A frameless motor based on porous hydrogel and a heat dissipation method thereof

Abstract

The application discloses a frameless motor based on porous hydrogel and a heat dissipation method thereof. The front and rear ends of a motor stator are respectively provided with a front sealing shell and a rear sealing shell, the front sealing shell, the motor stator and the rear sealing shell are annular, a motor rotor is arranged on the inner side of the motor stator, the front sealing shell and one end of the motor stator are matched and embedded to form a plurality of axially distributed slot positions, a hot end hydrogel is arranged in the slot positions, the rear sealing shell is embedded with the other end of the motor stator, the rear sealing shell is provided with an annular cold end hydrogel close to the rear end of the motor stator, the cold end hydrogel and the hot end hydrogel are in contact, the inner side and the outer side of the annular cold end hydrogel are respectively provided with an inner side graphene heat conduction band and an outer side graphene heat conduction band, and cavities are arranged on the hot end hydrogel and the cold end hydrogel and are in communication and filled with cooling liquid. The heat dissipation scheme is simple in structure and convenient to integrate, the capillary structure close to the motor heat source is manufactured through the hydrogel, the porous hydrogel has high heat conductivity and is simple in preparation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of frameless motor, and particularly relates to a frameless motor based on porous hydrogel and a heat dissipation method thereof. BACKGROUND

[0002] With the continuous development of embodied intelligence technology, humanoid robots, as the next generation of computing terminals after PCs, smart phones and new energy vehicles, have become an important carrier of embodied intelligence technology due to their high flexibility and similar motion patterns to humans. In particular, they have shown great potential in intelligent manufacturing, medical assistance, housekeeping services and other aspects, and are gradually becoming a disruptive industry with broad market application prospects.

[0003] In the design of humanoid robots, the joint driving system is the core part to realize flexible motion. Frameless motors, due to their high efficiency, compactness and high integration, have become the preferred power source for driving the joint motion of humanoid robots. However, although frameless motors have many advantages, the heat management problem during their operation is still a major challenge, especially in high-load and long-time operation scenarios, the influence of heat loss on motor performance cannot be ignored.

[0004] During the operation of the frameless motor, eddy current effect and Joule effect will cause heat accumulation, leading to temperature rise of the stator and rotor, and thus reducing the output torque and power of the motor. In addition, the winding resistance increases with temperature rise, further increasing the Joule heat loss, which significantly reduces the overall efficiency of the motor and the energy utilization rate. Under the condition of long-term high-temperature operation, the insulation material of the winding will gradually age, increasing the risk of internal short circuit of the motor. The mechanical properties of the rotor and stator materials under high temperature will also decrease, resulting in weakened structural strength and easy mechanical failure. Especially in the application of high dynamic response humanoid robot joints, the motor is often in a state of frequent start, stop and acceleration, and this thermal fatigue effect may accelerate the aging process of the motor. Therefore, it is crucial to solve the heat loss problem of the frameless motor.

[0005] Among the current heat dissipation schemes for frameless motors, air cooling often causes the overall volume and weight of the motor to increase dramatically due to the installation of fans, and liquid cooling requires the design of multiple cooling liquid circulation channels, which will significantly increase the power consumption of the cooling liquid pump and the system complexity when the number of motors in the driving system is large. Humanoid robots often have multiple joint modules, so the above methods are not conducive to the application of frameless motors in humanoid robots. In order to maintain the stability of the frameless motor during long-time operation, it is urgent to develop a small, simple, efficient and easy-to-integrate heat dissipation scheme to solve the heat loss problem. SUMMARY

[0006] In order to solve the problems of severe heat loss, serious thermal fatigue and complex heat dissipation system during the operation of the frameless motor, the purpose of the present application is to provide a frameless motor based on porous hydrogel and a heat dissipation method thereof, which prepares the porous hydrogel close to the winding in the motor by a simple method, realizes the circulation of the cooling liquid between the motor winding and the rear sealing shell through the capillary force of the porous hydrogel and the phase change principle of the cooling liquid, and conducts the heat to the cooling equipment through the graphene heat conduction band in the rear sealing shell, so as to realize high-efficiency heat dissipation.

[0007] The technical scheme adopted by the present application is:

[0008] The present application comprises a front sealing shell, a hot-end hydrogel, a motor rotor, a motor stator, an inner graphene heat conduction band, a cold-end hydrogel, an outer graphene heat conduction band and a rear sealing shell.

[0009] The front end and the rear end of the motor stator are respectively provided with the front sealing shell and the rear sealing shell, the front sealing shell, the motor stator and the rear sealing shell are annular, the motor rotor is coaxially arranged inside the motor stator, the front sealing shell and one end of the motor stator are fitted and embedded to form a plurality of axially distributed slot positions, each slot position is provided with the hot-end hydrogel inside, the rear sealing shell is fitted and embedded 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, and the inner and outer sides of the annular cold-end hydrogel are respectively provided with the inner graphene heat conduction band and the outer graphene heat conduction band.

[0010] Each hot-end hydrogel is provided with a cavity structure as an internal cavity of the hot-end hydrogel, and the cold-end hydrogel is provided with a plurality of cavity structures, one cavity structure as an internal cavity of the cold-end hydrogel, the internal cavities of the hot-end hydrogel and the cold-end hydrogel are in communication to form a heat dissipation cavity and contain cooling liquid inside.

[0011] The motor stator comprises a stator core and a winding, a plurality of stator slots are uniformly distributed on the inner side of the stator core along the circumference, the winding is wound on the teeth between the stator slots of the stator core, a plurality of sealing inserts pointing to the rear sealing shell are uniformly distributed on the inner side of the front sealing shell along the circumference, the sealing inserts are embedded into the slot openings of the stator slots and seal the slot openings so that the stator slots form slot positions for installing the hot-end hydrogel.

[0012] The cold-end hydrogel is provided with a cavity structure opposite to the cavity structure on each hot-end hydrogel as an internal cavity of the cold-end hydrogel, and one internal cavity of the cold-end hydrogel and one internal cavity of the hot-end hydrogel are in communication to form a heat dissipation cavity and contain cooling liquid inside.

[0013] The inner circumferential surface of the cold-end hydrogel ring and the inner graphene heat-conducting band are in close contact, the front end surface of the cold-end hydrogel and the hot-end hydrogel in the slot of the motor stator are in close contact, the outer circumferential surface and the rear end surface of the cold-end hydrogel ring are in close contact with the outer graphene heat-conducting band, and the inner graphene heat-conducting band, the cold-end hydrogel and the outer graphene heat-conducting band are covered by the rear sealing shell and are sealingly connected to the rear end surface of the motor stator.

[0014] The side wall of the rear sealing shell is provided with an opening, and the inner graphene heat-conducting band and the outer graphene heat-conducting band extend outward through the opening and merge, and the extended part serves as an outer extension end of the graphene heat-conducting band and is attached to the external heat sink.

[0015] The frameless motor is in a whole ring shape, and the motor rotor is connected to the output shaft in the direction of the front sealing shell or the rear sealing shell.

[0016] The hot-end hydrogel and the cold-end hydrogel are both porous hydrogels, and the porous hydrogel is prepared by the following method:

[0017] S1, polyvinyl alcohol is added to water for stirring to obtain a hydrogel precursor;

[0018] S2, nano-copper particles are added to the hydrogel precursor, and an ultrasonic disperser is inserted into the hydrogel precursor for vibration to obtain a solidified hydrogel as a porous hydrogel.

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

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

[0021] When the frameless motor works, the temperature of the motor stator rises, the cooling liquid in the hot-end hydrogel is heated and vaporized to become hot steam which enters the internal cavity of the hot-end hydrogel, the hot steam flows from the internal cavity of the hot-end hydrogel to the internal cavity of the cold-end hydrogel under the action of internal gas pressure, the temperature of the cold-end hydrogel is relatively low, the hot steam is liquefied into condensate in the internal cavity of the cold-end hydrogel and releases the absorbed heat, the cold-end hydrogel absorbs the heat and transmits the heat to the external heat sink through the inner graphene heat-conducting band and the outer graphene heat-conducting band, and the condensate is absorbed by the cold-end hydrogel and flows back to the hot-end hydrogel under the action of the capillary force of the porous hydrogel, so that the heat dissipation is realized through the circulation.

[0022] The beneficial effects of the present application are:

[0023] 1) The capillary structure close to the motor heat source is realized by the hydrogel. The motor heat is mainly generated by the winding, which is wound by multiple coils, and the surface of the winding is uneven, so the gap structure between each winding is irregular. If the capillary heat pipe is directly filled between the windings, on the one hand, the surface of the heat pipe cannot be closely combined with the coil, and on the other hand, the excess thermal resistance of the sealing material outside the heat pipe greatly reduces the heat dissipation efficiency. If the capillary structure is directly manufactured between the windings, the copper powder sintering method is mostly used to manufacture the capillary structure in the current industrial field. The high temperature in the sintering process will damage the motor. Therefore, the use of hydrogel to manufacture the capillary structure between the windings can realize the close combination of the capillary structure and the winding, and can avoid the damage to the motor in the manufacturing process.

[0024] 2) The thermal conductivity of the porous hydrogel is high and the preparation method is simple. The currently widely used porous hydrogel manufacturing method is to place the hydrogel in a vacuum device, and the gas bubbles in the glue are extracted to realize the manufacturing of the internal pores during the solidification process. However, this method has slow solidification speed, complicated steps, and it is difficult to manufacture cavities for gas flow in the porous hydrogel. The ultrasonic vibration copper particle method proposed in the present application can realize the rapid manufacturing of micropores, and the heat generated by ultrasonic vibration can accelerate the evaporation of water in the hydrogel, and speed up the solidification speed. In addition, a large number of nano copper particles are distributed in the porous hydrogel, which can improve the thermal conductivity of the hydrogel.

[0025] 3) The heat dissipation scheme proposed in the present application has simple structure, is easy to manufacture and integrate. When multiple motors in a driving system need to be cooled, the air cooling often causes the overall volume and weight to increase dramatically due to the mounting of fans, and the liquid cooling needs to design multiple cooling liquid circulation flow channels, which increases the power consumption of the pump and the complexity of the system. These methods are not conducive to the application of frameless motors in humanoid robots. The heat dissipation scheme proposed in the present application can realize the synchronous cooling of multiple motors by connecting the graphene heat conduction belts to the same heat sink, which is simple and reliable and ensures high heat dissipation performance. BRIEF DESCRIPTION OF DRAWINGS

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

[0027] Figure 2 is the three-dimensional exploded schematic view of the present application.

[0028] Figure 3 is the motor stator sectional view of the present application.

[0029] Figure 4 is the front sealing cover and motor stator core assembly drawing of the present application.

[0030] Figure 5 is the rear end cover sectional view of the present application.

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

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

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

[0034] In the figure: 1, graphene heat conduction band extension end; 2, front sealing shell; 3, hot-end hydrogel; 4, motor rotor; 5, motor stator; 6, inner graphene heat conduction band; 7, cold-end hydrogel; 8, outer graphene heat conduction band; 9, rear sealing shell; 10, stator core; 11, winding; 12, hot-end hydrogel inner cavity; 13, sealing plug; 14, cold-end hydrogel inner cavity. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with the accompanying drawings and examples.

[0036] A frameless motor based on porous hydrogel as shown in Figure 2 and Figure 3 includes a front sealing shell 2, a hot-end hydrogel 3, a motor rotor 4, a motor stator 5, an inner graphene heat conduction band 6, a cold-end hydrogel 7, an outer graphene heat conduction band 8, and a rear sealing shell 9.

[0037] The front end and the rear end of the motor stator 5 are respectively provided with the front sealing shell 2 and the rear sealing shell 9, and 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 by sealing glue, and is filled with porous hydrogel and cooling liquid. The motor rotor 4 is coaxially arranged inside the motor stator 5, the front sealing shell 2 and one end of the motor stator 5 cooperatively fit to form a plurality of axially distributed slot positions, each slot position is provided with a hot-end hydrogel 3, and the rear sealing shell 9 cooperatively fits with the other end of the motor stator 5, and 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 hydrogels 3 in all the slot positions of the motor stator 5, and the inner and outer sides of the annular cold-end hydrogel 7 are respectively provided with the inner graphene heat conduction band 6 and the outer graphene heat conduction band 8.

[0038] As shown in Figure 8 , each hot-end hydrogel 3 is provided with a cavity structure as a hot-end hydrogel inner cavity 12, and the cold-end hydrogel 7 is provided with a plurality of cavity structures, one cavity structure as a cold-end hydrogel inner cavity 14, the hot-end hydrogel inner cavity 12 and the cold-end hydrogel inner cavity are in correspondence and communication to form a heat dissipation cavity and are sealed and filled with cooling liquid.

[0039] As shown in Figure 3 and 4 The motor stator 5 includes a stator core 10 and a winding 11, the inside of the stator core 10 is evenly distributed with a plurality of stator slots in the circumferential direction, the winding 11 is wound on the teeth between the stator slots of the stator core 10, the inside of the front sealing shell 2 is evenly distributed with a plurality of sealing inserts 13 pointing to the rear sealing shell 9 in the circumferential direction, the sealing inserts 13 are embedded at the slot openings of the stator slots and seal the slot openings so that the stator slots form slot positions for installing the hot end hydrogel 3 and the winding 11.

[0040] The cold end hydrogel 7 is provided with a cavity structure at a position opposite to the cavity structure on each hot end hydrogel 3, and each cold end hydrogel 7 is provided with a cavity structure as a cold end hydrogel inner cavity 14, and 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 and are sealed and internally filled with cooling liquid.

[0041] As shown in Figure 5 The inner circumferential surface of the annular cold end hydrogel 7 and the inner graphene heat conduction band 6 are in close contact, the front end surface of the cold end hydrogel 7 and the hot end hydrogel 3 in the slot position of the motor stator 5 are in close contact, the outer circumferential surface and the rear end surface of the annular cold end hydrogel 7 are in close contact with the outer graphene heat conduction band 8, and the inner graphene heat conduction band 6, the cold end hydrogel 7 and the outer graphene heat conduction band 8 are covered by the rear sealing shell 9 and are sealed and connected to the rear end surface of the motor stator 5.

[0042] The side wall of the rear sealing shell 9 is provided with an opening, and the inner graphene heat conduction band 6 and the outer graphene heat conduction band 8 extend outward through the opening and merge, and the extended part serves as the graphene heat conduction band outer extension end 1 and is attached to the external heat sink.

[0043] As shown in Figure 1 The frameless motor is annular as a whole, 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. The heat dissipation scheme is integrated in the motor, and no additional shell is needed.

[0044] The hot end hydrogel 3 and the cold end hydrogel 7 are both porous hydrogels, which are prepared by the following method:

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

[0046] S2, nano copper particles are added to the hydrogel precursor, a column ultrasonic disperser is inserted into the hydrogel precursor and vertically fixed at the middle position of every two windings for vibration, and a solidified hydrogel is obtained as a porous hydrogel.

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

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

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

[0050] The nano-copper particles are nano-copper particles with a particle size of 60-100 nm, and the mass ratio of the nano-copper particles 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 in contact with the winding 11 and is heated, so it is called the hot-end hydrogel 3, and the cold-end hydrogel 7 is low in temperature and is attached to the external heat sink through the inner graphene heat conduction band 6 and the outer graphene heat conduction band 8, so it is called the cold-end hydrogel 7.

[0052] As shown in Figure 6 When the frameless motor is working, the cooling liquid in the cavity of the hot-end hydrogel 3 is heated and circulates in the hot-end hydrogel 3, the cold-end hydrogel 7 and the heat dissipation cavity, thereby realizing efficient heat dissipation of the motor.

[0053] Specifically, when the frameless motor is working, the temperature of the motor stator 5 rises, the cooling liquid in the hot-end hydrogel 3 is heated and vaporized to become 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, and since the temperature of the cold-end hydrogel 7 is low, the hot steam is liquefied to become condensate when it enters the inner cavity 14 of the cold-end hydrogel, and releases the absorbed heat, the cold-end hydrogel 7 absorbs the heat and transmits it to the external heat sink through the inner graphene heat conduction band 6 and the outer graphene heat conduction band 8, and the condensate is absorbed by the cold-end hydrogel 7 and flows back to the hot-end hydrogel 3 under the action of the capillary force of the porous hydrogel, thereby realizing efficient heat dissipation through circulation.

[0054] The circulation of the cooling liquid between the motor winding and the rear sealing shell is realized by the capillary force of the porous hydrogel and the phase change principle of the cooling liquid, and the heat is conducted to the cooling device through the graphene heat conduction belt in the rear sealing shell, so as to realize high-efficiency heat dissipation. The heat conduction process of the heat dissipation scheme is as follows: the hot end, i.e. the motor stator, transmits heat to the cooling liquid in the hydrogel, the cooling liquid transmits heat to the cold end, i.e. the rear sealing shell, through phase change circulation, and then the inner and outer graphene heat conduction belts of the rear sealing shell transmit heat to the external heat sink. The rear sealing shell is connected with the external heat sink through the graphene heat conduction belt, so the temperature is lower than that of the motor stator, and the temperature difference drives the phase change circulation of the cooling liquid.

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

[0056] S1, the front sealing shell 2 and the motor stator 5 are matched and embedded to form a plurality of axially distributed slot positions;

[0057] S2, the hydrogel precursor doped with nano-copper particles is injected into each slot position through a syringe. Due to the liquid flowability, the hydrogel precursor can be closely combined with the irregular surface of the winding 11 on the motor stator 5 after a period of standing. Then a column ultrasonic disperser is inserted into the hydrogel precursor in each slot position, all the column ultrasonic dispersers vibrate at the same time, the nano-copper particles are subjected to high-frequency vibration through the cavitation effect generated by ultrasonic waves, so that a large number of pores are formed in the hydrogel during the solidification process of the hydrogel. After the hydrogel precursor is solidified, the vibration is stopped, and the column ultrasonic disperser is taken out. The original position of the column ultrasonic disperser forms a hot-end hydrogel inner cavity 12, and the hot-end hydrogel 3 with the hot-end hydrogel inner cavity 12, the front sealing shell 2 and the motor stator 5 loaded with the hot-end hydrogel 3 are obtained;

[0058] S3, the rear sealing shell 9, the inner graphene heat conduction belt 6 and the outer graphene heat conduction belt 8 are assembled to form an annular cavity;

[0059] S4, the hydrogel precursor doped with nano-copper particles is injected into the annular cavity through a syringe. Then a plurality of column ultrasonic dispersers are inserted into the hydrogel precursor in the annular cavity, all the column ultrasonic dispersers vibrate at the same time. After the hydrogel precursor is solidified, the vibration is stopped, and the column ultrasonic disperser is taken out. The original position of the column ultrasonic disperser forms a cold-end hydrogel inner cavity 14, and the cold-end hydrogel 7 with the cold-end hydrogel inner cavity 14, and the rear sealing shell 9 loaded with the cold-end hydrogel 7 are obtained;

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

[0061] ​S5, add appropriate amount of cooling liquid in the hot end hydrogel inner cavity 12 of the hot end hydrogel 3 and the cold end hydrogel inner cavity 14 of the cold end hydrogel 7, and the cooling liquid is absorbed by the hot end hydrogel 3 and the cold end hydrogel 7;

[0062] S6, the front sealing shell 2 provided with the hot end hydrogel 3 and the motor stator 5, the motor rotor 4 and the rear sealing shell 9 provided with the cold end hydrogel 7 are sequentially assembled to obtain the frameless motor.

[0063] The winding is formed by winding a plurality of wires, the surface is uneven, and there is a small gap between the wires, and because of the fluidity of the hydrogel precursor, the hydrogel precursor can closely fit the irregular surface of the winding 11.

[0064] S4 is specifically: the hydrogel precursor doped with nano-copper particles is injected into the annular cavity through a syringe, then a column ultrasonic disperser is inserted into the hydrogel precursor in the annular cavity at a position corresponding to each hot end hydrogel inner cavity 12, all the column ultrasonic dispersers vibrate at the same time, the vibration is stopped after the hydrogel precursor is solidified, the column ultrasonic disperser is taken out, and the cold end hydrogel 7 with the cold end hydrogel inner cavity 14 is obtained. The distribution position of the column ultrasonic disperser is the same as that when the cold end hydrogel is prepared, so that the hot end hydrogel inner cavity 12 and the cold end hydrogel inner cavity 14 correspond to each other after the preparation is completed.

[0065] The hot end hydrogel precursor is filled between the motor windings, and the nano-copper particles in the hydrogel are vibrated at high frequency during the solidification of the hydrogel, so that a large number of pores are formed, and the preparation of the porous hydrogel closely fitted to the winding is realized.

[0066] The frameless motor adopting the heat dissipation scheme has a small volume, is suitable for a driving system in which multiple motors work at the same time, and only needs to connect the graphene heat conduction band outer extension end 1 of each motor with an external heat sink, so that synchronous and efficient cooling of multiple motors can be realized. Other heat dissipation methods using air cooling and liquid cooling will generate additional volume, more power consumption and complex system, which is not conducive to the application of humanoid robots.

[0067] The above specific embodiments are used to explain and illustrate the present application, rather than limit the present application, and equivalent changes and modifications made within the spirit and protection scope of the claims of the present application, i.e. the protection scope and content of the specification of the present application, should fall into the protection scope of the present application.

Claims

1. A frameless motor based on a porous hydrogel, characterized by: It comprises a front sealing shell (2), a hot end hydrogel (3), a motor rotor (4), a motor stator (5), an inner graphene heat conduction band (6), a cold end hydrogel (7), an outer graphene heat conduction band (8) and a rear sealing shell (9). The front end and the rear end of the motor stator (5) are respectively provided with the front sealing shell (2) and the rear sealing shell (9), the front sealing shell (2), the motor stator (5) and the rear sealing shell (9) are annular, the motor rotor (4) is coaxially arranged inside the motor stator (5), the front sealing shell (2) and one end of the motor stator (5) are matched and embedded to form a plurality of axially distributed slot positions, each slot position is internally provided with the hot end hydrogel (3), the rear sealing shell (9) is matched and embedded with the other end of the motor stator (5), the rear sealing shell (9) is internally provided with the 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 the inner graphene heat conduction band (6) and the outer graphene heat conduction band (8). Each hot end hydrogel (3) is provided with a cavity structure as a hot end hydrogel internal cavity (12), the cold end hydrogel (7) is provided with a plurality of cavity structures, one cavity structure is as a cold end hydrogel internal cavity (14), the hot end hydrogel internal cavity (12) and the cold end hydrogel internal cavity are in communication to form a heat dissipation cavity and internally contain cooling liquid.

2. A frameless motor based on a porous hydrogel according to claim 1, characterized in that: The motor stator (5) comprises a stator core (10) and a winding (11), the inner side of the stator core (10) is uniformly distributed with a plurality of stator slots along the circumference, the winding (11) is wound on the teeth between the stator slots of the stator core (10), the inner side of the front sealing shell (2) is uniformly distributed with a plurality of sealing inserts (13) pointing to the rear sealing shell (9) along the circumference, the sealing inserts (13) are embedded into the slot openings of the stator slots and seal the slot openings so that the stator slots form slot positions for installing the hot end hydrogel (3).

3. A frameless motor based on a porous hydrogel according to claim 2, characterized in that: The cold end hydrogel (7) and the cavity structure opposite to each hot end hydrogel (3) are provided with a cavity structure as a cold end hydrogel internal cavity (14), one cold end hydrogel internal cavity (14) and one hot end hydrogel internal cavity (12) are in communication to form a heat dissipation cavity and internally contain cooling liquid.

4. A frameless motor based on porous hydrogel according to claim 1, characterized in that: The inner circumferential surface of the annular cold end hydrogel (7) and the inner graphene heat conduction band (6) are in close contact, the front end surface of the cold end hydrogel (7) and the hot end hydrogel (3) in the slot position of the motor stator (5) are in close contact, the outer circumferential surface and the rear end surface of the annular cold end hydrogel (7) and the outer graphene heat conduction band (8) are in close contact, the inner graphene heat conduction band (6), the cold end hydrogel (7) and the outer graphene heat conduction band (8) are covered by the rear sealing shell (9) and are sealingly 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 side wall of the rear sealing shell (9) is provided with an opening, the inner graphene heat conduction band (6) and the outer graphene heat conduction band (8) extend outward through the opening and merge, the extended part is as a graphene heat conduction band extension end (1) and is attached to an external heat sink.

6. A frameless motor based on porous hydrogel according to claim 1, characterized in that: The frameless motor is annular as a whole, and the motor rotor (4) is connected with an output shaft in a 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: The hot-end hydrogel (3) and the cold-end hydrogel (7) are both porous hydrogels, and the porous hydrogel is prepared by the following method: S1, polyvinyl alcohol is added into water for stirring to obtain a hydrogel precursor; S2, nano-copper particles are added into the hydrogel precursor, and an ultrasonic disperser is inserted into the hydrogel precursor for vibration to obtain a solidified hydrogel as the porous hydrogel.

8. A frameless motor based on a porous hydrogel according to claim 7, characterized in that: The mass ratio of the polyvinyl alcohol to water is 1:5-10.

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

10. A heat dissipation method applied to the frameless motor of any one of claims 1-9, characterized in that: When the frameless motor works, the temperature of the motor stator (5) rises, the cooling liquid in the hot-end hydrogel (3) is heated to absorb heat and vaporize into hot steam which then enters the internal cavity (12) of the hot-end hydrogel, the hot steam flows from the internal cavity (12) of the hot-end hydrogel to the internal cavity (14) of the cold-end hydrogel under the action of internal air pressure, the temperature of the cold-end hydrogel (7) is relatively low, the hot steam in the internal cavity (14) of the cold-end hydrogel is liquefied into condensed liquid under cooling, and the absorbed heat is released, the cold-end hydrogel (7) absorbs the heat and transmits the heat to the external heat sink through the internal graphene heat conduction belt (6) and the external graphene heat conduction belt (8), and the condensed liquid is absorbed by the cold-end hydrogel (7) and flows back to the hot-end hydrogel (3) under the action of the capillary force of the porous hydrogel, so that the heat dissipation is realized through the circulation.

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