Direct drive motor heat dissipation stator module and robot joint direct drive motor

Abstract

This invention discloses a heat-dissipating stator module for a direct-drive motor, comprising a stator core, several winding slots arranged radially outside the stator core, and coil windings wound within the winding slots. It also includes a heat-dissipating stator base in thermal contact with the stator core. Heat pipes are disposed within the winding slots, with the evaporation sections of the heat pipes in thermal contact with both the stator core and the coil windings, and the condensation sections of the heat pipes extending to and in thermal contact with the heat-dissipating stator base. Simultaneously, a jointed direct-drive motor is also disclosed, comprising a heat-dissipating stator module and a rotor module. The rotor module includes a rotor shaft and a rotor magnet assembly. The rotor magnet assembly is located radially outside the stator core and coaxially arranged with it. The rotor shaft is rotatably connected to the heat-dissipating stator base and coaxially arranged with the stator core. The rotor shaft and the rotor magnet assembly are connected by a connecting bracket. This invention possesses highly efficient heat dissipation performance and thermal reliability, enabling the motor to withstand longer and higher-intensity peak torque operation.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a heat dissipation stator module for a direct-drive motor and a direct-drive motor for robot joints. Background Technology

[0002] Robot joint drive motors are core components for achieving high-dynamic motion in biomimetic robots, and their performance directly determines the robot's agility and load-bearing capacity. Unlike traditional industrial servo motors, robot joint motors are limited by the small internal space of the joint, high sealing requirements, and lightweight needs. Therefore, most commercial robot joint motors still rely primarily on natural convection cooling from the casing surface. However, robot joint motors demand high torque density output, which means extremely high coil phase current and significant heat generation. Relying solely on natural convection cooling severely restricts the motor's peak performance output and continuous operating capability. Although some joint motors employ forced cooling methods such as water cooling or oil cooling to improve heat dissipation, these solutions require additional pumps, piping, radiators, and sealing structures, significantly increasing the system's complexity, weight, and size. These solutions are difficult to apply in highly integrated robot joints and are considered exceptional cases. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a heat dissipation stator module for a direct drive motor that can improve the heat dissipation capacity of the motor stator heat source and enhance the reliability of the motor.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A heat dissipation stator module for a direct drive motor includes a stator core, a plurality of winding slots disposed radially outside the stator core, and coil windings wound in the winding slots. It also includes a heat dissipation stator base that is in thermal contact with the stator core. At least one winding slot is provided with a heat pipe. The evaporation section of the heat pipe is in thermal contact with the stator core and the coil windings, respectively. The condensation section of the heat pipe extends to the heat dissipation stator base and is in thermal contact with it.

[0006] In this invention, by embedding heat pipes within the stator winding slots, and ensuring that the evaporation section simultaneously contacts both the stator core and the coil windings—the two main heat sources—while the condensation section connects to the heat dissipation stator base, a highly efficient and low-thermal-resistance heat dissipation path is created from the core heat-generating area inside the motor to the external heat dissipation components. Furthermore, the heat pipes being embedded within the existing winding slots solves the problem of traditional forced cooling methods being unsuitable for articulated motors due to their extremely compact space, significantly improving the heat dissipation capacity of the stator components.

[0007] As an optimization, the heat dissipation stator base has a fixing part and a heat dissipation part. The stator core is fixed to and in contact with the fixing part, and the condensation section of the heat pipe is in contact with the heat dissipation part. The fixing part ensures the stable installation and mechanical reliability of the stator core, while the heat dissipation part is dedicated to dissipating heat from the stator core and heat pipe, allowing heat to be directed to the most effective heat dissipation area, avoiding turbulent heat flow paths, and further improving the efficiency of the heat dissipation system.

[0008] As an optimization, a stator mounting hole coaxial with the stator core is provided through the stator core, and the stator core is fitted onto the outer circumferential surface of the fixing part through the stator mounting hole. The stator core is directly fitted onto the fixing part through the mounting hole, which not only achieves precise centering and secure installation, but more importantly, forms a large direct contact surface, greatly reducing the contact thermal resistance between the stator core and the heat sink.

[0009] As an optimization, heat dissipation fins are also provided on the surface of the heat dissipation part. By providing heat dissipation fins, the heat exchange area between the heat dissipation stator base and the surrounding air is directly increased, thereby improving heat dissipation efficiency.

[0010] As an optimization, the heat pipe is in thermal contact with the heat dissipation stator base via a thermally conductive potting compound. The thermally conductive potting compound, as a highly thermally conductive medium, can completely fill and cure the microscopic gap between the heat pipe's condensation section and the heat dissipation stator base, eliminating the significant contact thermal resistance caused by surface unevenness and the presence of air.

[0011] As an optimization, the evaporation section of the heat pipe extends axially parallel to the stator core. This allows the evaporation section of the heat pipe to absorb heat along the entire length of the coil winding, increasing the heat absorption area.

[0012] The present invention also discloses a robot joint direct drive motor, including a stator module and a rotor module. The stator module is the heat dissipation stator module described above. The rotor module includes a rotor shaft and a rotor magnet assembly. The rotor magnet assembly is located radially outside the stator core and is coaxially arranged with the stator core. The rotor shaft is rotatably connected to the heat dissipation stator base and is coaxially arranged with the stator core. The rotor shaft and the rotor magnet assembly are fixedly connected by a connecting bracket.

[0013] As an optimization, the connecting bracket includes connecting ribs evenly spaced around the rotor shaft axis and extending radially along the rotor shaft. Blades are mounted on the connecting ribs, which, when the rotor shaft rotates, disturb and guide airflow towards the heat pipe. This expands the function of the connecting bracket from a simple mechanical connection to a power-cooled component. The blades utilize the rotational power of the motor rotor itself to generate a directional forced airflow directly towards the stator heat pipe area. This is equivalent to building a fan into the motor without requiring additional equipment, achieving a synergistic effect of passive conduction cooling and active forced convection cooling, further enhancing the heat dissipation capacity.

[0014] As an optimization, the rotor shaft and the heat dissipation stator housing are rotatably connected by bearings. This ensures the mechanical efficiency of the entire motor power transmission and long-term operational reliability.

[0015] Compared to existing technologies, this invention integrates heat pipes within the stator winding slots, ensuring the evaporation section is in close contact with both the stator core and the coil windings—the main heat sources—while the condensation section connects to the heat dissipation stator base. This creates the shortest and most direct high thermal conductivity channel from the internal core heat source to external heat dissipation. Combined with the application of thermally conductive potting compound, this significantly reduces interfacial thermal resistance, resulting in heat dissipation efficiency far exceeding that of traditional structures. This allows the motor to achieve extremely high torque density while possessing highly efficient heat dissipation performance and thermal reliability, enabling it to withstand longer and more intense peak torque operation. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the direct-drive motor of the robot joint in this invention;

[0017] Figure 2 This is a schematic diagram of the heat dissipation route for the direct-drive motor of the robot joint in this invention;

[0018] Figure 3 This is a three-dimensional structural view of the heat dissipation stator base in this invention;

[0019] Figure 4 This is a three-dimensional structural view of the connection between the rotor shaft and the connecting bracket in this invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] like Figures 1 to 4 As shown, the heat dissipation stator module of the direct drive motor in this specific embodiment includes a stator core 1, a plurality of winding slots arranged radially outside the stator core 1, and a coil winding 3 wound in the winding slots. It also includes a heat dissipation stator base 4 that is in thermal contact with the stator core 1. At least one winding slot is provided with a heat pipe 5. The evaporation section of the heat pipe 5 is in thermal contact with the stator core 1 and the coil winding 3, respectively. The condensation section of the heat pipe 5 extends to the heat dissipation stator base 4 and is in thermal contact with it.

[0022] In this specific embodiment, the heat dissipation stator base 4 has a fixing part and a heat dissipation part, the stator core 1 is fixed on the fixing part and in contact with it, and the condensation section of the heat pipe 5 is in contact with the heat dissipation part.

[0023] In this specific embodiment, a stator mounting hole coaxial with the stator core 1 is provided through the stator core 1, and the stator core 1 is fitted onto the outer peripheral surface of the fixing part through the stator mounting hole.

[0024] In this specific embodiment, heat dissipation ribs 6 are also provided on the surface of the heat dissipation part.

[0025] In this specific embodiment, the heat pipe 5 is in thermal contact with the heat dissipation stator 4 through the thermally conductive potting compound 2.

[0026] In this specific embodiment, the evaporation section of the heat pipe 5 extends along the axial direction parallel to the stator core 1.

[0027] A robot joint direct drive motor includes a stator module and a rotor module. The stator module is the heat-dissipating stator module described above. The rotor module includes a rotor shaft 7 and a rotor magnet assembly 8. The rotor magnet assembly 8 is located radially outside the stator core 1 and is coaxially arranged with the stator core 1. The rotor shaft 7 is rotatably connected to the heat-dissipating stator base 4 and is coaxially arranged with the stator core 1. The rotor shaft 7 and the rotor magnet assembly 8 are fixedly connected by a connecting bracket.

[0028] In this specific embodiment, the connecting bracket includes connecting ribs 9 that are evenly spaced around the axis of the rotor shaft 7 and extend in the radial direction of the rotor shaft 7. Blades 10 are provided on the connecting ribs 9. When the rotor shaft 7 rotates, the blades 10 can be disturbed and the airflow can be guided to the direction of the heat pipe 5.

[0029] In this specific embodiment, the rotor shaft 7 and the heat dissipation stator seat 4 are rotatably connected together by a bearing 11.

[0030] In the overall construction of the joint direct drive motor, the heat dissipation stator base is preferably made of high thermal conductivity aluminum alloy (such as 7075), with its lower outer surface covered with heat dissipation fins to maximize the heat dissipation area; the inner plane has stator connection holes for fixing to the robot joint structure. The stator core is made of high magnetic permeability, low loss silicon steel sheets (such as grade 35DW300) stacked together, with a 36-slot structure. The stator core is tightly fitted onto the outer circumference of the upper cylindrical fixing part of the heat dissipation stator base through the central stator mounting hole using an interference fit, achieving mechanical fixation and good basic thermal contact. The coil is wound on each stator tooth of the stator core. Multiple heat pipes (made of copper) are placed in the winding slots of the stator core, with their evaporation sections (i.e., evaporation ends) close to the slot wall, thus making direct contact with the stator core, and are simultaneously wrapped by the coil in the slot, achieving close thermal contact with the coil. The condensing section (i.e., the condensing end) of the heat pipe extends through the stator core, reaching and closely adhering to the corresponding heat dissipation area on the heat sink stator base. To ensure a near-zero thermal resistance connection between the heat pipe condensing section and the heat sink stator base, a high thermal conductivity potting compound (e.g., 908G type) is filled in the gap between the stator core and the heat sink stator base. After curing, the potting compound firmly bonds the heat pipe condensing section, the end of the stator core, and the heat sink stator base into a single integrated structure, providing not only reliable mechanical fixation but, more importantly, eliminating air gaps and establishing an extremely efficient heat conduction interface.

[0031] The rotor shaft is supported in the central bearing chamber of the heat-dissipating stator housing by upper and lower ball bearings and is axially positioned by retaining rings, thus enabling smooth rotation relative to the stator module. The rotor shaft has multiple evenly distributed rotor connection holes for connecting external loads. Multiple ribs (e.g., seven) extend from the rotor shaft, each with an integrally formed air-disrupting blade; these ribs and their blades together form the connecting bracket. Forty-two high-performance neodymium iron boron magnets (e.g., grade N54SH) constitute the rotor magnet assembly, which is located radially outside the stator core, maintaining a small air gap, forming an outer rotor structure. The inner ends of the connecting bracket ribs are fixedly connected to the rotor shaft, and the outer ends are fixedly connected to the rotor core, thereby transmitting the rotational motion of the rotor shaft to the rotor magnet assembly.

[0032] When the motor is running, the coil windings and stator core generate a large amount of heat, which is mainly transferred through two paths (see appendix). Figure 2 (The arrows in the diagram indicate the direction of heat transfer): First, the heat is directly conducted from the stator core to the heat sink stator base via contact; second, heat is absorbed by the evaporation section of the heat pipe, causing the internal working fluid to undergo phase change and evaporate. The vapor flows to the condensation section, where it releases heat to the heat sink stator base, and the working fluid condenses and flows back. All heat conducted to the heat sink stator base is dissipated into the surrounding environment through convection and radiation via the heat dissipation fins on its outer surface. Simultaneously, the rotor shaft rotates, and the blades fixed to it rotate synchronously, generating forced airflow inside the motor. This airflow is guided to the stator region, directly blowing towards the area where the heat pipes and coil ends are located, significantly improving the convective heat transfer coefficient in this region, thus enabling faster removal of heat from the heat pipes and stator components. The synergistic heat dissipation mechanism of passive heat conduction and active air cooling in this application achieves a significant improvement in the heat dissipation capacity of the robot joint direct-drive motor, possessing extremely high practical value and broad application prospects.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described with reference to preferred embodiments, those skilled in the art should understand that various changes in form and detail can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A heat dissipation stator module for a direct-drive motor, comprising a stator core, a plurality of winding slots disposed radially outside the stator core, and coil windings wound within the winding slots, characterized in that: It also includes a heat dissipation stator base that is in thermal contact with the stator core, and a heat pipe is provided in at least one winding slot. The evaporation section of the heat pipe is in thermal contact with the stator core and the coil winding, respectively, and the condensation section of the heat pipe extends to the heat dissipation stator base and is in thermal contact with it.

2. The heat dissipation stator module of the direct drive motor according to claim 1, characterized in that: The heat dissipation stator base has a fixing part and a heat dissipation part. The stator core is fixed on the fixing part and in contact with it. The condensation section of the heat pipe is in contact with the heat dissipation part.

3. The heat dissipation stator module of the direct drive motor according to claim 2, characterized in that: The stator core has a stator mounting hole coaxial with it, and the stator core is fitted onto the outer circumferential surface of the fixing part through the stator mounting hole.

4. The heat dissipation stator module of the direct drive motor according to claim 2, characterized in that: The surface of the heat dissipation part is also provided with heat dissipation ribs.

5. The heat dissipation stator module of the direct drive motor according to claim 1, characterized in that: The heat pipe is in thermal contact with the heat dissipation stator base through thermally conductive potting compound.

6. The heat dissipation stator module of the direct drive motor according to claim 1, characterized in that: The evaporation section of the heat pipe extends along an axial direction parallel to the stator core.

7. A direct-drive motor for a robot joint, characterized in that: The system includes a stator module and a rotor module. The stator module is the heat-dissipating stator module as described in any one of claims 1 to 6. The rotor module includes a rotor shaft and a rotor magnet assembly. The rotor magnet assembly is located radially outside the stator core and is coaxially arranged with the stator core. The rotor shaft is rotatably connected to the heat-dissipating stator base and is coaxially arranged with the stator core. The rotor shaft and the rotor magnet assembly are fixedly connected by a connecting bracket.

8. The robot joint direct drive motor according to claim 7, characterized in that: The connecting bracket includes connecting ribs that are evenly spaced around the axis of the rotor shaft and extend radially along the rotor shaft. The connecting ribs are provided with blades, which can disturb the blades and guide the airflow to the direction of the heat pipe when the rotor shaft rotates.

9. The robot joint direct drive motor according to claim 7, characterized in that: The rotor shaft and the heat dissipation stator base are rotatably connected together by bearings.

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