Joint module

Abstract

The utility model provides a joint module relates to mechanical technical field, including hollow shaft, wherein at least one end has through -hole, speed reducer, axial flux motor, high -speed end code disc sets up in the one end of axial flux motor back, low -speed end code disc is fixed in second end, encoder mainboard is provided with high / low encoder reading head and hardware interface. The hollow axial flux motor of this application is in its unique disc type magnetic circuit structure, improves the torque output under the same volume, shortens the module axial size simultaneously, simultaneously, the encoder mainboard integration double encoder reading head and hardware interface, shortens signal transmission path, eliminates the space of separate driver, cooperates double encoder to improve signal quality and sampling synchronism, the through -hole design of hollow shaft provides built -in passageway for signal line and power line, combines motor, speed reducer, double code disc along the compact layout of axle core, eliminates the risk of exposed wiring, improves space utilization.

Description

Technical Field

[0001] This utility model relates to the field of mechanical technology, and in particular to a joint module. Background Technology

[0002] Rotary joint modules, as core components in robotics, robotic arms, and related applications, provide speed and torque output and precise position control. They typically consist of a reducer, a brushless motor, and an encoder. Currently, common joint modules on the market often use a radial brushless motor with a separate encoder, which suffers from issues such as small size, low torque, and poor control accuracy. To increase torque, only reducers with large reduction ratios can be used, significantly increasing weight. Furthermore, the lack of dedicated wiring for signal and power lines, coupled with discrete module drivers, further increases the space required for module use, hindering miniaturization and lightweight design. Utility Model Content

[0003] The main purpose of this invention is to propose a joint module that aims to solve the problems of low volume torque, poor control precision, low integration and difficulty in lightweighting existing technologies.

[0004] To achieve the above objectives, this application proposes a joint module, comprising:

[0005] A hollow shaft has a first end and a second end disposed opposite to each other along its own axial direction, wherein at least one end has a through hole;

[0006] The speed reducer is fitted onto the hollow shaft;

[0007] An axial flux motor is sleeved on the hollow shaft, and the power output end of the axial flux motor is connected to the first end through the reducer;

[0008] A high-speed end encoder is located at one end of the axial flux motor facing away from the reducer and is connected to the power output end;

[0009] A low-speed end encoder disk is fixed to the second end, and the low-speed end encoder disk is disposed inside the high-speed end encoder disk sleeve.

[0010] The encoder motherboard has a first surface and a second surface that are arranged opposite to each other. The first surface faces the axial flux motor and is provided with a high / low encoder read head corresponding to the high / low speed end code disk. The second surface is provided with a hardware interface for electrical connection to external devices.

[0011] In one embodiment, the reducer includes:

[0012] The input end is located on the side of the reducer facing the axial flux motor and is connected to the power output end of the axial flux motor;

[0013] The output end is fixedly connected to the first end.

[0014] In one embodiment, the input end of the reducer includes a sun gear engagement chamber, which is located outside the hollow shaft.

[0015] In one embodiment, the axial flux motor includes:

[0016] case;

[0017] The motor shaft passes through the housing and extends out of the housing at one end toward the reducer. The outer wall of the end of the motor shaft facing the reducer is provided with a sun gear that meshes with the sun gear meshing cavity.

[0018] A stator assembly is disposed within the housing and sleeved on the motor shaft;

[0019] The rotor assembly is disposed within the housing and is fitted and fixed to the motor shaft.

[0020] In one embodiment, the motor shaft is a hollow structure with both ends through it, the hollow shaft passing through the motor shaft and the second end extending out of the motor shaft.

[0021] In one embodiment, a mounting portion is provided on the side of the housing facing away from the reducer, and the encoder main board is connected to the housing through the mounting portion. The axes of the high-speed end code disk, the low-speed end code disk and the encoder main board are coincident on the same straight line.

[0022] In one embodiment, the high-speed end encoder includes:

[0023] A high-speed end encoder mounting bracket is fixed to the end of the motor shaft facing away from the reducer.

[0024] A high-speed end code disk magnetic ring is disposed on the side of the high-speed end code disk mounting bracket facing away from the motor shaft;

[0025] The low-speed end encoder includes:

[0026] A low-speed end encoder mounting bracket is fixed to the end of the second end, and the low-speed end encoder mounting bracket is disposed inside the high-speed end encoder mounting bracket;

[0027] The low-speed end code disk magnetic ring is located on the side of the low-speed end code disk mounting bracket facing away from the second end, and the low-speed end code disk magnetic ring is located inside the high-speed end code disk magnetic ring.

[0028] In one embodiment, the surface of the high-speed encoder read head is axially aligned with the surface of the high-speed end code disk magnetic ring and is provided with a gap, and the surface of the low-speed encoder read head is axially aligned with the surface of the low-speed end code disk magnetic ring and is provided with a gap.

[0029] In one embodiment, it further includes:

[0030] A driver is electrically connected to the axial flux motor to drive the axial flux motor to operate.

[0031] In one embodiment, the encoder motherboard is integrated on the driver.

[0032] This application proposes a joint module, including an axial flux motor, a hollow shaft, dual encoders, and an encoder motherboard. The axial flux motor, with its unique disc-type magnetic circuit structure, increases torque output within the same volume while shortening the module's axial dimension. Simultaneously, the encoder motherboard integrates dual encoder readers and hardware interfaces, shortening the signal transmission path, eliminating the space occupied by discrete drivers, and improving signal quality and sampling synchronization in conjunction with the dual encoders. The through-hole design of the hollow shaft provides built-in channels for signal and power lines. Combined with the compact layout of the motor, reducer, and dual encoder discs along the shaft, it eliminates the risk of exposed wiring and improves space utilization. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 This is an exploded view of a joint module structure according to the present invention;

[0035] Figure 2 This is a cross-sectional view of a joint module according to the present invention;

[0036] Figure 3 This is a cross-sectional view of a joint module reducer according to the present invention;

[0037] Figure 4 This is a diagram showing the internal structure of an axial flux motor for a joint module according to this utility model.

[0038] Figure 5 This is a structural diagram of a high-speed end encoder and a low-speed end encoder of a joint module according to this utility model;

[0039] Figure 6 This is a structural diagram of a joint module encoder motherboard according to the present invention;

[0040] Figure 7 This is an exploded view of an embodiment of a joint module according to the present invention.

[0041] Reference numerals: Hollow shaft 01, Through hole 11, Reducer 02, Sun gear meshing cavity 21, Axial flux motor 03, Housing 31, Motor shaft 32, Sun gear 33, High-speed end code disk 04, High-speed end code disk mounting bracket 41, High-speed end code disk magnetic ring 42, Low-speed end code disk 05, Low-speed end code disk mounting bracket 51, Low-speed end code disk magnetic ring 52, Encoder main board 06, High encoder read head 61, Low encoder read head 62, Driver 07.

[0042] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0044] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0045] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0046] This application proposes a joint module, such as Figure 1 and Figure 2As shown, it includes: a hollow shaft 01, having a first end and a second end arranged opposite to each other along its own axial direction, wherein at least one end has a through hole 11; a reducer 02, sleeved on the hollow shaft 01; an axial flux motor 03, sleeved on the hollow shaft 01, the power output end of the axial flux motor 03 being connected to the first end through the reducer 02; a high-speed code disk 04, disposed at the end of the axial flux motor 03 facing away from the reducer 02 and connected to the power output end; a low-speed code disk 05, fixed to the second end, the low-speed code disk 05 being disposed inside the high-speed code disk 04; and an encoder main board 06, having a first surface and a second surface arranged opposite to each other, the first surface facing the axial flux motor 03 and having a high / low encoder read head 61 / 62 corresponding to the high / low speed code disks 04 / 05, and the second surface having a hardware interface for electrical connection with external devices.

[0047] More specifically, rotary joint modules are core components in automated equipment such as robots and robotic arms, enabling motion functions. Their core function is to accurately output the required rotational speed and torque, and achieve precise position control. A typical joint module usually integrates a brushless motor to provide power, a reducer to adjust output characteristics, and an encoder to provide real-time position information.

[0048] Currently, most mainstream joint module designs on the market employ a brushless motor with a radial magnetic circuit structure, paired with a separately mounted position encoder. This traditional configuration has some inherent limitations, primarily stemming from the trade-off between size and performance. To achieve high torque output within a limited space, designers are often forced to use a high-reduction-ratio reducer, which, while increasing torque, also significantly increases the overall weight and size of the module, contradicting the modern trend towards miniaturization and lightweighting. Furthermore, in terms of control accuracy, assembly errors and signal transmission delays between the separately mounted encoder and motor can adversely affect the final position control accuracy.

[0049] The physical structure design of the modules also has shortcomings. The lack of dedicated, optimized routing channels for signal and power lines leads to messy cable arrangements, affecting aesthetics, increasing space consumption, and raising potential failure risks. Even more troubling is that these modules typically require external discrete drivers (07) to operate, further occupying valuable internal space and reducing the overall integration of the drive system, resulting in low space utilization and posing a significant obstacle to applications requiring compact designs. To effectively overcome these limitations, the key lies in fundamentally changing the integrated design philosophy of the modules, seeking solutions that deeply integrate the motor, encoder, driver (07), and even the wiring channels. This requires addressing both physical layout and electrical architecture to achieve truly high power density and a compact design.

[0050] To address the aforementioned issues, this application proposes a joint module, including a hollow shaft 01 that runs through the entire module. The shaft has a first end and a second end arranged opposite each other along its own axial direction, with at least one end having a through hole 11. The hollow shaft 01 is not only the mechanical core for transmitting torque, but its internal cavity also provides dedicated wiring channels for power and signal lines, thereby changing the traditional exposed or messy wiring situation of modules, further saving wiring space and increasing installation flexibility.

[0051] The module's power source is an axial flux motor 03, which is mounted on the hollow shaft 01. Unlike common radial flux motors, the flux direction of the axial flux motor 03 is parallel to its rotation axis, i.e., the direction of the hollow shaft 01. This structural characteristic allows it to generate significantly higher torque than radial motors within the same volume, exhibiting extremely high torque density. The power output of the axial flux motor 03 is directly connected to the reducer 02, which is also mounted on the hollow shaft 01. The reducer 02 converts the high speed and relatively low torque output of the axial flux motor 03 into the lower speed and significantly increased torque required for the final joint output. The output of the reducer 02 is connected to the first end of the hollow shaft 01, thus directly transmitting the amplified torque to the hollow shaft 01 to drive the load to rotate.

[0052] To achieve high-precision closed-loop control, this application employs a dual-encoder feedback system. The high-speed encoder 04 is located at one end of the axial flux motor 03 facing away from the reducer 02 and connected to the power output end. The low-speed encoder 05 is fixed to the second end, positioned inside the high-speed encoder 04. Essentially, the high-speed encoder 04 is directly mounted on the power output end of the axial flux motor 03, located at the end facing away from the reducer 02. It directly follows the high-speed rotation of the motor rotor, accurately measuring the rotor's rotational speed and angular position. The low-speed encoder 05 is fixedly mounted on the second end of the hollow shaft 01. Since the hollow shaft 01 has already undergone reduction by the reducer 02, the low-speed encoder 05 directly reflects the final output end of the joint, i.e., the rotational speed and absolute position of the second end of the hollow shaft 01. Notably, the low-speed encoder 05 is positioned within the space inside the high-speed encoder 04; this compact nested layout significantly saves axial space.

[0053] The dual encoder feedback system also involves an encoder motherboard 06, which has a first surface and a second surface arranged opposite to each other. The first surface faces the axial flux motor 03 and is provided with high / low encoder read heads 62 corresponding to the high / low speed end code disks 05. The second surface is provided with hardware interfaces for electrical connection to external devices. In essence, the first surface integrates two encoder read heads: a high encoder read head 61 facing the high-speed end code disk 04, used to read the rotor position information of the motor under high-speed rotation; and a low encoder read head 62 facing the low-speed end code disk 05, used to read the position information of the second end of the hollow shaft 01. The second surface of the encoder motherboard 06 integrates hardware interfaces, which are directly used for electrical connection and data communication with external control devices. This design highly integrates the originally discrete photoelectric reading elements and interface circuits onto a single motherboard, not only eliminating the need for connecting lines and installation space between discrete components but also improving the stability and reliability of signal transmission.

[0054] The working principle of this application is briefly described as follows: An external drive signal is input through the hardware interface on the second surface of the encoder motherboard 06, driving the axial flux motor 03 to rotate. The motor rotor drives the high-speed end code disk 04 to rotate, and the power is transmitted to the first end of the hollow shaft 01 through the reducer 02, driving the hollow shaft 01 to rotate with a reduced speed and increased torque. The low-speed end code disk 05, fixed at the second end, rotates accordingly. The high-speed encoder reader 61 reads the information of the high-speed end code disk 04 in real time, providing precise speed and position feedback for the motor rotor; the low-speed encoder reader 62 reads the information of the low-speed end code disk 05 in real time, providing absolute position and speed feedback for the final output end of the joint. These two high-precision feedback signals are processed by the encoder motherboard 06 and transmitted back to the external control system in real time through its hardware interface. The control system compares and calculates the target command and these two feedback signals to generate precise control commands, dynamically adjusts the motor input, and thus achieves extremely precise and stable closed-loop control of the speed, torque, and position of the joint output end. Meanwhile, all necessary power and signal cables can pass through the through-hole 11 inside the hollow shaft 01, achieving neat, compact, and reliable internal wiring. The entire design achieves deep integration in physical layout and electrical architecture, effectively improving torque density and control precision, while significantly reducing size and weight.

[0055] This application proposes a joint module, including an axial flux motor 03, a hollow shaft 01, dual encoders, and an encoder motherboard 06. The axial flux motor 03, with its unique disc-type magnetic circuit structure, increases torque output within the same volume while shortening the module's axial dimension. Meanwhile, the encoder motherboard 06 integrates dual encoder readers and hardware interfaces, shortening the signal transmission path, eliminating the space occupied by the discrete driver 07, and improving signal quality and sampling synchronization in conjunction with the dual encoders. The through-hole 11 of the hollow shaft 01 provides an internal channel for signal and power lines. Combined with the compact layout of the motor, reducer 02, and dual encoder discs along the axis, it eliminates the risk of exposed wiring and improves space utilization.

[0056] In one embodiment, such as Figure 3 As shown, the reducer 02 includes:

[0057] The input end is located on the side of the reducer 02 facing the axial flux motor 03 and is connected to the power output end of the axial flux motor 03; the output end is fixedly connected to the first end.

[0058] In this embodiment, the reducer 02 is a planetary reducer; in other embodiments, it can also be a harmonic reducer, RV reducer, or other reducer 02. In this embodiment, the reducer 02 is the core mechanism for power conversion and transmission. Its core function is to efficiently and reliably convert the high speed and relatively low torque output by the axial flux motor 03 into the low speed and high torque required for the final joint output, directly driving the hollow shaft 01 to rotate. The reducer 02 is spatially fitted tightly around the hollow shaft 01, and its structure mainly includes two key functional ends: an input end and an output end. The input end of the reducer 02 is located on the side facing the axial flux motor 03, and it is directly and rigidly meshed with the power output end of the axial flux motor 03. When the motor rotates, its power output end rotates like the sun gear 33 of a planetary system, transmitting the original output speed and torque of the motor intact to the input end of the reducer 02, serving as the initial power source for the entire deceleration process.

[0059] The output end of the reducer 02 is fixedly connected to the first end of the hollow shaft 01. In the planetary reducer 02, the final output is typically achieved by the planet carrier. The planet carrier gathers the motion of all the planet gears' revolutions, and its rotational speed is much lower than the input speed of the sun gear 33, but the output torque is significantly amplified. A key structural innovation of this embodiment is that the output end is not simply connected to a solid shaft, but rather to an output hollow shaft 01. It extends out from the input end of the reducer 02. That is, one end of the output hollow shaft 01 is fixed to the output end of the reducer 02, and then its shaft body passes through the inside of the reducer 02 in the opposite direction, finally extending out from the end of the reducer 02 that was originally the input side. This design, where the output shaft passes through the input side in the opposite direction, is key to achieving high integration, compact layout, and internal wiring. Although this embodiment uses planetary reducer 02 as an example, the core input-output connection concept (the input end engages with the motor, and the output end is fixedly connected to the output shaft with a hollow wiring hole) is also applicable to the integrated application of other types of reducers 02 such as harmonic reducer 02 and RV reducer 02.

[0060] In one embodiment, the input end of the reducer 02 includes a sun gear engagement cavity 21, which is located outside the hollow shaft 01. Specifically, the sun gear engagement cavity 21 serves as the connection point for power input, directly and rigidly engaging with the power output end of the axial flux motor 03. When the motor rotor rotates, its output shaft, like the sun gear 33 in a planetary gear system, is precisely accommodated and driven within this engagement cavity. Therefore, the sun gear engagement cavity 21 essentially carries and transmits the entire original speed and torque output of the motor, inputting it as the initial power source for the deceleration process into the reducer 02.

[0061] The power output end of the axial flux motor 03 is directly inserted into and meshes with the sun gear meshing cavity 21 at the input end of the planetary reducer 02, driving the sun gear 33 to rotate at high speed. The sun gear 33 drives the rotation of multiple planet gears meshing with it. While rotating, the planet gears also revolve around the sun gear 33 because they mesh with the stationary internal gear ring. The planet carrier, which drives the planet gears to revolve, serves as the confluence point of the entire planetary reduction system. Its rotational speed is much lower than the input speed of the sun gear 33, but its output torque is amplified many times over. This amplified torque is transmitted through the planet carrier to the output hollow shaft 01, which is fixedly connected to it. Finally, the output hollow shaft 01, with its reduced speed and increased torque, drives the entire hollow shaft 01 to rotate, thereby driving the load movement at the joint end.

[0062] In one embodiment, such as Figure 4 As shown, the axial flux motor 03 includes:

[0063] Housing 31; motor shaft 32, which passes through the housing 31 and extends out of the housing 31 at one end toward the reducer 02, and a sun gear 33 that meshes with the sun gear meshing cavity 21 is provided on the outer wall of the end of the motor shaft 32 facing the reducer 02; stator assembly, which is disposed in the housing 31 and sleeved on the motor shaft 32; rotor assembly, which is disposed in the housing 31 and sleeved and fixed on the motor shaft 32.

[0064] In this embodiment, the axial flux motor 03 serves as the power core of the joint module. Compared to the traditional radial flux motor, the axial flux motor 03 has a smaller axial dimension and a higher output torque, thus reducing the installation space occupied by the joint module and increasing the torque density of the module. The axial flux motor 03 includes a single stator-single rotor configuration ("rotor-stator-rotor"), a single stator-double rotor configuration ("rotor-stator-rotor"), and a double stator-single rotor configuration ("stator-rotor-stator").

[0065] This embodiment adopts a "stator-rotor-stator" dual-stator single-rotor configuration to achieve a stronger magnetic field and higher power density. The axial flux motor 03 mainly consists of a housing 31, a motor shaft 32, a rotor assembly, and a dual-stator assembly. The housing 31 serves as a support and protective structure, housing all core components. The motor shaft 32 runs through the entire housing 31, and its key feature is that one end extends out of the housing 31 towards the reducer 02. The outer wall of this shaft end extending out of the housing 31 is directly machined or fixedly fitted with a sun gear 33 that meshes with the input end of the reducer 02, such as the sun gear meshing cavity 21. This means that the motor shaft 32 not only transmits the rotational power of the motor itself, but its end itself also plays the role of the input sun gear 33 of the planetary reducer 02, realizing direct power transmission between the motor and the reducer 02 without additional connecting parts, improving rigidity and efficiency. It is worth noting that the motor shaft 32 and the sun gear 33 at its end are both provided with through holes 11, and the hollow shaft 01 can pass through the motor shaft 32 and the sun gear 33 at its end.

[0066] Specifically, each stator assembly includes an iron core and copper wire winding coils embedded in the iron core. These coils are connected in a specific manner, generating an axial magnetic field in the iron core when energized. The rotor assembly is fixedly mounted on the motor shaft 32, located between the upper and lower stator assemblies. Permanent magnets are embedded in the rotor assembly, also arranged in a specific polarity, with their magnetization direction also axial. When current flows through the upper and lower stator windings, each stator assembly generates an axial magnetic field on its core air gap surface. Since the rotor assembly is located between the two stators, its permanent magnets are simultaneously subjected to the interaction force of the magnetic fields of the upper and lower stators. The combined magnetic fields of the two stators drive the rotor assembly with permanent magnets to rotate around its axis. The rotational power of the motor shaft 32 is output through the sun gear 33 directly integrated at its end, and immediately engages with the sun gear engagement chamber 21 of the reducer 02. This "double stator clamping single rotor" structure allows the permanent magnets on both sides of the rotor to be effectively utilized, generating a powerful driving torque within a compact axial space and improving the motor's torque output capability.

[0067] Meanwhile, temperature sensing elements embedded between the stator coils continuously monitor the winding temperature, providing overheat protection for the motor and ensuring safe and reliable operation. The through-hole 11, passing through the motor shaft 32 and the sun gear 33, provides an ideal path for cables to travel directly from inside the motor to the reducer 02 and the joint output end, solving the problems of limited wiring space and reliability in traditional joints. This deeply integrated axial flux motor 03 design is the core foundation for achieving miniaturization, high torque density, and high efficiency in the joint module.

[0068] In one embodiment, the motor shaft 32 is a hollow structure with both ends through it. The hollow shaft 01 passes through the motor shaft 32 and extends out of the motor shaft 32 at its second end.

[0069] In this embodiment, the motor shaft 32 is designed as a hollow structure that extends through both ends, forming an internal channel along its axial direction. Closely integrated with the hollow structure of the motor shaft 32 is a hollow shaft 01. The hollow shaft 01 does not exist independently of the motor shaft 32 but is arranged in a nested, through-type configuration: the hollow shaft 01 extends from the reducer 02 direction, i.e., the end of the motor shaft 32 extending out of the housing 31 and carrying the sun gear 33, into the hollow internal channel of the motor shaft 32, and continues to extend along this channel into the motor, finally exiting from the other end of the motor shaft 32 and extending outwards. Therefore, both the first and second ends of the hollow shaft 01 are located outside the two ends of the motor shaft 32.

[0070] In one embodiment, such as Figure 2 and Figure 6As shown, the housing 31 has a mounting part on the side facing away from the reducer 02. The encoder main board 06 is connected to the housing 31 through the mounting part. The axes of the high-speed end code disk 04, the low-speed end code disk 05 and the encoder main board 06 are coincident on the same straight line.

[0071] Specifically, the housing 31 has a specially designed mounting section, which typically includes a positioning structure to ensure high repeatability and stability of the main board's position after it is fixed. The encoder main board 06 is connected to this mounting section by screws or clips, making it a stationary reference component in the entire module. After the main board is fixed in place and the code disk is installed, a very precise axial gap, i.e., the working air gap, is formed between the upper surface of the sensing surface of the reading head and the upper surface of the corresponding code disk magnetic ring. The existence of this air gap and its precise control are the core physical basis for the normal operation of the magnetic induction encoder. The existence of the working air gap ensures that there is no physical contact between the reading head and the rotating magnetic ring, eliminating mechanical friction, wear, and the resulting noise, and ensuring long-term reliability and high accuracy of the measurement.

[0072] The axes of the high-speed end code disk 04, the low-speed end code disk 05, and the encoder main board 06 must be strictly coincident on the same straight line, i.e., highly concentric. The rotation axes of the motor shaft 32 and the hollow shaft 01 themselves need to be highly coaxial with the bearings, housing 31 holes, etc. This ensures that the axial distance of the working air gap remains constant throughout the entire rotation process, the magnetic ring does not shift or wobble relative to its corresponding reading head in the radial plane, and the magnetized magnetic poles / tracks on the magnetic ring can sweep across the sensing area of ​​the reading head evenly and equidistantly.

[0073] In one embodiment, such as Figure 5 As shown, the high-speed encoder 04 includes: a high-speed encoder mounting bracket 41, fixed to one end of the motor shaft 32 facing away from the reducer 02; and a high-speed encoder magnetic ring 42, disposed on the side of the high-speed encoder mounting bracket 41 facing away from the motor shaft 32. The low-speed encoder 05 includes: a low-speed encoder mounting bracket 51, fixed to the end of the second end, the low-speed encoder mounting bracket 51 being disposed inside the high-speed encoder mounting bracket 41; and a low-speed encoder magnetic ring 52, disposed on the side of the low-speed encoder mounting bracket 51 facing away from the second end, the low-speed encoder magnetic ring 52 being disposed inside the high-speed encoder magnetic ring 42.

[0074] This can be understood as the encoder assembly employing a magnetic induction non-contact measurement scheme, with its core consisting of three parts: a high-speed code disk 04, a low-speed code disk 05, and an encoder mainboard 06. The key to this design lies in simultaneously acquiring precise position and speed information from both the motor input shaft and the reducer 02 output shaft, achieving high-precision dual closed-loop control.

[0075] Both the high-speed and low-speed code disk magnetic rings 42 and 52 have special magnetic pole arrays formed on their surfaces through a precision magnetization process. The magnetizer etches multiple sets of annular magnetic tracks onto the magnetic rings. Each track consists of hundreds to thousands of periodically alternating N / S magnetic poles, and the pole arrangement between adjacent tracks has a predetermined phase difference or encoding pattern. When the code disk rotates with the shaft, these regularly arranged magnetic poles generate a continuously changing rotating magnetic field in space. The magnetic field strength and direction change sinusoidally / cosinely with the angular position.

[0076] The high-speed encoder 04 directly measures the rotation of the motor shaft 32. It is mounted on the end of the motor shaft 32 facing away from the reducer 02. Its structure includes a high-speed encoder mounting bracket 41, securely fixed to the end of the motor shaft 32, and a high-speed encoder magnetic ring 42 attached to the outward-facing surface of the mounting bracket. When the motor runs, the motor shaft 32 directly drives the entire high-speed encoder 04 to rotate synchronously. The low-speed encoder 05 directly measures the rotation of the output end of the final reducer 02. It is mounted on the second end of the hollow shaft 01. Its structure includes a low-speed encoder mounting bracket 51, securely fixed to the end of the hollow shaft 01, and a low-speed encoder magnetic ring 52 attached to the outward-facing surface of the mounting bracket. The low-speed encoder mounting bracket 51 is located inside the high-speed encoder mounting bracket 41, and its magnetic ring is also located inside the high-speed magnetic ring, forming a coaxial nested structure.

[0077] The core functional components of the motherboard are the high-speed code disk 04 readhead and the low-speed code disk 05 readhead. These two readheads are precisely aligned with the high-speed code disk 04 and the low-speed code disk 05, respectively. Each magnetic ring surface undergoes a special magnetization treatment, forming magnetic poles and tracks arranged in a specific pattern. As the code disks rotate with their respective shafts, these regularly arranged magnetic fields on the magnetic rings produce periodic and predictable changes relative to the stationary readheads. The readheads are sensitive magnetic sensing elements, capable of non-contactly detecting these subtle magnetic field changes and converting them into electrical signals.

[0078] In practical applications, the high-speed code disk 04 is directly driven to rotate at high speed by the motor shaft 32. The regularly changing magnetic field on its magnetic ring is sensed and captured in real time by the high-speed end reading head on the encoder mainboard 06. The low-speed code disk 05 is directly driven to rotate at low speed by the hollow shaft 01 output from the reducer 02. The regularly changing magnetic field on its magnetic ring is sensed and captured in real time by the low-speed end reading head on the encoder mainboard 06. After receiving the electrical signals from the high-speed and low-speed end reading heads, the encoder mainboard 06 performs calculation processing. By counting and analyzing the magnetic field change cycles, the mainboard can accurately calculate the current absolute / relative position, rotational speed, and direction of the motor shaft 32, as well as the current absolute / relative position, rotational speed, and direction of the hollow shaft 01 output from the reducer 02. These crucial real-time data are output to the outside through the signal interface on the mainboard.

[0079] This provides real-time, precise position and speed of the joint's final output shaft, enabling high-precision position / force control of the joint. It completely bypasses the transmission chain of reducer 02, directly measuring the actual motion state of the load end, thus greatly eliminating the accumulated errors caused by conversions based on motor position and reduction ratio, and improving the control accuracy and response performance of the joint end effector. The encoder motherboard 06 integrates not only two reading heads and their processing circuits, but also the connection interfaces (pads, solder holes, or connectors) for the motor power lines, temperature sensing element signal lines, and external communication signal lines. This design highly integrates functions that would otherwise require multiple circuit boards and numerous independent connectors onto a single motherboard, reducing the number of internal cables in the joint module, simplifying installation, and improving the overall reliability and integration of the system.

[0080] In one embodiment, such as Figure 2 As shown, the surface of the high-speed encoder read head 61 is axially aligned with the surface of the high-speed end code disk magnetic ring 42 and is spaced apart, and the surface of the low-speed encoder read head 62 is axially aligned with the surface of the low-speed end code disk magnetic ring 52 and is spaced apart.

[0081] After the mainboard is fixed in place and the code disk is installed, a very precise axial gap, known as the working air gap, will be formed between the upper surface of the sensing surface of the reading head and the upper surface of the corresponding code disk magnetic ring. The existence of this air gap and its precise control are the core physical basis for the normal operation of the magnetic induction encoder. The existence of the working air gap ensures that there is no physical contact between the reading head and the rotating magnetic ring, eliminating mechanical friction, wear, and the resulting noise, thus guaranteeing long-term reliability and high accuracy of the measurement.

[0082] In one embodiment, such as Figure 7 As shown, it also includes:

[0083] The driver 07 is electrically connected to the axial flux motor 03 to drive the axial flux motor 03. The driver 07 is the power control center of the joint module, and its core function is to convert external commands into precise three-phase excitation current. When the driver 07 receives a control command, it converts the DC bus voltage into three-phase alternating current with a 120° phase difference through an internal algorithm. This current is input to the stator windings of the axial flux motor 03 through the motor power lines, generating a high-speed rotating magnetic field in the stator teeth. This magnetic field interacts with the rotor permanent magnets, driving the rotor to generate continuous electromagnetic torque, ultimately converting electrical energy into mechanical energy output.

[0084] In one embodiment, such as Figure 7 As shown, the encoder motherboard 06 is integrated on the driver 07.

[0085] This application uses an integrated driver 07, installed at the tail of the motor. The functions of the encoder mainboard 06 are integrated into the driver 07—it also has high-speed and low-speed end reading heads, and forms a working air gap with the magnetic ring. The motor copper wires and temperature sensing elements are directly soldered to the integrated driver. The driver also has two power interfaces (one input and one output) and two signal interfaces, facilitating the series connection of multiple modules. The series connection wires also run through the hollow hole of the hollow shaft 01 at the output of the reducer 02.

[0086] In traditional split-type designs, encoder signals must be transmitted to the external driver 07 via cables, which is susceptible to electromagnetic interference and introduces delays. However, the integrated board design allows the position data calculated by the encoder motherboard 06 to be directly transmitted to the control chip of the driver 07 via internal copper traces. This ensures strict synchronization between motor commutation and rotor position, improves control accuracy at high frequencies, avoids noise introduced by long-distance cables, and enhances low-speed motion smoothness. Using an integrated driver further improves the module's compactness, greatly contributing to the miniaturization and lightweight design of robot products. The reduced cabling also improves signal quality, increasing control accuracy and stability.

[0087] The above embodiments are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A joint module, characterized in that, include: A hollow shaft has a first end and a second end disposed opposite to each other along its own axial direction, wherein at least one end has a through hole; The speed reducer is fitted onto the hollow shaft; An axial flux motor is sleeved on the hollow shaft, and the power output end of the axial flux motor is connected to the first end through the reducer; A high-speed end encoder is located at one end of the axial flux motor facing away from the reducer and is connected to the power output end; A low-speed end encoder disk is fixed to the second end, and the low-speed end encoder disk is disposed inside the high-speed end encoder disk sleeve. The encoder motherboard has a first surface and a second surface that are arranged opposite to each other. The first surface faces the axial flux motor and is provided with a high / low encoder read head corresponding to the high / low speed end code disk. The second surface is provided with a hardware interface for electrical connection to external devices.

2. The joint module as described in claim 1, characterized in that, The speed reducer includes: The input end is located on the side of the reducer facing the axial flux motor and is connected to the power output end of the axial flux motor; The output end is fixedly connected to the first end.

3. The joint module as described in claim 2, characterized in that, The input end of the reducer includes a sun gear meshing cavity, which is located outside the hollow shaft.

4. The joint module as described in claim 3, characterized in that, The axial flux motor includes: case; The motor shaft passes through the housing and extends out of the housing at one end toward the reducer. The outer wall of the end of the motor shaft facing the reducer is provided with a sun gear that meshes with the sun gear meshing cavity. A stator assembly is disposed within the housing and sleeved on the motor shaft; The rotor assembly is disposed within the housing and is fitted and fixed to the motor shaft.

5. The joint module as described in claim 4, characterized in that, The motor shaft is a hollow structure with both ends through it. The hollow shaft passes through the motor shaft and extends out of the motor shaft at the second end.

6. The joint module as described in claim 4, characterized in that, The housing has a mounting part on the side facing away from the reducer. The encoder main board is connected to the housing through the mounting part. The axes of the high-speed end code disk, the low-speed end code disk and the encoder main board are coincident on the same straight line.

7. The joint module as described in claim 4, characterized in that, The high-speed end encoder includes: A high-speed end encoder mounting bracket is fixed to the end of the motor shaft facing away from the reducer. A high-speed end code disk magnetic ring is disposed on the side of the high-speed end code disk mounting bracket facing away from the motor shaft; The low-speed end encoder includes: A low-speed end encoder mounting bracket is fixed to the end of the second end, and the low-speed end encoder mounting bracket is disposed inside the high-speed end encoder mounting bracket; The low-speed end code disk magnetic ring is located on the side of the low-speed end code disk mounting bracket facing away from the second end, and the low-speed end code disk magnetic ring is located inside the high-speed end code disk magnetic ring.

8. The joint module as described in claim 1, characterized in that, The surface of the high-speed encoder read head is axially aligned with the surface of the high-speed end code disk magnetic ring and is spaced apart, while the surface of the low-speed encoder read head is axially aligned with the surface of the low-speed end code disk magnetic ring and is spaced apart.

9. The joint module as described in claim 1, characterized in that, Also includes: A driver is electrically connected to the axial flux motor to drive the axial flux motor to operate.

10. The joint module as described in claim 9, characterized in that, The encoder motherboard is integrated on the driver.

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