Frameless electric motor based on porous hydrogel, and heat dissipation method therefor

Abstract

Disclosed in the present invention are a frameless electric motor based on a porous hydrogel, and a heat dissipation method therefor. A front sealing shell and a rear sealing shell are respectively mounted at a front end and a rear end of a motor stator, and the front sealing shell, the motor stator and the rear sealing shell are all annular; a motor rotor is arranged on the inner side of the motor stator, the front sealing shell mates with one end of the motor stator in an embedded manner to form a plurality of axially distributed slots, and a hot-end hydrogel is provided inside the slots; the rear sealing shell and the other end of the motor stator are embedded, an annular cold-end hydrogel is provided inside the rear sealing shell close to the rear end of the motor stator, the cold-end hydrogel is in contact with the hot-end hydrogel, and an inner graphene heat-conducting strip and an outer graphene heat-conducting strip are respectively provided on the inner side and the outer side of the annular cold-end hydrogel; and the hot-end hydrogel and the cold-end hydrogel are both provided with cavities which are in communication with each other, and are internally filled with a cooling liquid. The heat dissipation solution provided by the present invention has a simple structure and is easy to integrate. The manufacturing of a capillary structure closely fitting against a heat source of an electric motor is realized by means of the hydrogel. The porous hydrogel has high thermal conductivity and a simple preparation method.

Description

A frameless motor based on porous hydrogel and its heat dissipation method Technical Field

[0001] This invention relates to the field of frameless motor technology, and in particular to a frameless motor based on porous hydrogel and its heat dissipation method. Background Technology

[0002] With the continuous development of embodied intelligence technology, humanoid robots, as the next generation of computing terminals after PCs, smartphones and new energy vehicles, have become an important carrier of embodied intelligence technology due to their high flexibility and human-like movement patterns. They have shown great potential, especially in intelligent manufacturing, medical assistance and domestic services, and are gradually becoming a disruptive industry with broad market application prospects.

[0003] In the design of humanoid robots, the joint actuation system is the core component for achieving flexible movement. Frameless motors, due to their high efficiency, compactness, and high integration, have become the preferred power source for driving the joint movements of humanoid robots. However, despite the many advantages of frameless motors, thermal management during operation remains a significant challenge, especially under high loads and long-term operation, where heat loss has a considerable impact on motor performance.

[0004] During the operation of frameless motors, eddy current and Joule effects cause heat accumulation, leading to increased stator and rotor temperatures and consequently reducing the motor's output torque and power. Furthermore, winding resistance increases with temperature, further amplifying Joule heat loss and significantly reducing overall motor efficiency and energy utilization. Under prolonged high-temperature operation, the winding insulation material gradually ages, increasing the risk of internal short circuits. The mechanical properties of the rotor and stator materials also deteriorate at high temperatures, weakening structural strength and increasing susceptibility to mechanical failures. Particularly in high-dynamic-response humanoid robot joint applications, where motors frequently start, stop, and accelerate, this thermal fatigue effect can accelerate the motor's aging process. Therefore, addressing the heat loss problem in frameless motors is crucial.

[0005] Current heat dissipation solutions for frameless motors often involve significant increases in size and weight due to the addition of fans, while liquid cooling requires multiple coolant circulation channels, which can drastically increase coolant pump power consumption and system complexity when there are many motors in the drive system. Humanoid robots typically have multiple joint modules, making these methods unsuitable for the application of frameless motors in humanoid robots. To maintain the stability of frameless motors during long-term operation, there is an urgent need to develop a compact, simple, efficient, and easily integrated heat dissipation solution to address heat loss issues. Summary of the Invention

[0006] To address the problems of severe heat loss, thermal fatigue, and complex heat dissipation systems during the operation of frameless motors, this invention aims to provide a frameless motor based on porous hydrogel and its heat dissipation method. A porous hydrogel is prepared inside the motor, closely adhering to the windings. The coolant circulates between the motor windings and the rear sealing shell through the capillary action of the porous hydrogel and the phase change principle of the coolant. Heat is then conducted to the cooling equipment through a graphene heat-conducting tape within the rear sealing shell, thereby achieving efficient heat dissipation.

[0007] The technical solution adopted in this invention is:

[0008] The present invention includes a front sealing shell, a hot-end hydrogel, a motor rotor, a motor stator, an inner graphene conductive tape, a cold-end hydrogel, an outer graphene conductive tape, and a rear sealing shell.

[0009] The front and rear ends of the motor stator are respectively equipped with a front sealing shell and a rear sealing shell. The front sealing shell, the motor stator and the rear sealing shell are all annular. The motor rotor is coaxially arranged inside the motor stator. The front sealing shell is fitted with one end of the motor stator to form several axially distributed slots. Each slot is provided with hot end hydrogel. The rear sealing shell is fitted with the other end of the motor stator. The rear sealing shell is provided with an annular cold end hydrogel near the rear end of the motor stator. The cold end hydrogel and the hot end hydrogel are in contact. The inner and outer sides of the annular cold end hydrogel are respectively provided with inner graphene conductive heat pack and outer graphene conductive heat pack.

[0010] Each hot-end hydrogel has a cavity structure as an inner cavity of the hot-end hydrogel, and the cold-end hydrogel has several cavity structures. Each cavity structure serves as an inner cavity of the cold-end hydrogel. The inner cavities of the hot-end hydrogel and the inner cavities of the cold-end hydrogel are interconnected to form a heat dissipation cavity, which is filled with coolant.

[0011] The motor stator includes a stator core and windings. Multiple stator slots are evenly distributed circumferentially on the inner side of the stator core. The windings are wound on the teeth between the stator slots of the stator core. Multiple sealing plates pointing towards the rear sealing shell are evenly distributed circumferentially on the inner side of the front sealing shell. The sealing plates are embedded in the slot openings of the stator slots and seal the slot openings, thus forming slots for installing hot-end hydrogels inside the stator slots.

[0012] Each cold-end hydrogel and each hot-end hydrogel has a cavity structure at a position directly opposite to the cavity structure on the cold-end hydrogel, which serves as an inner cavity of the cold-end hydrogel. The inner cavity of the cold-end hydrogel and the inner cavity of the hot-end hydrogel are interconnected to form a heat dissipation cavity, which is filled with coolant.

[0013] The inner circumferential surface of the cold-end hydrogel ring is in close contact with the inner graphene conductive tape, the front end surface of the cold-end hydrogel is in close contact with the hot-end hydrogel in the motor stator slot, and the outer circumferential surface and rear end surface of the cold-end hydrogel ring are in close contact with the outer graphene conductive tape. The inner graphene conductive tape, the cold-end hydrogel, and the outer graphene conductive tape are covered by the rear sealing shell and sealed to the rear end surface of the motor stator.

[0014] The rear sealing shell has an opening on its side wall, through which the inner graphene conductive tape and the outer graphene conductive tape extend outward and merge. The extended portion serves as the outer end of the graphene conductive tape and is attached to the external heat sink.

[0015] The frameless motor is ring-shaped, and the motor rotor is connected to the output shaft along the direction pointing towards the front or rear sealing shell.

[0016] Both the hot-end hydrogel and the cold-end hydrogel are porous hydrogels, which are prepared using the following method:

[0017] S1. Polyvinyl alcohol is added to water and stirred to obtain a hydrogel precursor;

[0018] S2. Add nano-copper particles to the hydrogel precursor, and use an ultrasonic disperser inserted into the hydrogel precursor to vibrate it, so as to obtain a solidified hydrogel as a porous hydrogel.

[0019] The mass ratio of polyvinyl alcohol to water is 1:5~10.

[0020] The copper nanoparticles are copper nanoparticles with a particle size of 60~100nm, and the mass ratio of the copper nanoparticles to the hydrogel precursor is 1:7~9.

[0021] When the frameless motor is working, the stator temperature rises. The coolant in the hot-end hydrogel absorbs heat and vaporizes into hot steam, which then enters the inner cavity of the hot-end hydrogel. Under the action of internal air pressure, the hot steam flows from the inner cavity of the hot-end hydrogel to the inner cavity of the cold-end hydrogel. The cold-end hydrogel has a lower temperature, so the hot steam condenses into condensate in the inner cavity of the cold-end hydrogel and releases the absorbed heat. The cold-end hydrogel absorbs the heat and transfers it to the external heat sink through the inner and outer graphene conductive heat pipes. The condensate is absorbed by the cold-end hydrogel and flows back to the hot-end hydrogel under the action of capillary force of the porous hydrogel. This cycle repeats to achieve heat dissipation.

[0022] The beneficial effects of this invention are as follows:

[0023] 1) Hydrogel was used to create a capillary structure that closely adheres to the motor's heat source. Motor heat generation primarily occurs in the windings, which are composed of multiple coils wound together. Their surfaces are uneven, resulting in irregular gaps between each winding. Directly filling the spaces between windings with capillary heat pipes would not achieve a tight fit between the heat pipe surface and the coils, and the external sealing material of the heat pipes would introduce excessive thermal resistance, significantly reducing heat dissipation efficiency. Conversely, directly manufacturing capillary structures between windings currently relies on copper powder sintering, a process whose high temperatures can damage the motor. Therefore, using hydrogel to create the capillary structure between windings achieves a tight fit between the capillary structure and the windings while avoiding damage to the motor during manufacturing.

[0024] 2) Porous hydrogels exhibit high thermal conductivity and are simple to prepare. Currently, the most widely used method for manufacturing porous hydrogels typically involves placing the hydrogel in a vacuum chamber and using negative pressure to extract air bubbles during curing to create internal pores. However, this method is slow to cure, cumbersome, and makes it difficult to create cavities within the porous hydrogel for gas flow. The ultrasonic vibration copper particle method proposed in this invention enables rapid fabrication of micropores. Furthermore, the heat generated by ultrasonic vibration accelerates the evaporation of water within the hydrogel, speeding up the curing process. In addition, the abundant distribution of nano-copper particles within the porous hydrogel improves its thermal conductivity.

[0025] 3) The heat dissipation solution proposed in this invention has a simple structure, making it easy to manufacture and integrate. When multiple motors in a drive system require heat dissipation, air cooling often increases the overall size and weight due to the addition of fans, while liquid cooling requires the design of multiple coolant circulation channels, increasing pump power consumption and system complexity. These methods are unfavorable for the application of frameless motors in humanoid robots. This heat dissipation solution, however, uses graphene conductive tape to conduct heat away from the motors. In a system with multiple motors, simply connecting the graphene conductive tape to the same heat sink achieves simultaneous cooling of multiple motors. The system is simple, reliable, and ensures high heat dissipation performance. Attached Figure Description

[0026] Figure 1 is an overall isometric view of the present invention.

[0027] Figure 2 is a three-dimensional exploded view of the present invention.

[0028] Figure 3 is a cross-sectional view of the motor stator of the present invention.

[0029] Figure 4 is an assembly diagram of the front sealing cover and the motor stator core of the present invention.

[0030] Figure 5 is a cross-sectional view of the rear cover of the present invention.

[0031] Figure 6 is a schematic diagram of the heat dissipation principle of the porous hydrogel of the present invention.

[0032] Figure 7 is a schematic diagram of the preparation steps of the hot-end hydrogel of the present invention.

[0033] Figure 8 is a schematic diagram showing the correspondence between the hot-end hydrogel and the cold-end hydrogel cavity of the present invention.

[0034] In the figure: 1. Graphene conductive tape extension end; 2. Front sealing shell; 3. Hot end hydrogel; 4. Motor rotor; 5. Motor stator; 6. Inner graphene conductive tape; 7. Cold end hydrogel; 8. Outer graphene conductive tape; 9. Rear sealing shell; 10. Stator core; 11. Winding; 12. Hot end hydrogel inner cavity; 13. Sealing plate; 14. Cold end hydrogel inner cavity. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] A frameless motor based on porous hydrogel is shown in Figures 2 and 3, including a front sealing shell 2, a hot end hydrogel 3, a motor rotor 4, a motor stator 5, an inner graphene conductive tape 6, a cold end hydrogel 7, an outer graphene conductive tape 8, and a rear sealing shell 9.

[0037] The front and rear ends of the motor stator 5 are respectively equipped with a front sealing shell 2 and a rear sealing shell 9. The front sealing shell 2, the motor stator 5, and the rear sealing shell 9 are all annular. The front sealing shell, the motor stator, and the rear sealing shell form a sealed chamber, which is sealed with sealant. The chamber is filled with porous hydrogel and coolant. The motor rotor 4 is coaxially set inside the motor stator 5. The front sealing shell 2 is fitted with one end of the motor stator 5 to form several axially distributed slots. Each slot is provided with hot-end hydrogel 3. The rear sealing shell 9 is fitted with the other end of the motor stator 5. The rear sealing shell 9 is provided with an annular cold-end hydrogel 7 near the rear end of the motor stator 5. The cold-end hydrogel 7 is in contact with the hot-end hydrogel 3 in all the slots of the motor stator 5. The inner and outer sides of the annular cold-end hydrogel 7 are respectively provided with an inner graphene conductive tape 6 and an outer graphene conductive tape 8.

[0038] As shown in Figure 8, each hot-end hydrogel 3 has a cavity structure as a hot-end hydrogel inner cavity 12, and the cold-end hydrogel 7 has several cavity structures. Each cavity structure serves as a cold-end hydrogel inner cavity 14. The hot-end hydrogel inner cavities 12 and the cold-end hydrogel inner cavities are interconnected to form a heat dissipation cavity, which is sealed and filled with coolant.

[0039] As shown in Figures 3 and 4, the motor stator 5 includes a stator core 10 and a winding 11. The stator core 10 has multiple stator slots evenly distributed circumferentially on its inner side. The winding 11 is wound on the teeth between the stator slots of the stator core 10. The front sealing shell 2 has multiple sealing plates 13 evenly distributed circumferentially on its inner side, pointing towards the rear sealing shell 9. The sealing plates 13 are embedded in the slot openings of the stator slots and seal the slot openings, thus forming slots in the stator slots for installing the hot-end hydrogel 3 and the winding 11.

[0040] Each cold-end hydrogel 7 and each hot-end hydrogel 3 has a cavity structure at the position directly opposite to the cavity structure, which serves as a cold-end hydrogel inner cavity 14. The cold-end hydrogel inner cavity 14 and the hot-end hydrogel inner cavity 12 are connected to each other to form a heat dissipation cavity, which is sealed and filled with coolant.

[0041] As shown in Figure 5, the inner circumferential surface of the cold-end hydrogel 7 ring is in close contact with the inner graphene conductive tape 6, the front end surface of the cold-end hydrogel 7 is in close contact with the hot-end hydrogel 3 in the slot of the motor stator 5, and the outer circumferential surface and rear end surface of the cold-end hydrogel 7 ring are in close contact with the outer graphene conductive tape 8. The inner graphene conductive tape 6, the cold-end hydrogel 7, and the outer graphene conductive tape 8 are covered by the rear sealing shell 9 and sealed to the rear end surface of the motor stator 5.

[0042] The rear sealing shell 9 has an opening on its side wall. The inner graphene conductive tape 6 and the outer graphene conductive tape 8 extend outward and merge through the opening. The extended part serves as the graphene conductive tape extension end 1 and is attached to the external heat sink.

[0043] As shown in Figure 1, the frameless motor is ring-shaped, and the motor rotor 4 is connected to the output shaft along the direction pointing towards the front sealing shell 2 or the rear sealing shell 9. The heat dissipation solution is integrated inside the motor, eliminating the need for an additional housing.

[0044] Both hot-end hydrogel 3 and cold-end hydrogel 7 are porous hydrogels, which were prepared using the following method:

[0045] S1. Polyvinyl alcohol is added to water and stirred to obtain a hydrogel precursor;

[0046] S2. Add nano-copper particles to the hydrogel precursor, insert a column-type ultrasonic disperser into the hydrogel precursor and fix it vertically in the middle of every two windings for vibration, and obtain the solidified hydrogel as a porous hydrogel.

[0047] The ultrasonic disperser emits sound waves to generate a cavitation effect, causing the nano-copper particles to vibrate at high frequency, thereby forming a large number of pores during the hydrogel solidification process. At the same time, the ultrasonic dispersion process generates heat due to cavitation, which accelerates the evaporation of water in the hydrogel, thereby speeding up the hydrogel solidification. The large number of nano-copper particles distributed in the process can improve the thermal conductivity of the hydrogel.

[0048] The hydrogel precursor is the hydrogel in a liquid state.

[0049] The mass ratio of polyvinyl alcohol to water is 1:5~10.

[0050] The copper nanoparticles are copper nanoparticles with a particle size of 60~100nm, and the mass ratio of the copper nanoparticles to the hydrogel precursor is 1:7~9.

[0051] Both the hot-end hydrogel 3 and the cold-end hydrogel 7 are porous hydrogels. The hot-end hydrogel 3 is called the hot-end hydrogel 3 because it is heated in contact with the winding 11. The cold-end hydrogel 7 is called the cold-end hydrogel 7 because it has a lower temperature and is cooled by being bonded to the external heat sink through the inner graphene conductive tape 6 and the outer graphene conductive tape 8.

[0052] As shown in Figure 6, when the frameless motor is working, the coolant inside the cavity of the hot end hydrogel 3 is heated and then circulates within the hot end hydrogel 3, the cold end hydrogel 7, and the heat dissipation cavity, thereby achieving efficient heat dissipation of the motor.

[0053] Specifically, when the frameless motor is working, the temperature of the motor stator 5 rises. The coolant in the hot-end hydrogel 3 absorbs heat and vaporizes into hot steam, which then enters the inner cavity 12 of the hot-end hydrogel. The hot steam flows from the inner cavity 12 of the hot-end hydrogel to the inner cavity 14 of the cold-end hydrogel under the action of internal air pressure. Since the temperature of the cold-end hydrogel 7 is lower, the hot steam is cooled and liquefied into condensate in the inner cavity 14 of the cold-end hydrogel, releasing the absorbed heat. The cold-end hydrogel 7 absorbs the heat and transfers the heat to the external heat sink through the inner graphene conductive tape 6 and the outer graphene conductive tape 8. The condensate is absorbed by the cold-end hydrogel 7 and flows back to the hot-end hydrogel 3 under the action of capillary force of the porous hydrogel. This cycle repeats to achieve efficient heat dissipation.

[0054] The cooling system utilizes the capillary action of porous hydrogel and the phase change principle of the coolant to achieve coolant circulation between the motor windings and the rear sealing shell. Heat is then conducted to the cooling equipment via graphene conductive tape within the rear sealing shell, resulting in efficient heat dissipation. The heat transfer process is as follows: the hot end, i.e., the motor stator, transfers heat to the coolant within the hydrogel; the coolant then transfers heat to the cold end, i.e., the rear sealing shell, through phase change circulation. Subsequently, the inner and outer graphene conductive tapes of the rear sealing shell transfer the heat to an external heat sink. Since the rear sealing shell is connected to the external heat sink via the graphene conductive tapes, its temperature is lower than that of the motor stator, and this temperature difference drives the coolant phase change circulation.

[0055] The manufacturing process of a frameless motor includes the following steps, as shown in Figure 7.

[0056] S1. The front sealing shell 2 and the motor stator 5 are fitted together to form several axially distributed slots;

[0057] S2. The hydrogel precursor doped with copper nanoparticles is injected into each slot using a syringe. Due to its fluidity, after standing for a period of time, the hydrogel precursor can fit tightly against the irregular surface of the winding 11 on the motor stator 5. Then, a column ultrasonic disperser is inserted into the hydrogel precursor in each slot. All column ultrasonic dispersers vibrate simultaneously. The cavitation effect generated by the ultrasonic waves causes the copper nanoparticles to vibrate at high frequency, thereby forming a large number of pores during the hydrogel curing process. After the hydrogel precursor has cured, the vibration is stopped, and the column ultrasonic disperser is removed. The original position of the column ultrasonic disperser forms a hot-end hydrogel inner cavity 12, resulting in a hot-end hydrogel 3 with a hot-end hydrogel inner cavity 12, a front sealing shell 2 containing the hot-end hydrogel 3, and a motor stator 5.

[0058] S3. Assemble the rear sealing shell 9, the inner graphene conductive tape 6, and the outer graphene conductive tape 8 to form an annular cavity.

[0059] S4. The hydrogel precursor doped with nano-copper particles is injected into the annular cavity using a syringe. Then, several column-type ultrasonic dispersers are inserted into the hydrogel precursor in the annular cavity. All column-type ultrasonic dispersers vibrate simultaneously. After the hydrogel precursor solidifies, the vibration is stopped, and the column-type ultrasonic dispersers are removed. The original position of the column-type ultrasonic dispersers forms a cold-end hydrogel inner cavity 14, resulting in a cold-end hydrogel 7 with a cold-end hydrogel inner cavity 14 and a rear sealing shell 9 containing the cold-end hydrogel 7.

[0060] The number of column-type ultrasonic dispersers depends on the number of motor windings.

[0061] S5. Add appropriate amounts of coolant to the hot end hydrogel cavity 12 of the hot end hydrogel 3 and the cold end hydrogel cavity 14 of the cold end hydrogel 7. The coolant is absorbed by the hot end hydrogel 3 and the cold end hydrogel 7.

[0062] S6. The front sealing shell 2 containing hot-end hydrogel 3, the motor stator 5, the motor rotor 4, and the rear sealing shell 9 containing cold-end hydrogel 7 are assembled in sequence to obtain a frameless motor.

[0063] The winding is made of multiple turns of wire, with an uneven surface and tiny gaps between the wires. Due to the liquid fluidity of the hydrogel precursor, it can fit tightly against the irregular surface of the winding 11.

[0064] S4 specifically involves injecting a hydrogel precursor doped with copper nanoparticles into an annular cavity using a syringe. Then, a columnar ultrasonic disperser is inserted into the hydrogel precursor within the annular cavity at a position corresponding to each hot-end hydrogel cavity 12. All columnar ultrasonic dispersers vibrate simultaneously. After the hydrogel precursor solidifies, vibration is stopped, and the columnar ultrasonic dispersers are removed, resulting in a cold-end hydrogel 7 with a cold-end hydrogel cavity 14. The distribution of the columnar ultrasonic dispersers is the same as during the preparation of the cold-end hydrogel, ensuring that the hot-end hydrogel cavities 12 and cold-end hydrogel cavities 14 are connected in pairs after preparation.

[0065] The hot-end hydrogel precursor is filled between the motor windings. During the hydrogel curing process, the internal nano-copper particles vibrate at high frequency, thereby forming a large number of pores and realizing the preparation of a porous hydrogel that is closely attached to the windings.

[0066] The frameless motor using the heat dissipation solution of this invention is compact and suitable for drive systems with multiple motors operating simultaneously. Simply connecting the graphene heat pipe extension 1 of each motor to an external heat sink achieves synchronous and efficient cooling for multiple motors. Other heat dissipation methods using air cooling and liquid cooling result in additional volume, higher power consumption, and system complexity, which are disadvantageous for humanoid robot applications.

[0067] The above specific embodiments are used to explain and illustrate the present invention, but not to limit the present invention. All equivalent changes and modifications made within the spirit and scope of the claims of the present invention, that is, within the scope of protection of the present invention and the content of the specification, should fall within the scope of protection of the present invention.

Claims

1. A frameless motor based on a porous hydrogel, characterized by: It includes a front sealing shell (2), a hot end hydrogel (3), a motor rotor (4), a motor stator (5), an inner graphene conductive tape (6), a cold end hydrogel (7), an outer graphene conductive tape (8), and a rear sealing shell (9). The front end and rear end of the motor stator (5) are respectively equipped with a front sealing shell (2) and a rear sealing shell (9). The front sealing shell (2), the motor stator (5) and the rear sealing shell (9) are all annular. The motor rotor (4) is coaxially arranged inside the motor stator (5). The front sealing shell (2) is fitted with one end of the motor stator (5) to form several axially distributed slots. Each slot is provided with hot end hydrogel (3). The rear sealing shell (9) is fitted with the other end of the motor stator (5). The rear sealing shell (9) is provided with an annular cold end hydrogel (7) near the rear end of the motor stator (5). The cold end hydrogel (7) and the hot end hydrogel (3) are in contact. The inner and outer sides of the annular cold end hydrogel (7) are respectively provided with an inner graphene conductive heat pack (6) and an outer graphene conductive heat pack (8). Each hot-end hydrogel (3) has a cavity structure as a hot-end hydrogel inner cavity (12), and the cold-end hydrogel (7) has several cavity structures. Each cavity structure serves as a cold-end hydrogel inner cavity (14). The hot-end hydrogel inner cavity (12) and the cold-end hydrogel inner cavity are interconnected to form a heat dissipation cavity, which is filled with coolant.

2. The frameless motor based on porous hydrogel according to claim 1, characterized in that: The motor stator (5) includes a stator core (10) and a winding (11). The stator core (10) has multiple stator slots evenly distributed along the circumferential direction on its inner side. The winding (11) is wound on the teeth between the stator slots of the stator core (10). The front sealing shell (2) has multiple sealing plates (13) evenly distributed along the circumferential direction on its inner side, pointing towards the rear sealing shell (9). The sealing plates (13) are embedded in the slot opening of the stator slot and seal the slot opening so that a slot for installing the hot end hydrogel (3) is formed in the stator slot.

3. A frameless motor based on a porous hydrogel according to claim 2, characterized in that: Each of the cold-end hydrogels (7) and each hot-end hydrogel (3) has a cavity structure at the position opposite to the cavity structure, which serves as a cold-end hydrogel cavity (14). The cold-end hydrogel cavity (14) and the hot-end hydrogel cavity (12) are interconnected to form a heat dissipation cavity and are filled with coolant.

4. A frameless motor based on porous hydrogel according to claim 1, characterized in that: The inner circumferential surface of the cold end hydrogel (7) is in close contact with the inner graphene conductive tape (6), the front end surface of the cold end hydrogel (7) is in close contact with the hot end hydrogel (3) in the slot of the motor stator (5), the outer circumferential surface and the rear end surface of the cold end hydrogel (7) are in close contact with the outer graphene conductive tape (8), and the inner graphene conductive tape (6), the cold end hydrogel (7) and the outer graphene conductive tape (8) are covered by the rear sealing shell (9) and sealed and connected to the rear end surface of the motor stator (5).

5. A frameless motor based on porous hydrogel according to claim 1, characterized in that: The rear sealing shell (9) has an opening on its side wall. The inner graphene conductive tape (6) and the outer graphene conductive tape (8) extend outward through the opening and merge. The extended part serves as the graphene conductive tape extension end (1) and is attached to the external heat sink.

6. A frameless motor based on porous hydrogel according to claim 1, characterized in that: The frameless motor is ring-shaped, and the motor rotor (4) is connected to the output shaft in the direction pointing to the front sealing shell (2) or the rear sealing shell (9).

7. A frameless motor based on porous hydrogel according to claim 1, characterized in that: Both the hot-end hydrogel (3) and the cold-end hydrogel (7) are porous hydrogels, which are prepared by the following method: S1. Polyvinyl alcohol is added to water and stirred to obtain a hydrogel precursor; S2. Add nano-copper particles to the hydrogel precursor, and use an ultrasonic disperser inserted into the hydrogel precursor to vibrate it, so as to obtain a solidified hydrogel as a porous hydrogel.

8. A frameless motor based on porous hydrogel according to claim 6, characterized in that: The mass ratio of polyvinyl alcohol to water is 1:5~10.

9. A frameless motor based on porous hydrogel according to claim 6, characterized in that: The copper nanoparticles are copper nanoparticles with a particle size of 60~100nm, and the mass ratio of the copper nanoparticles to the hydrogel precursor is 1:7~9.

10. A heat dissipation method applied to any of the frameless motors described in claims 1-9, characterized in that: When the frameless motor is working, the temperature of the motor stator (5) rises. The coolant in the hot end hydrogel (3) is heated and vaporizes into hot steam, which then enters the inner cavity (12) of the hot end hydrogel. The hot steam flows from the inner cavity (12) of the hot end hydrogel to the inner cavity (14) of the cold end hydrogel under the action of internal air pressure. The temperature of the cold end hydrogel (7) is lower. The hot steam is cooled and liquefied into condensate in the inner cavity (14) of the cold end hydrogel and releases the absorbed heat. The cold end hydrogel (7) absorbs the heat and transfers the heat to the external heat sink through the inner graphene conductive tape (6) and the outer graphene conductive tape (8). The condensate is absorbed by the cold end hydrogel (7) and flows back to the hot end hydrogel (3) under the action of capillary force of the porous hydrogel. The heat dissipation is achieved by this cycle.

Images