A cycloidal reducer and a geared motor

Abstract

This application relates to a cycloidal reducer and a geared motor. The cycloidal reducer includes: a fixed part with an annular assembly groove, the inner wall of which is a cycloidal ring repeating N times circumferentially; an annular component coaxial with the assembly groove, rotating only around the axis and positioned radially / axially, with M equally spaced radial holes on its outer circumference; a limiting pin slidably placed in the holes, its outer end abutting against the inner wall of the cycloidal ring, and its inner end contacting the outer ring of the first bearing of the eccentric component, the inner ring of the first bearing rotating and eccentrically e relative to the center of the annular component; and an output component rigidly connected to the annular component. N and M are positive integers and |N−M|≥1. During operation, the outer ring pushes the limiting pin radially back and forth and rolls / slides along the cycloidal ring, driving the annular component to output at a reduction ratio determined by the difference between N and M. Due to the above structure, a wide range of single-stage reduction ratios can be achieved by adjusting N or its ratio with M without increasing the overall size, solving the problems of volume increase, hysteresis / pulsation caused by traditional diameter enlargement / stage addition, and achieving miniaturization, high reduction ratio, high torque density, low hysteresis, easy assembly, and serialization.

Description

Technical Field

[0001] This utility model relates to a speed reducer and a speed reducer motor, and more particularly to a cycloidal speed reducer and a speed reducer motor. Background Technology

[0002] With the widespread adoption of collaborative robots, AGVs / AMRs, electric joints, precision positioning platforms, and lightweight servo actuators, reduction gear units are required to simultaneously meet the demands of high reduction ratios, high torque density, low backlash, low pulsation, and high reliability within a compact size. To reduce system integration difficulty and cost, there is a clear trend towards integrating the motor and reducer, and there is a desire to be able to quickly adjust the reduction ratio to adapt to different operating conditions (torque / speed levels) without altering the external mounting interface.

[0003] Most existing cycloidal reducers are of the eccentrically driven type, consisting of a cycloidal wheel and a pin tooth (or roller) external gear ring meshing mechanism: the motor drives the cycloidal wheel through an eccentric shaft to generate a compound motion, and the cycloidal wheel teeth mesh with the equally spaced pin teeth of the external gear ring, usually through a pin / sleeve or spline for output. The reduction ratio is mainly determined by the difference in the number of meshing teeth (e.g., the difference between the number of pin teeth on the external gear ring and the number of cycloidal teeth).

[0004] However, when a significant increase in the single-stage reduction ratio is required, it is often necessary to increase the number of pin teeth / outer ring diameter or reduce the number of cycloidal teeth / module and pitch. In miniaturization scenarios, this is subject to geometric and strength constraints such as the minimum size of the pin teeth, center distance / pitch, contact strength, and machining and assembly tolerances, making it difficult to simultaneously guarantee load capacity, efficiency, and lifespan. Therefore, in engineering, multi-plate cycloidal gears / multi-stage series connection is often used to obtain a higher overall reduction ratio, but this leads to increased size, longer axial dimensions, more complex structure, and increased cost, and is prone to introducing problems such as backlash control and torque ripple. Therefore, there is an urgent need to propose a cycloidal reducer and geared motor. Utility Model Content

[0005] The purpose of this invention is to provide a cycloidal reducer and geared motor that achieves a wide range of fine-grained single-stage reduction ratio adjustment by matching the geometric wave number N and the number of components M without significantly changing the outline and installation conditions, while taking into account structural compactness, clear motion constraints, low backlash and manufacturability.

[0006] The technical solution adopted by this utility model to solve the above problems is: a cycloidal reducer, comprising:

[0007] The fixing part forms an annular assembly groove through the first direction. The inner wall of the assembly groove has an annular cycloidal profile with N peaks and N troughs arranged alternately on a radial section perpendicular to the first direction. The cycloidal profile is repeated N times periodically in the circumferential direction.

[0008] An annular component, the axis of which is coaxial with the axis of the assembly groove, and the annular component is constrained to rotate only about the axis of the assembly groove relative to the fixed part and is positioned radially and axially; the outer periphery of the annular component is provided with M first through holes along the radial direction, and each first through hole is distributed in an equally spaced annular array with the center of the annular component as the center;

[0009] A plurality of limiting pins are provided, each of which is movably inserted into each of the first through holes, and the spacing between any two adjacent limiting pins is equal; the axis of the limiting pin is arranged radially along the annular part, and the end of the limiting pin away from the center of the annular part abuts against the inner wall of the assembly groove.

[0010] An eccentric assembly includes a first bearing disposed in the inner hole of the annular member. The axis of the first bearing is parallel to the first direction, and the center of the first bearing has a non-zero eccentricity e relative to the center of the annular member. The inner ring of the first bearing is controlled to rotate, and the outer peripheral side of the outer ring of the first bearing abuts against the end of each of the limiting pins near the center of the annular member.

[0011] The output component is rigidly connected to the annular component to output the rotation of the annular component.

[0012] Where N and M are both positive integers, and |N−M|≥1, when the inner ring of the first bearing rotates, the outer ring of the first bearing pushes each of the limiting pins to make radial reciprocating motion in the corresponding first through hole. The end of the limiting pin away from the center of the annular part rolls and / or slides along the inner wall of the assembly groove corresponding to the annular cycloidal contour, thereby driving the annular part to rotate relative to the fixed part about the axis of the annular part with a reduction ratio determined by the difference between N and M, and outputs torque through the output component.

[0013] Preferably, the number of limiting pins is M, and each limiting pin is slidably inserted into each of the first through holes.

[0014] Preferably, both ends of the limiting pin are provided with arc-shaped surfaces.

[0015] Preferably, the limiting pin includes:

[0016] A pin, wherein the end of the pin is provided with a ball socket, and an opening groove is formed on the side of the ball socket away from the pin;

[0017] A ball is rolled within the socket, and at least a portion of the ball's spherical surface is exposed outside the socket via the opening groove. The surface of the ball exposed outside the socket is the arc-shaped surface.

[0018] Preferably, the outer periphery of the annular component is further provided with M second through holes along the radial direction, and each second through hole is distributed in a ring array with equal spacing around the center of the annular component;

[0019] The number of limiting pins is 2M, and each limiting pin is slidably inserted into each of the first through holes and each of the second through holes; and the outer peripheral side of the outer ring of the first bearing abuts against the end of each limiting pin located in the first through hole away from the center of the annular part.

[0020] The eccentric component also includes:

[0021] A central shaft is disposed in the inner hole of the annular component. The axis of the central shaft is collinear with the axis of the annular component. The central shaft is fixedly connected to the inner ring of the first bearing so as to rotate synchronously with the inner ring of the first bearing. The central shaft is constrained to rotate only about its own axis relative to the annular component and is positioned radially and axially.

[0022] The second bearing is disposed in the inner hole of the annular member. The axis of the second bearing is parallel to the first direction. The center of the second bearing has a non-zero eccentricity e relative to the center of the annular member. The second bearing and the first bearing are 180° out of phase in the circumferential direction. The inner ring of the second bearing is fixedly connected to the central shaft to rotate with the central shaft. The outer circumferential side of the outer ring of the second bearing abuts against the end of the limiting pin located in the second through hole away from the center of the annular member.

[0023] Preferably, a first raceway is provided on the outer periphery of the central shaft, a second raceway is provided on the inner wall of the annular component, a third raceway is provided on the outer periphery of the annular component, and a fourth raceway is provided on the periphery of the inner wall of the mounting groove in the fixing part.

[0024] The cycloidal reducer also includes:

[0025] A first cage and a plurality of first rollers mounted on the first cage, the first rollers being disposed between the central shaft and the annular member, and the first rollers being drively connected to the first raceway and the second raceway;

[0026] A second retainer and a plurality of second rollers mounted on the second retainer, the second rollers being disposed between the annular member and the fixed portion, and the second rollers being drively connected to the third raceway and the fourth raceway.

[0027] Preferably, the fixing part includes:

[0028] Two coaxially arranged fixing rings, the inner wall of the fixing rings being the inner wall of the assembly groove, the fixing rings having the annular cycloidal profile on a radial section perpendicular to the first direction, and the peak of the annular cycloidal profile on one fixing ring being aligned with the trough of the annular cycloidal profile on the other fixing ring.

[0029] The outer ring is coaxially disposed between the two fixed rings and is fixedly connected to the fixed rings. The fourth raceway is formed on the inner wall of the outer ring.

[0030] Preferably, there are two regions in the assembly groove that correspond to the annular cycloid profile, and the peak of one annular cycloid profile is aligned with the trough of the other annular cycloid profile.

[0031] Preferably, N takes any value between 10 and 50.

[0032] Specifically, a geared motor includes:

[0033] The housing, including the accommodating space;

[0034] A drive assembly, disposed within the accommodating space, has a first output element that is controlled to rotate;

[0035] A first reducer is connected to the housing. The first reducer has a first input end and a first output end that is drivenly connected to the first input end. The first input end is drivenly connected to the first output end.

[0036] The second reducer is the cycloidal reducer described above. The fixing part is fixedly disposed in the accommodating space and is coaxially arranged with the first reducer in the first direction. The input component of the second reducer is the inner ring of the first bearing, and the inner ring of the first bearing is connected to the first output end in a transmission connection.

[0037] The first reducer is used to reduce the speed of the first output component in one stage and provide input rotation to the second reducer. The second reducer achieves two-stage reduction according to the cycloidal tooth difference relationship of |N−M|≥1 and outputs torque to the outside through the output component.

[0038] The beneficial effects of the embodiments of this utility model are as follows:

[0039] 1. Due to the adoption of technical means such as "the inner wall of the annular assembly groove of the fixed part forms an annular cycloidal profile that repeats N times circumferentially, the annular part can only rotate around the groove axis and is positioned radially / axially, the outer circumference of the annular part is provided with M equally spaced radial through holes and cooperates with sliding guide limit pins, the outer ring of the first bearing in the eccentric assembly pushes the inner end of each limit pin while its outer end rolls / slides along the inner wall of the cycloidal part, and the reduction ratio is set by using the difference between N and M as the tooth difference (|N−M|≥1) and the force is taken from the rigidity of the output component", it is possible to change the reduction ratio without significantly increasing the outer diameter and axial dimensions. The fixed part allows for fine-grained and wide-range adjustment of the single-stage reduction ratio by the cycloidal wave number N (or its ratio with M). This effectively solves the technical problems of existing cycloidal reducers, which require increasing the outer ring diameter / adding stages to obtain a high reduction ratio. These problems result in increased size, complex assembly, difficulty in controlling backlash and torque pulsation, and limitations in manufacturing tolerances and contact strength. As a result, it achieves a combination of technical effects, including small size, high reduction ratio, high torque density, simple and clear structural and motion constraints (the ring part only rotates), short force path of the meshing pair that is easy to process and assemble, easier backlash and pulsation suppression, and rapid serialization of the reduction ratio under the same external interface.

[0040] 2. Due to the adoption of an integrated structure of "motor - first reducer - second reducer" coaxially connected in series, the first reducer performs a first-stage pre-deceleration on the first output component of the motor and directly drives the inner ring of the eccentric bearing of the second reducer. The second reducer adopts a fixed part with an annular cycloidal profile (repeated N times circumferentially), a ring part that rotates only and is radially / axially positioned, and a slidable guide pin in M ​​radial guide holes. The outer ring of the eccentric bearing pushes the inner end of the limit pin and its outer end into rolling / sliding contact along the inner wall of the cycloidal axis, and the reduction ratio is set with a tooth difference relationship of |N−M|≥1 (and can be combined with optimization methods such as double eccentric 180° phase offset, double hole arrangement, raceway / roller support, and double cycloidal peak and valley alignment in the subordinate scheme). Therefore, without significantly increasing the outer diameter and axial dimensions, a higher overall reduction ratio and higher torque density can be obtained. Furthermore, fine-grained and wide-range serialized reduction ratios can be achieved by adjusting N and M. This effectively solves the technical problems in existing integrated geared motors, such as volume expansion, complex structure, difficulty in assembly and tolerance control, large backlash and torque ripple, and difficulty in balancing efficiency and lifespan, which often require increasing the outer diameter or the number of stages to improve the reduction ratio. As a result, it achieves a comprehensive technical effect of miniaturization and high ratio compatibility, short transmission chain and high rigidity, low backlash and low ripple, reduced friction and wear, improved noise and vibration, friendly assembly and manufacturing, and easy rapid parameter reuse and product serialization under the same installation interface. Attached Figure Description

[0041] Figure 1 A schematic side sectional view of a cycloidal reducer according to an embodiment of the present invention is shown.

[0042] Figure 2A schematic main sectional view of a cycloidal reducer according to an embodiment of the present invention is shown.

[0043] Figure 3 A schematic side sectional view of a geared motor according to an embodiment of the present invention is shown.

[0044] Wherein: 10, housing; 110, accommodating space; 20, drive assembly; 210, first output component; 30, first reducer; 310, first input end; 320, first output end; 40, second reducer; 410, fixing part; 411, fixing ring; 412, outer ring; 413, assembly groove; 414, cycloidal profile; 415, fourth raceway; 420, annular component; 421, second raceway; 422, third raceway; 423, first through hole; 424, second through hole; 430, limiting pin; 431, arc-shaped surface; 440, eccentric assembly; 441, first bearing; 442, central shaft; 4421, first raceway; 443, second bearing; 50, first cage; 60, first roller; 70, second cage; 80, second roller. Detailed Implementation

[0045] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0046] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this application, it should be noted that, unless otherwise expressly 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 between two components. Those skilled in the art will be able to understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] Figure 1 A schematic side sectional view of a cycloidal reducer according to an embodiment of the present invention is shown; Figure 2 A schematic main sectional view of a cycloidal reducer according to an embodiment of the present invention is shown. See also Figures 1 to 2 A preferred embodiment of this application provides a miniature cycloidal reducer for joint transmission in robots and robotic arms. The reducer includes a fixed part 410, an annular part 420, several limiting pins 430, an eccentric assembly 440, and an output component, all of which are arranged around the same axis and installed in a housing 10 or a mounting base.

[0049] The cycloidal reducer includes a fixed part 410, an annular part 420, several limit pins 430, an eccentric assembly 440, and an output component. The fixing part 410 forms an annular assembly groove 413 through a first direction. The inner wall of the assembly groove 413 has an annular cycloidal profile 414 with N peaks and N troughs arranged alternately on a radial section perpendicular to the first direction. The cycloidal profile 414 is repeated N times circumferentially. The axis of the annular member 420 is coaxial with the axis of the assembly groove 413, and the annular member 420 is constrained to rotate only around the axis of the assembly groove 413 relative to the fixing part 410 and is positioned radially and axially. The outer periphery of the annular member 420 is provided with M first through holes 423 radially, and each first through hole 423 is distributed in an equally spaced annular array with the center of the annular member 420 as the center. Both ends of the limiting pin 430 are provided with arc-shaped surfaces 431, and each limiting pin 430 is movably inserted through the pin. Within each of the first through holes 423, the spacing between each pair of adjacent limiting pins 430 is equal; the axis of each limiting pin 430 is arranged radially along the annular member 420, and the end of each limiting pin 430 away from the center of the annular member 420 abuts against the inner wall of the assembly groove 413; the eccentric assembly 440 includes a first bearing 441 disposed in the inner hole of the annular member 420, the axis of the first bearing 441 being parallel to the first direction, and the center of the first bearing 441 having a non-zero eccentricity e relative to the center of the annular member 420; the inner ring of the first bearing 441 is controlled to rotate, and the outer circumference of the outer ring of the first bearing 441 abuts against the end of each limiting pin 430 near the center of the annular member 420; an output component is rigidly connected to the annular member 420 to output the rotation of the annular member 420. Where N and M are both positive integers, and |N−M|≥1, when the inner ring of the first bearing 441 rotates, the outer ring of the first bearing 441 pushes each of the limiting pins 430 to make radial reciprocating motion in the corresponding first through hole 423. The end of the limiting pin 430 away from the center of the annular member 420 rolls and / or slides along the inner wall of the assembly groove 413 corresponding to the annular cycloidal profile 414, thereby driving the annular member 420 to rotate relative to the fixed part 410 about the axis of the annular member 420 with a reduction ratio determined by the difference between N and M, and outputs torque through the output member.

[0050] Specifically:

[0051] The fixing part 410 extends along the first direction to form an annular assembly groove 413. The inner wall of the radial section of the assembly groove 413 is an annular cycloidal profile 414, which repeats periodically along the circumference. The assembly groove 413 can be obtained by machining an integrally formed ring or by assembling multiple coaxial ring segments. The cycloidal profile 414 is preferably machined by CNC grinding or forming EDM. The inner wall can be carburized, quenched, or nitrided, and a solid lubricating film can be sprayed to reduce friction. End face positioning shoulders or annular flanges are provided on both sides of the assembly groove 413 to axially position and cooperate with the annular part 420.

[0052] The annular component 420 is a coaxial ring body with an inner hole for accommodating the eccentric assembly 440. Its outer circumference has equally spaced first through holes 423 along its radial direction, with the axis of the through holes being substantially radial. The annular component 420 is radially positioned by a rolling bearing or wear-resistant guide ring between itself and the fixed part 410, and axially positioned by a thrust washer, angular contact bearing, or end face shoulder, allowing the annular component 420 to rotate only about the axis of the mounting groove 413 relative to the fixed part 410. To improve guide life, a bushing or linear bearing bushing can be press-fitted into the through hole, and a circumferential oil reservoir or radial oil injection hole can be formed in the hole wall.

[0053] Each limiting pin 430 is correspondingly installed in each of the first through holes 423, guided by a clearance sliding method. Each limiting pin 430 has arc-shaped surfaces 431 at both ends. The end closer to the center of the annular component 420 contacts the outer ring of the bearing in the eccentric assembly 440, and the end farther from the center of the annular component 420 contacts the cycloidal inner wall of the assembly groove 413. To reduce contact stress and friction, the limiting pin 430 can be made of alloy steel with hardening treatment, polished ends, and coated with a diamond-like carbon film; alternatively, a subsequent "pin with ball end" structure can be used, where the ball rolls in the ball socket, and the exposed spherical surface contacts the mating surface instead of end-face sliding. To prevent the limiting pin 430 from accidentally dislodging, a retaining ring or end cap can be provided on the outside of the through hole for limiting.

[0054] The eccentric assembly 440 includes a first bearing 441, whose axis is parallel to a first direction, and whose center has a non-zero eccentricity e relative to the center of the annular member 420. The inner ring of the first bearing 441 is fixedly connected to the input shaft or coupling and rotates under control, while the outer ring is located inside the inner hole of the annular member 420 and contacts the end of each limiting pin 430 near the center. Optionally, the eccentric assembly 440 adopts a form with two bearings arranged coaxially and the two eccentricities having opposite phases, and a second through hole 424 is added to the outer circumference of the annular member 420, corresponding to the outer rings of the two bearings respectively, to counteract torque pulsation and improve output smoothness.

[0055] The output component is rigidly connected to the annular component 420. A spline, key, or integral molding structure is preferred, and the component extends coaxially with the device axis. A flange or hollow shaft interface can be provided at the end for connection to joint components. An oil seal and labyrinth seal can be installed between the output component and the bearing housing to maintain lubrication and dust prevention.

[0056] When the number of limiting pins 430 is less than the number of through holes, the limiting pins 430 are arranged in a circular pattern at equal angular intervals in the corresponding through holes, and the angular distance between any two adjacent limiting pins 430 is equal; when the number of limiting pins 430 is equal to the number of through holes, each limiting pin 430 is set in its own through hole, forming a one-to-one correspondence.

[0057] During operation, the input shaft drives the inner ring of the first bearing 441 to rotate. Due to the eccentric relationship, the outer ring of the first bearing 441 makes a circular motion relative to the center of the annular component 420 and periodically pushes the inner ends of each limiting pin 430, causing the limiting pins 430 to reciprocate radially within the through hole. The outer ends of each limiting pin 430 roll or slightly slide along the inner wall of the cycloidal axis, forming a circumferential pushing effect on the annular component 420. Under the constraint that the annular component 420 is radially and axially positioned and only allowed to rotate, the annular component 420 slowly rotates at a reduction ratio determined by the difference between the cycloidal wave number and the number of limiting pins 430, and outputs torque outward through the output component.

[0058] During start-up and shutdown, the contact stress concentration is alleviated due to the curved surface or ball bearing contact at the ends; the double eccentric implementation can mutually cancel out pulsations and lateral forces, improving low-speed stability. During reversal, the movement phase sequence of the limit pin 430 is reversed, and the mechanism outputs reverse torque with the same reduction ratio. Lubrication is achieved through oil bath or grease lubrication, with replenishment and heat removal via oil grooves and guide holes during operation.

[0059] Under sudden load increases, the normal force of the limiting pin 430 on the inner wall of the cycloidal element rises, and the composite contact between the arc surface or the ball end helps to disperse stress and inhibit early wear. Dimensional expansion caused by temperature rise is compensated for by the radial clearance between the annular part 420 and the fixed part 410, the bushing material selection, and the internal clearance of the bearing. During assembly, the axial clearance of the annular part 420 is controlled by the locating shoulder and preload element to reduce hysteresis and stabilize the contact state. If directly connected to a motor, the speed and torque control strategy on the motor side can employ a speed loop with torque limiting protection, combined with temperature sensing and lubrication monitoring to achieve adaptive operating conditions.

[0060] This embodiment is suitable for applications such as robot joints, collaborative robotic arms, and light-load positioning platforms where space is limited and high reduction ratios and high torque density are required. It is recommended for use in ambient to medium-temperature environments, ensuring dust and liquid isolation and continuous lubrication. In high-humidity or dusty conditions, high-grade sealing and corrosion-resistant treatment should be employed. In frequent start-stop and low-speed heavy-load scenarios, a combination of double eccentricity and ball end limit pins 430 is preferred to reduce pulsation and wear.

[0061] In this embodiment, by employing a sliding guide pin 430 with the inner wall of the annular cycloidal mechanism and the outer ring of the eccentric bearing driving the pin 430 to reciprocate radially, the annular component 420 can only rotate and is precisely positioned, the output component and the annular component 420 rigidly take force, and the reduction ratio is set by the difference between the number of cycloidal waves and the number of limit pins 430, the technical problems caused by the traditional cycloidal mechanism having to increase the size or add stages to improve the reduction ratio, such as increased volume, complex assembly, difficult control of backlash and pulsation, and limited durability, are effectively solved. Thus, a comprehensive technical effect of high reduction ratio and high torque density, low backlash and low pulsation, reduced friction and wear, friendly assembly and maintenance, and easy serialization of the reduction ratio is achieved in a compact shape.

[0062] Further, see Figure 1 In some embodiments, the number of limiting pins 430 is M, and each limiting pin 430 is slidably inserted into each of the first through holes 423. Each limiting pin 430 includes a pin rod and a ball. The end of the pin rod is provided with a ball socket, and the side of the ball socket away from the pin rod is provided with an opening groove. The ball is rolled in the ball socket, and at least a portion of the spherical surface of the ball is exposed outside the ball socket through the opening groove. The surface of the ball exposed outside the ball socket is the arc-shaped surface 431.

[0063] Specifically:

[0064] The number of limiting pins 430 is the same as the number of first through holes 423. Each limiting pin 430 is slidably and guideably disposed within its corresponding through hole, forming a one-to-one guide pair. Each limiting pin 430 includes a pin rod and a ball. The pin rod extends axially, with a ball socket near its inner end. The ball socket has a narrow, elongated opening groove facing away from the pin rod body. The ball is accommodated in the ball socket and can roll freely relative to it. A portion of the outer circumference of the ball is exposed through the opening groove, serving as an arc-shaped contact surface that mates with the inner wall of the annular cycloid. The outer circumference of the pin rod and the through hole have a clearance sliding fit. A thin-walled bushing or wear-resistant guide ring can be provided at the hole opening to stabilize guidance and reduce wear. The hole wall can be machined with end chamfers and circumferential oil reservoirs for easy assembly and lubrication maintenance. Preferably, the pin rod is made of carburized and hardened alloy steel or martensitic stainless steel, with a polished surface and a diamond-like carbon film coating. The ball is preferably made of high-purity bearing steel or silicon nitride ceramic to achieve higher contact fatigue life and lower rolling resistance. The width and thickness of the opening groove and the rounded transition are determined according to the diameter of the ball and the required exposed amount, ensuring that the ball can form a stable line-surface contact when under force without wedging; a low-friction composite liner can be set inside the ball socket to further reduce rolling resistance and noise.

[0065] In some embodiments, to prevent the limit pin 430 from slipping out, a retaining ring groove and a retaining ring can be provided on the outside of the through hole, or an end cap pressure plate can be used for axial limiting. At the same time, a dustproof ring and a labyrinth seal are provided on the outside to suppress dust intrusion and lubricant leakage. During installation, the bushing is first pressed into the through hole, and then the pre-lubricated limit pin 430 is inserted from the outside to the inside until it is in place, ensuring that the exposed surface of the ball faces the inner wall of the mounting groove 413; then it is fixed with an end retaining ring or pressure plate. The annular part 420 is still positioned radially and axially relative to the fixed part 410 by bearings or wear rings, and is only allowed to rotate around the axis of the device; the outer ring of the first bearing 441 in the eccentric assembly 440 is located in the inner hole of the annular part 420, and pushes each limit pin 430 near the center end, so that the exposed surface of the ball contacts the corresponding area of ​​the inner wall of the cycloidal part.

[0066] The inner ring of the eccentric bearing in the input-side drive eccentric assembly 440 rotates. Due to the eccentricity, the outer ring of the bearing pushes the inner ends of each limiting pin 430 in sequence along the circumference. The limiting pins 430 reciprocate radially within the through hole. The exposed balls roll or slightly slide on the inner wall of the cycloidal axis, forming a low-damping rolling contact. Each limiting pin 430 is alternately loaded in an equiangular distribution in the circumferential direction, generating a circumferential driving torque on the annular component 420. Under the constraint of radial and axial positioning, the annular component 420 only rotates, and the output component is rigidly connected to it for synchronous output. During start-up, shutdown, and reversal, the balls roll adaptively within the ball socket, mitigating contact impact. During continuous operation, the through hole bushing and oil reservoir maintain a lubricating film, reducing friction and temperature rise. During maintenance, grease is added through the outer oil filling hole or by removing the end cover, and the integrity of the retaining ring and seal is checked.

[0067] When the load increases or there are minor assembly deviations, the balls automatically find a low-resistance path within the ball socket through their self-aligning function. The exposed spherical surface maintains near-line contact with the inner wall of the cycloidal line, thereby reducing contact stress concentration and suppressing edge scratches. When temperature changes cause changes in the fit clearance, the rolling pair between the ball socket and the balls can still maintain low-friction operation. The through-hole bushing absorbs minor runout and lateral forces, preventing interference between the pin and the hole wall. In cases of insufficient lubrication, thanks to the rolling contact mechanism that replaces pure sliding, basic functions can still be maintained under short-term conditions, but it is recommended to replenish lubrication promptly to restore optimal performance.

[0068] In this embodiment, the use of a limiting pin 430 structure with a ball socket at the pin end and exposed balls, and the balls rolling on the inner wall of the cycloidal axis to transmit force and displacement, while being guided by clearance and stably supported by a wear-resistant bushing in the through hole, effectively solves the technical problems of edge wear, meshing noise and efficiency reduction of traditional flat-end pins under high contact load and micro-slip conditions. This results in a comprehensive technical effect of low friction and low wear, more uniform contact stress distribution, smoother start-stop and low-speed operation, improved life and reliability, and more user-friendly lubrication and maintenance in a compact structure.

[0069] In some embodiments, see Figures 1 to 2The outer periphery of the annular component 420 is further provided with M second through holes 424 radially, and each second through hole 424 is distributed in a ring array with equal spacing around the center of the annular component 420; the number of limiting pins 430 is 2M, and each limiting pin 430 is slidably inserted into each of the first through holes 423 and each of the second through holes 424; and the outer periphery of the outer ring of the first bearing 441 abuts against the end of each limiting pin 430 located in the first through hole 423 away from the center of the annular component 420; the eccentric assembly 440 also includes a central shaft 442 and a second bearing 443. The central shaft 442 is disposed in the inner hole of the annular member 420, and the axis of the central shaft 442 is collinear with the axis of the annular member 420. The central shaft 442 is fixedly connected to the inner ring of the first bearing 441 so as to rotate synchronously with the inner ring of the first bearing 441. The central shaft 442 is constrained to rotate only about its own axis relative to the annular member 420 and is positioned radially and axially. The second bearing 443 is disposed in the inner hole of the annular member 420, and the axis of the second bearing 443 is parallel to the first direction. The center of the second bearing 443 has a non-zero eccentricity e relative to the center of the annular member 420. The second bearing 443 and the first bearing 441 are 180° out of phase in the circumferential direction. The inner ring of the second bearing 443 is fixedly connected to the central shaft 442 so as to rotate with the central shaft 442. The outer peripheral side of the outer ring of the second bearing 443 abuts against the end of the limiting pin 430 located in the second through hole 424 away from the center of the annular member 420.

[0070] Specifically:

[0071] Two rows of through holes are radially arranged around the outer periphery of the annular component 420, with the two rows of through holes arranged in a ring at equal angular intervals with the center of the annular component 420 as the center. The number of limiting pins 430 is the same as the sum of the two rows of through holes, and they are slidably and guideably arranged in the corresponding through holes, so that each through hole corresponds to one limiting pin 430. Each limiting pin 430 is arranged radially, with its outer end contacting the inner wall of the annular cycloidal groove 413 of the fixing part 410, and its inner end contacting the outer ring of the bearing of the eccentric component 440; the limiting pin 430 can be an arc-shaped end of an integrally hardened cylindrical pin, or it can be a composite structure of a pin rod and a ball end, with the ball rolling in the ball socket, and the exposed spherical surface forming a low-friction contact with the inner wall of the cycloidal groove.

[0072] An eccentric assembly 440 is arranged within the inner hole of the annular member 420 and includes a central shaft 442, a first bearing 441, and a second bearing 443. The central shaft 442 is collinear with the axis of the annular member 420 and is fixedly connected to the inner ring of the first bearing 441. The central shaft 442 is only allowed to rotate about its own axis and is positioned radially and axially. The second bearing 443 is also disposed within the inner hole of the annular member 420, with its axis parallel to the first direction. The center of the second bearing 443 has a non-zero eccentricity relative to the center of the annular member 420, and its eccentricity direction is opposite to that of the first bearing 441 in the circumferential direction. The outer ring of the first bearing 441 contacts the inner end of a limiting pin 430 located in the first row of through holes, and the outer ring of the second bearing 443 contacts the inner end of a limiting pin 430 located in the second row of through holes.

[0073] The fixing part 410 extends axially to form an annular assembly groove 413. The inner wall of the assembly groove 413 has an annular cycloidal profile 414 in radial section and repeats periodically in the circumferential direction. The annular component 420 is positioned radially relative to the fixing part 410 by a guide surface or rolling bearing, and axially by an end face shoulder, thrust element, or angular contact bearing, so that the annular component 420 can only rotate around the axis of the assembly groove 413. The output component and the annular component 420 are rigidly connected by transmission, which can be a spline, key connection, or integral molding structure, and is led out in the same direction as the device axis. A flange can be provided at the end for docking with joint components. The contact surface can be carburized or nitrided and polished, and coated with a solid lubricant coating; a wear-resistant bushing can be press-fitted into the through hole, and the orifice is chamfered and has an annular oil reservoir for assembly and lubrication maintenance; a sealing ring and a labyrinth structure are provided on the outside to suppress dust and lubricant leakage.

[0074] The input side drives the central shaft 442 and the inner ring of the first bearing 441 to rotate. Due to eccentricity, the outer ring of the first bearing 441 moves circumferentially within the coordinate system of the annular component 420, sequentially pushing the inner ends of the first row of limiting pins 430, causing them to reciprocate radially within the through hole. The outer ring of the second bearing 443 moves with a phase trajectory opposite to that of the first bearing 441, sequentially pushing the inner ends of the second row of limiting pins 430, achieving alternating and staggered force and drive for the two rows of limiting pins 430. The outer ends of each limiting pin 430 roll or slightly slide against the inner wall of the cycloidal axis, combining to push the annular component 420 circumferentially. Under the constraint of radial and axial positioning, the annular component 420 only performs rotation, and the output component synchronously outputs torque. During start-up, shutdown, and reversal, the two rows of limiting pins 430 share the load with opposite phases, which helps to mitigate impact. During continuous operation, the radial forces of the two rows cancel each other out on average, significantly reducing the eccentric load on the annular component 420 and the bearing housing. Lubrication can be achieved using oil bath or grease lubrication. A stable lubricating film is formed through the oil reservoir and oil guide hole, which carries away frictional heat. Temperature and vibration monitoring can be set up when necessary to determine when to add grease and perform maintenance.

[0075] Under low-speed, heavy-load, or rapidly changing load conditions, the two rows of limit pins 430 will be subjected to forces alternately in opposite phases. The transient peak force is shared by the two paths and diffused through the combined line-surface contact of the balls or the curved ends, thereby suppressing contact stress concentration and edge abrasion. Due to the opposite phases of the two eccentric paths, the radial resultant force and bending moment tend to cancel each other out within one cycle, significantly reducing the lateral load on the bearing and guide surface, and lowering friction and temperature rise. In the presence of minor assembly deviations or thermal expansion differences, the balls can self-track within the ball socket, and the bushing and guide surface absorb minor runouts, maintaining stable contact and low-noise operation.

[0076] The two rows of through holes can be distributed in a semi-circular offset in the circumferential direction, or a small phase adjustment can be made to optimize pulsation and noise; the eccentricity of the two eccentric bearings can be set equally or differentially according to the target torque waveform; the end of the limit pin 430 can be selected between the arc surface and the ball end, or ceramic balls or boron-infiltrated steel balls can be used to improve wear resistance and corrosion resistance; the bushing material can be selected from self-lubricating copper-based alloy, fluoropolymer composite material or oil-containing powder metallurgy material; the cycloidal area of ​​the assembly groove 413 can use replaceable bushings, which can facilitate quick adjustment of wave number to achieve serialized transformation ratio without changing the external installation interface; the seal can use a combination of labyrinth and oil slinger ring to obtain long-term maintenance-free capability.

[0077] In this embodiment, by employing two rows of equally angularly distributed through holes on the outer periphery of the annular component 420 and cooperating with two sets of limiting pins 430, and by using double eccentric bearings with opposite phases to drive the two rows of limiting pins 430 to reciprocate radially, with the outer ends rolling in contact with the inner wall of the cycloidal axis, and the annular component 420 only able to rotate and be precisely positioned, and the output component and the annular component 420 rigidly taking force, the technical problems of radial off-center load and torque pulsation, contact stress concentration and increased wear, and excessive noise and temperature rise that are easily generated under high loads in single-row drive are effectively solved. Thus, it achieves a comprehensive technical effect of radial force self-balancing, more stable torque output, reduced friction and noise, improved life and reliability, and more user-friendly assembly and maintenance in a compact shape.

[0078] Further, see Figure 1The cycloidal reducer includes: a first raceway 4421 on the outer periphery of the central shaft 442; a second raceway 421 on the inner wall of the annular member 420; a third raceway 422 on the outer periphery of the annular member 420; and a fourth raceway 415 on the periphery of the inner wall of the mounting groove 413 in the fixing part 410. The cycloidal reducer further includes: a first retainer 50 and a plurality of first rollers 60 mounted on the first retainer 50; a second retainer 70 and a plurality of second rollers 80 mounted on the second retainer 70; the first rollers 60 are disposed between the central shaft 442 and the annular member 420, and are drively connected to the first raceway 4421 and the second raceway 421; the second retainer 70 and a plurality of second rollers 80 mounted on the second retainer 70; the second rollers 80 are disposed between the annular member 420 and the fixing part 410, and are drively connected to the third raceway 422 and the fourth raceway 415.

[0079] Specifically:

[0080] An inner rolling support pair is provided between the central shaft 442 and the annular member 420, and an outer rolling support pair is provided between the annular member 420 and the fixed part 410. The outer periphery of the central shaft 442 is machined into a continuous annular groove as the first raceway 4421, and the inner wall of the annular member 420 is machined into a second raceway 421 concentric with it. The two raceways cooperate to form an inner rolling channel. The outer periphery of the annular member 420 is machined into a third raceway 422, and the circumferential side of the inner wall of the mounting groove 413 of the fixed part 410 is machined into a fourth raceway 415 facing it. The two raceways cooperate to form an outer rolling channel. The first cage 50 is an open or integral annular structure, which limits and guides the roller spacing in both the radial and axial directions. The cage material can be bearing brass, polyetheretherketone, or oil-impregnated powder metallurgy material to reduce weight and friction. Several first rollers 60 are circumferentially and angularly distributed on the first cage 50, and are located between the first and second raceways 421 during operation. The second cage 70 has the same structure and function. Several second rollers 80 are circumferentially and angularly distributed on the second cage 70, positioned between the third and fourth raceways 415 during operation. To improve durability, the raceway surface can be carburized, quenched, or nitrided and polished to a low roughness, and if necessary, coated with a solid lubricant coating. The rollers can be made of bearing steel or silicon nitride ceramic, with chamfered end faces to improve the transition into the raceway. Oil reservoirs and oil guide grooves can be provided on the cage, and labyrinth seals or skeleton oil seals are provided at the end faces of the annular part 420 and the fixed part 410 to maintain lubrication and dust prevention. During assembly, the first cage 50 and the first roller 60 are first assembled between the central shaft 442 and the annular part 420. Then, the second cage 70 and the second roller 80 are assembled between the annular part 420 and the fixed part 410. After that, the annular part 420 is axially positioned by end face shoulders, washers or angular contact bearings, and radially positioned by matching diameter or thin-walled guide rings, thereby ensuring that the annular part 420 can only rotate around the axis relative to the fixed part 410.

[0081] The input end drives the eccentric component 440 to work. The limiting pin 430 reciprocates radially within the through hole and rolls against the inner wall of the cycloidal axis to generate a circumferential thrust. The annular component 420 rotates with low friction under the constraint of two sets of rolling support pairs. The inner rolling support pair bears the radial guidance and part of the axial reaction force between the annular component 420 and the central shaft 442, while the outer rolling support pair bears the main radial load and rolling guidance of the annular component 420 relative to the fixed part 410. The two sets of rollers roll along the raceway to form a stable oil film. The cage separates the rollers at a predetermined pitch to prevent mutual interference and reduce noise. During start-up, shutdown, and reversal, the rollers achieve elastic contact and elastohydrodynamic lubrication within the raceway, avoiding dry friction. During continuous operation, the load between the raceway and the rollers is distributed along the contact ellipse. Combined with the throttling oil guiding and flow-directing structure of the cage, frictional heat is carried away in a timely manner.

[0082] Under pulsating or eccentric load conditions, the roller group of the outer rolling bearing pair shares the radial resultant force of the annular member 420 on the fixed part 410, significantly suppressing lateral sway caused by eccentric drive; the inner rolling bearing pair provides high-rigidity guidance for the annular member 420 on the central axis 442, limiting minute radial runout, thereby stabilizing the linear reciprocating motion of the limit pin 430 in the through hole. The thermal expansion difference caused by temperature rise is absorbed by the working clearance between the raceway and the rollers, and the thermal stability of the cage material and the viscosity-temperature characteristics of the lubricant together ensure dimensional and frictional stability during long-term operation. If increased vibration or abnormal temperature rise is detected, lubrication can be added through the oil filler port or the end face preload can be adjusted to restore the optimal contact state.

[0083] In this embodiment, a rolling support structure consisting of paired raceways, cages, and rollers is adopted between the central shaft 442 and the annular member 420, and between the annular member 420 and the fixed part 410. This allows the annular member 420 to obtain low-friction, high-rigidity constraint and guidance in both the radial and axial directions. Therefore, it effectively solves the technical problems in the existing solution, such as high sliding guide friction, rapid runout and wear due to off-center load, high temperature rise and noise, and difficulty in lubrication maintenance. As a result, it achieves comprehensive technical effects such as improved transmission efficiency, more stable torque output, significantly reduced lateral load, improved life and reliability, and more user-friendly maintenance and assembly.

[0084] In one embodiment, see Figure 1 The fixing part 410 includes two coaxially arranged fixing rings 411 and an outer ring 412. The inner wall of the fixing ring 411 is the inner wall of the assembly groove 413. The fixing ring 411 has the annular cycloidal profile 414 on a radial section perpendicular to the first direction, and the peak of the annular cycloidal profile 414 on one fixing ring 411 is aligned with the trough of the annular cycloidal profile 414 on the other fixing ring 411. The outer ring 412 is coaxially arranged between the two fixing rings 411 and is fixedly connected to the fixing rings 411. The fourth raceway 415 is formed on the inner wall of the outer ring.

[0085] In this embodiment, the fixing part 410 is composed of an inner fixing ring 411 and an outer fixing ring 411 arranged coaxially, and an outer ring 412 located between them. The inner walls of the two fixing rings 411 jointly define the cycloidal region of the mounting groove 413. Their radial sections are machined into annular cycloidal profiles 414, and they have a peak-to-valley phase relationship in the circumferential direction so as to form corresponding cycloidal guide surfaces in the axial direction. The outer ring 412 is fixed between the two fixing rings 411 by interference fit or positioning shoulder fasteners, forming an integral rigid frame. The inner wall of the outer ring 412 is machined into a cylindrical or slightly bulging base surface and a fourth raceway 415 is provided for the outer rolling support pair to fit. The fixing rings 411 and the outer ring 412 are preferably made of carburized alloy steel or stainless steel. The cycloidal region and the raceway region are finely ground and polished after heat treatment. To reduce friction, a solid lubricating coating can be applied to the inner wall of the cycloidal region and the surface of the raceway. The outer circle of the fixing part 410 is provided with a coaxial positioning step and a system of mounting holes to facilitate assembly with the housing 10 or the end cover.

[0086] The annular component 420 is located within the mounting groove 413 of the fixed part 410, coaxially arranged therewith, and positioned radially and axially by inner and outer rolling bearing pairs, allowing only rotation about its axis. Through holes with equal angular distribution are arranged radially around the outer circumference of the annular component 420, with wear-resistant bushings press-fitted into the holes and oil reservoir grooves provided. Limiting pins 430 are correspondingly and slidably guided in each through hole, with their inner ends contacting the outer ring of the bearing in the eccentric assembly 440 and their outer ends contacting the inner wall of the cycloidal axis. The eccentric assembly 440 is arranged within the inner hole of the annular component 420, with the input shaft fixedly connected to the inner ring of the bearing, and the output component rigidly connected to the annular component 420 to extract torque.

[0087] The input shaft drives the inner ring of the eccentric bearing to rotate, and the outer ring moves circumferentially, pushing the inner end of the limiting pin 430 in sequence. The limiting pin 430 reciprocates radially within the through hole, and its outer end rolls along the cycloidal inner wall formed by the two fixed rings 411, thereby applying a pushing torque to the annular component 420 in the circumferential direction. Because the cycloidal contours 414 of the two fixed rings 411 are arranged with peaks and valleys opposite each other, the outer end of the limiting pin 430 simultaneously makes planar or linear composite contact with the opposite cycloidal guide surfaces in the axial direction, improving contact stability and suppressing lateral force. The fourth raceway 415 on the inner wall of the outer ring 412 and the outer circumferential raceway of the annular component 420 form an outer rolling support pair, bearing the main radial load and reducing friction. During start-up, shutdown, and reversal, the roller group maintains elastohydrodynamic lubrication, and the limiting pin 430 maintains continuous contact with the cycloidal surface.

[0088] When the load fluctuates or there is a slight assembly misalignment, the cycloidal surface with peaks and valleys axially envelops the outer end of the limiting pin 430, limiting its tilt and suppressing edge wear; the raceway of the outer ring 412 shares the off-center load, reducing the lateral force of the annular part 420 on the fixed part 410. The thermal expansion difference is absorbed by the rolling pair clearance and the elasticity of the bushing, and lubrication is maintained through the oil reservoir groove and the oil guide hole.

[0089] In this embodiment, the combination frame of the split fixed ring 411 with the cycloidal guide surface of the peak and valley and the raceway of the outer ring 412 enables the limiting pin 430 to obtain axial enveloping support and the radial load to be borne by the outer rolling pair. Therefore, it effectively solves the technical problem that the integral structure is prone to lateral swaying and contact instability under high load, thereby achieving the technical effects of improved contact stiffness, reduced wear, more stable torque output and more user-friendly assembly and maintenance.

[0090] In another embodiment, the number of regions in the assembly groove 413 corresponding to the annular cycloidal profile 414 is two, with the peak of one annular cycloidal profile 414 aligned with the trough of the other annular cycloidal profile 414.

[0091] Specifically:

[0092] In this embodiment, the fixing part 410 is an integrally formed ring. Two cycloidal regions are spaced apart along the axial direction on its inner wall, maintaining a peak-to-valley phase relationship in the circumferential direction. The middle region is a cylindrical or slightly bulging base, which can serve as a fourth raceway 415 or as a space for lubrication and sealing. The integral ring ensures the coaxiality and phase consistency of the two cycloidal regions through overall heat treatment and precision grinding, and has mounting shoulders and positioning holes on its end face. The ring part 420, the limiting pin 430, the eccentric assembly 440, and the output component are configured as described above. The ring part 420 can only rotate due to internal and external guides and thrust constraints.

[0093] The eccentric component 440 drives the limiting pin 430 to reciprocate radially. Simultaneously, its outer end makes axial following contact with two cycloidal regions, forming a peak-to-valley alignment. This circumferential rolling fit applies a uniform pushing torque to the annular component 420. The peak-to-valley relationship between the two cycloidal regions ensures a symmetrical axial distribution of the contact lines, limiting the overturning tendency of the limiting pin 430's outer end and stabilizing the normal load distribution. If the central cylindrical region is machined as a raceway, it shares radial guidance with the outer circumferential raceway of the annular component 420.

[0094] Under heavy load or low-speed crawling conditions, the bicycloidal region provides an axially symmetrical envelope, reducing local edge stress; the one-piece molded structure avoids assembly errors of the ring parts, improving the geometric consistency and operational repeatability of the assembly groove 413. Temperature rise and dimensional changes are adaptively compensated by the rolling pairs and mating clearances, and lubrication is maintained through the ring grooves and oil passages.

[0095] In this embodiment, by adopting a double cycloidal region on the inner wall of the integrated fixing part 410 and maintaining the phase relationship between the peaks and valleys, the limiting pin 430 obtains a symmetrical envelope in the axial direction and the sources of cycloidal geometric error are reduced. Therefore, it effectively solves the technical problems of uneven contact and increased noise caused by phase deviation and coaxial error that may be introduced by the assembled structure. This achieves the technical effects of improved geometric consistency, enhanced contact stability, reduced operating noise, and simplified manufacturing and assembly process.

[0096] Figure 3 A schematic side sectional view of a geared motor according to an embodiment of the present invention is shown. See also Figure 3 Based on the aforementioned cycloidal reducer, a geared motor is proposed, comprising a housing 10, a drive assembly 20, a first reducer 30, and a second reducer 40. The housing 10 includes an accommodating space 110; the drive assembly 20 is disposed within the accommodating space 110 and has a first output component 210 with controlled rotation; the first reducer 30 is connected to the housing 10, and the first reducer 30 has a first input end 310 and a first output end 320 tractively connected to the first input end 310, the first input end 310 being tractively connected to the first output component 210; the second reducer 40 is the aforementioned cycloidal reducer... The speed reducer has a fixed part 410 fixedly disposed in the accommodating space 110 and coaxially arranged with the first speed reducer 30 in the first direction. The input component of the second speed reducer 40 is the inner ring of the first bearing 441, and the inner ring of the first bearing 441 is connected to the first output end 320. The first speed reducer 30 is used to reduce the speed of the first output component 210 in one stage and provide input rotation to the second speed reducer 40. The second speed reducer 40 achieves two stages of speed reduction according to the cycloidal tooth difference relationship of |N−M|≥1 and outputs torque to the outside through the output component.

[0097] Specifically:

[0098] The housing 10 forms an accommodating space 110 for the coaxially integrated drive assembly 20, first reducer 30, and second reducer 40. The output shaft of the drive assembly 20 is connected to the input end of the first reducer 30 via a coupling, and the output end of the first reducer 30 is rigidly connected to the inner ring of the eccentric bearing of the second reducer 40 by interference fit or spline.

[0099] The second reducer 40 includes a fixing part 410 fixedly connected to the housing 10, an annular part 420 positioned radially and axially and only allowed to rotate about the axis, a limiting pin 430 distributed in the through hole on the outer periphery of the annular part 420, an eccentric assembly 440 arranged in the inner hole of the annular part 420, and an output member rigidly connected to the annular part 420.

[0100] The fixing part 410 forms an annular assembly groove 413 through the axial direction. The inner wall of the assembly groove 413 is a circumferentially repeating annular cycloidal profile 414. The annular component 420 has radially distributed through holes, and each limiting pin 430 slides and guides within the corresponding hole. The end closer to the center contacts the outer ring of the eccentric bearing, and the end farther from the center contacts the inner wall of the cycloidal profile. The output component is fixed to the annular component 420 by a key or spline and leads out along the motor axis. It can be designed to be hollow to facilitate wiring or fluid flow. To meet the requirements of long service life and high reliability, the cycloidal area of ​​the fixing part 410 and the rolling support raceway can be heat-treated and polished to a low roughness. Wear-resistant bushings can be press-fitted into the holes of the annular component 420. The two ends of the housing 10 are equipped with sealing and labyrinth structures. Lubrication can be achieved using oil bath or high-temperature grease, and injection and drainage ports are provided. For monitoring status, temperature and vibration sampling points can be arranged on the housing 10. The output end is equipped with a positioning reference and a fastening hole system for easy and quick installation in the robot joint.

[0101] After being powered on, the drive assembly 20 outputs a rotational speed, which is reduced and increased in torque by the first reducer 30 before being transmitted to the inner ring of the eccentric bearing. The outer ring of the eccentric bearing moves circumferentially relative to the center of the annular component 420, sequentially pushing the inner ends of each limiting pin 430, causing the limiting pins 430 to reciprocate radially within the guide hole; the outer ends of the limiting pins 430 roll or slightly slide along the inner wall of the cycloid, combining to push the annular component 420 circumferentially, thereby driving the annular component 420 to rotate slowly at a ratio determined by the difference between the number of cycloid waves and the number of limiting pins 430, and the output component synchronously outputs a smooth torque. During start-up, shutdown, and reversal, the guide and support pairs provide sufficient geometric constraints, and the limiting pins 430 maintain continuous contact with the cycloid surface; during continuous operation, lubrication is maintained through the oil reservoir and oil guide channel, and frictional heat is dissipated by the housing 10 or carried away by the oil.

[0102] Under conditions of sudden load changes or minor assembly deviations, the guide bushing and rolling bearing absorb lateral components, while the arc-shaped or ball-bearing contact at the end of the limit pin 430 disperses stress and suppresses edge wear. Dimensional expansion due to temperature rise is adaptively compensated through fit clearance and material elasticity, and the coaxial power take-off structure at the output ensures stable torque output under different postures. The control strategy can employ a speed loop and torque- and temperature-limiting logic, combined with temperature and vibration thresholds for maintenance prompts.

[0103] This geared motor is suitable for joint applications requiring high performance ratio, low backlash, and low pulsation in compact spaces, including collaborative robotic arms, steering hubs of mobile platforms, and precision positioning actuators. During installation, ensure the coaxiality and perpendicularity of the housing's 10 positioning surface with the external interface. The environment should be dustproof and provide adequate heat dissipation. In humid or dusty environments, high-grade sealing and corrosion-resistant treatments should be used, and lubrication and maintenance should be performed according to operating time or temperature rise.

[0104] The first reducer 30 is a friction-driven reducer, which is existing technology; the cycloidal reducer can adopt a double eccentric and double hole staggered arrangement to further reduce pulsation; the end of the limit pin 430 can be changed from an arc surface to a ball end to reduce friction; the guide bushing can be a self-lubricating composite material to extend the maintenance-free cycle; the output component can be hollow to integrate the circuit and fluid; the fixing part 410 can be an integrated double cycloidal region or a split peak-valley structure to balance manufacturing assembly, rigidity and maintainability.

[0105] In this embodiment, due to the adoption of a coaxially integrated motor with a first-stage pre-reduction and a cycloidal second-stage reduction structure within the housing 10, the pre-reduction directly drives the inner ring of the eccentric bearing, the limiting pin 430 reciprocates radially within the guide hole and rolls along the inner wall of the cycloidal gear, and the annular component 420 only rotates and is rigidly driven by the output component, the technical problems of traditional integrated geared motors requiring enlarged shape or additional stages to achieve high reduction ratios, resulting in volume expansion, large backlash and pulsation, difficulty in assembly and tolerance control, and difficulty in heat dissipation and lubrication are effectively solved. Thus, a comprehensive technical effect is achieved with a high reduction ratio and high torque density, low backlash and low noise, smoother lubrication and heat dissipation paths, and more user-friendly installation and maintenance within a compact shape.

[0106] In some embodiments, the drive component 20 is a motor, and the first output component 210 is a drive shaft that is connected to the inner rotor or outer rotor of the motor.

[0107] Specifically:

[0108] The drive assembly 20 is a motor. The motor can be an internal rotor type or an external rotor type. The rotor of the motor is connected to the first output component 210, i.e., the drive shaft, via a rigid connecting member. In the internal rotor type, the rotor is arranged inside the stator, and the drive shaft and the rotor hub are connected to achieve a backlash-free transmission connection through splines, flat keys, interference fits, or clamping sleeves. In the external rotor type, the rotor housing and the drive shaft are connected via a special flange hub or an internal tapered clamping structure to ensure coaxiality and dynamic balance. The drive shaft is radially and axially positioned within the housing 10 by front and rear support bearings, and is equipped with oil seals or labyrinth seals to maintain lubrication and dust prevention; the shaft shoulder and end face retaining ring are used to limit the axial position.

[0109] The controller supplies power to the motor stator to create a rotating magnetic field. The rotor rotates with the magnetic field and transmits power to the drive shaft via the rotor hub. The drive shaft inputs the speed and torque to the first reducer 30 for pre-deceleration. The rotation after pre-deceleration further drives the inner ring of the eccentric bearing in the cycloidal stage, and finally outputs stable torque through the cooperation of the limit pin 430 and the ring component 420. During start-up, shutdown, and reversing, the drive shaft and the connection interface maintain rigid coupling and are geometrically constrained by the support bearing. During continuous operation, the lubrication and cooling system maintains the temperature rise within the allowable range, and the encoder, current loop, speed loop, or position loop together achieve closed-loop control. In case of overload or abnormal temperature rise, the control strategy triggers torque limiting and derating logic and records the status for maintenance.

[0110] The above description in this specification is merely illustrative of the present invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the content of this specification or exceed the scope defined in the claims, all of which shall fall within the protection scope of this invention.

Claims

1. A cycloidal reducer, characterized in that, include: The fixing part forms an annular assembly groove through the first direction. The inner wall of the assembly groove has an annular cycloidal profile with N peaks and N troughs arranged alternately on a radial section perpendicular to the first direction. The cycloidal profile is repeated N times periodically in the circumferential direction. An annular component, the axis of which is coaxial with the axis of the assembly groove, and the annular component is constrained to rotate only about the axis of the assembly groove relative to the fixed part and is positioned radially and axially; the outer periphery of the annular component is provided with M first through holes along the radial direction, and each first through hole is distributed in an equally spaced annular array with the center of the annular component as the center; A plurality of limiting pins are provided, each of which is movably inserted into each of the first through holes, and the spacing between any two adjacent limiting pins is equal; the axis of the limiting pin is arranged radially along the annular part, and the end of the limiting pin away from the center of the annular part abuts against the inner wall of the assembly groove. An eccentric assembly includes a first bearing disposed in the inner hole of the annular member. The axis of the first bearing is parallel to the first direction, and the center of the first bearing has a non-zero eccentricity e relative to the center of the annular member. The inner ring of the first bearing is controlled to rotate, and the outer peripheral side of the outer ring of the first bearing abuts against the end of each of the limiting pins near the center of the annular member. An output component is rigidly connected to the annular component to transmit the rotation of the annular component. Where N and M are both positive integers, and |N−M|≥1, when the inner ring of the first bearing rotates, the outer ring of the first bearing pushes each of the limiting pins to make radial reciprocating motion in the corresponding first through hole. The end of the limiting pin away from the center of the annular part rolls and / or slides along the inner wall of the assembly groove corresponding to the annular cycloidal contour, thereby driving the annular part to rotate relative to the fixed part about the axis of the annular part with a reduction ratio determined by the difference between N and M, and outputs torque through the output component.

2. The cycloidal reducer according to claim 1, characterized in that, The number of limiting pins is M, and each limiting pin is slidably inserted into each of the first through holes.

3. A cycloidal reducer according to claim 1, characterized in that, Both ends of the limiting pin are provided with arc-shaped surfaces.

4. A cycloidal reducer according to claim 3, characterized in that, The limiting pin includes: A pin, wherein the end of the pin is provided with a ball socket, and an opening groove is formed on the side of the ball socket away from the pin; A ball is rolled within the socket, and at least a portion of the ball's spherical surface is exposed outside the socket via the opening groove. The surface of the ball exposed outside the socket is the arc-shaped surface.

5. A cycloidal reducer according to claim 1, characterized in that: The outer periphery of the annular component is further provided with M second through holes along the radial direction, and each second through hole is distributed in a ring array with equal spacing around the center of the annular component. The number of limiting pins is 2M, and each of the limiting pins is slidably inserted into each of the first through holes and each of the second through holes; and the outer peripheral side of the outer ring of the first bearing abuts against the end of each limiting pin located in the first through hole that is away from the center of the annular part. The eccentric component also includes: A central shaft is disposed in the inner hole of the annular component. The axis of the central shaft is collinear with the axis of the annular component. The central shaft is fixedly connected to the inner ring of the first bearing so as to rotate synchronously with the inner ring of the first bearing. The central shaft is constrained to rotate only about its own axis relative to the annular component and is positioned radially and axially. The second bearing is disposed in the inner hole of the annular member. The axis of the second bearing is parallel to the first direction. The center of the second bearing has a non-zero eccentricity e relative to the center of the annular member. The second bearing and the first bearing are 180° out of phase in the circumferential direction. The inner ring of the second bearing is fixedly connected to the central shaft to rotate with the central shaft. The outer circumferential side of the outer ring of the second bearing abuts against the end of the limiting pin located in the second through hole away from the center of the annular member.

6. A cycloidal reducer according to claim 5, characterized in that: The outer periphery of the central shaft is provided with a first raceway, the inner wall of the annular part is provided with a second raceway, the outer periphery of the annular part is provided with a third raceway, and the inner wall of the mounting groove in the fixing part is provided with a fourth raceway. The cycloidal reducer also includes: A first cage and a plurality of first rollers mounted on the first cage, the first rollers being disposed between the central shaft and the annular member, and the first rollers being drively connected to the first raceway and the second raceway; A second retainer and a plurality of second rollers mounted on the second retainer, the second rollers being disposed between the annular member and the fixed portion, and the second rollers being drively connected to the third raceway and the fourth raceway.

7. A cycloidal reducer according to claim 6, characterized in that, The fixing part includes: Two coaxially arranged fixing rings, the inner wall of the fixing rings being the inner wall of the assembly groove, the fixing rings having the annular cycloidal profile on a radial section perpendicular to the first direction, and the peak of the annular cycloidal profile on one fixing ring being aligned with the trough of the annular cycloidal profile on the other fixing ring. The outer ring is coaxially disposed between the two fixed rings and is fixedly connected to the fixed rings. The fourth raceway is formed on the inner wall of the outer ring.

8. A cycloidal reducer according to claim 1 or 6, characterized in that, The number of regions corresponding to the annular cycloid profile in the assembly groove is two, and the peak of one annular cycloid profile is aligned with the trough of the other annular cycloid profile.

9. A geared motor, characterized in that, include: The housing, including the accommodating space; A drive assembly, disposed within the accommodating space, has a first output element that is controlled to rotate; A first reducer is connected to the housing. The first reducer has a first input end and a first output end that is drivenly connected to the first input end. The first input end is drivenly connected to the first output end. The second reducer is a cycloidal reducer as described in any one of claims 1 to 8. The fixing part is fixedly disposed in the accommodating space and is coaxially arranged with the first reducer in the first direction. The input component of the second reducer is the inner ring of the first bearing, and the inner ring of the first bearing is connected to the first output end in a transmission manner. The first reducer is used to reduce the speed of the first output component in one stage and provide input rotation to the second reducer. The second reducer achieves two-stage reduction according to the cycloidal tooth difference relationship of |N−M|≥1 and outputs torque to the outside through the output component.

10. The geared motor according to claim 9, characterized in that, The drive component is a motor, and the first output component is a drive shaft that is connected to the inner rotor or the outer rotor of the motor.

Images