transmitted in the opposite direction to each stage of the planetary gear train, resulting in a decrease in the coaxiality of each stage of the planetary gear train, which affects the operating stability and service life of the reducer. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a reducer integrating multi-stage planetary gears to achieve efficient load sharing and coaxiality maintenance, thereby improving the overall performance and reliability of the reducer.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a reducer integrating multi-stage planetary gears, comprising an outer cylinder, wherein the outer cylinder is provided with a plurality of planetary gear systems connected in series, each planetary gear system comprising a planet carrier, a gear ring fixedly connected to the outer cylinder, planet gears rotatably connected to the planet carrier and meshing with the gear ring, and a sun gear fixedly connected to the planet carrier on the same axis.

[0006] The first-stage planetary gear train near the input end has a fixed axial position, while the axial positions of the remaining planetary gear trains are not fixed. The planet carrier of each planetary gear train has an integrally formed annular boss on the end face of the side of the next-stage planetary gear train. An opening is formed in the middle of the annular boss, and the sun gear is fixedly connected to the opening in the middle of the annular boss. The sun gear is coaxial with the annular boss. The sun gear extends into the planet carrier of the next-stage planetary gear train and meshes with the planet gears of the next-stage planetary gear train. The end face of the sun gear does not contact the inner wall of the annular boss of the next-stage planetary gear train.

[0007] The above scheme has the following characteristics: Since the first-stage planetary gear train is fixed in the axial direction, while the remaining planetary gear trains are axially floating, each subsequent stage of the planetary gear train, except for the first-stage planetary gear train which directly connects to the input end, has a slight axial / radial floating space. Because the sun gear end face does not contact the inner wall of the next-stage annular boss, the next-stage planetary carrier has axial and radial floating space. Since the annular boss is integrally formed with the planetary carrier and the sun gear is located in its central opening, the annular boss is not absolutely rigid and can undergo slight elastic deformation when the sun gear is impacted.

[0008] Except for the first stage, the axial direction of the planet carriers in each stage of the planetary gear system is not fixed, and when the sun gear meshes with the next stage planetary gear, the next stage planetary carrier is allowed to produce a small radial displacement. When the load on a certain planetary gear is too large, the next stage planetary carrier will shift to the side with a smaller load, automatically adjusting the center distance between the sun gear and the planetary gears, so that the meshing force of all planetary gears tends to be balanced.

[0009] The sun gear end face does not contact the inner wall of the next-stage annular boss, and a small axial clearance is maintained between each stage of the planet carrier. When the gears mesh and generate axial component force, or when there is axial error in the assembly, the planet carrier can move slightly axially to eliminate axial interference of the tooth surface, allowing the tooth surface to achieve full tooth width contact and avoiding off-center loading caused by uneven local force.

[0010] The elasticity of the annular boss itself provides incomplete rigidity support for the sun gear. When the sun gear meshes with the planet gears and generates an impact, the annular boss will produce a small elastic deformation to absorb the meshing impact and redistribute the load among multiple planet gears, further reducing the risk of single-gear overload.

[0011] When there is a coaxiality deviation due to machining / assembly, the planetary carrier undergoes a slight displacement under meshing force until the meshing clearance between the sun gear and all planet gears is uniform, achieving passive alignment and reducing coaxiality deviation. Under heavy load impact, the center of the planetary carrier may shift. The annular boss (the central sun gear fixing area of ​​the planetary carrier) undergoes elastic deformation to absorb the relative deformation between the sun gear and the planetary carrier. The floating space of the next-stage planetary carrier then compensates for the center shift, avoiding edge contact on the tooth surface and dynamically correcting the coaxiality error.

[0012] Furthermore, the inner and outer corners of the annular boss integrally formed on the end face of the planetary carrier near the next-stage planetary gear system are provided with rounded corner transition structures, which are smoothly connected to the end face of the annular boss and the outer peripheral wall of the planetary carrier, respectively.

[0013] The above solution addresses the issue that, under start-up, stop-and-go, and variable load conditions, the annular boss in a multi-stage planetary reducer will bear high-frequency alternating loads. The rounded corner transition structure reduces the stress concentration factor and improves the boss's fatigue resistance. By dispersing stress at the corners, the rounded corner transition structure allows for more uniform elastic deformation of the boss under load, preventing localized stress overload and ensuring long-term stable operation of the reducer.

[0014] Furthermore, the planet carrier of the next-level planetary gear system has a receiving groove on the end face of the side near the annular boss. The annular boss is partially or completely embedded in the receiving groove, and a gap is left between the outer wall of the annular boss and the inner wall of the receiving groove.

[0015] The above solution, compared to the slotless structure, can limit the large movement of the planetary carrier, prevent gear meshing deviation caused by excessive floating, and take into account both the requirements of floating compensation and stable operation; moreover, the embedded fit can reduce the overall axial length of the reducer.

[0016] Furthermore, planetary shims are provided between adjacent planetary gear systems. The planetary shims are provided between the planet carriers of each planetary gear system or between the sun gear and the planet carrier of each planetary gear system.

[0017] Furthermore, a thrust bearing is provided between adjacent planetary gear systems. The thrust bearing is located between the planet carriers of each planetary gear system or between the sun gear and the planet carrier of each planetary gear system.

[0018] The above solution utilizes the wear-resistant properties of planetary gaskets to significantly reduce the coefficient of friction at the contact surfaces, minimizing frictional heat generation and energy loss, and improving the transmission efficiency of the reducer. Simultaneously, it avoids direct wear on metal contact surfaces, extending the service life of the planetary carrier and sun gear. Under heavy load and high-speed conditions, gear meshing generates a large axial force, which, when acting directly on the end face of the planetary carrier, can easily lead to deformation of the planetary carrier and eccentricity of the sun gear. Thrust bearings can convert axial force into rolling friction, effectively bearing large axial loads, preventing plastic deformation of the planetary carrier end face, ensuring the meshing accuracy of the sun gear and planetary gears, and avoiding eccentric loading caused by axial force.

[0019] Furthermore, a planetary washer or a thrust bearing is provided between the planetary gears and the planet carrier of the planetary gear system, and the two end faces of the planetary washer or the thrust bearing are respectively clearance-fitted with the planetary gears and the planet carrier.

[0020] The above solution avoids direct contact friction between the planetary gears and the planetary carrier by using planetary washers or thrust bearings, thereby improving the operational stability of the planetary gears; the use of thrust bearings can further eliminate wear between the planetary gears and the planetary carrier, thus improving transmission efficiency.

[0021] Furthermore, the mating end faces of the sun gears of adjacent planetary gear systems are provided with opposing conical holes, and the two conical holes enclose a receiving cavity, in which a floating ball is provided; in the initial state, there is a gap between the floating ball and the side wall of the receiving cavity, and the gap is used for the floating ball to roll radially to compensate for the coaxiality error of the sun gear.

[0022] The above scheme works as follows: When the planet carrier experiences impact fluctuations, the conical bore fluctuates with the planet carrier, thus compressing the floating ball within the opposing conical bores of the sun gears in the two-stage planetary gear system. The axial movement of the floating ball, caused by the pressure from the inclined sidewalls of the conical bores, results in close contact with the sidewalls of one side of the conical bore, and vice versa. The enclosed cavity of the opposing conical bores provides rolling space for the floating ball. When there is a coaxiality deviation between adjacent sun gears, the floating ball rolls along the direction of the error on the sidewalls of the conical bores. Through its own displacement, it slightly adjusts the center position of the sun gear, automatically aligning the sun gear axis with the planet gear's revolution center, dynamically correcting the coaxiality error, ensuring uniform contact of all planet gear tooth surfaces, and reducing the probability of off-center loading. The initial clearance design allows the floating ball to operate without interference when the reducer is error-free and to respond quickly when errors occur, avoiding jamming caused by rigid constraints. Compared to a single floating planetary carrier, this structure has higher centering accuracy, which can prevent the sun gear from disengaging due to excessive floating, and make the load sharing effect more stable.

[0023] Furthermore, the edges of the conical holes on the mating end faces of the two adjacent sun gears are provided with rounded corners, which are used to guide the floating ball to slide along the side wall of the conical hole.

[0024] The above solution introduces a rounded transition at the edge of the conical hole, making the contact between the floating ball and the side wall of the conical hole smoother, especially when the floating ball floats towards the side closer to the opening of the conical hole; when there is a coaxiality deviation between two adjacent sun gears, the floating ball can roll smoothly along the rounded corner to adjust the center position of the sun gear, ensuring efficient and stable achievement of load sharing and coaxiality correction.

[0025] Furthermore, the sun gear, which has tapered holes on both ends, has a through hole extending along its axis inside. The two ends of the through hole are respectively connected to the tapered holes on both ends of the sun gear, forming a through receiving channel. A floating block is slidably fitted inside the receiving channel. Both ends of the floating block are connected to elastic elements. The end of the elastic element away from the floating block is fixedly connected to a floating ball in the corresponding tapered hole. There is a movable gap between the elastic element and the inner wall of the through hole. When the floating block is located at any position in the receiving channel and the elastic element does not undergo elastic deformation, the elastic element supports the floating balls at both ends to suspend in the tapered hole, and at least one side of the outer wall of the floating ball maintains a floating gap with the side wall of the tapered hole and does not come into contact.

[0026] The above solution: This solution uses elastic elements to support the floating ball within the conical hole. The elastic elements and floating ball work together to ensure that the coaxiality of each sun gear is in good condition after assembly. When the reducer is under load or experiences fluctuations in operating conditions, the meshing force of the planetary gears drives the sun gear to produce a slight displacement. The floating ball rolls, causing the floating block to slide along the receiving channel, and the elastic elements are stretched / compressed accordingly. The displacement of the floating ball adaptively adjusts the relative position of the two adjacent sun gears, redistributing the meshing load of each planetary gear and reducing the occurrence of local overload. The stretching / compression of the elastic elements makes the adaptive adjustment of the two adjacent sun gears flexible.

[0027] When the impact fluctuations at the output end are transmitted to the sun gear, the deformation of the elastic element will absorb most of the vibration, preventing the rigid impact from being directly transmitted to the input end. In addition, the sliding of the floating block and the rolling of the floating ball convert the rigid transmission of vibration into flexible kinetic energy consumption, which greatly reduces the amplification effect of the fluctuations between each stage of the planetary gear system and improves the overall stability of the machine. At the same time, the damping characteristics of the elastic element can suppress high-frequency vibration and reduce gear meshing noise.

[0028] The elastic element can restrain the floating ball, preventing excessive floating from causing large-scale disengagement of the sun gear and planet gears, and also preventing tooth surface impact caused by excessive floating. The stiffness of the elastic element can be customized according to the working conditions to adapt to reducers of different load levels.

[0029] Under steady-state load conditions, the elastic element is not subjected to axial compression or is subjected to only slight axial compression, making radial deformation easy. This allows the floating block, the corresponding sun gear, and the planetary carrier to easily generate slight radial displacement, achieving coaxiality and off-center load compensation. Under abnormal impact conditions at the output end, the impact load will significantly push the sun gear to axially compress the elastic element. After the elastic element is significantly axially compressed, its internal stress distribution changes, the gap between the wire diameters decreases, and the resistance to radial bending increases significantly. This increases the difficulty of radial displacement for the floating block, the corresponding sun gear, and the planetary carrier, thus constraining the offset vibration of the sun gear and planetary carrier due to abnormal impact. This prevents the impact fluctuations at the output end from being continuously transmitted to the input end, reducing the impact fluctuations experienced by each stage of the planetary gear system near the input end.

[0030] Furthermore, only one floating ball is provided in the cavity formed by the tapered holes of the sun gear mating end faces of the two adjacent planetary gear systems; the two ends of the floating ball are respectively fixedly connected to the elastic elements in the through holes of the sun gears of the two adjacent planetary gear systems; along the power transmission direction of the reducer, the elastic modulus of the elastic element gradually increases to adapt to the gradually increasing load fluctuations.

[0031] The above scheme features a gradually increasing elastic modulus along the power transmission direction (input end → output end), matching the operating characteristics of a multi-stage planetary reducer where loads are amplified and fluctuations are intensified at each stage. Near the input end, the elastic element is more flexible, allowing for fine-tuning of the floating ball and floating block through elastic deformation, enabling rapid response to minor coaxiality deviations and load sharing under light load conditions. Near the output end, the elastic element is more rigid, capable of withstanding heavy impacts at the output end, while also improving the radial stiffness of the elastic element after axial compression.

[0032] Furthermore, the inner wall of the conical hole, the outer surface of the floating ball, the outer surface of the floating block, and the inner wall of the through hole are all coated with a wear-resistant coating.

[0033] The above solution: The wear-resistant coating can effectively delay wear, maintain the stability of the fit clearance, and ensure long-term reliability of load distribution and coaxiality compensation.

[0034] The beneficial effects of this invention are:

[0035] By configuring the first-stage planetary gear train to be axially fixed while the remaining stages of the planetary gear train are axially floating, combined with the annular boss structure integrally formed by the planet carrier, the annular boss can generate a small elastic deformation when the sun gear is impacted, thereby absorbing the meshing impact and redistributing the load between the planet gears, thus achieving efficient load sharing.

[0036] Meanwhile, the design that the sun gear end face does not contact the inner wall of the next-stage annular boss provides axial and radial floating space for the planet carrier, allowing the planet carrier to move slightly under meshing force to automatically adjust the center distance, thus realizing passive alignment and dynamic correction of coaxiality error.

[0037] Furthermore, by setting up a receiving channel, floating block, and elastic element inside the sun gear, the floating ball is suspended in the conical hole by the elastic element. The flexible load sharing and coaxiality compensation of the shafts of the two adjacent sun gears are achieved through the cooperation of the elastic element and the suspended ball. When the output end is subjected to impact, the vibration is absorbed by the deformation of the elastic element, which effectively avoids the continuous transmission of impact fluctuations to the input end, and significantly improves the operating stability and service life of the reducer. Attached Figure Description

[0038] Figure 1 This is an overall isometric view of Embodiment 1 of the present invention;

[0039] Figure 2 This is an exploded view of Embodiment 1 of the present invention;

[0040] Figure 3 This is a cross-sectional view of Embodiment 1 of the present invention;

[0041] Figure 4 This is an exploded view of Embodiment 2 of the present invention;

[0042] Figure 5 This is a cross-sectional view of Embodiment 2 of the present invention;

[0043] Figure 6 for Figure 5 A magnified view of part of I;

[0044] Figure 7 This is an exploded view of Embodiment 3 of the present invention;

[0045] Figure 8 This is a cross-sectional view of Embodiment 3 of the present invention;

[0046] Figure 9 for Figure 8 A magnified schematic diagram of part L.

[0047] The reference numerals in the accompanying drawings include: 10, outer cylinder; 20, gear ring; 30, output bearing; 40, planetary washer; 50, annular boss; 101, first-stage planetary carrier; 102, first-stage planetary gear; 103, first-stage sun gear; 201, second-stage planetary carrier; 202, second-stage planetary gear; 203, second-stage sun gear; 301, third-stage planetary carrier; 302, third-stage planetary gear; 303, third-stage sun gear; 401, floating ball; 402, elastic element; 403, floating block. Detailed Implementation

[0048] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] The following detailed description illustrates the specific implementation method:

[0052] Example 1: As Figures 1 to 3 As shown, this embodiment provides a reducer integrating multi-stage planetary gears. The reducer includes an outer cylinder 10, on which several stages of planetary gear trains are sequentially connected. This embodiment uses a three-stage series connection as an example; it should be understood that in other embodiments, there may be two, four, or more stages, with the same principle. Each stage of the planetary gear train includes a planet carrier, a ring gear 20 fixedly connected to the outer cylinder 10, planet gears rotatably connected to the planet carrier and meshing with the ring gear 20, and a sun gear fixedly connected coaxially to the planet carrier.

[0053] Specifically, such as Figure 2 and Figure 3 As shown, the first-stage planetary gear system includes a first-stage planet carrier 101, a first-stage planetary gear 102, and a first-stage sun gear 103; the second-stage planetary gear system includes a second-stage planet carrier 201, a second-stage planetary gear 202, and a second-stage sun gear 203; and the third-stage planetary gear system includes a third-stage planet carrier 301, a third-stage planetary gear 302, and a third-stage sun gear 303. The third-stage planet carrier 301 is connected to an output shaft, which serves as the output end of the reducer. An output bearing 30 is provided between the output shaft and the outer cylinder 10 to support rotation.

[0054] In this embodiment, the axial position of the first-stage planetary gear train near the input end is fixed, while the axial positions of the remaining planetary gear trains are not fixed. Specifically, the first-stage planetary gear train, as the starting point of power input, has its axial position restricted within the outer cylinder 10 by bearings or other fixed structures, thereby providing a stable reference for the entire reducer transmission chain. The subsequent second-stage and third-stage planetary gear trains are not completely restricted, allowing for slight axial and radial displacements within a certain range. Through this structural layout, during reducer operation, when the load on a certain planetary gear is too high, the subsequent stage planetary carriers can generate a slight displacement towards the side with a smaller load, automatically adjusting the center distance between the sun gear and the planetary gears. This ensures that the meshing force of all planetary gears tends to be balanced, effectively solving the problem of uneven load caused by manufacturing errors or load deformation in multi-stage planetary gear trains.

[0055] This embodiment makes corresponding improvements to the structure of the planet carrier. The planet carrier of the planetary gear system has an integrally formed annular boss 50 on the end face near the next-stage planetary gear system. An opening is formed in the center of the annular boss 50, and the sun gear is fixedly connected to the opening in the center of the annular boss 50. The sun gear is coaxial with the annular boss 50 and extends into the planet carrier of the next-stage planetary gear system, meshing with the planet gears of the next-stage planetary gear system. For example... Figure 2 and Figure 3 As shown, an annular boss 50 is integrally formed on the end face of the first-stage planetary carrier 101 facing the second-stage planetary gear system. The first-stage sun gear 103 is fixed in the opening of the annular boss 50 and extends into the interior of the second-stage planetary carrier 201 to mesh with the second-stage planetary gear 202. Similarly, the annular boss 50 on the second-stage planetary carrier 201 is used to fix the second-stage sun gear 203 and make it mesh with the third-stage planetary gear 302. As a connecting component, the annular boss 50 has a structural characteristic that gives it a small amount of elastic deformation capability. When the sun gear is subjected to an impact load, the annular boss 50 can generate a small elastic deformation, thereby absorbing the meshing impact and redistributing the load among multiple planetary gears, further weakening the risk of single-gear overload.

[0056] Furthermore, in this embodiment, the end face of the sun gear does not contact the inner wall of the annular boss of the next-stage planetary gear system. For example... Figure 3 As shown, a preset axial clearance is maintained between the lower end face of the first-stage sun gear 103 and the bottom inner wall of the annular boss 50 on the second-stage planetary carrier 201, and a similar clearance is maintained between the lower end face of the second-stage sun gear 203 and the bottom inner wall of the annular boss 50 on the third-stage planetary carrier 301. This provides the necessary physical space for the floating of the planetary carrier, allowing the next-stage planetary carrier to move slightly axially without rigid constraints, thereby eliminating axial component forces generated during gear meshing or axial interference on the tooth surface caused by assembly errors, achieving full tooth width contact, and avoiding uneven loading caused by localized force unevenness. Simultaneously, in the radial direction, in conjunction with the assembly clearance between the annular boss 50 and the sun gear, the planetary carrier can generate a small radial displacement under the action of meshing force, dynamically correcting coaxiality errors. When there is a coaxiality deviation caused by machining or assembly, the planetary carrier will move slightly under the action of meshing force until the meshing clearance between the sun gear and all planet gears is uniform, achieving a load-sharing effect.

[0057] Furthermore, in this embodiment, a planetary washer or a thrust bearing is provided between the planetary gears and the planet carrier of the planetary gear system, with both end faces of the planetary washer or thrust bearing respectively having a clearance fit with the planetary gears and the planet carrier. When using a planetary washer, the planetary washer avoids direct contact friction between the planetary gears and the planet carrier, improving the operational stability of the planetary gears; when using a thrust bearing, the thrust bearing avoids direct contact friction between the planetary gears and the planet carrier, improving the operational stability of the planetary gears; and further eliminates wear between the planetary gears and the planet carrier, improving transmission efficiency.

[0058] This embodiment provides a stable input reference through the axial fixation of the first-stage planetary gear system, while the floating of subsequent stages of the planetary gear system, combined with the slight elastic deformation support of the annular boss 50, achieves dynamic compensation for errors and effective buffering of impact loads, significantly improving the operating stability and service life of the reducer.

[0059] Example 2: As Figures 4 to 6 As shown, to address the issue of the annular boss 50 being susceptible to high-frequency alternating loads under start-stop and variable load conditions in multi-stage planetary reducers, this embodiment addresses this problem. The annular boss 50, integrally formed on the end face of the planetary carrier near the next-stage planetary gear train, has rounded corner transition structures at both its inner and outer corners. These rounded corner transition structures smoothly connect to the end face of the annular boss 50 and the outer peripheral wall of the planetary carrier, respectively. Specifically, this embodiment effectively disperses stress distribution at the corners by providing a large-radius rounded corner transition structure at the connection root between the annular boss 50 and the planetary carrier body. The design of the rounded corner transition structure is not limited to the single arc form shown in the figure; it can also adopt an elliptical arc or a combination of multiple arc segments, as long as a smooth stress transition can be achieved. The above structure significantly reduces the stress concentration factor, improves the fatigue resistance of the annular boss 50, and ensures the structural stability of the reducer under long-term high-load operation.

[0060] In this embodiment, the planet carrier of the next-stage planetary gear system has a receiving groove on the end face near the annular boss 50. The annular boss 50 is partially or completely embedded in the receiving groove, and a gap is left between the outer wall of the annular boss 50 and the inner wall of the receiving groove. Figure 6 As shown, the end face of the secondary planetary carrier 201 is provided with a receiving groove, and the annular boss 50 on the primary planetary carrier 101 extends into the receiving groove. First, the receiving groove guides and limits the annular boss 50, restricting the large-scale movement of the planetary carrier and preventing gear meshing deviation caused by excessive floating; second, the annular boss 50 is accommodated in the receiving groove, which can effectively reduce the overall axial length of the reducer and make the structure more compact.

[0061] In this embodiment, planetary shims 40 are provided between adjacent planetary gear sets. The planetary shims 40 are positioned between the planet carriers of each stage of the planetary gear set, or between the sun gear and the planet carrier of each stage of the planetary gear set. The planetary shims 40 are typically made of wear-resistant materials. Their placement between the relatively rotating planet carriers significantly reduces the coefficient of friction on the contact surfaces, minimizing frictional heat generation and energy loss, thereby improving the transmission efficiency of the reducer. Simultaneously, the planetary shims 40 prevent direct wear on the metal contact surfaces, extending the service life of critical components such as the planet carrier and sun gear. As another embodiment, thrust bearings (not shown in the attached figures) are provided between adjacent planetary gear sets. The thrust bearings are positioned between the planet carriers of each stage of the planetary gear set, or between the sun gear and the planet carrier of each stage of the planetary gear set. Under heavy load and high-speed conditions, gear meshing generates a large axial force. If this force acts directly on the end face of the planet carrier, it can easily lead to deformation of the planet carrier or eccentricity of the sun gear. Thrust bearings convert sliding friction into rolling friction, effectively bearing large axial loads, preventing plastic deformation of the planetary carrier end face, ensuring the meshing accuracy of the sun gear and planet gears, and avoiding off-center loading caused by axial forces. In practical applications, planetary washers 40, thrust bearings alone, or a combination of both can be used depending on the load characteristics to adapt to different working conditions.

[0062] This embodiment, based on Embodiment 1, improves the load-sharing mechanism inside the sun gear to further enhance the reducer's coaxiality error compensation capability and operational stability under complex operating conditions. The mating end faces of the sun gears in adjacent planetary gear systems are provided with opposing conical holes, which together form a receiving cavity. A floating ball 401 is placed within the receiving cavity. Initially, a gap exists between the floating ball 401 and the side wall of the receiving cavity, allowing the floating ball 401 to roll radially to compensate for the coaxiality error of the sun gears. Specifically, taking the mating of the first-stage sun gear 103 and the second-stage sun gear 203 as an example, conical holes are provided on the end face of the first-stage sun gear 103 near the second-stage sun gear 203 and on both sides of the second-stage sun gear 203. A conical hole is also provided on the end face of the third-stage sun gear 303 near the second-stage sun gear 203. Two adjacent conical holes interlock to form a receiving cavity. The floating ball 401 is disposed in the receiving cavity, and its diameter is slightly smaller than the maximum inner diameter of the receiving cavity, thereby forming a preset radial gap between the floating ball 401 and the side wall of the tapered hole.

[0063] When the reducer is running, if a misalignment occurs in the coaxiality of the axes of adjacent sun gears due to manufacturing errors or load deformation, the floating ball 401 will roll along the direction of the error within the receiving cavity. Because the sidewall of the tapered bore is inclined, the rolling of the floating ball 401 forces the sun gear to produce a slight radial and / or axial displacement, thereby automatically adjusting the center position of the sun gear to align its axis with the revolution center of the planetary gears, dynamically correcting the coaxiality error, and adapting to the load-sharing requirements of the reducer. The cone angle of the tapered bore can be designed according to the required compensation sensitivity; a larger cone angle results in stronger radial compensation capability but reduces sensitivity to axial displacement, and vice versa. The initial clearance design ensures that the floating ball 401 does not interfere with gear meshing when the reducer is running without errors, and can respond quickly when errors occur, avoiding additional stress generated by the rigid connection structure.

[0064] In this embodiment, the edges of the conical hole openings on the mating end faces of adjacent sun gears are all provided with rounded corners. These rounded corners guide the floating ball 401 to slide along the sidewall of the conical hole. During the rolling process of the floating ball 401, especially when it floats closer to the opening of the conical hole, the rounded corner structure provides a smooth transition, preventing the floating ball 401 from colliding hard with or getting stuck on the edge of the conical hole. The radius of the rounded corner can be optimized according to the movement trajectory of the floating ball 401, ensuring smooth guidance while avoiding weakening the structural strength of the conical hole sidewall due to an excessively large rounded corner.

[0065] In this embodiment, the sun gear, which has tapered holes on both ends, has a through hole extending along its axis inside. The two ends of the through hole are connected to the tapered holes on both ends of the sun gear, forming a through receiving channel. A floating block 403 is slidably fitted inside the receiving channel. Both ends of the floating block 403 are connected to elastic members 402. The end of the elastic member 402 away from the floating block 403 is fixedly connected to a floating ball 401 in the tapered hole on the corresponding side. There is a movable gap between the elastic member 402 and the inner wall of the through hole. When the floating block 403 is located at any position in the receiving channel and the elastic member 402 does not undergo elastic deformation (when the reducer is not running), the elastic member 402 supports the floating balls 401 at both ends to suspend in the tapered hole, and the outer wall of at least one floating ball 401 maintains a floating gap with the side wall of the tapered hole and does not come into contact.

[0066] like Figure 5 and Figure 6 As shown, taking the secondary sun gear 203 as an example, it has a through hole along the axial direction inside, and a cylindrical floating block 403 is installed in the through hole. Elastic elements 402 are connected to both ends of the floating block 403. The maximum diameter of the elastic element 402 is smaller than the diameter of the through hole, ensuring that there is a movable gap between the elastic element 402 and the inner wall of the through hole. The elastic element 402 is preferably a rectangular spring, with one end away from the floating block 403 extending into a conical hole and fixedly connected to the floating ball 401.

[0067] When the reducer is not running, the floating block 403 is naturally suspended at any position within the channel due to gravity. The elastic element 402 does not undergo elastic deformation (because the first-stage sun gear 103 and the third-stage sun gear 303 on both sides do not compress the floating ball 401). Its own structure supports the floating ball 401, causing the floating ball 401 to suspend within the receiving cavity formed by the conical holes on both sides. Because the floating block 403 is naturally suspended due to gravity, the floating ball 401 near the first-stage sun gear 103 may land in the conical hole on the end face of the first-stage sun gear 103. The floating ball 401 inside or near the third-stage sun gear 303 may land in the conical hole on the end face of the third-stage sun gear 303. The floating ball 401 on the side not landing in the conical hole maintains a floating clearance with the side wall of the conical hole and does not make contact. When the reducer is horizontally positioned, the floating block 403 may be suspended in the middle of the channel, so that the floating ball 401 does not land in the conical hole on the end face of the first-stage sun gear 103 and the third-stage sun gear 303. Therefore, the floating balls 401 on both sides maintain a floating clearance with the side wall of the conical hole and do not make contact. When the first-stage sun gear 103 and the third-stage sun gear 303 generate axial and / or radial displacement, the floating balls 401 on both sides contact and abut against the side wall of the conical hole for coaxiality and off-center load compensation.

[0068] During reducer operation, under steady-state load-sharing conditions, the elastic element 402 is not subjected to axial compression or only slight compression, resulting in low radial stiffness. This allows the floating block 403, the corresponding sun gear, and the planetary carrier (secondary sun gear 203 and secondary planetary carrier 201 in this embodiment) to easily generate slight radial displacement, achieving coaxiality and off-center load compensation. At this time, the elastic element 402 mainly serves as a flexible connection and positioning aid. Under abnormal impact conditions at the output end, the impact load will significantly push the sun gear to move axially and / or radially, thereby significantly compressing the elastic element 402 through the rolling of the floating ball 401. When the elastic element 402 is significantly axially compressed, its internal stress distribution changes, the gap between the spring wire diameters decreases, and the resistance to radial bending increases significantly, i.e., the radial stiffness of the elastic element 402 increases. This allows the radial displacement of the sun gear and planetary carrier to be synchronously constrained when subjected to impact, preventing the impact fluctuations at the output end from being continuously transmitted to the input end, thus achieving adaptive control of steady-state flexible compensation and impact-state constraint. The movable gap between the elastic element 402 and the inner wall of the through hole provides space for the radial deformation of the elastic element 402, preventing it from interfering with the inner wall of the sun gear.

[0069] Example 3: As Figures 7 to 9 As shown, only one floating ball 401 is provided in the cavity formed by the tapered holes of the sun gear mating end faces of the two adjacent planetary gear systems; the two ends of the floating ball 401 are fixedly connected to the elastic element 402 in the through holes of the sun gears of the two adjacent planetary gear systems; along the power transmission direction of the reducer, the elastic modulus of the elastic element 402 gradually increases to adapt to the gradually increasing load fluctuations.

[0070] Specifically, in a multi-stage planetary gear reducer, the transmitted torque and load increase progressively from the input to the output, and the fluctuations also increase progressively. Therefore, the first-stage planetary gear system near the input has a smaller elastic modulus and greater flexibility in its elastic element 402, enabling it to quickly respond to minor coaxiality deviations and load-sharing requirements under light load conditions through elastic deformation. Conversely, the third-stage planetary gear system near the output has a larger elastic modulus and greater rigidity in its elastic element 402, enabling it to withstand heavy load impacts and rapidly increase radial stiffness after axial compression, suppressing impact transmission. This progressively increasing elastic modulus design effectively matches the load distribution pattern of the multi-stage planetary gear reducer, achieving optimal load sharing and stability control under all operating conditions. The increase in elastic modulus can be achieved by selecting different spring materials, changing the spring wire diameter, and altering the effective number of spring coils.

[0071] In addition, the inner wall of the tapered hole, the outer surface of the floating ball 401, the outer surface of the floating block 403, and the inner wall of the through hole are all coated with a wear-resistant coating. Since the floating ball 401 and the floating block 403 will frequently experience rolling or sliding friction during operation, the wear-resistant coating can effectively delay the wear of key components, maintain the long-term stability of the mating clearance, and thus ensure the long-term reliability of the load-sharing mechanism and the coaxiality compensation function.

[0072] Specifically, in this embodiment, through holes are provided in the secondary sun gear 203 and the tertiary sun gear 303, and floating blocks 403 and elastic elements 402 are arranged in the through holes, with conical holes provided on both end faces; a conical hole is also provided on the end face of the tertiary planetary carrier 301 adjacent to the tertiary sun gear 303, forming a receiving cavity with the conical hole on the end face of the tertiary sun gear 303; three floating balls 401 are connected in series by the floating blocks 403 and elastic elements 402 arranged in the secondary sun gear 203 and the tertiary sun gear 303, respectively located between the primary sun gear 103 and the secondary sun gear 203, between the secondary sun gear 203 and the tertiary sun gear 303, and between the tertiary sun gear 303 and the tertiary planetary carrier 301 (with the conical holes). The elastic modulus of the elastic element 402 arranged in the tertiary sun gear 303 is greater than that of the elastic element 402 arranged in the secondary sun gear 203.

[0073] In this embodiment, the floating ball 401 is connected in series. Only one floating ball 401 is placed in the cavity formed by the tapered holes on the mating end faces of two adjacent sun gears. The floating ball 401 serves as a linkage reference component for adjusting the coaxiality of the two adjacent sun gears. When any sun gear is radially offset, the tapered hole sidewall on the offset side will generate a lateral squeezing force on the floating ball 401. This squeezing force causes the floating ball 401 to roll, which in turn causes the floating block 403 to slide along the through hole. At the same time, the elastic element 402 on the other side generates a reverse pulling / pushing force, providing a force to reset the offset sun gear in the axial direction, maintaining the coaxiality of the multi-stage sun gears and avoiding the accumulation of inter-stage deviations.

[0074] Under abnormal impact conditions at the output end, the elastic element 402 absorbs part of the impact energy through its flexibility and then transmits it to the next-stage sun gear, achieving graded absorption and gradual attenuation of impact energy, thus preventing the impact from being directly transmitted to the input end. Furthermore, the elastic element 402, located far from the output end, can respond quickly and compress synchronously. The radial stiffness of the elastic element 402 within each stage of the sun gear increases synchronously, and each stage of the sun gear and planet carrier is simultaneously constrained, which can more quickly and effectively prevent the continuous transmission of impact fluctuations from the output end to the input end.

[0075] In some other embodiments, magnetic elements (such as permanent magnets) are embedded in the inner wall of the through hole and the outer wall of the floating block 403. The magnetic attraction force provided by the paired magnetic elements is used to reset the floating block 403 to the middle of the through hole, so that the floating block 403 has a tendency to reset to the middle of the through hole. When the planetary gear system of each stage does not require coaxiality and off-center load compensation or only requires a small amount of coaxiality and off-center load compensation, the floating ball 401 does not contact the tapered hole sidewall or only has a small amount of contact.

[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A reducer integrating multi-stage planetary gears, comprising an outer cylinder, wherein the outer cylinder is provided with a plurality of planetary gear systems connected in series, each planetary gear system comprising a planet carrier, a gear ring fixedly connected to the outer cylinder, planet gears rotatably connected to the planet carrier and meshing with the gear ring, and a sun gear fixedly connected to the planet carrier on the same axis. Its features are, The first-stage planetary gear train near the input end has a fixed axial position, while the axial positions of the remaining planetary gear trains are not fixed. The planet carrier of each planetary gear train has an integrally formed annular boss on the end face of the side of the next-stage planetary gear train. An opening is provided in the middle of the annular boss. The sun gear is fixedly connected to the opening in the middle of the annular boss, and the sun gear is coaxial with the annular boss. The sun gear extends into the planet carrier of the next-stage planetary gear train and meshes with the planet gears of the next-stage planetary gear train. The end face of the sun gear does not contact the inner wall of the annular boss of the next-stage planetary gear train. The mating end faces of the sun gears of two adjacent planetary gear systems are provided with opposing conical holes. The two conical holes enclose a receiving cavity, and a floating ball is provided in the receiving cavity. In the initial state, there is a gap between the floating ball and the side wall of the receiving cavity. The gap is used to allow the floating ball to roll radially to compensate for the coaxiality error of the sun gear. The edges of the conical holes on the mating end faces of two adjacent sun gears are provided with rounded corners, which are used to guide the floating ball to slide along the side wall of the conical hole; A sun gear, with tapered holes on both ends, has a through hole extending along its axis inside. The two ends of the through hole are connected to the tapered holes on both ends of the sun gear, forming a through-passage. A floating block is slidably fitted within the through-passage. Both ends of the floating block are connected to elastic elements. The end of the elastic element furthest from the floating block is fixedly connected to a floating ball inside the corresponding tapered hole. A movable gap is left between the elastic element and the inner wall of the through hole. When the floating block is located at any position within the through-passage and the elastic element does not undergo elastic deformation, the elastic element supports the floating balls at both ends, suspending them within the tapered hole. At least one side of the outer wall of the floating ball maintains a floating gap with the side wall of the tapered hole, preventing contact. A floating ball is placed in the cavity formed by the tapered holes of the sun gear mating end faces of two adjacent planetary gear systems; the two ends of the floating ball are fixedly connected to the elastic elements in the through holes of the sun gears of the two adjacent planetary gear systems; along the power transmission direction of the reducer, the elastic modulus of the elastic element gradually increases to adapt to the gradually increasing load fluctuations.

2. The reducer with integrated multi-stage planetary gears according to claim 1, characterized in that, The annular boss, integrally formed on the end face of the planetary carrier near the next-stage planetary gear system, has rounded corner transition structures at both its inner and outer corners. These rounded corner transition structures are smoothly connected to the end face of the annular boss and the outer peripheral wall of the planetary carrier, respectively.

3. The reducer with integrated multi-stage planetary gears according to claim 1, characterized in that, The planet carrier of the next-level planetary gear system has a receiving groove on the end face near the annular boss. The annular boss is partially or completely embedded in the receiving groove, and there is a gap between the outer wall of the annular boss and the inner wall of the receiving groove.

4. The reducer with integrated multi-stage planetary gears according to claim 1, characterized in that, Planetary shims are provided between adjacent planetary gear trains. The planetary shims are provided between the planet carriers of each planetary gear train or between the sun gear and the planet carrier of each planetary gear train.

5. The reducer with integrated multi-stage planetary gears according to claim 1, characterized in that, A thrust bearing is provided between each two adjacent planetary gear trains. The thrust bearing is located between the planet carriers of each planetary gear train or between the sun gear and the planet carrier of each planetary gear train.

6. The reducer with integrated multi-stage planetary gears according to claim 1, characterized in that, The planetary gear system has planetary washers or thrust bearings between the planetary gears and the planetary carrier, with the two end faces of the planetary washers or thrust bearings respectively having clearance fits with the planetary gears and the planetary carrier.

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