Motor axial heat dissipation system, frameless torque motor and robot temperature control joint

Abstract

The application discloses a motor axial heat dissipation system, a frameless torque motor and a robot temperature control joint, and belongs to the technical field of motor heat dissipation. The motor comprises a stator core and a shell, and the stator core has an axial end face and a radial outer circumferential face. The axial heat dissipation system comprises a heat-conducting interface layer, a heat-conducting component and an active heat dissipation assembly. The heat-conducting interface layer is arranged on the axial end face of the stator core; the first end of the heat-conducting component is thermally coupled with the axial end face through the heat-conducting interface layer to receive heat from the axial end face; and the active heat dissipation assembly is independent of the shell and is thermally coupled with the second end of the heat-conducting component. In a use state, the heat-conducting component and the active heat dissipation assembly form an independent heat transmission channel which starts from the axial end face of the stator core and does not pass through the shell, and work in parallel with a conventional radial shell heat dissipation path to realize heat diversion. The application bypasses the bottleneck of the shell conduction thermal resistance and the natural convection thermal resistance, greatly improves the heat dissipation capacity, is especially suitable for robot joint applications with high integration and high power density, and can significantly improve the continuous working capacity and reliability of the motor.

Description

Technical Field

[0001] This invention relates to the field of motor heat dissipation technology, specifically to an axial heat dissipation system for motors. This system is particularly suitable for frameless torque motors and can be integrated into robot joints to form a robot temperature-controlled joint with highly efficient autonomous heat dissipation capabilities, thus solving the thermal management challenges in high-integration, high-power-density applications. Background Technology

[0002] With the increasing demands for motor power density and integration in fields such as robotics, aerospace, and precision servo motors, the heat generated during motor operation has become a key factor restricting their performance and reliability. This is especially true for frameless torque motors used in robot joints, where the stator core and windings are typically encapsulated directly within the joint housing. Heat can only be transferred to the housing via the radial outer circumference of the stator core, and then dissipated to the surrounding environment through natural convection or radiation from the housing surface. This single radial heat dissipation path results in significant thermal resistance, and the compact shape and enclosed working environment of robot joints limit the heat dissipation capacity of the housing surface, making it difficult to meet the heat dissipation requirements of high-power-density motors under continuous operation and overload conditions.

[0003] In existing technologies, some solutions attempt to incorporate heat-conducting devices between the stator winding ends and the housing to improve localized heat dissipation. However, these solutions essentially still utilize the housing as a heat dissipation terminal, failing to overcome the inherent bottleneck of the radial housing heat dissipation path. The housing's own thermal resistance and the low heat dissipation capacity of its external surface through natural convection limit the overall improvement in heat dissipation. Especially for robot joints, the joint housing typically needs to withstand loads and provide protection, further restricting its potential as an efficient heat dissipation terminal due to its structural and material choices.

[0004] Therefore, there is an urgent need for a heat dissipation solution that can provide additional heat dissipation channels for motors without relying on the motor housing as a heat dissipation terminal. This is particularly important for applications such as frameless torque motors and robot joints with high integration and harsh heat dissipation conditions. If an efficient heat dissipation path independent of the joint housing can be constructed, it is expected to fundamentally solve the thermal bottleneck problem of robot joints, thereby promoting the realization of a new generation of temperature-controlled robot joints with higher continuous torque density and reliability. Summary of the Invention

[0005] The purpose of this invention is to address the problems of limited heat dissipation paths and insufficient heat dissipation capacity in existing motor technologies, particularly the reliance on the housing as the heat dissipation terminal, which fails to overcome the inherent bottleneck of radial housing heat dissipation paths. This invention provides an axial heat dissipation system for motors that extracts heat from the axial end face of the stator core, forming an independent heat transfer channel that bypasses the motor housing. Applying this system to robot joints enables proactive and efficient management of the motor temperature inside the joint, resulting in a temperature-controlled robot joint with excellent thermal performance, significantly improving the joint's continuous working capacity and reliability.

[0006] To achieve the above-mentioned objective, according to one aspect of the present invention, an axial heat dissipation system for an electric motor is provided. The electric motor includes a stator core and a housing. The stator core has an axial end face and a radial outer peripheral face. The axial heat dissipation system includes: a thermally conductive interface layer configured to be disposed on the axial end face of the stator core; a heat-conducting member made of a thermally conductive material, having a first end and a second end, the first end being configured to be thermally coupled to the axial end face of the stator core through the thermally conductive interface layer to receive heat from the axial end face; and an active heat dissipation assembly configured independently of the motor housing and thermally coupled to the second end of the heat-conducting member. In use, the heat-conducting member and the active heat dissipation assembly form a heat transfer channel originating from the axial end face of the stator core and not passing through the housing, such that a portion of the heat generated by the stator core is discharged through this channel, while another portion of the heat is transferred to the housing via the radial outer peripheral face.

[0007] Optionally, an insulation structure is provided between the active heat dissipation component and the motor housing to prevent heat backflow and ensure the effectiveness of the independent heat dissipation channel.

[0008] Optionally, the second end of the heat conduction member passes through a through hole in the housing, so that the active heat dissipation component is located outside the housing, thereby directly dissipating heat to the external environment.

[0009] Optionally, the heat conduction component includes at least one of a solid heat-conducting rod, a heat spreader, a heat-conducting block with an embedded heat pipe, or a flexible heat-conducting pipe.

[0010] Optionally, the heat conduction member has a variable cross-sectional shape, with a larger cross-sectional area at the end near the stator core to reduce the interfacial heat flux density.

[0011] Optionally, the motor axial cooling system further includes an elastic clamping assembly configured to apply pressure to a first end of the heat conduction member toward the axial end face of the stator core to reduce contact thermal resistance.

[0012] Optionally, the thermal interface layer is a graphene-reinforced thermal pad or thermal grease.

[0013] Optionally, the heat-conducting component may be partially made of carbon fiber reinforced composite material.

[0014] Optionally, a thermoelectric cooling chip is disposed between the heat conduction component and the active heat dissipation component, wherein the cold end of the thermoelectric cooling chip is attached to the second end of the heat conduction component, and the hot end is attached to the active heat dissipation component.

[0015] Optionally, the active heat dissipation component is an air-cooled heat dissipation component, including a heat sink and a fan.

[0016] Optionally, the active heat dissipation component is a liquid-cooled heat dissipation component, including a liquid cooling plate and a pump, wherein the liquid cooling plate is thermally coupled to the second end of the heat conduction component.

[0017] Optionally, the heat-conducting member is configured to receive heat only from the axial end face of the stator core, without directly contacting the windings wound on the stator core, so as to avoid affecting the winding insulation.

[0018] According to another aspect of the present invention, a frameless torque motor is provided, comprising a stator core, stator windings, and an axial heat dissipation system as described in any of the preceding claims.

[0019] According to another aspect of the present invention, a robot temperature-controlled joint is provided, comprising a housing and a frameless torque motor as described above, mounted within the housing. This robot temperature-controlled joint integrates the aforementioned axial heat dissipation system, enabling it to actively manage heat within the joint, thereby maintaining excellent and stable performance output under high load and high speed conditions.

[0020] Optionally, the radial outer circumferential surface of the stator core and the housing are filled with thermally conductive potting compound to optimize the traditional radial heat dissipation path, so that it works in conjunction with the axial heat dissipation path to further improve the overall heat dissipation efficiency of the joint.

[0021] Compared with existing technologies, the beneficial effects of this invention are as follows: The axial heat dissipation system of this invention extracts heat from the axial end face of the stator core through heat conduction components, and in conjunction with an active heat dissipation component independent of the housing, constructs an independent heat dissipation channel directly from the end face of the stator core to the external environment. This channel works in parallel with the traditional heat dissipation path from the outer periphery of the stator core to the housing, achieving heat diversion. The independent heat dissipation channel bypasses the housing, circumventing the dual bottlenecks of the housing's conductive thermal resistance and the natural convection thermal resistance of the housing surface, significantly improving the system's heat dissipation capacity. In particular, applying this system to robot joints can create a novel temperature-controlled robot joint. This joint can effectively solve the heat dissipation problem caused by high integration without changing the main electromagnetic structure of the motor, raising the joint's continuous torque output capability to a new level, and significantly enhancing its reliability and lifespan, providing core technological support for the development of high-performance robots. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the frameless torque motor and the motor axial heat dissipation system according to the first embodiment of the present invention;

[0023] Figure 2 This is a partially enlarged view of the frameless torque motor and motor axial heat dissipation system according to the second embodiment of the present invention, wherein the second end of the heat conduction member passes through the through hole of the housing;

[0024] Figure 3 This is a partially enlarged view of the frameless torque motor and motor axial heat dissipation system according to the third embodiment of the present invention, wherein a heat insulation structure is provided between the active heat dissipation component and the housing.

[0025] Figure 4 This is a schematic diagram of the structure of the heat conduction component according to the fourth embodiment of the present invention, wherein the heat conduction component has a variable cross-sectional shape;

[0026] Figure 5 This is a schematic diagram of the structure of the heat conduction component according to the fifth embodiment of the present invention, wherein a heat pipe is embedded inside the heat conduction component;

[0027] Figure 6 This is a partial enlarged view of a portion of the structure of the motor axial heat dissipation system according to the sixth embodiment of the present invention, wherein a thermoelectric cooling element is disposed between the heat conduction component and the active heat dissipation component;

[0028] Figure 7 This is a schematic diagram of the active heat dissipation component according to the seventh embodiment of the present invention, wherein the active heat dissipation component is a liquid cooling heat dissipation component. Detailed Implementation

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and do not constitute a limitation thereof. In each embodiment, the same or similar components are represented by the same reference numerals.

[0030] Example 1

[0031] Reference Figure 1 In this embodiment, a robot temperature control joint includes a housing 2 and a frameless torque motor installed within the housing 2. The frameless torque motor includes a stator core 1, a stator winding 14, and an axial heat dissipation system.

[0032] The stator core 1 has an axial end face 11 and a radial outer peripheral face 12, and the stator winding 14 is wound on the stator core 1.

[0033] The motor axial cooling system includes a thermal interface layer 3, a heat conduction component 4, an active cooling component 5, and a fluid drive device 17.

[0034] A thermally conductive interface layer 3 is disposed on the axial end face 11 of the stator core 1. In this embodiment, the thermally conductive interface layer 3 is a graphene-reinforced thermal pad. In other embodiments, the thermally conductive interface layer 3 may also be thermally conductive silicone grease or other materials with high thermal conductivity and good interface compatibility.

[0035] The heat conduction component 4 is made of a highly thermally conductive material and has a first end 41 and a second end 42. The first end 41 is thermally coupled to the axial end face 11 of the stator core 1 through a thermally conductive interface layer 3 to receive heat from the axial end face 11. In this embodiment, the heat conduction component 4 is a solid aluminum alloy heat conduction rod with a variable cross-section, where the cross-sectional area of ​​the first end 41 is larger than that of the second end 42. This variable cross-section structure helps to obtain a larger contact area at the first end 41, reducing the interfacial heat flux density, while maintaining a smaller cross-section at the second end 42 to accommodate the limited installation space inside the joint. In other embodiments, the heat conduction component 4 may be at least partially made of copper, graphite, or carbon fiber reinforced composite materials to achieve better overall performance in terms of thermal conductivity and lightweight.

[0036] The active cooling component 5 is constructed independently of the device housing 2. The device housing 2, i.e., the housing of the robot joint, is a structural component that houses and protects the motors and other parts. The active cooling component 5 is mounted on the second end 42 of the heat conduction component 4 and is thermally coupled to the heat conduction component 4.

[0037] In this embodiment, the active heat dissipation component 5 is an air-cooled heat dissipation component, including a heat sink 10 and a fan 16 as a fluid drive device 17. The heat sink 10 is an aluminum profile finned heat sink, and the fan 16 generates a cooling airflow that flows through the heat sink 10.

[0038] In operation, the heat conduction component 4 and the active heat dissipation component 5 together form a heat transfer channel (i.e., axial heat dissipation path 31) that starts from the axial end face 11 of the stator core 1 and does not pass through the equipment housing 2. At the same time, a conventional radial heat dissipation path 30 is formed between the radial outer peripheral surface 12 of the stator core 1 and the equipment housing 2.

[0039] Under rated operating conditions, a portion of the heat generated by the stator core 1 is directly dissipated to the environment via the axial heat dissipation path 31, while the remaining heat is transferred to the equipment housing 2 via the radial heat dissipation path 30. Since the axial heat dissipation path 31 bypasses the equipment housing 2, thus avoiding the bottlenecks of conductive thermal resistance and natural convection thermal resistance on the housing surface, its thermal resistance is significantly lower than that of the radial heat dissipation path 30, thereby bearing most of the heat dissipation load. This allows the robot's temperature-controlled joint to maintain motor temperature far below that of traditional joints during continuous high-load operation, resulting in higher continuous torque output and a longer service life.

[0040] Example 2

[0041] Reference Figure 2 The main difference between this embodiment and the first embodiment is that the second end 42 of the heat conduction member 4 passes through the through hole 21 opened on the device housing 2, so that the active heat dissipation component 5 is located outside the device housing 2. This through-shell structure allows the active heat dissipation component 5 to directly contact the ambient air, further reducing the thermal resistance of the heat dissipation path, and avoiding the generation of additional heat accumulation inside the housing by the active heat dissipation component 5, which is particularly advantageous for application scenarios where the external dimensions of the joint are not strictly limited.

[0042] Example 3

[0043] Reference Figure 3 The main difference between this embodiment and the first embodiment is that a thermally conductive or thermally insulating structure 7 is provided between the active heat dissipation component 5 (specifically its heat sink 10) and the device housing 2. This structure decouples the axial heat dissipation path 31 from the radial heat dissipation path 30, preventing heat from flowing back to the device housing 2 and ensuring the independence of the axial heat dissipation path 31. This is crucial for improving the actual heat dissipation efficiency of the active heat dissipation component. The material of this thermally conductive or thermally insulating structure 7 can be aerogel, foam plastic, or other materials with low thermal conductivity.

[0044] Example 4

[0045] Reference Figure 4This embodiment illustrates a variation of the heat-conducting member 4. The heat-conducting member 4 has a variable cross-sectional shape, with the cross-sectional area of ​​its first end 41 being larger than that of its second end 42. This variable cross-sectional structure helps to obtain a larger contact area at the first end 41, reducing the interfacial heat flux density, while maintaining a smaller cross-section at the second end 42 to accommodate the limited installation space inside the joint. This variable cross-sectional structure can be used in conjunction with any other embodiment of the present invention.

[0046] Example 5

[0047] Reference Figure 5 This embodiment illustrates another variation of the heat conduction component 4. At least one micro heat pipe 8 is embedded within the heat conduction component 4, extending along its length. Utilizing the phase change heat transfer principle of the working fluid, the micro heat pipe possesses an extremely high equivalent thermal conductivity, further reducing the thermal resistance of the heat conduction component 4. This makes it particularly suitable for robot joint designs requiring long-distance heat transfer. The micro heat pipe 8 can be integrated with the main body of the heat conduction component 4 through brazing, interference fit, or integral molding. This heat pipe-type heat conduction component can be used in conjunction with any other embodiment of the present invention.

[0048] Example 6

[0049] Reference Figure 6 In this embodiment, based on the first embodiment, a thermoelectric cooling element 9 is added between the heat conduction component 4 and the active heat dissipation component 5. The cold end of the thermoelectric cooling element 9 is attached to the second end 42 of the heat conduction component 4, and the hot end is attached to the active heat dissipation component 5 (specifically, the substrate of its heat sink 10). The thermoelectric cooling element 9 actively pumps heat from the cold end to the hot end through the Peltier effect, which can provide additional heat transport driving force for the heat dissipation path under extreme conditions, thereby further improving the heat dissipation limit of the robot's temperature-controlled joint and enabling it to cope with short-term extreme overload conditions.

[0050] Example 7

[0051] Reference Figure 7 The main difference between this embodiment and the first embodiment lies in the type of active heat dissipation component 5. In this embodiment, the active heat dissipation component 5 is a liquid-cooled heat dissipation component, including a liquid cooling plate 12 and a pump 13 serving as a fluid drive device 17. The liquid cooling plate 12 is thermally coupled to the second end 42 of the heat conduction component 4, and its interior is provided with microchannels for the flow of liquid cooling medium. The pump 13 drives the liquid cooling medium to circulate between the liquid cooling plate 12 and an external heat exchanger to remove heat. This liquid cooling solution is suitable for robot applications with higher heat dissipation requirements or higher ambient temperatures, such as industrial robots or special robots that need to operate in high-temperature environments.

[0052] Example 8

[0053] In a preferred embodiment of the present invention, such as Figure 1-3 As shown, a microgroove array is machined on the contact surface of the first end 41 of the heat conduction component 4. This microgroove array can be formed by laser etching. Under the contact pressure, the thermally conductive interface layer 3 fills the microgrooves, forming a mechanical interlock, thereby significantly reducing contact thermal resistance and improving interface thermal conductivity. However, those skilled in the art will understand that, if the surface flatness of the heat conduction component 4 meets the requirements and the contact pressure is sufficient, even without the microgrooves, good interface thermal conductivity can be achieved by selecting a high-quality thermally conductive interface layer. Therefore, the microgrooves are an optional optimization feature of this invention.

[0054] Example 9

[0055] In another optional embodiment of the present invention, a phase change material capsule is embedded inside the substrate of the heat sink 10 of the active heat dissipation component 5. This phase change material absorbs peak heat load during short-term motor overload, slowing down the temperature rise rate and thus improving the short-term overload capability of the robot's temperature-controlled joints. However, those skilled in the art will understand that for continuous operation, the phase change material will no longer provide a thermal buffering effect after the first melting. Therefore, this phase change material capsule is an optional optimization feature of the present invention and can be selected for use according to actual operating conditions.

[0056] Example 10

[0057] In another optional embodiment of the present invention, the thermally conductive or thermally insulating structure 7 employs a multilayer composite thermal insulation film or a single-layer aerogel pad. The multilayer composite thermal insulation film may, for example, include alternating stacked aerogel layers and a metal reflective layer. However, those skilled in the art will understand that when the temperature difference between the active heat dissipation component and the housing is small, a single-layer aerogel pad is sufficient to meet the thermal insulation requirements. Therefore, this multilayer composite thermal insulation film is an optional optimization feature of the present invention, and those skilled in the art can select specific thermal insulation materials and structures according to actual thermal insulation needs.

[0058] Example 11

[0059] In another optional embodiment of the invention, the fluid drive device 17 is equipped with a controller and a temperature sensor. The controller performs PID regulation on the rotational speed of the fan 16 or pump 13 based on the temperature signal detected by the temperature sensor, thereby achieving an optimized balance between heat dissipation efficiency and energy consumption. This is of great significance for realizing the intelligence and energy saving of the robot's temperature-controlled joints. However, those skilled in the art will understand that for constant-speed operation, there is no need to set up a temperature sensor and complex control algorithms. Therefore, this intelligent speed control is an optional optimization feature of the invention and can be selected according to application requirements.

[0060] Regarding robot temperature-controlled joints

[0061] Reference Figures 1 to 3 The present invention also provides a robot temperature-controlled joint. This robot temperature-controlled joint includes a housing 2 and a frameless torque motor, as described in any of the above embodiments, installed within the housing 2. In robot joints, due to the compact space and harsh heat dissipation conditions, the motor axial heat dissipation system of the present invention can provide a highly efficient independent heat dissipation channel for the motor without significantly increasing the joint volume. This actively and effectively manages the heat inside the joint, reduces the motor temperature rise, and significantly improves the joint's continuous working capacity and reliability. This enables the robot joint to truly achieve a "temperature control" function, that is, to control the internal temperature within a preset, safe range under various operating conditions, thereby ensuring the stability and durability of the joint's performance.

[0062] Optionally, thermally conductive potting compound 15 is filled between the radial outer peripheral surface 12 of the stator core 1 and the equipment housing 2. The thermally conductive potting compound 15 fills the assembly gap between the stator core 1 and the equipment housing 2, reducing the thermal resistance in the radial heat dissipation path 30, making it better serve as an auxiliary heat dissipation channel for the axial heat dissipation path 31, working in conjunction with the axial heat dissipation system to jointly construct an efficient, three-dimensional joint heat dissipation network.

[0063] Optionally, the heat conduction member 4 is configured to not only receive heat from the axial end face 11 of the stator core 1, but also to indirectly contact the stator winding 14 wound on the stator core 1 through the thermally conductive potting compound 15 to absorb heat from the winding. This configuration avoids the potential impact of the heat conduction member 4 on the winding insulation, while directly targeting the hottest core area in the motor for heat extraction.

[0064] Those skilled in the art will understand that the axial heat dissipation system of the present invention and the robot temperature control joint thereof can be applied not only to frameless torque motors, but also similarly to other types of motors with axial end faces or similar rotating devices, all of which are within the protection scope of the present invention.

[0065] The above description is merely a preferred embodiment of the present invention and does not limit the scope of the patent. Any equivalent structural modifications made based on the inventive concept of the present invention and the description and drawings, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. An axial heat dissipation system for an electric motor, the motor comprising a stator core (1) and a housing (2), the stator core (1) having an axial end face (11) and a radial outer peripheral face (12), characterized in that, The axial heat dissipation system includes: A thermally conductive interface layer (3) is configured to be disposed on the axial end face (11) of the stator core (1); The heat conduction member (4) is made of a thermally conductive material and has a first end (41) and a second end (42). The first end (41) is configured to be thermally coupled to the axial end face (11) of the stator core (1) through the thermally conductive interface layer (3) to receive heat from the axial end face (11). An active heat dissipation assembly (5) is constructed independently of the housing (2) of the motor and is thermally coupled to the second end (42) of the heat conduction member (4); In use, the heat conduction component (4) and the active heat dissipation component (5) form a heat transfer channel (6) that starts from the axial end face (11) of the stator core (1) and does not pass through the housing (2), so that part of the heat generated by the stator core (1) is discharged through the channel, while another part of the heat is transferred to the housing (2) through the radial outer peripheral surface (12).

2. The motor axial heat dissipation system according to claim 1, characterized in that, A thermally conductive and thermally insulating structure (7) is provided between the active heat dissipation component (5) and the housing (2) of the motor.

3. The motor axial heat dissipation system according to claim 1, characterized in that, The heat conduction component (4) includes at least one of a solid heat conduction rod, a heat spreader, a heat conduction block with a heat pipe (8) embedded inside, or a flexible heat conduction pipe; and the heat conduction component (4) has a variable cross-sectional shape, with a larger cross-sectional area at one end (41) near the stator core (1); the heat conduction component (4) can be partially made of carbon fiber reinforced composite material.

4. The motor axial heat dissipation system according to claim 1, characterized in that, The thermal interface layer (3) is a graphene-reinforced thermal pad, thermal grease, liquid metal or other high thermal conductivity interface material.

5. The motor axial heat dissipation system according to claim 1, characterized in that, A thermoelectric cooling chip (9) is provided between the heat conduction component (4) and the active heat dissipation component (5). The cold end of the thermoelectric cooling chip (9) is attached to the second end (42) of the heat conduction component (4), and the hot end is attached to the active heat dissipation component (5).

6. The motor axial heat dissipation system according to claim 1, characterized in that, The active heat dissipation component (5) is an air-cooled heat dissipation component, including a heat sink (10) and a fan (16).

7. The motor axial heat dissipation system according to claim 1, characterized in that, The active heat dissipation component (5) is a liquid cooling heat dissipation component, including a liquid cooling plate (12) and a pump (13), wherein the liquid cooling plate (12) is thermally coupled to the second end (42) of the heat conduction component (4).

8. A frameless torque motor, characterized in that, It includes a stator core (1), a stator winding (14), and an axial heat dissipation system for the motor according to any one of claims 1 to 7.

9. A robot joint, characterized in that, Includes a housing (2) and a frameless torque motor according to claim 8 mounted within the housing (2).

10. The robot joint according to claim 9, characterized in that, The radial outer peripheral surface (12) of the stator core (1) and the housing (2) are filled with thermally conductive potting compound (15); and the heat conduction member (4) is configured to not only receive heat from the axial end face (11) of the stator core (1), but also to indirectly contact the stator winding (14) wound on the stator core (1) through the thermally conductive potting compound (15) to absorb the heat of the winding.

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