Epicyclic gear with few teeth difference
The low-tooth-difference cycloidal ball reducer solves the problem of insufficient backlash control in high-precision equipment by using double eccentric shaft drive and pure rolling meshing of steel balls, thus achieving efficient and stable transmission performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TUOGE POWER TECHNOLOGY (QINGDAO) CO LTD
- Filing Date
- 2025-08-05
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional gear reducers suffer from insufficient backlash control and size limitations in high-precision equipment, making it difficult to balance large reduction ratios and high positioning accuracy. Existing precision reduction solutions, such as harmonic reducers and RV reducers, suffer from complex structures or high costs.
It adopts a low-tooth-difference cycloidal ball reducer, and through the 180° phase difference design driven by double eccentric shafts, combined with the pure rolling meshing of steel balls, it realizes backlash-free multi-point contact transmission. By utilizing the reverse motion of the double moving discs and the precision cycloidal groove design, it eliminates backlash and provides high rigidity and a large reduction ratio.
It achieves high-precision, low-noise, and low-vibration transmission, meeting the stringent requirements of equipment such as robot joints and precision machine tools, improving transmission efficiency and lifespan, and reducing maintenance costs.
Smart Images
Figure CN224533362U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a cycloidal ball reducer with a small tooth difference, belonging to the field of high-precision reducers. Background Technology
[0002] In the field of mechanical transmission, the reduction mechanism is the core component for realizing power conversion and motion control. Traditional gear reducers generally suffer from transmission backlash due to meshing clearance, which can easily lead to positioning deviations during frequent starts, stops, or reversals, making it difficult to meet the motion control requirements of high-precision equipment. Especially for applications such as attitude adjustment mechanisms in spacecraft and precision instruments, traditional structures, due to insufficient backlash control and size limitations, struggle to balance high reduction ratios and high positioning accuracy.
[0003] With the development of high-end manufacturing, industrial automation and intelligent equipment place higher demands on the performance of speed reducers. Industrial robot joint drives require precise angle transmission with no lag; CNC machine tool feed systems require zero backlash throughout the transmission process; and equipment such as medical surgical robots need to ensure absolute reliability of transmission under strictly sealed conditions. Among existing mainstream precision speed reduction solutions, harmonic reducers are prone to flexible ring fatigue damage, and RV reducers have complex structures and high costs, both of which have technical limitations.
[0004] To overcome the aforementioned bottlenecks, low-tooth-difference cycloidal ball drive technology replaces gear contact with pure rolling meshing of steel balls, eliminating backlash at its source. Initially, this technology was primarily used in the aerospace field, benefiting from its zero backlash, high rigidity, and compact structure. In recent years, with the widespread adoption of industrial automation and the upgrading of medical devices, the market urgently needs a reduction solution that combines ultra-high precision with high cost-effectiveness. Utility Model Content
[0005] To overcome the shortcomings of existing technologies, this utility model provides a cycloidal ball reducer with a small tooth difference. The technical solution of this utility model is as follows: A cycloidal ball reducer with a small tooth difference includes a body. A first moving plate (10) and a second moving plate (12) are sequentially arranged on a double eccentric shaft (6) between the fixed plate (1) and the output plate (13) of the body. The first moving plate (10) and the second moving plate (12) are arranged adjacent to each other and have a phase difference of 180°. The double eccentric shaft (6) drives the first moving plate (10) and the second moving plate (12) to perform a composite motion of radial displacement oscillation and rotation, and the reduction is achieved by a reduction assembly.
[0006] The eccentric phase difference of the double eccentric shaft (6) is 180°. The first moving disk (10) is rotatably mounted on the double eccentric shaft (6) through the first moving disk bearing (8). The second moving disk (12) is rotatably mounted on the double eccentric shaft (6) through the second moving disk bearing (11). When the double eccentric shaft (6) rotates, the first moving disk (10) is driven to move radially through the first moving disk bearing (8) and rotate around the axial direction. The second moving disk (12) is driven to move radially through the second moving disk bearing (11) and rotate around the axial direction. The second moving disk (12) moves in the opposite direction to the first moving disk (10) and rotates in the same direction.
[0007] The deceleration assembly includes a fixed plate steel ball (2), a moving plate steel ball (3), and an output plate steel ball (4). The fixed plate steel ball (2) is rolled between the fixed plate (1) and the first moving plate (10). The moving plate steel ball (3) is rolled between the first moving plate (10) and the second moving plate (12). The output plate steel ball (4) is rolled between the second moving plate (12) and the output plate (13). The number of meshing teeth of the fixed plate steel ball (2) with the fixed plate (1) and the first moving plate (10) forms a difference. The number of meshing teeth of the output plate steel ball (4) with the output plate (13) and the second moving plate (12) forms a difference.
[0008] A cycloidal wave arc groove is provided on the left end face of the fixed plate (1); an cycloidal wave arc groove is provided on the right end face of the output plate (13); a first moving plate ball socket is provided on the left end face of the first moving plate (10), the diameter of which is twice the maximum eccentricity of the double eccentric shaft (6) plus the diameter of the moving plate steel ball (3); a first inward cycloidal wave arc groove is provided on the right end face of the first moving plate (10); a second moving plate ball socket is provided on the right end face of the second moving plate (12), the diameter of which is twice the maximum eccentricity of the double eccentric shaft (6) plus the diameter of the moving plate steel ball (3). The second moving plate (12) has a second inner cycloidal wave arc groove on its left end face; the first inner cycloidal wave arc groove corresponds to the fixed plate outer cycloidal wave arc groove; the fixed plate steel ball (2) is rolled in the space between the first inner cycloidal wave arc groove and the fixed plate outer cycloidal wave arc groove; the moving plate steel ball (3) is rolled in the space between the first moving plate ball socket and the second moving plate ball socket, the second moving plate ball socket corresponds to the first moving plate ball socket; the output plate steel ball (4) is rolled in the space between the second inner cycloidal wave arc groove and the output plate outer cycloidal wave arc groove.
[0009] The fixed plate (1) is mounted on the double eccentric shaft (6) via a fixed plate bearing (7), and the output flange (19) is located away from the fixed plate (1) and is mounted on the double eccentric shaft (6) via an output flange bearing (21).
[0010] When the first moving disk (10) moves radially, it decelerates through the pure rolling of the fixed disk steel ball (2) between the first inner cycloidal wave arc groove and the fixed disk outer cycloidal wave arc groove, and satisfies: N 定盘外摆线 -N 第一动盘内摆线 =1; When the second moving disk (12) moves radially, it achieves deceleration through the pure rolling of the steel ball (4) on the output disk between the second inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the output disk, and satisfies: N 输出盘外摆 Line − N 第二动盘内摆线 =1; where N is the equivalent number of teeth for the corresponding wavy circular groove.
[0011] The bearing body (15) is mounted on the output flange (19) by needle rollers (17). A first flat needle roller bearing (14) and a second flat needle roller bearing (16) are respectively mounted on the double eccentric shafts (6) on both sides of the bearing body (15). The bearing body (15) is axially positioned by the first flat needle roller bearing (14) and the second flat needle roller bearing (16).
[0012] The housing of the servo motor is bolted to the fixed plate (1). The output shaft of the servo motor is connected to the double eccentric shaft (6) by a locking sleeve (5) with an outer conical surface. A pull rod screw (20) is installed at the end of the locking sleeve. The pull rod screw (20) locks the output shaft of the servo motor through the locking sleeve (5).
[0013] A skeleton oil seal (18) is also installed between the bearing body (15) and the output flange (19).
[0014] The number of steel balls on the moving plate is the same as the number of the first or second moving plate ball sockets.
[0015] The advantages of this utility model are: (1) The design of double moving disks (first moving disk and second moving disk) with a phase difference of 180° is driven by double eccentric shafts to perform radial displacement and oscillation in opposite directions. This reverse motion, combined with the pure rolling meshing of three sets of steel balls (fixed disk steel ball, moving disk steel ball, and output disk steel ball) in the corresponding cycloidal wave arc grooves (fixed disk outer cycloidal groove, first and second inner cycloidal grooves, first moving disk ball socket, second moving disk ball socket, and output disk outer cycloidal groove), forms a continuous, multi-point, and gapless contact. The steel balls are simultaneously constrained to roll within the inner and outer cycloidal grooves, fundamentally eliminating the backlash of traditional gear meshing, ensuring absolute precise positioning during the transmission process, and meeting the stringent requirements of robot joints, precision machine tools, etc.
[0016] (2) The 180° eccentric phase difference of the double eccentric shafts not only drives the moving disc to move in the opposite direction, but its structure itself also provides good radial support. The moving disc is mounted on the eccentric shaft through special bearings (first moving disc bearing, second moving disc bearing), which reduces friction and avoids vibration. More importantly, the equivalent tooth number design of the wave arc groove follows the strict principle of low tooth difference, for example, there is a one-tooth difference between the fixed disc and the first moving disc, and between the output disc and the second moving disc. This single-stage high reduction ratio design, combined with two-layer series reduction components (fixed disc-moving disc, moving disc-output disc), can easily achieve an extremely high overall reduction ratio. At the same time, the power transmission mainly relies on the pure rolling friction of the steel balls, which significantly reduces energy loss, improves transmission efficiency, and reduces wear.
[0017] (3) The servo motor at the input end and the output disk and output flange at the output end are all stacked along the same axis. The two end faces of the moving disk are machined with internal cycloidal grooves to maximize the use of axial space, making the structure extremely compact. In addition, the 180° phase difference between the two moving disks causes the centrifugal force and inertial force they generate to cancel each other out, forming a dynamic torque balance, which greatly reduces vibration and noise, and improves the smoothness of operation and service life.
[0018] (4) The bearing body is mounted on the output flange by needle rollers and is precisely axially positioned by the first and second flat needle roller bearings, ensuring stable support and load-bearing capacity at the output end. The installation of the skeleton oil seal effectively prevents grease leakage and enhances sealing reliability. Key transmission components (such as steel balls) are designed as independent rolling elements, which are relatively easy to replace after wear without the need for a large overall disassembly, thus improving the maintainability of the equipment.
[0019] This reducer perfectly integrates key performance characteristics such as high rigidity, large reduction ratio, and high efficiency through a structure that combines the reverse motion of double moving discs with a 180° phase difference and the pure rolling meshing of steel balls in a precision cycloidal wave groove. Its compact axial stacked layout and torque balance design further improve space utilization and operational smoothness. Coupled with optimized bearing support and sealing design, it becomes a solution that meets the needs of high-end precision transmission. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the main structure of this utility model.
[0021] Figure 2 yes Figure 1 A schematic diagram of the structure of the central plate.
[0022] Figure 3 yes Figure 1 A schematic diagram of the structure of the central moving plate.
[0023] Figure 4 This is a schematic diagram of the moving plate and the moving plate in short-range engagement at 0° according to this utility model.
[0024] Figure 5 This is a schematic diagram of the moving plate and the moving plate in short-range engagement at 90° according to this utility model.
[0025] Figure 6 This is a schematic diagram of the moving plate and the moving plate in short-range engagement of 180° according to this utility model.
[0026] Figure 7 This is a schematic diagram of the moving plate and the moving plate in short-range engagement at 270° according to this utility model. Detailed Implementation
[0027] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result of the description. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solution of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.
[0028] See Figures 1 to 7 This utility model relates to a cycloidal ball reducer with a small tooth difference, comprising a body, on which a first moving plate 10 and a second moving plate 12 are sequentially arranged on a double eccentric shaft 6 between a fixed plate 1 and an output plate 13 of the body. The first moving plate 10 and the second moving plate 12 are arranged adjacent to each other and have a phase difference of 180°. A first reduction assembly is arranged between the fixed plate 1 and the first moving plate 10, and a second reduction assembly is arranged between the first moving plate 10 and the second moving plate 12. The double eccentric shaft 6 drives the first moving plate 10 and the second moving plate 12 to perform a composite motion of radial displacement oscillation and rotation, and the reduction is achieved by the reduction assembly.
[0029] The double eccentric shaft 6 drives the first moving disk 10 and the second moving disk 12, which have a phase difference of 180°, to perform radial displacement oscillation and rotation in opposite directions. Steel balls are provided between the first moving disk 10 and the fixed disk 1, between the second moving disk 12 and the output disk 13, and between the two moving disks, and they are engaged in pure rolling meshing in the corresponding cycloidal wave arc grooves.
[0030] The reverse motion of the double-acting disc, combined with the multi-point, continuous, and pure rolling contact of the steel balls in the precision groove, fundamentally eliminates transmission backlash, ensures zero lag in power transmission, achieves ultra-high positioning accuracy, and meets the stringent requirements of robot joints, precision machine tools, and other applications for backlash-free transmission.
[0031] The wave groove is designed with the principle of low tooth difference to form an equivalent number of teeth and form a two-layer series reduction assembly (fixed plate - first moving plate, first moving plate - second moving plate - output plate).
[0032] The double eccentric shaft 6 itself provides good rigidity support, and power is efficiently transmitted through the pure rolling of steel balls in the groove. A single-stage component can achieve a large reduction ratio (tooth difference of 1), and two stages in series can achieve an extremely high overall reduction ratio.
[0033] It achieves high rigidity (thanks to the force distribution of eccentric shaft support and rolling contact of steel balls) and ultra-large reduction ratio, solving the contradiction that traditional precision reducers struggle to balance between large reduction ratio, high rigidity and miniaturization.
[0034] The first moving disk 10 and the second moving disk 12 are driven by the double eccentric shaft 6 and are strictly 180° out of phase, moving in opposite directions. The centrifugal force and inertial force generated by the two moving disks cancel each other out due to their opposite phases, forming a dynamic couple balance.
[0035] It significantly reduces vibration and noise during transmission, improves the smoothness, reliability and service life of the equipment, and is especially suitable for high-end applications that are sensitive to noise and vibration (such as precision instruments, medical equipment and aerospace institutions).
[0036] The eccentric phase difference of the double eccentric shaft 6 is 180°. The first moving disk 10 is rotatably mounted on the double eccentric shaft 6 via the first moving disk bearing 8, and the second moving disk 12 is rotatably mounted on the double eccentric shaft 6 via the second moving disk bearing 11. When the double eccentric shaft 6 rotates, the first moving disk 10 is driven to move radially and rotate axially via the first moving disk bearing 8; the second moving disk 12 is driven to move radially and rotate axially via the second moving disk bearing 11. The movement direction of the second moving disk 12 is opposite to that of the first moving disk 10, and the rotation direction of the first and second moving disks is the same.
[0037] When the double eccentric shaft 6 rotates, the bearings force the two moving discs to perform a combined motion of radial movement and axial rotation, with the key point being that the two moving discs always move in opposite directions. This precisely controlled, 180° phase-difference reverse combined motion provides the core dynamic basis for the subsequent backlash-free meshing of the steel balls in the cycloidal groove, ensuring balanced force at the meshing point.
[0038] The radial movements of the first and second moving plates are opposite and symmetrical, causing the centrifugal and inertial forces they generate during movement to cancel each other out, forming a dynamic torque balance. This significantly reduces the vibration and noise of the entire transmission system, greatly improving the smoothness, reliability, and service life of the reducer, making it particularly suitable for applications requiring high precision and low noise.
[0039] Using a single double eccentric shaft 6 as the drive element, a single rotary input is directly, synchronously, and precisely converted into the composite motion required by the two moving discs.
[0040] By eliminating complex linkages or additional phase adjustment mechanisms, the motion transmission chain is extremely short and direct. The installation of the first and second moving plate bearings ensures that the moving plate can freely perform the required combined movements (radial movement and rotation), while significantly reducing sliding friction between moving parts, improving transmission efficiency and reliability, and maintaining the overall structural compactness.
[0041] This dual-eccentric shaft driven dual-moving-disc structure, through a 180° phase difference design and a dedicated bearing connection, achieves precise and opposite compound motion of the two moving discs, realizing efficient, direct, and structurally simplified motion transmission.
[0042] The speed reduction assembly includes a fixed plate steel ball 2, a moving plate steel ball 3, and an output plate steel ball 4. The fixed plate steel ball 2 is rotatably installed between the fixed plate 1 and the first moving plate 10. The moving plate steel ball 3 is rotatably installed between the first moving plate 10 and the second moving plate 12. The output plate steel ball 4 is rotatably installed between the second moving plate 12 and the output plate 13. The number of meshing teeth of the fixed plate steel ball 2 with the fixed plate 1 and the first moving plate 10 forms a difference. The number of meshing teeth of the output plate steel ball 4 with the output plate 13 and the second moving plate 12 also forms a difference.
[0043] The stationary steel ball 2 rolls purely between the outer cycloidal wave groove of the stationary plate 1 and the inner cycloidal wave groove of the first moving plate 10; the output plate steel ball 4 rolls purely between the inner cycloidal wave groove of the second moving plate 12 and the outer cycloidal wave groove of the output plate 13; simultaneously, the moving plate steel ball 3 rolls between the first moving plate 10 and the second moving plate 12. The steel balls form continuous, multi-point, conjugate pure rolling meshing in the precision-machined inner and outer cycloidal wave grooves. This meshing method fundamentally eliminates the tooth backlash of traditional gear meshing, ensuring no lag in power transmission and meeting the stringent requirements of robot joints and precision control; power transmission is achieved entirely through the pure rolling friction of the steel balls in the wave arc grooves.
[0044] Pure rolling friction significantly reduces energy loss during transmission and improves overall transmission efficiency. At the same time, compared to sliding friction, rolling friction greatly reduces wear on contact surfaces, increasing the service life and long-term accuracy retention of the reducer, and reducing maintenance costs.
[0045] The tooth difference between the meshing surfaces of the fixed plate steel ball 2 (outer side of the fixed plate and inner side of the first moving plate) is 1, and the tooth difference between the meshing surfaces of the output plate steel ball 4 (outer side of the output plate and inner side of the second moving plate) is also 1. These meshing components (fixed plate-first moving plate, first moving plate-second moving plate, second moving plate-output plate) are arranged in series along the axis of the double eccentric shaft 6.
[0046] A large reduction ratio can be achieved with a single set of meshing steel balls, while a total reduction ratio can be obtained by connecting three meshing components in series. The multi-point contact of the steel balls within the groove provides excellent load-bearing capacity and transmission rigidity.
[0047] A cycloidal wavy arc groove is provided on the left end face of the fixed plate 1; a cycloidal wavy arc groove is provided on the right end face of the output plate 13; a first moving plate ball socket is provided on the left end face of the first moving plate 10, the diameter of which is twice the maximum eccentricity of the double eccentric shaft 6 plus the diameter of the moving plate steel ball 3; a first inward cycloidal wavy arc groove is provided on the right end face of the first moving plate 10; a second moving plate ball socket is provided on the right end face of the second moving plate 12, the diameter of which is twice the maximum eccentricity of the double eccentric shaft 6 plus the diameter of the moving plate steel ball 3. The diameter of ball 3; the left end face of the second moving disk 12 is provided with a second inner cycloidal wave arc groove; the first inner cycloidal wave arc groove corresponds to the outer cycloidal wave arc groove of the fixed disk; the fixed disk steel ball 2 is rolled and installed in the space between the first inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the fixed disk; the moving disk steel ball 3 is rolled and installed in the space between the first moving disk 10 and the second moving disk 12; the output disk steel ball 4 is rolled and installed in the space between the second inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the output disk.
[0048] The stationary steel ball 2, the moving steel ball 3, and the output steel ball 4 are precisely rolled within the enclosed space formed by these pairs of inner and outer cycloidal grooves.
[0049] This design, with slots on both sides of a single moving disc, allows multiple reduction meshing pairs (fixed disc-first moving disc, first moving disc-second moving disc, second moving disc-output disc) to be tightly stacked along the same axis (double eccentric shaft 6), realizing the integration of multi-stage reduction functions and providing a structural basis for obtaining a large reduction ratio.
[0050] When the double eccentric shaft drives the moving plate to perform compound motion, the steel balls can only roll in the conjugate groove, completely eliminating transmission backlash and providing lag-free motion transmission, which is the core of achieving ultra-high transmission accuracy.
[0051] Power transmission and deceleration rely entirely on the pure rolling friction between steel balls and precision-machined inner and outer cycloidal wavy arc grooves. The steel balls are tightly enclosed in a closed rolling track formed by paired grooves. This pure rolling friction significantly reduces frictional resistance during transmission, thereby improving transmission efficiency and reducing energy loss and heat generation. Simultaneously, the steel balls bear load evenly at multiple points within the grooves, dispersing contact stress and providing extremely high radial load-bearing capacity and transmission rigidity. Compared to sliding friction (such as gear meshing), rolling friction greatly reduces wear, extends the service life of key transmission components (steel balls and groove surfaces), and ensures long-term operational reliability.
[0052] The fixed plate 1 is mounted on the double eccentric shaft 6 via a fixed plate bearing 7, and the output flange 19 is located away from the fixed plate 1 and is mounted on the double eccentric shaft 6 via an output flange bearing 21.
[0053] When the first moving disk 10 moves radially, it decelerates through the pure rolling of the stationary disk steel ball 2 between the first inner cycloidal wave arc groove and the stationary disk outer cycloidal wave arc groove, and satisfies: N 定盘外摆线 -N 第一动盘内摆线 =1; where, the fixed plate outer cycloid is 101, and the moving plate inner cycloid is 201 (the first moving plate inner cycloid or the second moving plate inner cycloid).
[0054] When the second moving disk 12 moves radially, it achieves deceleration through the pure rolling of the steel ball 4 on the output disk between the fourth inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the output disk, and satisfies: N 输出盘外摆 Line − N 第二动盘内摆线 =1; where N is the equivalent number of teeth for the corresponding wavy circular groove.
[0055] The bearing body 15 is mounted on the output flange 19 via needle rollers 17. A first flat needle roller bearing 14 and a second flat needle roller bearing 16 are respectively mounted on the double eccentric shafts 6 on both sides of the bearing body 15. The bearing body 15 is axially positioned by the first flat needle roller bearing 14 and the second flat needle roller bearing 16.
[0056] This double-sided clamping structure applies bidirectional (axially opposite) rigid constraints to the bearing body through two flat needle roller bearings, precisely limiting the axial movement of the bearing body 15 in any direction. The flat needle roller bearings themselves possess high load-bearing capacity and low cross-sectional height, ensuring excellent axial rigidity and positioning accuracy within a compact space, effectively resisting axial loads generated during transmission and guaranteeing output stability.
[0057] Needle roller 17 provides high-load-bearing radial support between the bearing body 15 and the output flange 19. The line contact characteristics of the needle roller bearing enable it to withstand high radial loads, while its extremely compact structure (small radial cross-section) perfectly meets the dual requirements of high rigidity and extreme space saving at the output end of the reducer, without affecting the overall miniaturized design.
[0058] The radial force is efficiently carried to the output end by the needle roller 17, and the axial force is directly transmitted to the double eccentric shaft 6 by the flat needle roller bearing. This reduces unnecessary structural deformation and energy loss, improves transmission efficiency, and helps maintain the smooth operation of the entire output system and reduce vibration.
[0059] The bearing support structure provides high-load radial support through the needle rollers 17 and achieves rigid bidirectional axial positioning through double-sided flat needle roller bearings. Its core advantages are that it provides excellent axial and radial rigidity for the output end, extremely compact space utilization, and a clear, efficient, and low-loss load transfer path, ensuring stable and reliable output of the reducer.
[0060] The housing of the servo motor is bolted to the fixed plate 1. The output shaft of the servo motor is connected to the double eccentric shaft 6 through a locking sleeve 5 with an outer conical surface. A pull rod screw 20 is installed at the end of the output shaft of the servo motor, and the pull rod screw 20 locks the output shaft of the servo motor through the locking sleeve 5.
[0061] A skeleton oil seal 18 is also installed between the bearing body 15 and the output flange 19 to isolate the lubricating grease from the external environment. Combined with the closed design of the output flange bearing, it enables long-term maintenance-free operation of medical and food-grade equipment.
[0062] The working principle of this utility model is as follows: 1. Power input: The servo motor housing is fixed on the fixed plate 1, and the motor shaft is rigidly connected to the double eccentric shaft 6 through the locking sleeve 5 and locked by the pull rod screw 20.
[0063] The rotation of the motor directly drives the double eccentric shaft 6 to rotate.
[0064] 2. Double eccentric shaft motion conversion: The two eccentric shafts of the double eccentric shaft 6 are 180° out of phase and drive the first moving disk 10 and the second moving disk 12 through the first moving disk bearing 8 and the second moving disk bearing 11, respectively.
[0065] The first moving plate 10 and the second moving plate 12 perform a compound motion (radial movement and circular rotation) in opposite directions.
[0066] The centrifugal force and inertial force of the two moving discs cancel each other out due to their opposite phases, forming a dynamic torque balance, which greatly reduces vibration and noise.
[0067] 3. Steel ball meshing deceleration: The steel ball rolls purely in a precision-machined cycloidal wave groove, forming a three-stage series deceleration: First-stage deceleration (fixed plate and first moving plate): The steel ball 2 of the fixed plate rolls between the outer cycloidal groove of the fixed plate and the inner cycloidal groove of the first moving plate.
[0068] Second-stage deceleration (first moving plate and second moving plate): The steel ball 3 of the moving plate rolls in the ball socket of the first moving plate and the ball socket of the second moving plate.
[0069] Third-stage reduction (second moving plate and output plate): the steel ball 4 of the output plate rolls between the second inner cycloidal groove of the second moving plate and the outer cycloidal groove of the output plate.
[0070] 4. Output power transmission: The decelerated power is transmitted to the output flange 19 through the output disc 13. The needle roller 17 provides high rigidity radial support; the double-sided flat needle roller bearing provides bidirectional axial positioning of the bearing body and resists axial load, and the skeleton oil seal (18) prevents grease leakage and meets medical / food grade sealing requirements.
[0071] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.
Claims
1. A cycloidal ball reducer with a small tooth difference, comprising a body, characterized in that, A first moving disk (10) and a second moving disk (12) are sequentially arranged on the double eccentric shaft (6) between the fixed disk (1) and the output disk (13) of the machine body. The first moving disk (10) and the second moving disk (12) are arranged adjacent to each other and have a phase difference of 180°. The double eccentric shaft (6) drives the first moving disk (10) and the second moving disk (12) to perform a composite motion of radial displacement and rotation, and deceleration is achieved through a deceleration assembly.
2. The cycloidal ball reducer with small tooth difference according to claim 1, characterized in that, The eccentric phase difference of the double eccentric shaft (6) is 180°. The first moving disk (10) is rotatably mounted on the double eccentric shaft (6) through the first moving disk bearing (8). The second moving disk (12) is rotatably mounted on the double eccentric shaft (6) through the second moving disk bearing (11). When the double eccentric shaft (6) rotates, the first moving disk (10) is driven to move radially through the first moving disk bearing (8) and rotate around the axial direction. The second moving disk (12) is driven to move radially through the second moving disk bearing (11) and rotate around the axial direction. The second moving disk (12) moves in the opposite direction to the first moving disk (10) and rotates in the same direction.
3. The low-tooth-difference cycloidal ball reducer according to claim 1 or 2, characterized in that, The deceleration assembly includes a fixed plate steel ball (2), a moving plate steel ball (3), and an output plate steel ball (4). The fixed plate steel ball (2) is rolled between the fixed plate (1) and the first moving plate (10). The moving plate steel ball (3) is rolled between the first moving plate (10) and the second moving plate (12). The output plate steel ball (4) is rolled between the second moving plate (12) and the output plate (13). The number of meshing teeth of the fixed plate steel ball (2) with the fixed plate (1) and the first moving plate (10) forms a difference. The number of meshing teeth of the output plate steel ball (4) with the output plate (13) and the second moving plate (12) forms a difference.
4. The cycloidal ball reducer with small tooth difference according to claim 3, characterized in that, A cycloidal wave arc groove is provided on the left end face of the fixed plate (1); a cycloidal wave arc groove is provided on the right end face of the output plate (13); a first moving plate ball socket is provided on the left end face of the first moving plate (10), the diameter of which is twice the maximum eccentricity of the double eccentric shaft (6) plus the diameter of the moving plate steel ball (3); a first inward cycloidal wave arc groove is provided on the right end face of the first moving plate (10); a second moving plate ball socket is provided on the right end face of the second moving plate (12), the diameter of which is twice the maximum eccentricity of the double eccentric shaft (6) plus the diameter of the moving plate steel ball (3); a first inward cycloidal wave arc groove is provided on the right end face of the first moving plate (10); a second moving plate ball socket is provided on the right end face of the second moving plate (12), the diameter of which is twice the maximum eccentricity of the double eccentric shaft (6) plus the diameter of the moving plate steel ball (3); a first inward cycloidal wave arc groove is provided on the right end face of the second moving plate (12). The left end face of the disk (12) is provided with a second inner cycloidal wave arc groove; the first inner cycloidal wave arc groove corresponds to the outer cycloidal wave arc groove of the fixed disk (1); the fixed disk steel ball (2) is rolled in the space between the first inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the fixed disk (1); the moving disk steel ball (3) is rolled in the space between the first moving disk ball socket and the second moving disk ball socket, the second moving disk ball socket corresponds to the first moving disk ball socket; the output disk steel ball (4) is rolled in the space between the second inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the output disk (13).
5. The cycloidal ball reducer with small tooth difference according to claim 4, characterized in that, The fixed plate (1) is mounted on the double eccentric shaft (6) via a fixed plate bearing (7), and the output flange (19) is located away from the fixed plate (1) and is mounted on the double eccentric shaft (6) via an output flange bearing (21).
6. The cycloidal ball reducer with small tooth difference according to claim 3, characterized in that, When the first moving disk (10) moves radially, it decelerates through the pure rolling of the fixed disk steel ball (2) between the first inner cycloidal wave arc groove and the fixed disk outer cycloidal wave arc groove, and satisfies: N 定盘外摆线 -N 第一动盘内摆线 =1; When the second moving disk (12) moves radially, it achieves deceleration through the pure rolling of the steel ball (4) on the output disk between the second inner cycloidal wave arc groove and the outer cycloidal wave arc groove of the output disk, and satisfies: N 输出盘外摆线 -N 第二动盘内摆线 =1; where N is the equivalent number of teeth for the corresponding wavy circular groove.
7. The cycloidal ball reducer with small tooth difference according to claim 5, characterized in that, The bearing body (15) is mounted on the output flange (19) by needle rollers (17). A first flat needle roller bearing (14) and a second flat needle roller bearing (16) are respectively installed on both sides of the bearing body (15). The bearing body (15) is axially positioned by the first flat needle roller bearing (14) and the second flat needle roller bearing (16).
8. The cycloidal ball reducer with small tooth difference according to claim 7, characterized in that, The housing of the servo motor is bolted to the fixed plate (1). The output shaft of the servo motor is connected to the double eccentric shaft (6) through a locking sleeve (5) with an outer conical surface. A pull rod screw (20) is installed at the end of the locking sleeve (5). The pull rod screw (20) locks the output shaft of the servo motor through the locking sleeve (5).
9. The cycloidal ball reducer with small tooth difference according to claim 8, characterized in that, A skeleton oil seal (18) is also installed between the bearing body (15) and the output flange (19).
10. The cycloidal ball reducer with small tooth difference according to claim 4, characterized in that, The number of steel balls on the moving plate is the same as the number of the first or second moving plate ball sockets.