Friction reducer based on bearing drive

Abstract

The application relates to a bearing transmission-based friction reducer, which comprises a first magnetic pole ring arranged in a containing space and a conductor ring fixed on a retainer, the conductor ring being oppositely arranged with the first magnetic pole ring and being separated by a magnetic gap, so that eddy current is induced in the conductor ring when the retainer and the first magnetic pole ring move relatively. The friction reducer effectively inhibits roller spinning / slip and low-speed crawling under light-load disturbance, improves damping stability, reduces torque ripple and noise temperature rise, realizes compact, maintenance-free and small-sized stable output suitable for robot joints by adopting the contactless eddy current damping technical means of the first magnetic pole ring, the magnetic gap, the retainer and the conductor ring without changing the main force chain conditions of the first outer ring fixed shell, the two inner rings in synchronization and the second outer ring output.

Description

TECHNICAL FIELD

[0001] The present application relates to a speed reducer, in particular to a bearing-based friction speed reducer. BACKGROUND

[0002] Robot joints, precision servo and miniaturized transmission devices are usually operated under the conditions of low speed, frequent start-stop, light load disturbance and lubrication in the Stribeck curve viscosity dominant area. Such scenarios put forward comprehensive requirements for the speed reduction unit, including compact volume, short assembly chain, continuous transmission, low noise, controllable temperature rise and long-term stability.

[0003] The existing friction transmission speed reducer mostly adopts a bearing-based structure: the first bearing and the second bearing are coaxially arranged in the accommodating space of the housing. The outer ring of the first bearing is usually fixedly connected with the housing, and the inner ring thereof serves as the input. The inner ring of the second bearing is synchronous with the inner ring of the first bearing, and the outer ring of the second bearing serves as the output and is connected with the output member. The two bearings can adopt an integrated or cooperative retainer structure. Such devices rely on the traction / micro-slip contact formed between the rolling elements and the adjacent raceways in the working state to realize speed coupling and torque transmission, and have the advantages of compact structure and simple assembly chain, and are thus widely used in speed reduction and transmission occasions in limited space.

[0004] However, in the above similar devices, the inherent damping of the retainer freedom degree is generally low, and the output side is sensitive to load and lubrication state: slight disturbance can induce roller spin / slip, resulting in low-speed crawling, increased torque ripple and noise / temperature rise fluctuations. Therefore, it is urgent to propose a new type of friction speed reducer to solve the above problems. SUMMARY

[0005] The present application aims to provide a friction speed reducer that can effectively improve the steady-state and dynamic stability of the retainer and the output side while maintaining the existing force chain and compact appearance, and reduce the performance fluctuations caused by stick-slip and torsional vibration.

[0006] The technical scheme adopted by the present application to solve the above problems is: a bearing transmission-based friction speed reducer, comprising a shell, an input end and an output member, a containing space is formed in the shell, a first bearing and a second bearing are arranged coaxially along an axis in the containing space, the first bearing comprises a first outer ring, a first inner ring, first rolling elements and a first retainer, the second bearing comprises a second outer ring, a second inner ring, second rolling elements and a second retainer, and the first retainer and the second retainer are an integrated retainer, the input end is rigidly and rotationally connected with the first inner ring and the second inner ring, and the output member is in transmission connection with the second outer ring; wherein, in a working state, a torque-transmissible friction / micro-slip traction contact is formed between at least the first rolling elements and their adjacent raceways and / or between the second rolling elements and their adjacent raceways, so as to establish a speed difference between the integrated retainer and the inner / outer rings and achieve a speed reduction output, the adjacent raceways refer to the inner raceways corresponding to the outer rings or the outer raceways corresponding to the inner rings, comprising:

[0007] A first magnetic pole ring is arranged in the containing space, and the first magnetic pole ring is fixedly connected with the shell.

[0008] A conductor ring is arranged on the integrated retainer, the conductor ring is arranged opposite to the first magnetic pole ring and separated by a magnetic gap, and the conductor ring is configured to have a continuous conductive loop, so that eddy current is induced in the conductor ring when the retainer moves relative to the first magnetic pole ring, and an electromagnetic damping torque is generated on the retainer.

[0009] Preferably, an end cover is arranged at one end of the shell close to the first bearing, a side of the end cover close to the shell is enclosed with the inner wall of the shell to form the containing space, the first magnetic pole ring is fixed to the inner side of the end cover, the conductor ring is arranged on the end face of the retainer and axially extends towards the end cover, and the magnetic gap is an axial magnetic gap.

[0010] Preferably, an annular recess is formed in the end cover.

[0011] The first magnetic pole ring is arranged in the annular recess, and the first magnetic pole ring comprises a first back iron ring and a first multi-pole permanent magnet array arranged on the side of the first back iron ring close to the first bearing.

[0012] Preferably, an annular structure is arranged on the inner wall of the shell between the first bearing and the second bearing, and the first magnetic pole ring is fixed to the annular inner wall of the annular structure.

[0013] The outer periphery side of the integrated holder corresponds to the position of the first magnetic pole ring, and is configured with a protruding second annular structure, the conductor ring is sleeved on the outer periphery side of the second annular structure, and the outer periphery wall of the second annular structure is arranged opposite to the inner periphery wall of the first annular structure, and the magnetic gap is a radial magnetic gap.

[0014] Preferably, the conductor ring is composed of two annular parts with different outer diameters, namely a first annular part and a second annular part, the first annular part and the second annular part are coaxially arranged side by side, and the first annular part is arranged opposite to the first magnetic pole ring.

[0015] The friction decelerator further comprises a second magnetic pole ring, which is arranged in the circumferential area of the second bearing outer ring inner wall which does not contact and bear the rolling elements of the second bearing in the working state, and is staggered with the raceway on the second bearing outer ring inner wall in the axial direction, and the second annular part is arranged opposite to the second magnetic pole ring.

[0016] Preferably, the first magnetic pole ring is a static magnetic pole ring, and the second magnetic pole ring is a follow-up magnetic pole ring.

[0017] Preferably, an annular groove is left between the first annular part and the second annular part.

[0018] Preferably, the central section of the first magnetic pole ring in the axial direction is arranged in alignment with the central section of the first annular part in the axial direction, and the ratio of the axial width of the first magnetic pole ring to the axial width of the first annular part is 1.1-1.6.

[0019] The central section of the second magnetic pole ring in the axial direction is arranged in alignment with the central section of the second annular part in the axial direction, and the ratio of the axial width of the second magnetic pole ring to the axial width of the second annular part is 1.1-1.6.

[0020] Preferably, the radial magnetic gap between the inner cylindrical surface of the first magnetic pole ring and the outer cylindrical surface of the first annular part satisfies the following condition:

[0021] .

[0022] The radial magnetic gap between the inner cylindrical surface of the second magnetic pole ring and the outer cylindrical surface of the second annular part satisfies the following condition: .

[0023] wherein:

[0024] is the outer radius of the first annular part;

[0025] the outer radius of the second ring member;

[0026] the radial thickness of the conductor ring.

[0027] Preferably, the ratio of the difference between the outer radius of the second ring member and the outer radius of the first ring member to the outer radius of the first ring member is 0.03-0.12.

[0028] The ratio of the axial width of the annular groove to the sum of the axial width of the first ring member and the axial width of the second ring member is 0.12-0.30.

[0029] The ratio of the groove depth of the annular groove to the radial thickness of the first ring member is any value in the range of 0.3-0.8, and the ratio of the groove depth of the annular groove to the radial thickness of the second ring member is any value in the range of 0.3-0.8.

[0030] Preferably, the first magnetic pole ring comprises a first back iron ring and a first multipole permanent magnet array arranged on the side of the first back iron ring facing the first ring member.

[0031] The second magnetic pole ring comprises a second back iron ring and a second multipole permanent magnet array arranged on the side of the second back iron ring facing the second ring member.

[0032] The pole pair number of the first multipole permanent magnet array is different from the pole pair number of the second multipole permanent magnet array, and the ratio of the phase shift φ in the circumferential direction between the two to the first single pole distance of the first multipole permanent magnet array or the second single pole distance of the second multipole permanent magnet array is any value in the range of 0.40-0.60.

[0033] The ratio of the thickness of the first back iron ring to the average thickness of the first multipole permanent magnet array and the ratio of the thickness of the second back iron ring to the average thickness of the second multipole permanent magnet array are each any value in the range of 0.5-1.5.

[0034] The non-working side of the first back iron ring and the non-working side of the second back iron ring are each provided with a demagnetization groove, and the ratio of the depth of the demagnetization groove to the thickness of the first back iron ring and the ratio of the depth of the demagnetization groove to the thickness of the second back iron ring are each any value in the range of 0.1-0.3.

[0035] wherein:

[0036] the pole pair number of the first multipole permanent magnet array refers to the number of pole pairs of the first multipole permanent magnet array arranged in the circumferential direction, when the array has alternating magnetic poles along the circumference, the pole pair number is , and the first single pole distance is the circumferential mechanical angle between the center lines of adjacent poles of the same name in the array, equal to .

[0037] the number of pole pairs of the second multi-pole permanent magnet array is the number of pole pairs of the second multi-pole permanent magnet array, which is equal to when the array has alternating magnetic poles along the circumference, and the number of pole pairs is , the second single-pole distance is the circumferential mechanical angle between the center lines of adjacent poles of the same name in the array, equal to .

[0038] is the circumferential mechanical angle between the center lines of adjacent poles of the same name in the array, equal to

[0039] The beneficial effects of the embodiments in the present application are:

[0040] 1. Since the first and second bearings are coaxially arranged in the accommodation space of the housing and an integrated retainer is used, and in the working state, the friction / micro-slip traction contact capable of transmitting torque is formed between the rolling bodies of the first / second bearings and their adjacent raceways to establish a speed reduction transmission chain, and a conductor ring with a continuous conductive loop is arranged on the integrated retainer and is arranged opposite to the first magnetic pole ring with a magnetic gap, so that when the integrated retainer rotates relative to the first magnetic pole ring, eddy current is induced in the conductor ring and electromagnetic damping torque related to the relative speed is generated. This technical means effectively solves the problems of insufficient damping of the freedom degree of the retainer in the existing friction reducer, sensitivity to load and lubrication state, easy occurrence of low-speed crawling caused by roller spinning / slipping, increase of torque ripple, and noise / temperature rise fluctuation, etc. in the existing friction reducer, and further realizes stable speed suppression and anti-disturbance output under the premise of not changing the main force and assembly chain of the "fixed housing with outer ring, two inner rings synchronous and outer ring output", so that the speed reduction transmission is continuous, low noise, temperature rise controllable, and the overall structure is compact, the assembly chain is short, and it is suitable for small-sized scenes such as robot joints, etc.

[0041] 2、Due to the arrangement of the stationary first magnetic pole ring arranged on the first annular structure in the shell and the segmented conductor ring (first annular member, second annular member) arranged on the second annular structure outside the integrated cage and coaxially opposed to form a radial magnetic gap, and the second magnetic pole ring arranged on the non-load ring area of the inner wall of the second outer ring and axially staggered with the raceway, the electromagnetic damping torque of the "first magnetic pole ring and first annular member" relative to the shell of the integrated cage and the electromagnetic damping torque of the "second magnetic pole ring and second annular member" relative to the output outer ring (output side) of the integrated cage are generated, thereby forming the technical means of double-channel eddy current damping acting on the integrated cage and the output outer ring of the second bearing, so that the problems of providing damping only on one side of the shell, being difficult to stably maintain the magnetic gap in the limited space and easily interfering with the raceway load, and having no direct suppression on the speed ripple of the output side in the existing structure are effectively solved, and the coordinated suppression of the absolute speed of the cage and the relative speed of the cage-outer ring is realized without affecting the load surface, thereby widening the damping bandwidth, reducing the torque ripple and stick / slip / crawling, improving the output stability, and achieving the comprehensive technical effects of compact assembly and manufacturability. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A front cross-sectional view of a friction reducer in an embodiment of the application is shown.

[0043] Figure 2 A front cross-sectional view of a friction reducer in another embodiment of the application is shown.

[0044] Figure 3 A front cross-sectional view of a friction reducer in another embodiment of the application is shown. Figure 2 An enlarged schematic view of point A in FIG.

[0045] Figure 4 A schematic structural diagram of a friction reducer in an embodiment of the application is shown.

[0046] Wherein: 10, shell; 110, accommodation space; 120, first annular structure; 20, first bearing; 30, second bearing; 40, integrated cage; 410, second annular structure; 50, first magnetic pole ring; 510, first back iron ring; 520, first multi-pole permanent magnet array; 60, conductor ring; 610, first annular member; 620, second annular member; 630, annular groove; 70, second magnetic pole ring; 710, second back iron ring; 720, second multi-pole permanent magnet array; 80, end cover; 810, annular recess; 90, input end; 1000, output member. DETAILED DESCRIPTION

[0047] The specific embodiments of the application will be further described in detail below with reference to the drawings and examples. The following examples are used to illustrate the application, but are not used to limit the scope of the application.

[0048] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can be explicitly or implicitly included one or more. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0049] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0050] A friction reducer based on bearing transmission is provided in a preferred embodiment of the present application, which is applied to robot joints, precision servo and small transmission devices and the like scenes. The friction reducer in such scenes usually operates under the working conditions of low speed, frequent start and stop, light load disturbance and lubrication in the Stribeck curve viscosity dominant area, and such scenes put forward comprehensive requirements of compact volume, short assembly chain, continuous transmission, low noise, controllable temperature rise and long-term stability for the reduction unit.

[0051] Figure 1 A front sectional view of the friction reducer in an embodiment of the present application is shown; Figure 2 A front sectional view of the friction reducer in another embodiment of the present application is shown; Figure 3 An enlarged schematic view at A in the figure is shown; Figure 2 An enlarged schematic view at A in the figure is shown; Figure 2 A schematic structural diagram of the friction reducer in an embodiment of the present application is shown. Please refer to Figures 1-4The friction reducer comprises a housing 10, an input end 90 and an output member 1000, the housing 10 is formed with a containing space 110, the containing space 110 is provided with a first bearing 20 and a second bearing 30 coaxially arranged along an axis, the first bearing 20 comprises a first outer ring, a first inner ring, first rolling bodies and a first retainer, the second bearing 30 comprises a second outer ring, a second inner ring, second rolling bodies and a second retainer, and the first retainer and the second retainer are an integrated retainer, the input end 90 and the first inner ring and the second inner ring are rigidly and rotationally connected, and the output member 1000 is in transmission connection with the second outer ring; wherein, in a working state, at least a torque-transmissible friction / micro-slip traction contact is formed between the first rolling bodies and their adjacent raceways and / or between the second rolling bodies and their adjacent raceways, so as to establish a speed difference between the integrated retainer 40 and the inner / outer rings and achieve a speed reduction output, the adjacent raceways refer to the inner raceways of the corresponding outer rings or the outer raceways of the corresponding inner rings, the friction reducer further comprises a first magnetic pole ring 50 and a conductor ring 60, wherein the first magnetic pole ring 50 is arranged in the containing space 110, and the first magnetic pole ring 50 is fixedly connected with the housing 10; the conductor ring 60 is arranged on the integrated retainer 40, the conductor ring 60 is arranged opposite to the first magnetic pole ring 50 and is separated by a magnetic gap, and the conductor ring 60 is configured to have a continuous conductive loop, so that when the retainer moves relative to the first magnetic pole ring 50, eddy current is induced in the conductor ring 60 and electromagnetic damping torque is generated on the retainer.

[0052] Specifically:

[0053] The housing 10 is formed with a containing space 110 consistent with the axis, and the first bearing 20 and the second bearing 30 are coaxially arranged in the containing space 110. The first retainer and the second retainer are made as an integrated retainer, so that the retainer constitutes a unit in geometry and dynamics to transmit rotational speed and constrain relative motion between the two bearings. The input end 90 and the first inner ring and the second inner ring are rigidly and rotationally connected, and the output member 1000 is in transmission connection with the second outer ring, thereby forming a force bearing and assembly chain from the inner ring on the input side to the outer ring on the output side.

[0054] To improve the stability under the condition of maintaining the existing assembly chain, the decelerator is further provided with a first magnetic pole ring 50 and a conductor ring 60. The first magnetic pole ring 50 is installed in the accommodation space 110 and fixed with the shell 10 to form a static magnetic field source; the conductor ring 60 is installed on the integrated cage 40 and arranged opposite to the first magnetic pole ring 50 to maintain a stable magnetic gap. The conductor ring 60 is a continuous conductive loop, which can adopt an overall closed loop structure and pass through a conductive connection to ensure the continuity of the ring current path. The first magnetic pole ring 50 can be composed of a back iron and a multi-pole permanent magnet, the back iron is used for magnetic convergence and fixation, and the multi-pole permanent magnet is arranged alternately along the circumference to form a circumferentially varying magnetic field distribution. The shell 10 can adopt a metal material with good dimensional stability and heat dissipation performance; the first outer ring and the shell 10 are preferably matched by interference or positioning shoulder to ensure the concentricity and rigidity of the bearing outer ring and the shell 10; the conductor ring 60 can adopt a high-conductivity metal or metal composite material and be subjected to surface protection treatment to inhibit corrosion and wear; the cage can adopt a wear-resistant engineering material or a metal material to balance the quality and rigidity.

[0055] During assembly, the first outer ring is first positioned and fixed with the shell 10, and the first inner ring is concentrically installed with the input end 90; the second inner ring is concentrically installed with the input end 90, and the second outer ring is rotationally connected with the output member 1000; the integrated cage 40 and the two sets of rolling bodies are respectively introduced into the respective raceways; then the first magnetic pole ring 50 is fixed at the corresponding position of the shell 10 to form a uniform magnetic gap with the conductor ring 60 in the axial or radial direction; finally, the installation of the lubrication and sealing units is completed. Through the above assembly, the geometric relationship and force flow relationship between the input end 90, the two inner rings, the integrated cage 40, the two groups of rolling bodies, the second outer ring and the output member 1000 are determined.

[0056] Under normal working conditions, the first rolling body and its adjacent raceway and the second rolling body and its adjacent raceway form a frictional and micro-sliding traction contact that can transmit torque under the condition of existing lubrication, the input end 90 drives the two inner rings to rotate synchronously, and the integrated cage 40 obtains a controlled speed difference between the inner and outer rings under the dragging and traction of the rolling bodies, thereby establishing a friction-type deceleration and power transmission. Since the cage rotates relative to the shell 10, the conductor ring 60 installed on the cage moves relative to the magnetic field of the first magnetic pole ring 50 fixed to the shell 10, and a circumferential eddy current is generated in the conductor ring 60; the eddy current and the static magnetic field interact to form an electromagnetic damping torque on the cage, which is opposite to the direction of relative motion, thereby exerting a viscous type constraint on the speed fluctuation of the cage. Through this relative speed-dependent non-contact damping, the speed fluctuation of the cage is suppressed when the external load disturbance, lubrication state fluctuation or start-stop switching occurs, thereby reducing the output side torque ripple and low-speed crawling induced by the self-spinning of the rollers and stick-slip.

[0057] During the operation of the device, the magnetic gap remains stable, and the Joule heat generated by the conductor ring 60 is dissipated through the retainer and the surrounding medium; the back iron of the magnetic pole ring provides a low magnetic resistance path for the magnetic circuit and improves the utilization rate of magnetic flux; the shell 10 serves as a whole heat dissipation and positioning matrix, maintaining the coaxiality of each element. If the external load changes, the relative speed of the retainer changes accordingly, and the eddy current damping torque also changes accordingly, thereby achieving adaptive suppression of disturbances.

[0058] The speed reducer is suitable for space-limited and short transmission chain scenarios, and has advantages in low-speed, frequent start-stop, light load disturbance and lubrication in the viscous dominant area. During installation, the shell 10 and the input and output shafts should be coaxial to ensure that the magnetic gap between the magnetic pole ring and the conductor ring 60 is stable and free of interference. Lubrication can use lubricating medium suitable for traction transmission or compatible with existing bearing lubrication system, and sealing and ventilation structure can be set according to the working condition to maintain internal cleanliness and pressure balance. The environmental temperature and humidity should meet the stable working range of the shell 10 material, the magnet material and the lubricating material, and strong magnetic particles should be prevented from entering the magnetic gap area to affect the damping stability.

[0059] In this embodiment, by using the technical means of fixing the first magnetic pole ring 50 inside the shell 10 and setting the conductor ring 60 with a continuous conductive loop on the integrated retainer 40, maintaining a stable magnetic gap between the two and making the conductor ring 60 generate eddy current relative to the fixed magnetic field during operation to exert electromagnetic damping torque on the retainer, the technical problems of insufficient damping of the retainer's freedom in the existing friction-type speed reducer, sensitivity of the output side to load and lubrication state, easy occurrence of roller spin and slip and induced low-speed crawling and torque ripple, as well as noise and temperature rise fluctuation are effectively solved, and further adaptive stable damping of the relative motion of the retainer and the inner and outer rings is realized without changing the existing assembly and force chain of the fixed shell 10 with the outer ring, synchronous with the two inner rings and output of the outer ring, making the speed reduction transmission more continuous and stable, and the noise and temperature rise more controllable, while maintaining the compact structure and short assembly chain and being suitable for limited space scenarios such as robot joints and precision servo.

[0060] Further, it should be noted that the following is divided into two embodiments. In the first embodiment, the first magnetic pole ring 50 is fixed to the inner side of the end cover 80, and the conductor ring 60 is arranged on the end face of the retainer; in the second embodiment, the first magnetic pole ring 50 is arranged inside the shell 10 and replaced with a sleeve arranged outside the integrated retainer 40.

[0061] Please refer to Figure 1In the first embodiment, the housing 10 is provided with an end cover 80 at one end close to the first bearing 20, the end cover 80 is provided with an annular recess 810, the end cover 80 is close to the inner wall of the housing 10 to form the accommodating space 110, the first magnetic pole ring 50 is fixed to the inner side of the end cover 80 and located in the annular recess 810, wherein the first magnetic pole ring 50 comprises a first back iron ring 510 and a first multi-pole permanent magnet array 520 arranged on the side of the first back iron ring 510 close to the first bearing 20. The conductor ring 60 is arranged on the end face of the retainer and axially extends towards the end cover 80, and the magnetic gap is an axial magnetic gap.

[0062] Specifically,

[0063] The end cover 80 is arranged at one end of the housing 10 close to the first bearing 20. The side of the end cover 80 facing the accommodating space 110 and the inner wall of the housing 10 together form the accommodating space 110, and the annular recess 810 is processed on this side. The annular recess 810 is continuously arranged along the circumference, and the base is formed by the end cover 80 in the axial direction, and the inner and outer shoulders are limited in the radial direction to position and accommodate the first magnetic pole ring 50. The sealing and positioning structure can be arranged between the end cover 80 and the housing 10 to ensure the coaxiality and sealing performance.

[0064] The first magnetic pole ring 50 is fixed to the inner side of the end cover 80 and seated in the annular recess 810. The first magnetic pole ring 50 is composed of a first back iron ring 510 and a first multi-pole permanent magnet array 520. The first back iron ring 510 is integrally turned or powder metallurgically formed from a soft magnetic material, with the outer circular surface cooperating with the recess outer side shoulder ring, the inner circular surface cooperating with the recess inner side shoulder ring, and the axial direction being positioned by the recess bottom surface. The first multi-pole permanent magnet array 520 is located on the side of the back iron ring facing the first bearing 20, and is uniformly arranged along the circumference in a circular arc block manner, with adjacent magnetic poles alternately different in name, the pole surface facing the accommodation space 110, and the back surface reliably attached to the back iron ring. The permanent magnet can be made of high remanence material or rare earth material, with the surface being treated for corrosion resistance or insulation, and the installation method can be selected as a combination of structural adhesive bonding and mechanical pressure ring limiting. The back iron ring is used for converging and closing the magnetic flux, and at the same time serves as the installation base and anti-disengagement structure of the magnetic pole array. It should be noted that the permanent magnet is arranged with adjacent magnetic poles alternately different in name, which is the preferred arrangement of the eddy current damping structure. This polarity alternation allows the magnetic flux to be closed in the working magnetic gap, the magnetic circuit is shorter, the magnetic resistance is smaller, the magnetic flux density in the magnetic gap is higher and more uniform, the magnetic field fluctuation is obvious and regular in the circumferential direction, the conductor is more fully cut, the eddy current and damping torque are stronger and more controllable, the geometric symmetry leads to self-cancellation of the resultant force and the resultant torque, and does not form a direct current biasing force or eccentric torque, thereby reducing noise and additional load; the number of pole pairs and the phase are easy to adjust, and can be compromised between damping amplitude and bandwidth according to the target working condition; the magnetic flux is shared between the back iron and the adjacent magnet, reducing the risk of local saturation and demagnetization and making the heat distribution more uniform; the circular arc magnetic tile alternately cooperates with the back iron and the pressure ring to facilitate precise positioning and resistance to centrifugal force and vibration, and at the same time has a certain self-shielding effect, reducing the magnetic interference on the raceway and lubrication. In summary, the alternating polarity makes the magnetic flux easy to flow, the magnetic field easy to use, and the mechanics easy to bear, which not only significantly improves the eddy current damping performance and stability, but also suppresses the side effects of noise, biasing force, heating and leakage.

[0065] The conductor ring 60 is arranged on the end face of the integrated cage 40 and extends axially towards the end cover 80. The conductor ring 60 is a closed conductive loop, which can be made of a high-conductivity metal and is connected to the end face of the integrated cage 40 by mechanical fastening, riveting or overmolding. An insulating or wear-resistant spacer is arranged between the outer circle of the conductor ring 60 and the end face of the cage to isolate the oil film channel and prevent fretting wear. The end face of the conductor ring 60 is opposite to the pole face of the first multi-pole permanent magnet array 520, maintaining a uniform axial magnetic gap, which is defined by the positioning shoulder face in the end cover 80 and the stop face of the end part of the cage, and is compensated by a gasket or an adjustable ring. To ensure the stability of the magnetic gap during operation, the end cover 80, the housing 10, the bearing outer ring, the input end 90 and the bearing inner ring are all arranged with stable positioning reference and interference or positioning shoulder structure to ensure coaxiality and end face runout within a controllable range. Through the above arrangement, an axial magnetic circuit unit is formed, which has the recess cavity of the end cover 80 as the location, the first magnetic pole ring 50 as the magnetic source, the conductor ring 60 as the conductor loop, and the axial gap between the two as the working magnetic gap.

[0066] During operation of the device, the input end 90 drives the two inner rings to rotate synchronously, and the first rolling body and its adjacent raceway and the second rolling body and its adjacent raceway form a friction and micro-slip traction contact under the action of lubrication and normal load, thereby the integrated cage 40 obtains a controlled speed difference between the inner and outer rings, and the second outer ring outputs the reduced speed and torque through the transmission connection with the output member 1000.

[0067] Since the first magnetic pole ring 50 is fixed to the end cover 80 and is stationary with the housing 10, and the conductor ring 60 is arranged on the end face of the integrated cage 40 and rotates with the cage, the conductor ring 60 cuts the static magnetic field provided by the first magnetic pole ring 50 and generates eddy currents in the circumferential direction. The eddy currents interact with the magnetic field to form a braking torque on the conductor ring 60, which is related to the relative angular velocity, and the torque acts on the cage in the opposite direction, thereby applying viscous electromagnetic damping to the cage. The magnetic flux starts from the pole face of the multi-pole permanent magnet array, enters the conductor ring 60 through the axial magnetic gap, and is closed by the peripheral structure and the back iron ring, which reduces the magnetic resistance of the magnetic circuit and stabilizes the operating point. As the speed, load or lubrication state changes, the speed of the cage relative to the static magnetic field changes accordingly, the size of the eddy current changes, and the damping torque self-adapts to increase or decrease, thereby suppressing the speed fluctuations and torque fluctuations induced by low-speed crawling, roller spinning and stick-slip. During the start and stop of the device, the Joule heat in the conductor ring 60 is dissipated by conduction and convection through the cage and the surrounding oil film, the end cover 80 and the housing 10, and the recess cavity of the end cover 80 simultaneously serves as a magnetic source protection and heat dissipation guide.

[0068] This embodiment is suitable for scenarios where space is limited and the axial dimension needs to be prioritized, such as compact joints, precision servo units, and micro transmission modules. During installation, the positioning surfaces of the end cover 80 and the housing 10 should be clean and smooth, and the cooperation with the bearing outer ring should be reliable, with coaxiality meeting the requirements of stable magnetic gap. The connection between the conductor ring 60 and the retainer should have sufficient centrifugal and fatigue resistance, and there should be no hard contact or foreign matter intrusion between the end face of the conductor ring 60 and the pole face of the permanent magnet. Lubrication should be matched with the type of bearing to maintain oil film continuity and cleanliness; the environmental temperature and humidity should fall within the applicable range of the housing 10 material, permanent magnet material, and lubricating material, and strong magnetic particles should be prevented from entering the recess area.

[0069] The first back iron ring 510 can be a solid turned part or a sintered part. The solid turned part is easy to obtain good geometric precision and surface quality, suitable for scenarios with medium to high speed and higher damping consistency requirements; the sintered part is easy to mass produce and can pre-embed positioning features during forming. The axial width of the back iron ring can be slightly larger than the effective width of the conductor ring 60 to reduce end leakage; the radial thickness can be comparable to or slightly larger than the average thickness of the permanent magnet to avoid local saturation. The permanent magnet array can adopt equal arc length uniform distribution, with the pole face facing the accommodation space 110 and the back face adhering to the back iron ring; the selection of pole arc and inter-pole gap can consider both magnetic density uniformity and bonding reliability, and a non-magnetic pressure ring or end plate can be added outside the array to improve centrifugal resistance and durability. To improve assembly robustness, positioning ribs or shallow grooves can be provided at the bottom of the recess to limit the circumferential slip of the permanent magnet array; demagnetization grooves can also be arranged on the non-working side of the back iron ring to reduce edge current and improve heat distribution. The conductor ring 60 can be made of high-conductivity metal whole ring material or composite ring material, and if necessary, a damping layer or vibration isolation ring can be added at the connection with the retainer to reduce high-frequency vibration coupling to the retainer body. The setting of the axial magnetic gap can be achieved by the cooperation of the positioning shoulder in the end cover 80 and the stop at the end of the retainer, and assisted by a small amount of adjustment pad; when it is necessary to maintain damping linearity within a wider speed band, the number of poles and the effective width of the pole face of the permanent magnet array can be adjusted to match the spatial harmonics of the magnetic field with the target speed band. As long as the basic conditions of the first magnetic pole ring 50 being fixed in the recess of the end cover 80 to form a stable static magnetic field, the conductor ring 60 being rigidly connected with the end face of the integrated retainer 40 and forming a stable axial magnetic gap with the pole face of the permanent magnet are met, an equivalent electromagnetic damping effect can be obtained.

[0070] In this embodiment, by adopting the technical means of arranging an annular cavity 810 in the end cover 80, fixing the first magnetic pole ring 50 composed of a back iron ring and a multi-pole permanent magnet array in the cavity, and installing a continuous conductive loop conductor ring 60 on the end face of the integrated cage 40 and keeping a stable axial magnetic gap with the pole face of the first magnetic pole ring 50, the conductor ring 60 generates eddy current relative to the static magnetic field during operation and exerts viscous type electromagnetic damping on the cage, thus effectively solving the technical problems that the existing structure is difficult to introduce reliable damping elements in a compact space, the cage damping is insufficient, the load and lubrication fluctuation is sensitive, low-speed crawling and torque ripple are prone to occur, and noise and temperature rise fluctuation are prone to occur, and further realizing self-adaptive suppression of the speed fluctuation of the cage and improvement of the stability of the output side without changing the existing stress and assembly chain, so that the transmission is more continuous and smooth, and the assembly convenience and manufacturability are considered.

[0071] Please refer to Figures 2-3 In the second embodiment, the inner wall of the housing 10 is provided with a first annular structure 120 between the first bearing 20 and the second bearing 30, and the first magnetic pole ring 50 is fixed to the annular inner wall of the first annular structure 120. The outer periphery of the integrated cage 40 is provided with a protruding second annular structure 410 corresponding to the position of the first magnetic pole ring 50, the conductor ring 60 is sleeved on the outer periphery of the second annular structure 410, and the outer periphery wall of the second annular structure 410 is arranged opposite to the inner periphery wall of the first annular structure 120, and the magnetic gap is a radial magnetic gap.

[0072] Specifically:

[0073] The first annular structure 120 is arranged on the inner wall of the housing 10 between the two bearings, which is an annular step or a ring that is concentric with the axis and forms an annular inner wall surface facing the axis. The first magnetic pole ring 50 is fixed to the annular inner wall, so that it is rigidly connected to the housing 10 and remains stationary. The first magnetic pole ring 50 is composed of a first back iron ring 510 and a first multi-pole permanent magnet array 520:

[0074] The first back iron ring 510 is made of high permeability soft magnetic material and is integrally machined or sintered. The inner cylindrical surface is used as the assembly positioning surface of the magnetic pole ring, the outer cylindrical surface is precisely fitted with the inner wall of the first annular structure 120 of the housing 10, and the axial ends can be provided with limiting shoulders or press rings to obtain reliable axial positioning and anti-loose. The axial width of the back iron ring is preferably not less than the effective axial width of the conductor ring 60 to reduce end leakage; the radial thickness is preferably not less than the average radial thickness of the permanent magnet to avoid local magnetic saturation. The non-working side of the back iron ring can be provided with a circumferential demagnetization slot or a light weight slot for weakening the circulating current, improving heat distribution and reducing weight.

[0075] The first multipole permanent magnet array 520 is located on the side of the back iron ring facing the holder, with multiple circular arc magnetic steels uniformly arranged along the circumference, with adjacent magnetic poles alternating in opposite names, preferably radially magnetized or composite magnetized with a dominant radial component. The radial height of the pole surface of the permanent magnet and the ratio of the arc direction pole arc are determined comprehensively according to the target magnetic density and the assembly tolerance, and the pole surface should be coaxial and parallel to the working surface of the conductor ring 60 as much as possible; the permanent magnet is attached to the back iron ring through structural glue, and is assisted by a non-magnetic pressing ring or an end pressing plate for limiting, so as to improve the anti-centrifugal and anti-thermal cycle ability. The surface of the permanent magnet is subjected to corrosion-resistant coating or sealing and filling treatment to prevent moisture and lubricating medium from eroding.

[0076] The outer peripheral side of the integrated holder 40, which is opposite to the first magnetic pole ring 50, is integrally formed with a second annular structure 410, which is equivalent to a continuous annular flange processed on the outer periphery of the holder. The conductor ring 60 is mounted on the outer cylindrical surface of the second annular structure 410 in a sleeved manner, and the conductor ring 60 is a closed conductive loop, preferably a whole ring material or a multi-layer composite ring material with high conductivity, and is rigidly connected with the holder through expansion, mechanical buckle or ring locking; a thin layer of insulation or wear-resistant spacer can be added between the conductor ring 60 and the holder to suppress fretting wear and electrochemical corrosion. The inner peripheral side wall of the first annular structure 120 is opposite to the outer peripheral side wall of the second annular structure 410, and a uniform annular radial magnetic gap is formed between the two. The coaxiality of the shell 10 and the holder, the roundness of the two annular structures, and the assembly positioning shoulder jointly guarantee the radial magnetic gap, which can be finely set through micro-adjusting shims or adjustable check rings.

[0077] To ensure reliable operation, the shell 10 and the first outer ring are connected by positioning shoulder and interference or precise gap fit to maintain coaxiality and rigidity; the connection between the input end 90 and the two inner rings adopts a rigid method such as spline or keying to ensure synchronization and stable torque transmission path; the second outer ring and the output member 1000 are connected by interference fit or flange connection to ensure the coaxiality and bearing capacity of the output.

[0078] After the device is put into operation, the input end 90 drives the two inner rings to rotate synchronously. The first rolling body and its adjacent raceway, as well as the second rolling body and its adjacent raceway, form a friction and micro-slip traction contact that can transmit torque under the action of lubrication and normal load. The integrated holder 40 obtains a controlled speed difference between the inner and outer rings under the dragging action of the rolling body, and the second outer ring is connected to the output member 1000 through transmission to output the reduced speed and torque.

[0079] As the first magnetic pole ring 50 is fixed with the shell 10, and the conductor ring 60 is installed on the outer periphery of the retainer and rotates with the retainer, the conductor ring 60 generates a circumferential relative speed relative to the first magnetic pole ring 50. In the circumferential alternating static magnetic field established by the permanent magnet array, the circumferential path of the conductor ring 60 forms a closed loop, and eddy currents are induced due to the relative motion; the eddy currents interact with the magnetic field to generate an electromagnetic torque on the conductor ring 60 in the opposite direction of braking according to the electromagnetic force rule, which appears as viscous damping to the retainer. The radial magnetic gap allows the magnetic flux to cross the gap from the pole face of the permanent magnet into the body of the conductor ring 60, and then to close through the back iron ring and the surrounding metal path, which significantly reduces the magnetic resistance of the magnetic circuit and stabilizes the magnetic flux distribution. As the relative speed of the retainer changes due to changes in load or lubrication state, the size of the eddy current changes, and the damping torque adjusts adaptively, thereby suppressing the fluctuation of the retainer speed, reducing the roller spin and stick-slip, and further reducing the torque ripple and low-speed crawling on the output side. When the device starts and stops or the working condition fluctuates, the heat generated by the eddy currents in the conductor ring 60 is dissipated through convection and conduction of the retainer, shell 10 and lubricating medium, and the radial magnetic gap structure is open in the circumferential direction, which is beneficial to the removal of heat by oil mist and air flow.

[0080] During assembly, the first annular structure 120 inside the shell 10 is used as the only positioning reference for the magnetic pole ring. First, the back iron ring is installed with interference or positioning shoulder, then the permanent magnet array is attached and limited by the ring, ensuring that the pole face is concentric with the axis and the end face runout is controlled. Then the integrated retainer 40 and conductor ring 60 assembly is installed, the circumferential consistency of the radial magnetic gap is detected using special gauges or online measurement devices, and adjusted by adjusting the gaskets. During operation, monitor the bearing temperature rise and vibration to ensure clean lubrication; the connection between the conductor ring 60 and the retainer should not be loose or rub; hard particles should not enter the magnetic gap area; if a monitoring module is configured, the damping state can be indirectly evaluated through the output speed ripple and shell 10 vibration signals.

[0081] This embodiment is suitable for scenarios where the axial height is limited and the radial height is sufficient, or where electromagnetic damping needs to be introduced without modifying the end cover 80 and the input and output end structures. The installation environment should have good coaxial positioning conditions and clean lubrication supply; it is recommended to set up flow guide and heat dissipation channels on the shell 10 to improve the heat exchange efficiency of the radial magnetic gap area. The temperature and humidity conditions should meet the stable working range of the shell 10 material, permanent magnet material and lubricating material; strong magnetic dust should be avoided from entering the magnetic gap area between the first annular structure 120 and the second annular structure 410.

[0082] The first back iron ring 510 can be a whole turning piece to obtain higher geometric precision and surface quality, and is suitable for high-speed and high-damping consistency working conditions; or can be a sintered piece to be batched and to pre-locate positioning ribs or clamping grooves in the forming stage. The axial width of the back iron ring can be equivalent to or slightly larger than the effective width of the conductor ring 60 to suppress end magnetic leakage; the radial thickness can be equivalent to or slightly larger than the average radial height of the permanent magnet to reduce the risk of magnetic saturation. The permanent magnet array can be evenly distributed with equal arcs or optimally distributed with small pitch, and the pole arc duty ratio and the inter-pole gap width are comprehensively set according to the target magnetic flux density and the bonding strength; the magnetization direction is preferably radial, or a composite magnetization with an axial component can also be used to optimize the magnetic field waveform. A thin layer of insulation or adhesive primer can be added between the permanent magnet and the back iron ring to improve durability and corrosion resistance; a non-magnetic pressing ring or end plate is arranged outside the array to improve the anti-centrifugal and anti-vibration ability. The conductor ring 60 can be a whole high-conductivity metal ring or composed of multiple layers of metal, and the circumferential resistance and thickness are set according to the target damping and heating trade-off, and the equivalent thickness of the conductor ring 60 is preferably equivalent to or slightly smaller than the skin depth of the expected working frequency band to obtain better damping efficiency and heat management. A thin layer of vibration isolation or wear-resistant gasket can be added between the second ring structure 410 and the conductor ring 60 to reduce micro-motion wear and improve long-term stability. The tolerance band of the radial magnetic gap is set according to the coaxiality ability of the shell 10 and the retainer, and is preferably reviewed and compensated by adjustable check rings or micro-adjustment gaskets after assembly. As long as the basic conditions that the first magnetic pole ring 50 is fixed on the annular inner wall of the first ring structure 120 of the shell 10, the conductor ring 60 is rigidly sleeved on the outer periphery of the retainer second ring structure 410 and is concentric with it, and a stable annular radial magnetic gap is formed between them, the electromagnetic damping effect equivalent to the present embodiment can be achieved.

[0083] In the present embodiment, since the first magnetic pole ring 50 composed of a back iron ring and a multi-pole permanent magnet array is fixed at the first ring structure 120 of the inner wall of the shell 10 and is oppositely arranged and uniformly spaced from the conductor ring 60 mounted on the outer periphery of the integrated retainer 40 in a circumferential coaxial manner to generate eddy current in the conductor ring 60 relative to the static magnetic field and to exert viscous electromagnetic damping on the retainer, the problems of difficulty in introducing reliable damping elements under axial space limitation, damping instability caused by end face runout, and significant retainer speed fluctuation and roller spin slip under load and lubrication fluctuation are effectively solved, and the technical effects of obtaining stable and adjustable adaptive damping, reducing output torque ripple and low-speed crawling, and improving heat dissipation and assembly robustness are achieved without changing the existing stress and assembly chain.

[0084] On the basis of the second embodiment, in some further embodiments, the conductor ring 60 is composed of two annular pieces with different outer diameters, namely a first annular piece 610 and a second annular piece 620, the first annular piece 610 and the second annular piece 620 are coaxial and arranged side by side, and the first annular piece 610 is arranged opposite to the first magnetic pole ring 50; the friction speed reducer further comprises a second magnetic pole ring 70, the second magnetic pole ring 70 is arranged in the circumferential area of the outer wall of the second bearing 30 which does not contact and bear the rolling elements of the second bearing 30 in the working state, and the rolling track on the outer wall of the second bearing 30 is staggered in the axial direction, and the second annular piece 620 is arranged opposite to the second magnetic pole ring 70; wherein the first magnetic pole ring 50 is a static magnetic pole ring, and the second magnetic pole ring 70 is a follow-up magnetic pole ring. The first annular piece 610 and the second annular piece 620 are left with an annular groove 630.

[0085] Specifically:

[0086] A first annular structure 120 is formed on the inner wall of the shell 10 between the two bearings, which is an annular step or a ring that is concentric with the axis, and the inner cylindrical surface serves as a mounting reference. The first magnetic pole ring 50 is fixed to the annular inner wall of the annular structure, so that it is rigidly connected with the shell 10 and remains stationary. The first magnetic pole ring 50 is composed of a first back iron ring 510 and a first multi-pole permanent magnet array 520. The first back iron ring 510 is made of high-permeability soft magnetic material, and the outer circle is in interference or positioning fit with the annular structure of the inner wall of the shell 10, and the inner cylindrical surface serves as the limiting surface of the magnetic flux loop; the axial width of the back iron ring is preferably not less than the effective axial width of the conductor ring 60, and the radial thickness is preferably not less than the average radial height of the permanent magnet, so as to reduce the risk of end leakage and local saturation. The first multi-pole permanent magnet array 520 is located on the side of the back iron ring facing the retainer, and is uniformly arranged in the circumferential direction according to the circular arc blocks, the adjacent magnetic poles are alternately named, and the radial magnetization or the composite magnetization with a radial component is preferred; the magnetic pole surface of the magnet faces the conductor ring 60, and the back surface is attached to the back iron ring, which is attached by structural glue and supplemented by non-magnetic compression ring or end plate limiting, and the exposed surface is treated for corrosion resistance and protection.

[0087] The outer circumferential side of the integrated holder 40 is integrally formed with the second annular structure 410 corresponding to the position of the first magnetic pole ring 50, which is a continuous outer cylindrical surface. The conductor ring 60 is installed in a sleeved manner on the outer cylindrical surface and is rigidly connected with the holder. The conductor ring 60 is composed of two annular parts with different outer diameters, namely a first annular part 610 and a second annular part 620, which are coaxial and arranged side by side. The first annular part 610 is located on the side close to the first magnetic pole ring 50 and is arranged opposite to the first magnetic pole ring 50 in the radial direction; the second annular part 620 is located on the side away from the first magnetic pole ring 50 and is arranged opposite to the second magnetic pole ring 70. An annular groove 630 is left between the two annular parts, which is continuous in the axial direction and continuous in the circumferential direction, and functions as electromagnetic decoupling and thermal isolation, while providing a machining and assembly reference.

[0088] The second magnetic pole ring 70 is arranged on the inner wall of the second outer ring and is installed at a position that does not contact and bear the second rolling body in the working state, and is staggered with the raceway on the inner wall of the second outer ring in the axial direction to avoid affecting the raceway bearing and lubrication channel. The second magnetic pole ring 70 is rigidly connected with the second outer ring and rotates with it. The second magnetic pole ring 70 is composed of a second back iron ring 710 and a second multi-pole permanent magnet array 720. The second back iron ring 710 is made of high-permeability soft magnetic material, the inner circle is positioned in close contact with the non-bearing surface of the inner wall of the second outer ring, and the outer circle serves as the limiting surface of the magnetic flux loop; the axial width thereof is preferably equivalent to or slightly larger than the effective axial width of the second annular part 620, and the radial thickness thereof is preferably not less than the average radial height of the second permanent magnet. The second multi-pole permanent magnet array 720 is uniformly arranged along the circumference in the form of circular arc blocks, with adjacent magnetic poles alternately having different names, preferably being radially magnetized, with the pole surface facing the second annular part 620 and the back surface being in close contact with the second back iron ring 710, and being fixed by a composite fixing method of bonding and limiting members, and being treated for corrosion and moisture resistance.

[0089] The inner circumferential wall of the first annular structure 120 is arranged opposite to the outer circumferential wall of the second annular structure 410, and a uniform annular radial magnetic gap is formed therebetween. The first magnetic pole ring 50 is opposite to the first annular part 610 in the radial direction, and the second magnetic pole ring 70 is opposite to the second annular part 620 in the radial direction. Through the coaxiality control of the shell 10 and the holder, the roundness control of the annular structure, and the assembly surface runout control, the circumferential consistency and working stability of the two groups of radial magnetic gaps are ensured. The material of the conductor ring 60 is preferably high-conductivity metal or metal composite material, and the surface is treated for wear resistance and corrosion resistance; a thin layer of insulation or wear-resistant spacer can be added between the conductor ring 60 and the holder to suppress fretting wear and electrochemical corrosion.

[0090] The input end 90 drives the two inner rings to rotate synchronously, and the first rolling body and its adjacent raceway and the second rolling body and its adjacent raceway form a friction and micro-sliding traction contact under the action of lubrication and normal load, so that the integrated cage 40 obtains a controlled speed difference between the inner and outer rings under the dragging action of the rolling body, and the second outer ring outputs the reduced rotation speed and torque through the transmission connection with the output member 1000.

[0091] The stationary first magnetic pole ring 50 is radially opposite to the first annular member 610 mounted on the outer periphery of the cage, and when the cage rotates, the first annular member 610 cuts the magnetic lines in the static magnetic field generated by the first magnetic pole ring 50, and a closed vortex is formed in the first annular member 610, the vortex interacts with the magnetic field to generate a braking electromagnetic torque on the first annular member 610, which is a viscous type of damping to the cage and forms a counterforce path through the housing 10. At the same time, the second magnetic pole ring 70 rotating with the second outer ring is radially opposite to the second annular member 620 mounted on the outer periphery of the cage, and when the cage and the second outer ring have relative rotation, the second annular member 620 cuts the magnetic lines in the magnetic field of the second magnetic pole ring 70 to form a vortex, and an electromagnetic torque of the same size and opposite direction is generated between them, which on one hand continues to exert viscous damping on the cage, and on the other hand directly exerts a counter-torque on the second outer ring, thereby directly suppressing the speed fluctuation on the output side. The two groups of couplings work together, and the electromagnetic decoupling of the annular groove 630 significantly weakens the influence between them, and each mainly acts on different relative speed components of the cage relative to the housing 10 and the cage relative to the outer ring, thereby obtaining a wide-band, double-channel speed stabilization and vibration suppression effect.

[0092] During assembly, the first annular structure 120 in the housing 10 is used as the positioning reference of the first magnetic pole ring 50, the first back iron ring 510 is first assembled with interference or positioning shoulder, then the first permanent magnet array is attached piece by piece and limited by a pressure ring or end plate to ensure the concentricity of the pole surface and the axis. Then the integrated cage 40 assembly with the second annular structure 410 is assembled, the segmented conductor ring 60 is sleeved and locked, and the circumferential consistency of the radial magnetic gap between the first magnetic pole ring 50 and the first annular member 610 is detected; then the second back iron ring 710 and the second permanent magnet array are assembled with the non-load-bearing annular area of the inner wall of the second outer ring as the positioning surface, and after completion, the circumferential consistency of the radial magnetic gap between the second magnetic pole ring 70 and the second annular member 620 is detected. The limit deviation of the two groups of magnetic gaps is corrected by adjusting the gasket or adjustable check ring to ensure that rubbing and instability do not occur during operation. Lubrication, sealing and ventilation are implemented according to the standard process of the bearing and the housing 10 to keep the passage unobstructed and the interior clean.

[0093] This embodiment is suitable for scenarios where axial height is limited but radial space is relatively abundant, or where electromagnetic damping needs to be introduced without modifying the end structure and directly acting on the output side. The installation environment should have good coaxial positioning and size control capabilities to ensure the stability of the two sets of radial magnetic gaps. It is recommended to set up flow guide and heat dissipation channels on the shell 10 to improve the heat exchange efficiency of the segmented conductor ring 60 periphery. The working temperature and humidity should meet the stable range of the shell 10 material, permanent magnet material and lubricating material; magnetic particles should be prevented from entering the two sets of magnetic gap areas to prevent affecting the damping and gap stability.

[0094] The first back iron ring 510 can be a whole turning piece to obtain higher geometric precision and surface quality, or a sintered piece to facilitate batch production and pre-positioning ribs and clamping grooves in the forming stage. The second back iron ring 710 is the same. The permanent magnet array can use equal arc length uniform distribution or small pitch optimization distribution, and the pole arc and gap are determined comprehensively according to the target magnetic density, assembly process and bonding strength; a non-magnetic pressing ring or end pressing plate can be set on the outer side of the array to improve the anti-centrifugal and anti-thermal cycle ability. The first permanent magnet and the second permanent magnet are preferably radially magnetized, and can also use composite magnetization with an axial component to optimize the magnetic field waveform. The segmented conductor ring 60 can use a whole high-conductivity metal ring material or a multi-layer composite ring material, and the outer diameter difference between the first ring member 610 and the second ring member 620 is set to be moderate, so that the first magnetic pole ring 50 and the first ring member 610, the second magnetic pole ring 70 and the second ring member 620 establish reasonable magnetic gap and magnetic flux density at their respective working radii; the annular groove 630 between the two segments has moderate axial width and groove depth to balance electromagnetic decoupling, heat dissipation and structural strength. A thin layer of vibration isolation or wear-resistant gasket can be added between the conductor ring 60 and the retainer to reduce micro-motion wear and improve long-term stability. As long as the basic conditions of the stationary first magnetic pole ring 50 and the first ring member 610 being opposite in the radial direction, the following second magnetic pole ring 70 and the second ring member 620 being opposite in the radial direction, the two sets of magnetic gaps being stable and consistent, and the segmented conductor ring 60 and the retainer being rigidly connected, the electromagnetic damping effect equivalent to this embodiment can be obtained.

[0095] In this embodiment, the first magnetic pole ring 50 is arranged on the first annular structure 120 in the housing 10, and the segmented conductor ring 60 is arranged on the second annular structure 410 on the outer periphery of the integrated cage 40, and the two are coaxially opposed to form a radial magnetic gap. The second magnetic pole ring 70 is arranged on the non-load ring area of the inner wall of the second outer ring and is axially staggered with the raceway. The first magnetic pole ring 50 and the first annular member 610 generate an electromagnetic damping torque relative to the housing 10 of the integrated cage 40, and the second magnetic pole ring 70 and the second annular member 620 generate an electromagnetic damping torque relative to the second outer ring of the integrated cage 40, thereby forming a double-channel eddy current damping that simultaneously acts on the integrated cage 40 and the output outer ring of the second bearing 30. Therefore, the problems of providing damping only on one side of the housing 10, being difficult to stably maintain the magnetic gap in a limited space, easily interfering with the raceway load, and having no direct suppression of the output side speed ripple are effectively solved, and the absolute speed of the cage and the relative speed of the cage and the outer ring are cooperatively suppressed without affecting the load surface, thereby widening the damping bandwidth, reducing the torque ripple, reducing stick-slip and crawling, improving output stability, and achieving compact assembly and manufacturability.

[0096] Further, in some embodiments, the central cross section of the first magnetic pole ring 50 in the axial direction is aligned with the central cross section of the first annular member 610 in the axial direction, and the ratio of the axial width of the first magnetic pole ring 50 to the axial width of the first annular member 610 is 1.1-1.6; the central cross section of the second magnetic pole ring 70 in the axial direction is aligned with the central cross section of the second annular member 620 in the axial direction, and the ratio of the axial width of the second magnetic pole ring 70 to the axial width of the second annular member 620 is 1.1-1.6.

[0097] Specifically:

[0098] To improve the edge magnetic flux distribution and suppress leakage, the central cross section of the first magnetic pole ring 50 in the axial direction is aligned with the central cross section of the corresponding first annular member 610 in the conductor ring 60 in the axial direction. Correspondingly, when the device also includes a second magnetic pole ring 70 and a second annular member 620 in the conductor ring 60 related to the output side, the axial center cross section of the second magnetic pole ring 70 is aligned with the axial center cross section of the second annular member 620. To further suppress the pole edge leakage and improve the uniformity of the eddy current distribution, the axial effective width of the magnetic pole ring is slightly larger than the axial effective width of the corresponding annular member of the conductor ring 60, and the upper limit is not more than 1.6 and the lower limit is not less than 1.1. This ratio is also applicable to the first magnetic pole ring 50 and the first annular member 610, and the second magnetic pole ring 70 and the second annular member 620.

[0099] The axial width of the back iron ring is slightly wider than the conductor ring 60 ring, and the radial thickness is determined according to the principle of unsaturated magnetic circuit, so that the back iron does not enter the obvious saturation area under the working magnetic density. The conductor ring 60 is made of high-conductivity material and is rigidly connected with the integrated holder 40 as a closed conductive loop, and the axial effective width of the conductor ring 60 is matched with the corresponding width of the magnetic pole ring according to the above-mentioned matching relationship. If the radial magnetic gap scheme is adopted, the inside of the shell 10 forms a first annular structure 120 for fixing the first magnetic pole ring 50, and the outer periphery of the integrated holder 40 forms a second annular structure 410 for sleeving the conductor ring 60; if the axial magnetic gap scheme is adopted, a ring-shaped recess 810 is formed in the end cover 80 to accommodate the first magnetic pole ring 50, and the conductor ring 60 is arranged on the end face of the holder and extends axially towards the end cover 80. In both schemes, the center surfaces of the magnetic pole ring and the conductor ring 60 are aligned and the width matching is implemented in the same way.

[0100] Aligning the axial center surfaces of the magnetic pole ring and the conductor ring 60 can make the main magnetic flux more symmetrically distributed in the thickness range of the conductor ring 60, reduce the edge field strength gradient, make the eddy current density more uniform along the axial direction, and avoid local overheating and local strengthening of the conductor edge. Slightly increasing the axial effective width of the magnetic pole ring relative to the conductor ring 60 ring can make the main magnetic flux basically covered by the conductor, suppress the leakage magnetic flux of the pole edge and the torque pulsation caused by the edge effect, and at the same time, it is more fault-tolerant to the slight axial deviation caused by assembly.

[0101] The width matching of the slightly wider magnetic pole ring can adopt different width distribution methods in different embodiments, for example, the effective width of the magnetic pole ring remains unchanged and the effective width of the conductor ring 60 is reduced, or the effective width of the conductor ring 60 remains unchanged and the effective width of the magnetic pole ring is moderately widened, the principle is to ensure that the working area of the conductor is completely covered by the main magnetic flux, while not excessively increasing the volume of the magnet, so as to balance the damping efficiency and heat management. For the double magnetic pole ring scheme, different width matching can be used respectively to achieve staggered peaks and complementarity in the frequency band: the side magnetic circuit of the shell 10 focuses on improving low-frequency linearity and tolerance robustness, and the output side magnetic circuit focuses on suppressing the relative speed wave of the holder and the outer ring. If the application environment is extremely compact, the conductor ring 60 can be made into a multi-layer composite structure to achieve the magnetic circuit coverage effect equivalent to the above-mentioned matching by changing the combination of the equivalent thickness and the effective width between the layers.

[0102] The principle of center surface alignment comes from the symmetry design of the magnetic circuit: when the axial center surfaces of the magnetic pole ring and the conductor ring 60 are aligned, the main magnetic flux is approximately symmetrically distributed in the thickness direction of the conductor, the edge field strength peak is reduced, the eddy current density is more uniform along the axial direction, and the differential stiffness of the electromagnetic torque is more stable, thereby reducing the torque pulsation and the risk of edge overheating. If there is an axial offset, local magnetic saturation or eddy current concentration may occur on one side of the conductor, resulting in damping nonlinearity and uneven temperature rise.

[0103] The determination of the width ratio follows the comprehensive criteria of complete coverage, moderate leakage, leakage suppression, and loss control: when the pole ring is equal in width to the conductor ring 60, the magnetic lines of force at the edge tend to leak, and the eddy current density at the edge of the conductor is easily affected by assembly deviations; when the pole ring is slightly wider than the conductor ring 60, the main magnetic flux is basically closed within the working area of the conductor, the edge leakage is suppressed, and small axial misalignment is tolerated. If the pole ring is too wide, the volume of the magnet and the mass of the back iron increase unnecessarily, and the pole edge far from the conductor has limited contribution to the eddy current, with diminishing returns. Through comprehensive magnetic circuit simulation, sample testing, and manufacturing tolerance analysis, it is determined that the effective width ratio of the pole ring to the conductor ring 60 should be slightly greater than equal width and not more than about 1.6; the lower limit should not be less than about 1.1 to ensure a significant coverage margin. This interval takes into account the comprehensive realizability of magnetic circuit efficiency, damping linearity, edge temperature rise, and processing and assembly. Ordinary designers in the field can complete the value selection according to the following process: based on the target damping and temperature rise indicators, start with equal width for magnetic circuit simulation and sample measurement, and observe the torque ripple and edge temperature rise; gradually increase the effective width of the pole ring until the torque ripple and edge temperature rise enter the stable interval and the returns are no longer significantly increased, and then select a slightly wider ratio; independently determine the output side magnetic circuit according to the same process, and make fine adjustments according to the frequency band coverage requirements of the two channels.

[0104] In this embodiment, by adopting the technical means of aligning the axial center faces of the pole ring and the conductor ring 60 and making the axial effective width of the pole ring slightly greater than equal width and not more than 1.6 relative to the corresponding conductor ring 60, the technical problems of asymmetric distribution of main magnetic flux in the thickness direction of the conductor, significant leakage at the edge of the pole, unstable damping caused by assembly micro-deviation, edge overheating, and large torque ripple in the existing structure are effectively solved, thereby achieving more linear viscous damping, lower torque ripple, and more controllable temperature rise in a compact structure without changing the existing assembly chain, and improving the comprehensive technical effects of fault tolerance and long-term stability to assembly and operation deviations.

[0105] Further, the radial magnetic gap between the inner cylindrical surface of the first magnetic pole ring 50 and the outer cylindrical surface of the first annular member 610 satisfies the following condition: the radial magnetic gap between the inner cylindrical surface of the second magnetic pole ring 70 and the outer cylindrical surface of the second annular member 620 satisfies the following condition: wherein: R1 is the outer radius of the first annular member 610; R2 is the outer radius of the second annular member 620; h is the radial thickness of the conductor ring 60.

[0106] Specifically:

[0107] The radial thickness of the conductor ring 60 is denoted as t. The second pole ring 70 is composed of a second back iron 710 and a second multi-pole permanent magnet array 720, whose inner cylindrical surface serves as the magnetic gap reference surface opposite to the second ring 620. The outer radius of the first ring 610 is denoted as , and the outer radius of the second ring 620 is denoted as ; the first magnetic gap is denoted as (the radial separation between the inner cylindrical surface of the first pole ring 50 and the outer cylindrical surface of the first ring 610), and the second magnetic gap is denoted as (the radial separation between the inner cylindrical surface of the second pole ring 70 and the outer cylindrical surface of the second ring 620). The size of the two magnetic gaps determines the magnetic reluctance of the magnetic circuit, the eddy current distribution in the conductor, and the thermal management boundary, thereby determining the damping coefficient, linearity, and temperature rise level. The radial magnetic gap needs to be small enough to obtain effective magnetic flux density and damping, and large enough to accommodate manufacturing and running deviations and control heating. Two types of dimensionless ratios are introduced in engineering: the geometric ratio , which reflects the proportion of the magnetic gap relative to the conductor radius, and an excessive ratio will dilute the magnetic flux and reduce the damping, and an excessively small ratio will be too sensitive to coaxiality and runout; and the thickness ratio , which reflects the proportion of the magnetic gap relative to the effective thickness of the conductor, and an excessive ratio will result in weak damping, and an excessively small ratio will easily heat up and be extremely unfriendly to manufacturing.

[0108] Combined with magnetic circuit simulation and sample testing, the following engineering manufacturable range can be used: ; This range can obtain good damping efficiency and assembly robustness under most size and material combinations of miniaturized joints and precision servo.

[0109] Damping is mainly related to the effective current layer thickness in the conductor. The skin depth is estimated by the electrical resistivity of the conductor , the equivalent magnetic permeability , and the equivalent angular frequency of the eddy current . and the number of pole pairs of the permanent magnet (e.g., the order of ). In design, it is beneficial to make and of the same order of magnitude or slightly larger, which is conducive to obtaining high damping within the target speed band and avoiding overheating. If , the damping is weak; if , the benefit of increasing the thickness decreases and the weight increases the heating. Correspondingly, is too small, the magnetic flux density is high, but the loss and temperature rise quickly rise, is too large, and the damping is weakened.

[0110] The lower limit of the magnetic gap is determined by the following dimension:

[0111] Sum of coaxiality and roundness error of bearing and housing 10 (including the fit error of integrated cage 40 and outer ring) ;

[0112] Radial runout and thermal expansion difference of rotor operation;

[0113] Tolerance superposition of assembly positioning shoulder and retainer;

[0114] Take the most unfavorable side of the above deviation, and multiply by the safety factor to get the minimum magnetic gap . Generally Substitute the above formula into the lower half of the recommended interval.

[0115] The upper limit of the magnetic gap is determined by the target damping coefficient and the heat constraint:

[0116] In electromagnetic simulation, gradually increase , until the damping torque slope drops to the target lower limit or the torque ripple increases to an unacceptable level; in thermal simulation or prototype testing, confirm that the conductor and magnet temperature rise does not exceed the material and lubrication allowable value. Take the maximum , which is usually located in the upper half of the recommended interval.

[0117] When the housing 10 side is more inclined to suppress the absolute speed wave of the cage relative to the housing 10, the output side is more inclined to suppress the relative speed wave of the cage and the outer ring. The actual design can follow the "inside first, outside second" strategy: first to obtain the required baseline damping and linearity; then to match the second pole pair number and phase offset, expand the frequency band and suppress the output side ripple; the of the two can be adjusted respectively to take into account the heat and efficiency. Specific examples are as follows:

[0118] Material selection and initial setting: determine the conductor material and thickness , initially estimate and make or slightly larger.

[0119] Tolerance summary: statistics of coaxiality, runout, thermal expansion difference, and .

[0120] Initial value selection: take ( or ).

[0121] Simulation and sample: take as the starting point to scan , evaluate the damping slope, torque ripple and temperature rise, and the landing point remains within the upper limit of the interval.

[0122] Trial production and verification: Full-angle magnetic gap consistency testing, repeated testing under thermal steady-state and start-stop conditions, and fine-tuning to a process benchmark with batch tolerances.

[0123] Key aspects of the implementation process include:

[0124] Unified reference: The assembly reference of the first magnetic pole ring 50 is taken only from the inner wall of the first annular structure, and the assembly reference of the second magnetic pole ring 70 is taken only from the non-load-bearing area of ​​the inner wall of the outer ring, so as to avoid crosstalk between the two references.

[0125] Circumferential consistency: The roundness and coaxiality of the conductor ring 60 and the magnetic pole ring directly determine the circumferential uniformity of the magnetic gap. If necessary, adjustments can be made by measuring the inner and outer diameters and cooperating with the in-situ air gap gauge.

[0126] Magnetic gap protection: Non-contact protective covers and flow guide channels are set in the two magnetic gap areas to prevent hard particles from entering and enhance convective heat dissipation;

[0127] Oil circuit does not interfere: The second magnetic pole ring 70 is axially offset from the outer ring raceway and retains the oil return channel to ensure that load bearing and lubrication are not affected.

[0128] It should be noted that the conductor ring 60 can be made of high-conductivity copper or aluminum; the back iron can be made of pure iron or silicon steel; and the permanent magnet can be made of a high-remanence, low-temperature drift material with surface corrosion protection. Furthermore, a thin layer of vibration isolation or wear-resistant pads can be added between the conductor ring 60 and the cage; a flow channel can be added to the annular groove 630 between the two conductor rings 60 to improve convection. Moreover, when an increase in the number of pole pairs leads to an increase in the equivalent frequency and a decrease in the skin depth, the [material / material] can be appropriately reduced. or increase Temperature control; when the target's low-speed damping needs to be enhanced, it can be set at a temperature not lower than [specific value missing]. Slightly reduce under the premise And increase the cross section of the back iron to suppress saturation.

[0129] In this embodiment, the radial magnetic gap parameterization design constrained by dimensionless geometric ratio and thickness ratio is adopted. The values ​​of the two magnetic gaps are determined under the multi-objective conditions of taking into account mechanical tolerance, thermal expansion and electromagnetic efficiency. This allows the electromagnetic coupling between the shell 10 side and the output side to obtain stable and efficient viscous damping. Therefore, it effectively solves the technical problems in the existing structure where the magnetic gap is difficult to balance damping strength and assembly robustness, and where torque ripple and local overheating are prone to occur under load and lubrication fluctuations. Thus, it achieves the comprehensive technical effect of adaptive speed stabilization and vibration suppression, controlled temperature rise and mass manufacturability in a compact space.

[0130] Further, the ratio of the difference between the outer radius of the second ring member 620 and the outer radius of the first ring member 610 to the outer radius of the first ring member 610 is 0.03-0.12; the ratio of the axial width of the annular groove 630 to the sum of the axial width of the first ring member 610 and the axial width of the second ring member 620 is 0.12-0.30; the ratio of the groove depth of the annular groove 630 to the radial thickness of the first ring member 610 is any value in the range of 0.3-0.8, and the ratio of the groove depth of the annular groove 630 to the radial thickness of the second ring member 620 is any value in the range of 0.3-0.8.

[0131] In particular:

[0132] The overall force of the device and the transmission chain are similar to the foregoing embodiments.

[0133] The outer radius of the first ring member 610 is denoted as The outer radius of the second ring member 620 is denoted as The radial thickness of the conductor ring 60 is denoted as In the present embodiment, the following ratios and ranges are satisfied: the outer diameter difference ratio The axial width of the annular groove 630 is in the specified range, which is used for the working radius of the two misaligned magnetic circuits, reduces the magnetic coupling and the moment of inertia, and facilitates independent tuning of the two magnetic gaps; the ratio of the axial width of the annular groove 630 to the sum of the axial widths of the two ring members is in the specified range, which is used for electromagnetic decoupling and heat channel design, and takes into account structural stiffness and manufacturability. The ratio of the groove depth of the annular groove 630 to the radial thickness of the first ring member 610 and the second ring member 620 respectively falls within the specified range, so that the groove depth can form an effective magnetic barrier layer and a convection channel, without weakening the strength and stiffness of the ring members.

[0134] The material of the conductor ring 60 is preferably high-conductivity copper or aluminum, and the surface can be anodized or coated with corrosion-resistant material; the connection with the retainer is achieved by expansion, mechanical buckling or ring locking, and a thin layer of insulation or wear-resistant spacer is added to the contact surface to inhibit fretting wear and electrochemical corrosion. The annular groove 630 is machined by turning or milling, and the groove bottom is rounded to reduce stress concentration.

[0135] The difference in outer diameter of the two ring members facilitates the misalignment of the two ring members, so that different linear speeds and electromagnetic coupling strengths can be obtained at the same relative angular velocity, facilitating staggered peaks in the frequency band; the annular groove 630 forms a high-magnetic-resistance and low-thermal-resistance partition between the two segments of the conductor, weakening the electromagnetic crosstalk of the two magnetic circuits and the possibility of cross-segment closure of the ring vortex, while providing a convection channel to reduce the temperature rise of the conductor. The three work together to enable the two damping channels to function with the target bandwidth and strength, without interfering with each other.

[0136] The design target of the outer diameter difference ratio is to balance the bandwidth complementarity of the two magnetic circuits, the rotational inertia of the conductor ring 60, and the structural strength. The outer diameter difference ratio accounts for a proportion of the outer radius of the first annular member 610 within a given range, and the following can be obtained:

[0137] The clear working radius distinction makes the equivalent line speeds and electromagnetic pressures of the two couplings different, which facilitates the absolute speed wave of one coupling to be biased to suppress the cage and the speed wave of the other coupling to be biased to suppress the outer ring of the cage;

[0138] The tolerance friendliness of manufacturing and assembly is improved, and small radial deviations do not cause the two magnetic gaps to deviate from the optimal points at the same time.

[0139] The overall rotational inertia of the conductor ring 60 is not excessively increased, avoiding additional dynamic load and energy consumption.

[0140] Specifically, the separation of the two target working radii is determined based on the target damping curve of the device, combined with the conductor material and thickness and the number of pole pairs to preliminarily select the outer diameter difference ratio; joint simulation of electromagnetism, heat, and structure is performed to evaluate the damping slope, torque ripple, conductor stress, and temperature rise; and iterative fine-tuning is performed in sample testing to select a ratio that meets the damping and strength boundaries and is friendly to manufacturing tolerances.

[0141] The axial width ratio of the annular groove 630 determines the degree of electromagnetic and thermal coupling of the two annular members in the axial direction and the overall stiffness of the conductor ring 60. The groove width accounts for a proportion of the sum of the axial widths of the two annular members within a given range, which can effectively improve the magnetic resistance isolation of the two magnetic circuits, reduce the cross-section eddy current ring, form sufficient convection and oil return channels to improve local temperature rise, and ensure the overall axial stiffness and fatigue resistance of the conductor ring 60.

[0142] Specifically, the lower limit of the groove width is given from the perspective of electromagnetic decoupling, and the upper limit of the groove width is given from the perspective of structural strength and processing feasibility; the influence of the groove width on damping linearity, temperature rise, and conductor stress is scanned in simulation, and sample testing is used for verification, and finally a value within the specified range is selected.

[0143] The groove depth ratio of the annular groove 630 accounts for a proportion of the radial thickness of the respective annular members within a specified range, which can:

[0144] Form a sufficient high-magnetic-resistance layer in the magnetic circuit to suppress edge current;

[0145] Form an effective channel in thermal management to promote radial and circumferential convection heat transfer;

[0146] Reserve sufficient residual cross-section in structure to avoid the risk of plasticity under high-cycle fatigue and centrifugal load.

[0147] Specifically: the thickness of the conductor ring 60 and the working speed are used to determine the centrifugal stress and fatigue life constraints, and the upper limit of the groove depth is given; the electromagnetic decoupling and the demand for convection channel are used to give the lower limit of the groove depth; the two side constraints are taken in the specified interval after comprehensive, and the thermal coupling simulation and sample test verification are carried out.

[0148] The key links in the implementation process include:

[0149] Tolerance summary and minimum gap reservation: while determining the outer diameter difference and the groove width and depth, the tolerance chain of the two radial magnetic gaps needs to be coordinated to ensure that there is no collision and magnetic gap collapse under the most unfavorable working conditions;

[0150] Coaxiality and roundness control: the conductor ring 60 is fitted with the reference surface of the shell 10 and the outer ring, and after assembly, the full circumference air gap gauge or non-contact probe is used for point-by-point re-measurement, and if necessary, the micro-adjusting washer is used for correction;

[0151] Groove bottom transition and surface treatment: the groove bottom adopts a round corner transition, the conductor surface is treated for corrosion and wear resistance, and the groove opening is appropriately blunt to prevent stress concentration and burr oil scraping;

[0152] Thermal path communication: flow guide grooves and oil return grooves are arranged on the shell 10 and the outer ring to make the convection in the groove and the oil return channel communicate with the total lubrication circuit, and avoid heat accumulation.

[0153] When further suppression of crosstalk is required, a thin and shallow flow guide groove or a low magnetic permeability pad can be added in the annular groove 630; when the strength needs to be enhanced, the groove bottom can be partially thickened with a small round corner transition, and the axial effective width of the two sections of the ring-shaped part can be appropriately increased.

[0154] When the skin depth decreases due to the increase of the number of pole pairs or the target speed, the conductor thickness can be slightly reduced or the groove width can be increased to control the temperature; when the target low-speed damping needs to be enhanced, the outer diameter difference and the groove depth can be adjusted slightly without affecting the strength, so that the magnetic flux of the first channel is more concentrated and the thermal path of the second channel is more smooth.

[0155] In this embodiment, by using the geometric parameterized design of setting two sections of ring-shaped parts with different outer diameters on the conductor ring 60 and setting the annular groove 630 with a specific axial width and groove depth ratio between the two sections, the two magnetic circuits are effectively separated and coordinated in terms of working radius, electromagnetic coupling and thermal channel, so that the technical problems of mutual crosstalk of the double-channel damping, difficulty in heat dissipation, damping instability and large torque ripple caused by sensitivity to assembly deviation in the existing structure are effectively solved, and the comprehensive technical effects of wider damping bandwidth, lower output ripple and more controllable temperature rise in a compact space are achieved, and the strength and manufacturability are also considered.

[0156] Furthermore, the number of pole pairs in the first multi-pole permanent magnet array 520 is different from the number of pole pairs in the second multi-pole permanent magnet array 720, and the phase misalignment φ between the two in the circumferential direction is different from the first monopole pitch of the first multi-pole permanent magnet array 520. Or the second monopole pitch of the second multipole permanent magnet array 720 The ratio is any value between 0.40 and 0.60; the ratio of the thickness of the first back iron ring 510 to the average thickness of the first multi-pole permanent magnet array 520 and the ratio of the thickness of the second back iron ring 710 to the average thickness of the second multi-pole permanent magnet array 720 are both any values ​​between 0.5 and 1.5; both the non-working sides of the first back iron ring 510 and the second back iron ring 710 are provided with demagnetizing grooves, and the ratio of the depth of the demagnetizing groove to the thickness of the first back iron ring 510 and the ratio to the thickness of the second back iron ring 710 are both any values ​​between 0.1 and 0.3; wherein: the number of pole pairs of the first multi-pole permanent magnet array 520 is... This refers to the number of magnetic pole pairs arranged circumferentially in the first multi-pole permanent magnet array 520, where the array has alternating poles along the circumference. When there are 1 magnetic pole, the number of pole pairs is The first single pole distance This refers to the circumferential mechanical angle between adjacent pole centers of the same name in the array, equal to... The number of pole pairs of the second multi-pole permanent magnet array 720 This refers to the number of pole pairs arranged circumferentially in the second multi-pole permanent magnet array 720, where the array has alternating poles along the circumference. When there are 1 magnetic pole, the number of pole pairs is The second single pole distance This refers to the circumferential mechanical angle between adjacent pole centers of the same name in the array, equal to... Phase misalignment It refers to the circumferential mechanical angle between the nearest corresponding magnetic pole centers of the first multipole permanent magnet array 520 and the second multipole permanent magnet array 720 after they are projected axially onto the same cylindrical surface.

[0157] Specifically:

[0158] The overall device is the same as the aforementioned embodiments.

[0159] Definitions of Pole Pair Count and Single Pole Gap: The first multi-pole permanent magnet array 520 has alternating pole pairs distributed along the circumference, and its pole pair count is the number of pole pairs along the circumference; the first single pole gap is the circumferential mechanical angle between adjacent center lines of the same pole in the array. The second multi-pole permanent magnet array 720 has the same definition of the second single pole gap. Phase misalignment refers to the circumferential mechanical angle between the nearest center lines of the same pole after projecting the two arrays axially onto the same cylindrical surface.

[0160] The conductor ring 60 rotates with the integrated holder 40, and relative cutting is generated simultaneously with the static magnetic field of the first magnetic pole ring 50 on the side of the shell 10 and the follow-up magnetic field of the second magnetic pole ring 70 on the output side. The two magnetic circuits form a circumferential eddy current in the conductor ring 60 and interact with the magnetic field to generate a viscous electromagnetic torque. The two arrays of different pole pair numbers are arranged to offset the spatial harmonic and equivalent frequency distribution of the two magnetic fields; and the circumferential phase offset is introduced to make the dominant harmonics of the two magnetic fields not coincide at the peak value relative to the conductor ring 60, thereby reducing the torque ripple and widening the damping bandwidth. The ratio of the back iron thickness to the average thickness of the magnet is used to avoid the contradiction between magnetic saturation and invalid thickening, and to ensure the effective closure of the magnetic flux; the demagnetization slot on the non-working side of the back iron ring weakens the circulating current and edge leakage magnetic field in the back iron ring without affecting the main magnetic circuit, and provides space for heat stress release.

[0161] The key links in the implementation process include:

[0162] Array indexing and assembly: calibrate the reference indexing line on the working surface of the back iron ring, and paste the permanent magnets block by block according to the set pole pair number, and use structural glue to cooperate with non-magnetic pressure rings or end pressure plates for locking to ensure uniform pole arc and flat end surface;

[0163] Phase offset implementation: take the first magnetic pole ring 50 as the reference, and install the second magnetic pole ring 70 along the circumference with a phase offset; use indexing tool or visual positioning to ensure that the center lines of the same poles of the two arrays are offset at the target angle during the assembly stage;

[0164] Back iron thickness and demagnetization slot processing: the thickness of the back iron ring is processed according to the ratio, and the circumferential demagnetization slot is set on the non-working side, and the slot bottom is rounded to avoid stress concentration; the working side remains intact to ensure the minimum area of the paste and the minimum reluctance with the magnet;

[0165] Detection and review: after assembly, complete the magnetic flux density scanning, phase offset angle review and dynamic balance test to confirm that the torque ripple and temperature rise meet the target.

[0166] It should be noted that the design target of different pole pair numbers and phase offset ratio is to reduce the torque ripple and expand the damping bandwidth. The equivalent excitation frequency of the conductor ring 60 is related to the relative angular velocity and the pole pair number, and if the pole pair numbers of the two arrays are the same and the phases are aligned, the main harmonics will be superimposed, and the torque ripple will be increased. By setting the pole pair numbers of the two arrays to be different and making the circumferential phase offset of the two arrays occupy a proportion of the first or second single pole pitch in the middle range, the main harmonics can be close to the anti-phase or deviate from the superposition area, thereby significantly suppressing the combined ripple. The reason for selecting the proportion in the middle neighborhood is that on the one hand, it is away from the resonance area of zero offset and integral half pole pitch, and on the other hand, it has good fault tolerance to assembly and running deviation.

[0167] The back iron is easy to enter magnetic saturation near the working magnetic density, causing the nonlinearity of the magnetic flux clamping and damping. Although the excessive thickness of the back iron can further reduce the magnetic resistance, it brings the increase of volume and mass and the rapid decrease of benefits. The thickness of the back iron and the average thickness of the magnet are taken in the moderate matching range, which can ensure that the back iron works in the unsaturated area and the magnetic circuit is efficiently closed under most material and size combinations, and the structure is lightweight and the processing economy is considered.

[0168] The demagnetization slot is located on the non-working side of the back iron, which breaks the circulation path in the back iron, reduces the edge magnetic leakage and improves the heat distribution. The slot depth has limited inhibitory effect when it is too small, and the back iron section and stiffness are weakened when it is too large. Taking the ratio of the slot depth to the back iron thickness in the middle range, the significant circulation and cooling effect can be obtained without sacrificing the strength.

[0169] The determination process of each parameter in the embodiment is as follows:

[0170] First, according to the target damping frequency band and the allowed torque ripple, the pole pair combination of the two arrays is initially selected, and the phase misalignment ratio in the central range is taken as the initial value.

[0171] Second, according to the magnet material and the target magnetic density, the back iron thickness is preset according to the matching range, and the depth ratio of the demagnetization slot is arranged on the non-working side.

[0172] Third, the electromagnetic, thermal and structural joint simulation is carried out to investigate the damping slope, torque ripple, back iron magnetic saturation margin and temperature rise.

[0173] Fourth, the sample is verified, and the phase, back iron thickness and demagnetization slot depth are fine-tuned until the indicators are stably met within the batch tolerance. The above process and range are suitable for axial magnetic gap and radial magnetic gap arrangements.

[0174] Further, the pole arc duty ratio of the two arrays can be designed to further peak; the two arrays can use different magnetization methods or introduce a small non-uniform pole distance in the circumferential direction to diffuse harmonics; the back iron demagnetization slot can be made into multiple narrow slots or staggered slots to balance the strength and circulation effect; the phase misalignment can be realized by positioning pin, equal division hole or key identification to realize rapid and traceable assembly.

[0175] In the embodiment, the pole pair number of the two multi-pole permanent magnet arrays is different, the phase is staggered in the single-pole interval, the back iron thickness and the average thickness of the magnet are matched, the demagnetizing slot with appropriate depth ratio is arranged on the non-working side of the back iron to weaken the comprehensive technical means of the circulating current and the leakage magnetic field, so that the technical problems of large torque ripple, narrow damping bandwidth, back iron magnetic saturation and local heating caused by the superposition of harmonics in the existing structure are effectively solved, and the comprehensive technical effects of obtaining more linear viscous damping, lower output ripple and more controllable temperature rise without changing the original stress and assembly chain are realized.

[0176] The above description in the specification is only an example of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways without deviating from the content of the specification or exceeding the scope defined by the claims.

Claims

1. A bearing drive based friction reducer, comprising a housing, an input end and an output member, a receiving space is formed in the housing, a first bearing and a second bearing are arranged coaxially along an axis in the receiving space, the first bearing comprises a first outer ring, a first inner ring, first rolling bodies and a first cage, the second bearing comprises a second outer ring, a second inner ring, second rolling bodies and a second cage, and the first cage and the second cage are an integrated cage, the input end is rigidly and rotationally connected with the first inner ring and the second inner ring, and the output member is in driving connection with the second outer ring; wherein, In a working state, at least a friction / micro-slip traction contact capable of transmitting torque is formed between the first rolling element and its adjacent raceway and / or between the second rolling element and its adjacent raceway, the adjacent raceway refers to the inner raceway of the corresponding outer ring or the outer raceway of the corresponding inner ring, and the speed difference between the integrated cage and the first inner ring and the first outer ring and / or the second inner ring and the second outer ring is established to achieve a speed reduction output, characterized in that comprising: a first magnetic pole ring is arranged in the accommodation space, and the first magnetic pole ring is fixedly connected with the shell; a conductor ring is arranged on the integrated cage, the conductor ring is arranged opposite to the first magnetic pole ring with a magnetic gap therebetween, and the conductor ring is configured to have a continuous conductive loop to induce eddy current in the conductor ring when the cage moves relative to the first magnetic pole ring and generate an electromagnetic damping torque on the cage.

2. The friction reducer of claim 1, wherein, The shell is provided with an end cover near one end of the first bearing, the end cover is combined with the inner wall of the shell on one side near the shell to form the accommodation space, the first magnetic pole ring is fixed to the inner side of the end cover, the conductor ring is arranged on the end face of the cage and axially extends towards the end cover, and the magnetic gap is an axial magnetic gap.

3. The friction reducer according to claim 2, characterized in that: an annular recess is formed in the end cover; the first magnetic pole ring is arranged in the annular recess, and the first magnetic pole ring comprises a first back iron ring and a first multi-pole permanent magnet array arranged on the side of the first back iron ring near the first bearing.

4. The friction reducer according to claim 1, characterized in that: a first annular structure is arranged on the inner wall of the shell between the first bearing and the second bearing, and the first magnetic pole ring is fixed to the annular inner wall of the first annular structure; a second annular structure is arranged on the outer circumferential side of the integrated cage corresponding to the first magnetic pole ring, the conductor ring is arranged on the outer circumferential side of the second annular structure, and the outer circumferential side wall of the second annular structure is arranged opposite to the inner circumferential side wall of the first annular structure, and the magnetic gap is a radial magnetic gap.

5. The friction reducer according to claim 4, characterized in that: the conductor ring is composed of two annular members with different outer diameters, i.e. a first annular member and a second annular member, the first annular member and the second annular member are coaxially arranged side by side, and the first annular member is arranged opposite to the first magnetic pole ring; the friction reducer further comprises a second magnetic pole ring, the second magnetic pole ring is arranged on the inner wall of the second bearing outer ring in a circumferential area which is not in contact with the rolling elements of the second bearing in a working state, and the second magnetic pole ring is axially staggered with the raceway on the inner wall of the second bearing outer ring, the second annular member is arranged opposite to the second magnetic pole ring; wherein the first magnetic pole ring is a static magnetic pole ring, and the second magnetic pole ring is a follow-up magnetic pole ring.

6. The friction reducer of claim 5, wherein, an annular groove is arranged between the first annular member and the second annular member.

7. The friction reducer according to claim 6, characterized in that: The central section of the first magnetic pole ring in the axial direction is aligned with the central section of the first annular member in the axial direction, and the ratio of the axial width of the first magnetic pole ring to the axial width of the first annular member is 1.1-1.6; The central section of the second magnetic pole ring in the axial direction is aligned with the central section of the second annular member in the axial direction, and the ratio of the axial width of the second magnetic pole ring to the axial width of the second annular member is 1.1-1.

6.

8. The friction reducer according to claim 7, wherein: a radial magnetic gap between an inner cylindrical surface of the first magnetic pole ring and an outer cylindrical surface of the first annular member satisfies the following conditions: ； a radial magnetic gap between the inner cylindrical surface of the second magnetic pole ring and the outer cylindrical surface of the second annular member satisfies the following conditions: ； wherein: R1is the outer radius of the first ring member; R2 is the outer radius of the second ring member; is the radial thickness of the conductor ring.

9. The friction reducer according to claim 8, wherein: The ratio of the difference between the outer radius of the second annular member and the outer radius of the first annular member to the outer radius of the first annular member is 0.03-0.12; The ratio of the axial width of the annular groove to the sum of the axial width of the first annular member and the axial width of the second annular member is 0.12-0.30; The ratio of the groove depth of the annular groove to the radial thickness of the first annular member is any value in the range of 0.3-0.8, and the ratio of the groove depth of the annular groove to the radial thickness of the second annular member is any value in the range of 0.3-0.

8.

10. The friction reducer according to claim 5 or 6 or 8 or 9, wherein: The first magnetic pole ring comprises a first back iron ring and a first multi-pole permanent magnet array arranged on the side of the first back iron ring facing the first annular member; The second magnetic pole ring comprises a second back iron ring and a second multi-pole permanent magnet array arranged on the side of the second back iron ring facing the second annular member; the number of pole pairs of the first multi-pole permanent magnet array is different from the number of pole pairs of the second multi-pole permanent magnet array, and the ratio of the phase shift φ in the circumferential direction between the two and the first single-pole distance of the first multi-pole permanent magnet array or the second single-pole distance of the second multi-pole permanent magnet array is any value in the range of 0.40 to 0.

60. The ratio of the thickness of the first back iron ring to the average thickness of the first multi-pole permanent magnet array and the ratio of the thickness of the second back iron ring to the average thickness of the second multi-pole permanent magnet array are each any value in the range of 0.5-1.5; The non-working side of the first back iron ring and the non-working side of the second back iron ring are each provided with a demagnetization groove, and the ratio of the depth of the demagnetization groove to the thickness of the first back iron ring and the ratio of the depth of the demagnetization groove to the thickness of the second back iron ring are each any value in the range of 0.1-0.3; wherein: the number of pole pairs of the first multipole permanent magnet array refers to the number of pole pairs of the first multipole permanent magnet array arranged circumferentially, which is when the array has alternating magnetic poles along the circumference, the number of pole pairs is , the first single-pole distance refers to the circumferential mechanical angle between the center lines of adjacent poles of the same name in the array, which is equal to ; the number of pole pairs of the second multipole permanent magnet array refers to the number of pole pairs of the second multipole permanent magnet array arranged circumferentially, when the array has alternating poles along the circumference, the number of pole pairs is , the second single-pole distance refers to the circumferential mechanical angle between the center lines of adjacent poles of the same name in the array, equal to ; Phase misalignment is referred to as the circumferential mechanical angle between the centers of the nearest like poles of the first and second multipole permanent magnet arrays after axial projection of both arrays onto the same cylindrical surface.

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