A kind of speed reducer motor module based on servo motor and reducer direct connection

Abstract

The application discloses a kind of based on servo motor and reducer direct connection's reduction motor module, comprising: reducer;Servo motor group, power is provided for reducer, servo motor group includes first servo motor and second servo motor, first servo motor is connected with the input shaft of reducer, can input positive torque for reducer, second servo motor is connected with the output shaft of reducer, output shaft passes through second servo motor to carry out power output, second servo motor can input negative torque for reducer, positive torque is greater than negative torque.The application adopts double servo motor and connects the input shaft and output shaft of reducer respectively, positive torque is greater than negative torque, utilizes reverse torque to continuously eliminate backlash, improves accuracy;Driving and damping function are separated, and energy consumption is reduced;And compact lightweight is realized.

Description

Technical Field

[0001] This invention belongs to the field of geared motor technology, specifically relating to a geared motor module based on a direct connection between a servo motor and a reducer. Background Technology

[0002] With the rapid development of industrial automation and intelligent equipment, servo geared motors, as the power heart of equipment such as robots, CNC machine tools, and precision rotary tables, directly determine the control accuracy, response speed, and operational stability of the entire machine.

[0003] Early solutions typically assembled the servo motor, reducer, and driver as independent units. This resulted in bulky and heavy actuators, and a loose and uncompacted drive system, which was not suitable for use in mobile applications such as robots and automated guided vehicles.

[0004] Therefore, various integrated design solutions have emerged in recent years, such as integrating servo motors with planetary or harmonic reducers into the same housing, and reducing redundant structures by using a shared base, thereby achieving higher power density within a limited space. In terms of transmission accuracy, existing technologies mainly focus on gear manufacturing processes and control algorithms.

[0005] However, regardless of the gear manufacturing process used, there will inevitably be backlash between the gears in the reducer. The presence of backlash will cause inter-tooth impact during transmission, affecting the smoothness of transmission. At the same time, the dead zone characteristics of backlash will reduce the positioning accuracy of the servo system, especially during the commutation and start-up phases, where backlash will cause idle stroke and limit cycle oscillation.

[0006] Secondly, in precision positioning and motion control scenarios, when the output of the geared motor module encounters sudden changes in external load or interference, existing servo motor drive architectures typically can only respond through encoder feedback and controller adjustment of input torque. This response method has inherent latency, and overshoot is difficult to avoid. More seriously, the backlash in the transmission chain can cause variable load nonlinearity when the load changes alternately, causing the motor dynamic parameters to jump synchronously due to the alternation of loading and unloading, further deteriorating system stability and control accuracy.

[0007] Therefore, how to provide a geared motor module that can effectively eliminate or suppress the accuracy loss caused by gear transmission backlash, and can achieve rapid response and accurate compensation when encountering load disturbances at the output end, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] This invention provides a geared motor module based on a direct connection between a servo motor and a reducer. The first servo motor inputs positive torque to the reducer, and the second servo motor inputs negative torque to the reducer, with the positive torque being greater than the negative torque. This achieves dynamic damping and active backlash elimination control of the output shaft, enabling the geared motor module to quickly suppress backlash impact and compensate for external interference during startup, commutation, and load disturbances. This solves the problems of decreased transmission accuracy, commutation backlash, response delay, and control instability caused by inherent gear backlash in existing servo geared motors.

[0009] The technical solution adopted in this invention is as follows: A geared motor module based on direct connection between a servo motor and a reducer, comprising: reducer; A servo motor assembly provides power to the reducer. The servo motor assembly includes a first servo motor and a second servo motor. The first servo motor is connected to the input shaft of the reducer and can input positive torque to the reducer. The second servo motor is connected to the output shaft of the reducer, and the output shaft passes through the second servo motor to output power. The second servo motor can input negative torque to the reducer, and the positive torque is greater than the negative torque.

[0010] The geared motor module based on direct connection between the servo motor and the reducer used in this invention also has the following additional technical features: The aforementioned geared motor module also includes, The motor housing forms a reduction space to accommodate the reducer. The motor housing has an opening on one side to form an output side, and an input side on the opposite side. The first servo motor is fixed to the input side, and the second servo motor is fixed to the output side. The output shaft passes through the opening and is exposed outside the motor housing to output power.

[0011] The lower side of the motor housing is provided with multiple support members, each of which contains an elastic member. The elastic member includes a first elastic part and a second elastic part stacked on top of each other. The second elastic part is located below the first elastic part, and the horizontal cross-section of the second elastic part is larger than that of the first elastic part. The second elastic part protrudes outward from the support member to provide support.

[0012] The first servo motor includes a stator wire assembly and a rotor gear shaft with a permanent magnet embedded inside. The rotor gear shaft is driven to rotate by the rotating magnetic field generated by the stator wire assembly. The reducer contains at least two stages of gear pairs. At least a portion of the rotor gear shaft extends into the reducer to form the input shaft, which is connected to the first-stage gear pair.

[0013] The gear pair is a structure made of low-carbon alloy steel matrix, which is surface carburized, quenched and ground.

[0014] The output shaft is provided with a permanent magnet in at least a portion of its area. The second servo motor includes a stator wire assembly and is sleeved on the output shaft. The rotating magnetic field generated by the stator wire assembly applies a negative torque to the output shaft.

[0015] The geared motor module also includes: An encoder is used to monitor the output shaft. An interference detection module, electrically connected to the encoder, is used to determine the presence of external interference based on the deviation between the mechanical angle and position command fed back by the encoder, and / or the deviation between the angular velocity and speed command fed back by the encoder. The system includes a master controller and a slave controller. The master controller is electrically connected to the interference detection module to obtain a first control command and a second control command based on the deviation signal from the interference detection module. The first control command is used to control the first servo motor. The main controller is electrically connected to the slave controller to transmit the second control command for controlling the second servo motor; The time control module is electrically connected to the interference detection module and the main controller to trigger the main controller to perform control in response to the presence of external interference signal detected by the interference detection module.

[0016] The time control module, in response to an external interference signal from the interference detection module, triggers the main controller to perform control. The time control module, in response to the absence of external interference signal from the interference detection module, triggers the main controller to stop control.

[0017] The duration for which the time control module responds to trigger the main controller to perform control is greater than the duration of external interference signals.

[0018] The main controller obtains dynamic current commands based on the position deviation and / or speed deviation of the interference detection module; Based on the dynamic current command and the preset fixed bias current, a first control command and a second control command are obtained, wherein the current intensity of the first control command is greater than that of the second control command.

[0019] Due to the adoption of the above technical solution, the beneficial effects achieved by this invention are as follows: 1. In this invention, a structural layout is adopted in which two servo motors are respectively connected to the input shaft and output shaft of the reducer. The first servo motor provides positive driving torque, and the second servo motor applies negative torque in the opposite direction, with the positive torque amplitude being greater than the negative torque. The negative torque at the output end continuously generates tension force between the meshing surfaces of the gears inside the reducer, ensuring that the gears always maintain a one-sided engagement state, thus eliminating gear transmission backlash. By utilizing the reverse torque at the output end to achieve backlash elimination, no additional bias torque control logic is required during operation to automatically eliminate backlash, effectively avoiding transmission idle stroke and significantly improving position control accuracy.

[0020] Furthermore, a dual-end input / output coordination approach separates the driving function (first servo motor) from the damping and backlash elimination function (second servo motor). The first servo motor focuses on providing forward driving torque, while the second servo motor only needs to provide a small reverse damping torque to achieve backlash elimination and disturbance rejection functions, without needing to maintain a large bias torque, effectively reducing the system's continuous energy consumption. Simultaneously, the structural design where the output shaft passes through the second servo motor for power output achieves a high degree of integration between the motor and the reducer, making the overall structure more compact, conforming to miniaturization and lightweight requirements, and suitable for applications with strict size and weight requirements, such as robot joints and precision rotary tables.

[0021] This invention achieves synergistic effects in terms of backlash elimination, anti-disturbance capability, and system efficiency through a dual servo motor input-output collaborative architecture. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the geared motor module according to one embodiment of the present invention; Figure 2 This is a side view of the geared motor module according to one embodiment of the present invention.

[0023] in: 1. Reducer; 11. Input shaft; 12. Output shaft; 2. Servo motor assembly; 21. First servo motor; 22. Second servo motor; 3. Motor housing; 31. Output side; 32. Input side; 4. Support components; 5. Elastic element; 51. First elastic part; 52. Second elastic part; 6. Permanent magnet; 7. Encoder. Detailed Implementation

[0024] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0026] like Figure 1 and Figure 2 As shown, a geared motor module based on a direct connection between a servo motor and a reducer 1 includes: Reducer 1; The servo motor assembly 2 provides power to the reducer 1. The servo motor assembly 2 includes a first servo motor 21 and a second servo motor 22. The first servo motor 21 is connected to the input shaft 11 of the reducer 1 and can input positive torque to the reducer 1. The second servo motor 22 is connected to the output shaft 12 of the reducer 1. The output shaft 12 passes through the second servo motor 22 to output power. The second servo motor 22 can input negative torque to the reducer 1. The positive torque is greater than the negative torque.

[0027] In terms of structural layout, the reducer 1 has an input shaft 11 and an output shaft 12. The first servo motor 21 is directly connected to the input shaft 11 of the reducer 1. That is, the rotor shaft of the first servo motor 21 and the input shaft 11 of the reducer 1 are coaxially fixedly connected through couplings, key connections, or integral molding, so that the rotational power output by the first servo motor 21 can be directly transmitted to the input shaft 11 of the reducer 1.

[0028] The second servo motor 22 is connected to the output shaft 12 of the reducer 1, and the output shaft 12 extends outward after passing through the rotor center area of ​​the second servo motor 22 to realize power output to the external load, so that the second servo motor 22 can directly apply torque control to the output shaft 12.

[0029] Furthermore, in terms of torque control strategy, the first servo motor 21 is configured to input positive torque to the reducer 1. Positive torque means that the direction of the torque is consistent with the desired output rotation direction of the reducer 1, that is, the first servo motor 21 serves as the main drive source of the entire module, providing the main power to drive the load movement.

[0030] The second servo motor 22 is configured to input negative torque to the reducer 1. Negative torque means that the direction of the torque is opposite to the direction of the positive torque provided by the first servo motor 21, that is, the electromagnetic torque generated by the second servo motor 22 attempts to prevent the output shaft 12 from rotating in the positive direction.

[0031] Simultaneously, the system controls the amplitude of the positive torque output by the first servo motor 21 to be greater than the amplitude of the negative torque output by the second servo motor 22. Thus, when the module is working normally, the first servo motor 21 overcomes the reverse damping of the second servo motor 22 and the external load, driving the output shaft 12 to rotate and output in the positive direction.

[0032] Specifically, both the first servo motor 21 and the second servo motor 22 can be permanent magnet synchronous servo motors or AC asynchronous servo motors, each equipped with an independent servo driver. Taking the permanent magnet synchronous servo motor as an example, its stator winding generates a rotating magnetic field after a three-phase sinusoidal current is applied, and the permanent magnet 6 on the rotor rotates synchronously with the rotating magnetic field. The driver of the first servo motor 21 outputs a corresponding current to generate positive electromagnetic torque according to the speed or position command issued by the upper controller. The driver of the second servo motor 22 outputs a reverse current to generate negative electromagnetic torque according to the negative torque command preset by the system or the reverse damping command calculated in real time by the control algorithm. The system ensures that positive torque is dominant by controlling the driving current amplitude of the first servo motor 21 to be greater than that of the second servo motor 22.

[0033] For example, assuming the module needs to output a rated torque of 10 N·m and the reduction ratio of reducer 1 is 10, then the torque output by the first servo motor 21 is approximately 1 N·m. At this time, the second servo motor 22 can be set to output a negative torque of 0.2 N·m. Then, the positive driving torque on the gear meshing surface is 1 N·m (amplified to 10 N·m by reducer 1), the reverse damping torque is 0.2 N·m (amplified to 2 N·m by reducer 1), and the net output torque is 8 N·m. During this process, the negative torque ensures that the gears inside reducer 1 always maintain single-sided engagement, eliminating backlash.

[0034] Because the second servo motor 22 applies a negative torque opposite to the driving direction, this reverse torque is transmitted through the gears inside the reducer 1, ensuring that the meshing tooth surfaces of the driving gear and the driven gear are always in a pressed contact state, eliminating the backlash and reversing impact caused by gear backlash. This application requires no additional mechanical components, and the reverse torque can be adjusted in real time according to the working conditions, avoiding energy waste and motor overheating caused by a fixed bias torque.

[0035] Furthermore, the structural design of the output shaft 12 passing through the second servo motor 22 eliminates the need for the second servo motor 22 to occupy additional axial space, forming a coaxial integrated layout with the reducer 1 and the first servo motor 21. This results in a compact, small-sized, and lightweight overall structure, suitable for applications with stringent space and weight requirements, such as robot joints and precision turntables. Simultaneously, the second servo motor 22 only needs to provide a small negative torque to achieve backlash elimination and damping functions, and its power rating and energy consumption are significantly lower than those of the first servo motor 21, thus resulting in higher overall system energy efficiency.

[0036] This application achieves multiple effects of backlash elimination and structural optimization by using a first servo motor 21 to provide positive driving torque and a second servo motor 22 to provide reverse damping torque, with the positive torque amplitude being greater than the negative torque. This effectively solves the technical problems of low transmission accuracy, poor anti-disturbance capability, and structural redundancy in existing servo geared motors.

[0037] As a preferred embodiment of the present invention, such as Figure 1 As shown, the geared motor module also includes, The motor housing 3 forms a reduction space for accommodating the reducer 1. The motor housing 3 has an opening on one side to form an output side 31, and an input side 32 on the opposite side of the opening. The first servo motor 21 is fixed to the input side 32, and the second servo motor 22 is fixed to the output side 31. The output shaft 12 passes through the opening and is exposed outside the motor housing 3 to output power.

[0038] The geared motor module also includes a motor housing 3. The motor housing 3 forms a reduction space for accommodating the reducer 1, that is, all or most of the transmission components of the reducer 1 (such as gear pairs, bearings, input shaft 11, output shaft 12, etc.) are installed in the internal cavity defined by the motor housing 3, so as to provide support, protection and sealing.

[0039] The motor housing 3 has an opening on one side, which is defined as the output side 31, and the other side of the motor housing 3 opposite to the opening (i.e., the side opposite the opening) is defined as the input side 32. In other words, the motor housing 3 is a cylindrical or box-shaped structure with one end open and one end closed, or with mounting interfaces at both ends. The output side 31 has an opening for the output shaft 12 to extend out, and the input side 32 is used to mount the first servo motor 21.

[0040] The first servo motor 21 is fixed to the input side 32. Specifically, a first mounting flange or positioning stop is provided on the end face or inner wall of the input side 32 of the motor housing 3, and the stator housing of the first servo motor 21 is fixedly connected to the mounting structure by bolts, screws or pressure plates.

[0041] The second servo motor 22 is fixed to the output side 31. Specifically, a second mounting structure (e.g., an annular flange at the edge of the opening or a motor mount on the inner wall) is provided near the opening of the output side 31 of the motor housing 3, and the stator housing of the second servo motor 22 is fixedly connected to this mounting structure by fasteners.

[0042] The output shaft 12 passes through the opening in the motor housing 3 and is eventually exposed outside the motor housing 3 for connecting external loads (such as robot articulated arms, machine tool worktables, etc.). It should be noted that when the output shaft 12 passes through the opening, a bearing or sealing ring can be installed at the opening to ensure the rotational support and dust and oil protection performance of the output shaft 12.

[0043] The motor housing 3 forms the basic support framework for the entire geared motor module. The reducer 1 is located in the reduction space inside the housing, with its input shaft 11 facing the input side 32 and docking with the first servo motor 21, and its output shaft 12 facing the output side 31 and passing sequentially through the second servo motor 22 and the housing opening. This layout allows the first servo motor 21, reducer 1, and second servo motor 22 to be arranged sequentially along the same axis, resulting in a compact, series-connected structure. Furthermore, the opening design of the motor housing 3 makes the exposed portion of the output shaft 12 clearly visible, facilitating load connection.

[0044] The positive torque generated by the first servo motor 21 is amplified by the reducer 1 and transmitted to the output shaft 12, driving the output shaft 12 to rotate. The second servo motor 22 is fixed on the output side 31, and the negative electromagnetic torque generated by its stator acts directly on the output shaft 12, applying reverse damping to the output shaft 12. Since the second servo motor 22 is fixed on the output side 31 of the housing, its reaction torque is directly borne by the motor housing 3, which is beneficial to improving transmission smoothness and structural life.

[0045] As a preferred embodiment of this implementation, such as Figure 1 and Figure 2 As shown, a plurality of support members 4 are provided on the lower side of the motor housing 3. Each support member 4 has an elastic member 5. The elastic member 5 includes a first elastic part 51 and a second elastic part 52 stacked on top of each other. The second elastic part 52 is located below the first elastic part 51. The horizontal cross section of the second elastic part 52 is larger than that of the first elastic part 51. The second elastic part 52 protrudes outward from the support member 4 to provide support.

[0046] This embodiment aims to improve the vibration reduction performance, installation stability, and adaptability to uneven mounting surfaces of the geared motor module during operation. Specifically, multiple support members 4 are provided on the lower side of the motor housing 3. These support members 4 are distributed along the bottom of the motor housing 3 (i.e., the side facing the mounting foundation), for example, evenly arranged at both ends or around the perimeter of the housing, to support the entire geared motor module on an external mounting platform (such as an equipment base, robot joint bracket, etc.).

[0047] Each support member 4 has an internal elastic element 5. This elastic element 5 is not a simple single spring or rubber pad, but adopts a split composite structure, specifically including a first elastic part 51 and a second elastic part 52 stacked vertically. The term "stacked vertically" means that they are arranged sequentially along the vertical direction (i.e., perpendicular to the mounting base), with the first elastic part 51 located above the second elastic part 52, and the second elastic part 52 located below the first elastic part 51. The second elastic part 52 directly contacts the mounting base or is supported by a transition member.

[0048] The horizontal cross-section of the second elastic part 52 is larger than that of the first elastic part 51. A horizontal cross-section refers to a cross-section perpendicular to the vertical direction (i.e., parallel to the plane of the mounting base). In other words, viewed from above, the outline dimensions of the second elastic part 52 are larger than those of the first elastic part 51. For example, if the first elastic part 51 is cylindrical, the second elastic part 52 is disc-shaped or frustum-shaped, and the diameter or width of the second elastic part 52 is significantly larger than that of the first elastic part 51. Furthermore, the second elastic part 52 protrudes outward from the support member 4, meaning that at least a portion of the second elastic part 52 (typically its edge or bottom area) extends outward from the lower port of the support member 4. That is, the support member 4 itself has a cylindrical or frame-shaped outer shell, and the second elastic part 52 extends beyond the lower edge of this shell, directly exposed to the outside of the support member 4, for contact with the mounting base for support.

[0049] Specifically, the support member 4 can be a sleeve or bracket made of metal or engineering plastic, and is fixedly connected to the lower side of the motor housing 3 (e.g., by welding, bolting, or integral casting). The support member 4 has stepped holes or cavities inside to accommodate the elastic member 5. The first elastic part 51 and the second elastic part 52 of the elastic member 5 can be made of the same or different elastic materials, such as natural rubber, polyurethane, silicone, or a composite structure of metal spring and rubber.

[0050] In one embodiment, the first elastic part 51 and the second elastic part 52 are integrally molded rubber components, formed by vulcanization in a mold to create two columnar or disc-shaped structures with different diameters at the top and bottom. In another embodiment, the first elastic part 51 is a helical spring or disc spring, and the second elastic part 52 is a rubber pad or polyurethane pad. The two are then assembled by bonding or mechanical restraint and installed inside the support member 4. To ensure that the second elastic part 52 protrudes beyond the support member 4, the opening size at the lower end of the support member 4 is smaller than the horizontal cross-sectional size of the second elastic part 52, so that the second elastic part 52 is confined inside the support member 4 but partially protrudes; or the lower end of the support member 4 is open, and the overall thickness of the second elastic part 52 is greater than the height from the lower edge of the support member 4 to the internal step, thus naturally protruding outwards.

[0051] During operation, the weight of the motor housing 3 and its internal geared motor module is transferred through the support member 4 to the first elastic part 51 of the elastic member 5, and then from the first elastic part 51 to the second elastic part 52, which finally contacts the mounting base. Because the second elastic part 52 has a larger horizontal cross-section and protrudes beyond the support member 4, its contact area with the mounting base is larger, reducing contact pressure and minimizing localized pressure damage to the mounting base. Simultaneously, the protruding structure of the second elastic part 52 allows for localized deformation and contact even with minor protrusions or unevenness in the mounting base, ensuring stable support contact. The first elastic part 51 has a smaller cross-section, providing greater elastic deformation capacity per unit area, primarily serving to buffer high-frequency vibrations and impacts; the second elastic part 52 has a larger cross-section, providing a larger support area and low-frequency vibration isolation capability. The stacked components with different cross-sections form a two-stage elastic buffer system. The first elastic part 51 focuses on absorbing high-frequency micro-vibrations from the motor housing 3, while the second elastic part 52 focuses on absorbing low-frequency large-displacement vibrations from the mounting base. This reduces the impact of external vibrations on the precision gear pair and servo motor inside the geared motor module, helps maintain high transmission accuracy, and reduces operating noise.

[0052] In a preferred embodiment of the present invention, the first servo motor 21 includes a stator wire group and a rotor gear shaft with a permanent magnet 6 embedded inside. The rotor gear shaft is driven to rotate by the rotating magnetic field generated by the stator wire group. The reducer 1 contains at least two stages of gear pairs. At least a portion of the rotor gear shaft extends into the reducer 1 to form the input shaft 11, which is connected to the first stage gear pair.

[0053] This embodiment aims to achieve higher integration and a more compact drivetrain. The first servo motor 21 includes a stator winding assembly and a rotor gear shaft. The stator winding assembly consists of a stator core and winding coils embedded in the stator core. When multiphase alternating current (e.g., three-phase sinusoidal current) is applied, the stator winding assembly generates a rotating magnetic field. Permanent magnets 6 are embedded inside the rotor gear shaft. These permanent magnets 6 are arranged according to a certain number of pole pairs (e.g., surface-mounted or built-in), so that the rotor gear shaft as a whole constitutes a permanent magnet rotor. Under the action of the rotating magnetic field, the rotor gear shaft is driven and rotates synchronously without the need for additional excitation current, and has the characteristics of high efficiency and high power density.

[0054] It should be noted that in this embodiment, the rotor gear shaft not only serves as the rotor of the motor, but its shaft portion also simultaneously functions as the input shaft 11 of the reducer 1. Specifically, the shaft portion of the rotor gear shaft extends towards the reducer 1 and at least partially extends into the reducer 1. This extended portion directly forms the input shaft 11 of the reducer 1. In other words, the rotor gear shaft and the input shaft 11 of the reducer 1 are an integrated structure of the same shaft, rather than being assembled separately through couplings or keys.

[0055] The reducer 1 contains at least two stages of gear pairs, meaning that the reducer 1 has two or more sets of meshing gear pairs to achieve a large reduction ratio through multi-stage reduction. For example, the first stage is an input gear pair, and the second stage is an intermediate or output gear pair. The gear pairs can be planetary gear structures or parallel shaft cylindrical gear structures. After the rotor shaft extends into the reducer 1, gear teeth are directly machined on its shaft or mounted on a gear, forming a meshing connection with the driving gear of the first-stage gear pair.

[0056] The extended end of the rotor gear shaft is directly formed into a pinion through a hobbing or shaping process. This pinion serves as the driving gear of the first-stage gear pair and meshes with the driven gear (e.g., a larger gear or the sun gear of a planetary gear mechanism) inside the reducer 1. Alternatively, a gear is fixedly mounted on the extended end of the rotor gear shaft via a spline or flat key, and this gear meshes with another gear in the first-stage gear pair.

[0057] The permanent magnet 6 portion of the rotor gear shaft is located radially inside the stator winding assembly, forming the electromagnetic drive portion of the motor. The shaft extension of the rotor gear shaft enters the reducer 1 cavity and directly connects to the first-stage gear pair inside the reducer 1. In this way, the electromagnetic torque generated by the first servo motor 21 is directly transmitted to the first-stage gear pair of the reducer 1 through the rotor gear shaft, without any additional links such as couplings or key connections. This eliminates the gaps and elastic deformation at the connection point, significantly improving the torsional stiffness of the entire drive system, which is beneficial for achieving faster dynamic response and higher position control accuracy.

[0058] In addition, the rotor gear shaft simultaneously serves as both the motor rotor and the input shaft 11 of the reducer 1, eliminating the need for an additional input shaft 11 and its supporting bearings. This reduces the number of parts, shortens the axial distance between the motor and the reducer 1, and makes the whole machine more compact and lightweight, making it particularly suitable for applications where axial length is sensitive, such as robot joints.

[0059] As a preferred embodiment of this implementation, the gear pair is a structure made of low-carbon alloy steel matrix, which is subjected to surface carburizing, quenching and grinding.

[0060] This embodiment aims to improve the load-bearing capacity, wear resistance, and transmission accuracy of gears. All gears (including the driving and driven gears) in at least two stages of gear pairs contained within the reducer 1 are made of low-carbon alloy steel as the base material. Low-carbon alloy steel refers to steel with a low carbon content (typically 0.10%–0.25%) and containing appropriate amounts of alloying elements (such as chromium, nickel, molybdenum, and manganese), such as grades like 20CrMnTi, 20CrMo, or 18CrNiMo. This type of steel has excellent core toughness and machinability, and a high-hardness hardened layer can be obtained on the surface through subsequent heat treatment.

[0061] The final structure of the gear pair is manufactured through surface carburizing, quenching, and precision grinding. The first step involves forging and rough machining the gear blank. Low-carbon alloy steel bars are forged or rolled into gear blanks, which are then normalized or annealed to eliminate internal stress and improve the microstructure. Subsequently, the blanks undergo rough turning, drilling, and other machining processes, and the tooth profile is shaped using hobbing or gear shaping, with a certain grinding allowance reserved.

[0062] The second step is surface carburizing. The roughly machined gear is placed in a carburizing furnace, and a carburizing medium (such as methane, propane, or methanol cracking gas) is introduced at a high temperature (usually 900℃~950℃) to allow carbon atoms to diffuse into the surface layer of the gear. The carburizing time is determined according to the required depth of the hardened layer, generally ranging from several hours to more than ten hours. After carburizing, the carbon concentration on the gear surface increases, forming a precursor of high-carbon martensite.

[0063] The third step is quenching and tempering. After carburizing, the gear is quenched (usually oil quenching or high-pressure gas quenching) to obtain a high-hardness martensitic structure on the surface, while the core retains a low-carbon martensite or bainite structure, providing good toughness. This is followed by low-temperature tempering (approximately 150℃~200℃) to eliminate quenching stress and stabilize the structure. After this treatment, the gear surface hardness can reach 60~62HRC, the hardened layer depth is typically 0.5~1.5mm, and the core hardness is approximately 30~40HRC.

[0064] The fourth step is precision grinding. After quenching, the gear tooth surface will develop some deformation and oxide scale, and the tooth profile accuracy will be difficult to meet high-grade requirements. Therefore, worm wheel grinding or profile grinding processes are used to precisely grind the tooth surface, removing trace amounts of material to achieve a tooth profile accuracy of grade 5 (GB / T 10095 or ISO 1328 standard), with a surface roughness Ra of 0.2–0.4 μm. The grinding process also further eliminates minor deformations caused by heat treatment, ensuring the meshing quality of the gear pair.

[0065] After the above treatment, the high-hardness layer on the surface of the gear pair provides excellent wear resistance and resistance to contact fatigue (pitting, scuffing); the high toughness of the core provides sufficient resistance to bending fatigue and impact, preventing tooth breakage.

[0066] With minimal cumulative pitch deviation and tooth profile error, coupled with a dual servo motor design, transmission backlash is significantly reduced, greatly improving the position control accuracy and repeatability of the geared motor module, meeting the requirements of precision equipment such as robots and CNC machine tools. Furthermore, it possesses extremely high wear and pitting resistance, maintaining tooth profile integrity even under high load and frequent start-stop conditions, significantly extending the overall lifespan of reducer 1.

[0067] As a preferred embodiment of the present invention, such as Figure 2 As shown, the output shaft 12 is provided with a permanent magnet 6 in at least a portion of its area. The second servo motor 22 includes a stator wire group. The second servo motor 22 is sleeved on the output shaft 12. The rotating magnetic field generated by the stator wire group applies a negative torque to the output shaft 12.

[0068] This embodiment aims to achieve more direct negative torque application and higher integration. At least a portion of the output shaft 12 is provided with permanent magnets 6. The output shaft 12 is the power output element of the reducer 1, with one end connected to the last stage gear pair inside the reducer 1, and the other end extending outward to connect to the load. Permanent magnets 6 are fixedly installed in a certain axial section of the outer circumferential surface of the output shaft 12 (e.g., near one end or the middle of the reducer 1). These permanent magnets 6 are arranged according to a certain number of pole pairs (e.g., 2 poles, 4 poles or more) and magnetization direction (radial or tangential) to form the rotor portion of the second servo motor 22. The permanent magnets 6 can be fixed by methods such as bonding, press-fitting, or injection molding to ensure they do not fall off during high-speed rotation.

[0069] The second servo motor 22 includes a stator winding assembly, which consists of a stator core and winding coils embedded in the stator core. Unlike conventional servo motors, the second servo motor 22 is not installed independently and then connected to the output shaft 12 via a coupling; instead, it is directly mounted on the output shaft 12. Specifically, the stator winding assembly is fixed to the inner wall of the output side 31 of the motor housing 3 or to a dedicated stator support, forming a hollow inner cavity on its radially inner side. The output shaft 12, along with its permanent magnet 6, passes through this inner cavity, maintaining a uniform air gap between the permanent magnet 6 and the stator winding assembly. In other words, the output shaft 12 itself serves as the rotor shaft of the second servo motor 22.

[0070] The second servo motor 22 applies a negative torque to the output shaft 12 through the rotating magnetic field generated by the stator winding assembly. When a negative torque is required, the driver of the second servo motor 22 supplies a current of a specific direction and amplitude to the stator winding assembly, generating a rotating magnetic field opposite to the rotation direction of the output shaft 12. This rotating magnetic field interacts with the permanent magnet magnetic field on the output shaft 12, generating an electromagnetic braking torque, i.e., a negative torque. This negative torque acts directly on the output shaft 12 without being transmitted through the gear pair inside the reducer 1. Since the positive torque is greater than the negative torque, the output shaft 12 can still overcome the reverse damping and rotate in the positive direction, but the presence of the negative torque ensures that the gears always remain in contact on one side.

[0071] Compared to mounting the braking device on the input end or intermediate shaft, this embodiment eliminates the delay caused by transmission chain backlash and elastic deformation, which greatly shortens the response time of negative torque. It can apply reverse damping in a very short time when load disturbance occurs, effectively suppressing the speed fluctuation and position oscillation of the output shaft 12.

[0072] Furthermore, the second servo motor 22 is directly mounted on the output shaft 12, sharing the same bearings and housing, eliminating the need for a separate motor housing and coupling. The output shaft 12 simultaneously serves as both the transmission output and the motor rotor, further shortening the axial length of the entire geared motor module, resulting in a more compact structure and higher power density.

[0073] In a preferred embodiment of the present invention, the geared motor module further includes: Encoder 7 is used to monitor the output shaft 12. An interference detection module, electrically connected to the encoder 7, is used to determine the presence of external interference based on the deviation between the mechanical angle and position command fed back by the encoder 7, and / or the deviation between the angular velocity and speed command fed back by the encoder 7. The system includes a master controller and a slave controller. The master controller is electrically connected to the interference detection module to obtain a first control command and a second control command based on the deviation signal from the interference detection module. The first control command is used to control the first servo motor 21. The main controller is electrically connected to the slave controller to transmit the second control command for controlling the second servo motor 22; The time control module is electrically connected to the interference detection module and the main controller to trigger the main controller to perform control in response to the presence of external interference signal detected by the interference detection module.

[0074] This implementation aims to achieve rapid identification and dynamic compensation of load disturbances, thereby improving the anti-interference capability and control accuracy of the geared motor module.

[0075] Encoder 7 is used to monitor the motion parameters of output shaft 12. Encoder 7 can be a photoelectric encoder 7, a magnetoelectric encoder 7, or a rotary transformer. It is mounted on output shaft 12 or a detection shaft rigidly connected to output shaft 12, and can output the mechanical angular position and angular velocity information of output shaft 12 in real time. The feedback signal of encoder 7 is transmitted to the interference detection module and the main controller as feedback quantity for closed-loop control.

[0076] The interference detection module is electrically connected to encoder 7. Its core function is to determine the presence of external interference. Specifically, the interference detection module receives position and speed commands from the upper-level control system or user-defined commands, and simultaneously receives the actual mechanical angle and actual angular velocity fed back by encoder 7. Internally, the interference detection module contains a comparator or microprocessor to calculate at least one of the following two types of deviations: first, the deviation between the mechanical angle fed back by encoder 7 and the position command (position deviation); second, the deviation between the angular velocity fed back by encoder 7 and the speed command (speed deviation). When the absolute value of the deviation exceeds a preset threshold (e.g., a position deviation threshold of 0.01° or a speed deviation threshold of 5% of rated speed), the interference detection module determines that external interference exists and generates an external interference presence signal; conversely, if the deviation is less than the threshold, it determines that there is no external interference or the interference is negligible, and generates an external interference non-existence signal. This threshold can be calibrated and adjusted according to the accuracy requirements of the application scenario.

[0077] The interference detection module compares the deviation between the encoder 7 feedback value and the command value in real time. Only when the deviation exceeds the preset threshold is it determined that there is interference and compensation control is triggered. This avoids the controller performing complex dynamic compensation calculations under all operating conditions, which reduces the occupation of computing resources and prevents system jitter that may be caused by unnecessary control actions when there is no interference.

[0078] The master controller and slave controller form a two-stage control architecture. The master controller is electrically connected to the interference detection module and performs control algorithm calculations based on the deviation signals (specifically, position deviation values ​​and / or speed deviation values) output by the interference detection module to obtain a first control command and a second control command. The first control command controls the first servo motor 21 (i.e., the main drive motor at the input end), and the second control command controls the second servo motor 22 (i.e., the reverse damping motor at the output end). The master controller and slave controller are electrically connected via a communication interface (such as SPI, CAN, or PWM signal lines) to transmit the second control command to the slave controller. After receiving the second control command, the slave controller drives the driver of the second servo motor 22, causing the second servo motor 22 to output the corresponding negative torque.

[0079] Compared to a single controller handling both computation and drive simultaneously, this reduces control latency, allowing negative torque to respond more quickly to load disturbances. Simultaneously, it avoids the system stability degradation caused by the lack of coordination between the first servo motor 21 and the second servo motor 22.

[0080] It should be noted that the master controller and slave controller can be two independent microcontroller chips, or two independent control cores within the same chip. The master controller is responsible for the core control algorithm calculation and instruction distribution, while the slave controller is specifically responsible for the current loop or torque loop control of the second servo motor 22, in order to reduce the computational burden of the master controller and improve the response speed.

[0081] The time control module is electrically connected to the interference detection module and the main controller. The core function of the time control module is to respond to signals from the interference detection module and trigger the main controller to perform control.

[0082] Specifically, the time control module, in response to the external interference signal detected by the interference detection module, triggers the main controller to perform control. The time control module, in response to the absence of external interference signal from the interference detection module, triggers the main controller to stop control.

[0083] When the interference detection module outputs a signal indicating the presence of external interference, the time control module sends a trigger signal to the main controller, activating the main controller to execute the aforementioned deviation calculation and instruction generation process. When the interference detection module outputs a signal indicating the absence of external interference, the time control module sends a stop trigger signal to the main controller, which can then stop active compensation control or enter a standby low-power state.

[0084] The time control module can be implemented using a hardware comparator and a monostable multivibrator, or it can be implemented using a timer interrupt within the microcontroller in conjunction with software logic. In one embodiment, the time control module is integrated into the main controller, triggering an interrupt service routine by detecting a flag bit output by the interference detection module. When an interrupt is triggered, the main controller immediately executes the interference compensation control algorithm once or multiple times consecutively; when no interrupt is triggered, the main controller only performs conventional speed or position closed-loop control without initiating additional dynamic compensation.

[0085] It should be noted that the duration for which the time control module responds to trigger the main controller to perform control is greater than the duration of external interference signals.

[0086] If the time control module immediately stops triggering the main controller the moment the interference signal disappears, the following problems may occur: First, after the interference disappears, the system is still in the recovery process after the disturbance, and the actual position and speed of the output shaft 12 have not yet fully stabilized to the command value. If the compensation control is immediately canceled at this time, that is, the dynamic compensation calculation of the main controller and the negative torque adjustment of the second servo motor 22 are stopped, the residual oscillation may not be effectively suppressed, prolonging the system stabilization time. Second, the response of the control system itself has a delay. From the disappearance of the interference signal to the output of the last compensation command by the main controller, and then to the actual execution by the second servo motor 22, a certain amount of processing time and electromagnetic response time are required. If the trigger duration is exactly equal to the duration of the interference, the compensation control may terminate prematurely and fail to cover the entire recovery period.

[0087] The time control module is configured such that when the interference detection module outputs a signal indicating the presence of external interference, the time control module triggers the main controller to start control; when the interference detection module outputs a signal indicating the absence of external interference, the time control module does not immediately stop triggering, but continues to maintain the triggering state for a preset extended period of time, so that the total duration of control by the main controller is greater than the duration of the external interference signal.

[0088] In other words, the time control module has a built-in delay reset function. Control is triggered when the rising edge of the interference signal arrives, and a delay timer is started when the falling edge of the interference signal arrives. The trigger signal remains valid until the delay timer expires; only after the delay ends is the trigger signal deactivated, and the main controller stops compensation control. This embodiment, by reserving a time margin, ensures that the actual compensation time fully covers the interference process and subsequent recovery period, significantly shortening the adjustment time and improving the dynamic stability of the system.

[0089] It should be further noted that the extension duration can be calibrated and adjusted based on the rotational inertia of the geared motor module, load characteristics, and the response speed of the control system. Generally speaking, systems with larger inertia and slower response require a longer extension duration to ensure that residual oscillations are adequately suppressed.

[0090] In a preferred embodiment of this implementation, the main controller obtains a dynamic current command based on the position deviation and / or speed deviation of the interference detection module; Based on the dynamic current command and the preset fixed bias current, a first control command and a second control command are obtained, wherein the current intensity of the first control command is greater than that of the second control command.

[0091] This embodiment aims to achieve more precise drive force distribution and dynamic compensation. The main controller first calculates the dynamic current command based on the deviation signal output by the interference detection module. This deviation signal includes position deviation (the difference between the mechanical angle fed back by encoder 7 and the position command) and / or velocity deviation (the difference between the angular velocity fed back by encoder 7 and the velocity command). The dynamic current command can be calculated using PID control algorithms, sliding mode control algorithms, or model predictive control algorithms, etc. For example, the main controller reads the position deviation value at the current moment. and / or speed deviation value The dynamic current command is calculated according to the following formula. This represents the additional current value required to suppress the current disturbance and restore the output shaft to the commanded position or commanded speed, and its direction is opposite to the direction of the disturbance. in, This is a proportionality coefficient used to amplify the deviation at the current moment in real time, thus determining the sensitivity of the system response; It is a time variable; The integral coefficient is used to eliminate static error by integrating the historical accumulation of the deviation. These are differential coefficients used to predict the trend of deviation changes and improve the dynamic response and stability of the system.

[0092] In speed control mode, the dynamic current command can also be calculated directly based on the speed deviation. The formula is the same; you only need to... Replace with speed deviation That's all.

[0093] The system has a preset fixed bias current. The fixed bias current is a pre-set constant value. Its function is to provide a basic negative torque for the second servo motor 22 to maintain the single-sided engagement of the gears inside the reducer 1 in an interference-free state, that is, to achieve basic backlash elimination. The magnitude of the fixed bias current is usually determined based on the backlash of the reducer 1, the gear inertia, and the required backlash elimination torque. It is generally small to ensure energy efficiency.

[0094] The main controller, based on the dynamic current command and preset fixed bias current The first control command is obtained through superposition or allocation algorithms. Second control command Among them: the first control command The current used to control the first servo motor 21 (the main drive motor at the input end) is equal to the sum of the dynamic current command and the fixed bias current, i.e. Second control command Used to control the second servo motor 22 (output reverse damping motor), its current intensity is equal to the difference between the dynamic current command and the fixed bias current, i.e. Or, in some implementations, the absolute value of the second control instruction is... And the direction is opposite to the first control command (i.e., negative torque).

[0095] By combining dynamic current commands (reflecting interference suppression requirements) with fixed bias current (reflecting basic backlash elimination requirements), the main controller can simultaneously adjust the forward driving force of the first servo motor 21 and the reverse damping force of the second servo motor 22. When interference increases, the dynamic current command automatically increases, and the absolute values ​​of the first and second control commands increase synchronously, causing the forward driving force and reverse damping force to increase proportionally, thereby quickly suppressing disturbances. When interference decreases, both automatically decrease, avoiding overcompensation.

[0096] When there is no interference, the dynamic current command is zero, and the first control command is only equal to the fixed bias current (smaller value). The system standby is maintained by the small current of the first servo motor 21, which is significantly more energy-efficient than the scheme of continuously applying reverse bias.

[0097] For any parts not mentioned in this invention, existing technologies can be used or referenced.

[0098] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0099] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A geared motor module based on direct connection between a servo motor and a reducer, characterized in that, include: reducer; A servo motor assembly provides power to the reducer. The servo motor assembly includes a first servo motor and a second servo motor. The first servo motor is connected to the input shaft of the reducer and can input positive torque to the reducer. The second servo motor is connected to the output shaft of the reducer, and the output shaft passes through the second servo motor to output power. The second servo motor can input negative torque to the reducer, and the positive torque is greater than the negative torque.

2. The geared motor module according to claim 1, characterized in that, It also includes, The motor housing forms a reduction space to accommodate the reducer. The motor housing has an opening on one side to form an output side, and an input side on the opposite side. The first servo motor is fixed to the input side, and the second servo motor is fixed to the output side. The output shaft passes through the opening and is exposed outside the motor housing to output power.

3. The geared motor module according to claim 2, characterized in that, The lower side of the motor housing is provided with multiple support members, each of which contains an elastic member. The elastic member includes a first elastic part and a second elastic part stacked on top of each other. The second elastic part is located below the first elastic part, and the horizontal cross-section of the second elastic part is larger than that of the first elastic part. The second elastic part protrudes outward from the support member to provide support.

4. The geared motor module according to claim 1, characterized in that, The first servo motor includes a stator wire assembly and a rotor gear shaft with a permanent magnet embedded inside. The rotor gear shaft is driven to rotate by the rotating magnetic field generated by the stator wire assembly. The reducer contains at least two stages of gear pairs. At least a portion of the rotor gear shaft extends into the reducer to form the input shaft, which is connected to the first-stage gear pair.

5. The geared motor module according to claim 4, characterized in that, The gear pair is a structure made of low-carbon alloy steel matrix, which is surface carburized, quenched and ground.

6. The geared motor module according to claim 1, characterized in that, The output shaft is provided with a permanent magnet in at least a portion of its area. The second servo motor includes a stator wire assembly and is sleeved on the output shaft. The rotating magnetic field generated by the stator wire assembly applies a negative torque to the output shaft.

7. The geared motor module according to claim 1, characterized in that, Also includes: An encoder is used to monitor the output shaft. An interference detection module, electrically connected to the encoder, is used to determine the presence of external interference based on the deviation between the mechanical angle and position command fed back by the encoder, and / or the deviation between the angular velocity and speed command fed back by the encoder. The system includes a master controller and a slave controller. The master controller is electrically connected to the interference detection module to obtain a first control command and a second control command based on the deviation signal from the interference detection module. The first control command is used to control the first servo motor. The main controller is electrically connected to the slave controller to transmit the second control command for controlling the second servo motor; The time control module is electrically connected to the interference detection module and the main controller to trigger the main controller to perform control in response to the presence of external interference signal detected by the interference detection module.

8. The geared motor module according to claim 7, characterized in that, The time control module, in response to an external interference signal from the interference detection module, triggers the main controller to perform control. The time control module, in response to the absence of external interference signal from the interference detection module, triggers the main controller to stop control.

9. The geared motor module according to claim 8, characterized in that, The duration for which the time control module responds to trigger the main controller to perform control is greater than the duration of external interference signals.

10. The geared motor module according to claim 7, characterized in that, The main controller obtains dynamic current commands based on the position deviation and / or speed deviation of the interference detection module; Based on the dynamic current command and the preset fixed bias current, a first control command and a second control command are obtained, wherein the current intensity of the first control command is greater than that of the second control command.

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