Manufacturing method of robot motor micro-channel cooling transmission shaft

Abstract

This invention relates to the field of robot joint drive motor technology, and particularly to a method for manufacturing a microchannel cooling transmission shaft for a robot motor. The method includes the following steps: manufacturing a shaft with an internal blind hole and an axial limiting groove; pushing a separator into the blind hole along the limiting groove, the separator dividing the blind hole into a first flow channel and a second flow channel connected at the bottom; an inner nesting device is installed at the end of the shaft and abuts against the separator to achieve axial limiting; the separator has a first liquid guiding channel and a second liquid guiding channel, and the first and second flow guiding ports on the sidewalls are staggered; a sealing sheet is abutted against the outside of the inner nesting device, and an anti-rotation structure is provided between the sealing sheet and the inner nesting device. This invention achieves high-precision assembly and uniform heat exchange of the cooling channel through the limiting groove on the inner wall of the shaft blind hole, the separator pushed in along the limiting groove, the axially limiting inner nesting device, the staggered flow guiding port built into the separator, and the anti-rotation sealing structure. It solves the problems of low assembly accuracy and poor cooling uniformity in existing cooling channel partition structures.

Description

Technical Field

[0001] This invention relates to the field of robot joint drive motor technology, and in particular to a method for manufacturing a robot motor microchannel cooling transmission shaft. Background Technology

[0002] The cooling drive shaft of the robot joint drive motor is a core component of the servo motor heat dissipation system. It is used to remove the heat generated inside the motor during high-speed operation, ensuring that the motor's operating temperature remains within a reasonable range. As the load capacity and motion precision requirements of industrial robots continue to increase, the power density of robot joint drive motors is constantly improving, and the heat generation per unit volume is significantly increasing. This places increasingly higher demands on the heat exchange efficiency and operational reliability of the cooling structure inside the drive shaft.

[0003] In existing technologies, the internal cooling channels of motor cooling drive shafts often employ a dual-channel structure formed by inserting a central tube into a hollow shaft or welding a central blockage. An annular channel forms between the central tube and the hollow shaft, and a central channel is formed inside the central tube. The two channels connect at the bottom of the shaft to form a U-shaped loop. This structure suffers from the following problems: the assembly process of inserting or welding the central tube is complex, making it difficult to guarantee assembly accuracy; misalignment of the central tube can easily lead to uneven cross-sectional area of ​​the annular channel, affecting the uniform flow of the cooling medium; furthermore, the inlet and outlet ports are usually located at the same end of the shaft and are close in axial position, resulting in a short flow path for the coolant within the shaft, uneven heat exchange across different sections of the shaft, and good cooling near the inlet while insufficient cooling in areas far from the inlet. This makes it difficult to meet the high-efficiency and uniform cooling requirements of robot joint drive motors under high power density.

[0004] Therefore, improving the assembly accuracy of the cooling channel partition structure and enhancing the cooling uniformity of the drive shaft are pressing technical challenges that need to be addressed in this field. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for manufacturing a microchannel cooling drive shaft for a robot motor. This method achieves high-precision assembly and uniform heat exchange of the cooling channel through a limiting groove in the inner wall of the shaft's blind hole, a separator pushed in along the limiting groove, axial limiting nesting, a built-in misaligned guide port in the separator, and an anti-rotation sealing structure. This solves the problems of low assembly precision and poor cooling uniformity in existing cooling channel partition structures.

[0006] To achieve the above objectives, the present invention provides a method for manufacturing a robot motor microchannel cooling drive shaft, comprising the following steps: Step 1: Manufacturing a shaft with a blind hole inside, and at least one limiting groove machined along the axial direction on the inner wall of the blind hole; Step 2: Push the separator along the axial direction of the limiting groove into the blind hole, so that the outer wall of the separator abuts against the inner wall of the blind hole and divides the blind hole into a first flow channel and a second flow channel. The first flow channel and the second flow channel are connected at the bottom of the blind hole to form a communication point. Then, insert the inner nest into the end of the shaft and abut against the separator to confine the separator within the blind hole. The separator has a first liquid guiding channel and a second liquid guiding channel. The side wall of the separator has a first flow port communicating with the first liquid guiding channel and a second flow port communicating with the second liquid guiding channel. The first flow port and the second flow port are arranged axially offset to form a liquid supply phase difference, and the distance from the first flow port to the communication point is less than the distance from the second flow port to the communication point. Step 3: Place the sealing sheet with the through hole at the end of the shaft and abut against the inner nest. The sealing sheet and the inner nest are provided with an anti-rotation structure in a locked abutment state. The through hole is connected to the second flow channel. Tighten the sealing sleeve that is threaded to the shaft. The sealing sleeve is pressed against the outside of the sealing sheet. The anti-rotation structure resists the frictional torque applied to the sealing sheet when tightening, preventing the sealing sheet from circumferentially deflecting.

[0007] By machining blind holes inward at the end of the solid shaft, an internal cavity space is formed to accommodate and flow the cooling medium. A limiting groove is machined axially along the inner wall of the blind hole, providing a circumferential positioning reference and axial guide track for subsequent partition components. This allows the partition components to be automatically positioned circumferentially simply by being pushed in axially, achieving high-precision assembly and positioning of the flow channel partition structure and avoiding the uneven flow channel cross-sectional area problem caused by the misalignment of the traditional central tube insertion method. The surface contact and abutment between the outer wall of the partition component and the inner wall of the blind hole form a reliably sealed flow channel interface, dividing the inner cavity of the blind hole axially into two independent flow channels. The two flow channels connect at the bottom of the blind hole, forming a U-shaped cooling circuit. This extends the flow path of the coolant within the blind hole to nearly twice the depth of the blind hole, achieving uniform heat exchange throughout the entire axial section of the shaft and eliminating the uneven axial heat exchange problem caused by the traditional method of liquid entering and exiting from the same side. By inserting the partition into the shaft end through an internal nesting mechanism and abutting against the end of the separator, the partition is clamped from both ends by the stepped surface at the bottom of the blind hole, limiting the axial movement of the partition under coolant pressure impact. This ensures a constant cross-sectional area for the first and second flow channels, improving the operational stability of the cooling channels. By integrating the first and second liquid guiding channels inside the partition, the inlet and outlet channels are built into the partition, achieving a highly integrated drive shaft cooling structure. The first and second flow inlets, respectively connected to the first and second liquid guiding channels, enable a complete closed-loop circulation of coolant from inside the partition into the blind hole flow channel and from the blind hole flow channel back out, reducing external piping connections. By placing the first flow inlet near the bottom connection point of the blind hole and the second flow inlet away from the connection point and near the shaft end, a phase difference is created between the inlet and outlet in the axial direction. The coolant flow path covers the entire axial length of the blind hole, achieving sufficient and uniform heat exchange in all sections of the shaft. The sealing plate seals the end opening of the blind hole, and the through hole on the sealing plate connects with the second flow channel to allow the coolant to flow in and out. An anti-rotation structure between the sealing plate and the inner nest locks their circumferential relative positions in a concave-convex meshing manner. The threaded connection between the sealing sleeve and the shaft provides axial clamping force, ensuring the sealing plate is tightly pressed against the end of the inner nest, guaranteeing the reliability of the end seal. The anti-rotation structure resists the circumferential frictional torque applied to the outer end face of the sealing plate during tightening of the sealing sleeve, keeping the sealing plate circumferentially fixed during tightening. This ensures that the through hole and the second flow channel are always precisely aligned, avoiding problems such as reduced flow area or flow channel misalignment and blockage caused by sealing plate deflection.

[0008] Preferably, the shaft is integrally manufactured using a metal injection molding process, comprising the following steps: The first step, mixing and granulation: Metal powder is produced using a pure gas atomization method. The metal powder is spherical with an average particle size of 5-18 micrometers. The metal powder formulation, by mass percentage, includes: Cr 13.5%-15.5%, Ni 6.0%-8.0%, Al 2.2%-3.8%, Mo 1.2%-2.0%, Cu 1.5%-2.5%, Nb and Ti total 0.3%-0.6%, Si 0.4%-0.8%, with the balance being Fe; the metal powder and binder are blended at a mass ratio of 88:12 to 93:7; wherein the binder comprises the following components by mass percentage: 35%-45% oligomeric isobutylene, 25%-32% cyclic olefin copolymer, 12%-18% amphiphilic microcrystalline beeswax, 4%-8% fatty alcohol polyoxyethylene ether phosphate, and 0.5%-1.5% azobisisobutyronitrile; the metal powder and the binder are preheated and stirred in a closed mixer at a mixing temperature of 135-165℃, a mixer speed of 45-65 r / min, and a mixing time of 2.5-3.5 hours; after cooling, the mixture is crushed to obtain metal feedstock; The second step, injection molding: The prepared metal feedstock is added into the barrel of a precision injection molding machine. The barrel injection temperature is set to 155-185℃, the injection pressure is 80-140MPa, and the mold temperature is controlled at 40-68℃. After holding pressure and cooling, the green shaft blank is integrally formed. The third step, in-situ micro-foaming and water-based extraction degreasing: The green shaft blank is immersed in an aqueous slightly alkaline washing solution at a temperature of 60-80℃. The azobisisobutyronitrile in the green shaft blank decomposes and releases inert gas, forming directional micro-nano exhaust channels in situ inside the green shaft blank. The aqueous slightly alkaline washing solution enters the blind holes through the openings of the blind holes, making the degree of extraction degreasing in the surface area of ​​the inner wall of the blind holes and the distribution density of the directional micro-nano exhaust channels greater than those in the core area of ​​the shaft. After 80-140 minutes of washing and extraction degreasing, the oligomeric isobutylene and amphiphilic microcrystalline beeswax in the green shaft blank are partially dissolved and removed, resulting in a porous shaft blank. The fourth step, micro-positive pressure hot degreasing and pre-sintering: In a furnace with a micro-positive pressure argon or argon-hydrogen mixture, the dried shaft blank is first hot-degreased at a slow rate of 1.5-3℃ / min to 420-480℃ and held for 90-150 minutes; then it is rapidly heated to 820-880℃ at a rate of 8-12℃ / min for a dense pre-sintering time of 60-120 minutes to obtain a high-strength pre-sintered blank; The fifth step, high-temperature densification sintering and toughening aging: In a fully sealed hydrogen atmosphere sintering furnace or vacuum sintering furnace, the high-strength pre-sintered billet is heated to 1280-1350℃ at a heating rate of 4-8℃ / min and held for sintering for 140-200 minutes; finally, aging heat treatment is completed at 460-520℃ to induce in-situ precipitation of nano-sized nickel-aluminum intermetallic compounds and nano-sized copper-containing reinforcing phases in the matrix; In this process, since the distribution density of the directional micro-nano exhaust channels in the surface region of the inner wall of the blind hole is greater than that in the core region, the core region achieves full densification during the sintering densification process, while the directional micro-nano exhaust channels in the surface region of the inner wall of the blind hole are retained in a directional manner, forming a capillary microporous layer covering the first flow channel wall and the second flow channel wall. The porosity of the capillary microporous layer decreases to zero along the radial direction of the shaft from the inner wall of the blind hole to the core region.

[0009] Spherical metal powders are prepared using a gas atomization method, with the powder particle size controlled within the range of 5-18 micrometers to ensure good powder flowability and filling density. A multi-element iron-based alloy formulation containing Cr, Ni, Al, Mo, Cu, Nb, Ti, and Si is designed to ensure the sintered material possesses high strength, corrosion resistance, and age-strengthening potential. A uniform metal feedstock is obtained by mixing the metal powder with a specific ratio of binder at 135-165℃ for 2.5-3.5 hours, ensuring the binder uniformly coats the metal powder particles. This metal feedstock is then injected into a mold cavity at 40-68℃ at 155-185℃ and 80-140MPa pressure, allowing the feedstock to fill the mold and solidify upon cooling. This integrally forms a green shaft green blank containing blind holes and limiting grooves, achieving near-net-shape forming of complex internal hole structures and avoiding the process difficulties and material waste associated with traditional machining methods for deep holes and internal grooves. By immersing the green shaft blank in an aqueous slightly alkaline washing solution at 60-80℃, the azobisisobutyronitrile in the blank is decomposed by heat, releasing inert gas and forming directional micro-nano exhaust channels in situ inside the blank. The aqueous slightly alkaline washing solution is then inserted into the inner wall of the blind hole through the blind hole opening, resulting in a higher degree of extraction and degreasing in the surface area of ​​the blind hole inner wall and a higher distribution density of directional micro-nano exhaust channels than in the core area of ​​the shaft. After extraction for 80-140 minutes, oligomeric isobutylene and amphiphilic microcrystalline beeswax are partially dissolved and removed, resulting in a porous shaft blank. This process achieves the prefabrication of a gradient pore structure from the surface to the core, laying the foundation for the subsequent sintering to directionally retain the capillary microporous layer. Under the protection of slightly positive pressure argon or argon-hydrogen mixture, the temperature is first slowly increased to 420-480℃ at 1.5-3℃ / min and held for 90-150 minutes for hot degreasing, slowly removing the remaining binder and avoiding cracking and deformation of the green blank; then the temperature is rapidly increased to 820-880℃ at 8-12℃ / min and held for 60-120 minutes for dense pre-sintering, so that the powder particles are initially metallurgically bonded to form a high-strength pre-sintered blank with a certain strength, providing structural support for subsequent high-temperature sintering. High-temperature sintering is performed in a hydrogen or vacuum atmosphere at a rate of 4-8℃ / min to 1280-1350℃, followed by holding at that temperature for 140-200 minutes. This process achieves complete densification of the core region, while the directional micro-nano exhaust channels on the surface of the blind hole inner wall are retained, forming a capillary microporous layer covering the walls of the first and second flow channels. The porosity of the capillary microporous layer decreases radially from the inner wall of the blind hole towards the core. Through aging heat treatment at 460-520℃, nano-sized nickel-aluminum intermetallic compounds and nano-copper-containing reinforcing phases are precipitated in situ within the matrix. The capillary microporous layer maintains continuous wetting of the flow channel walls through capillary wicking, further enhancing the heat transfer effect.

[0010] Preferably, during the aging heat treatment in the fifth sub-step, auxiliary heating is applied to the surface region of the inner wall of the blind hole, so that the aging temperature of the surface region of the inner wall of the blind hole is higher than that of the core region. Due to the radial difference in aging temperature, the nano-sized nickel-aluminum intermetallic compound and the nano-sized copper-containing reinforcing phase are enriched and precipitated in the surface region of the inner wall of the blind hole, while being depleted and precipitated in the core region, forming a reinforcing phase structure with a radial gradient distribution. The thermal conductivity of the surface region of the inner wall of the blind hole is higher than that of the core region. The core region maintains the toughness of the matrix, thereby decoupling the heat transfer performance and torsional mechanical properties of the shaft radially.

[0011] By applying auxiliary heating to the surface region of the blind hole inner wall during the aging heat treatment process, the aging temperature of the surface region of the blind hole inner wall is made higher than that of the core region. The radial difference in aging temperature drives the enrichment and precipitation of nano-sized nickel-aluminum intermetallic compounds and nano-sized copper-containing reinforcing phases in the surface region of the blind hole inner wall, while simultaneously reducing their precipitation in the core region, forming a reinforcing phase structure with a radial gradient distribution. The enrichment of the surface reinforcing phase improves the thermal conductivity of the surface region, while the reduction of the core reinforcing phase preserves the toughness of the matrix. This achieves a radial decoupling design of the shaft's heat transfer performance and torsional mechanical properties, enabling the shaft to simultaneously meet the dual requirements of high heat transfer efficiency and high torsional strength.

[0012] Preferably, the outer surface of the separator is provided with a mating surface and a first mating part, a limiting step is provided between the mating surface and the first mating part, the mating surface abuts against the inner wall of the blind hole, and the first mating part is disposed in the limiting groove; In step one, a first recessed platform and a second recessed platform are respectively provided at the end of the shaft corresponding to the blind hole opening end, and both the first recessed platform and the second recessed platform are eccentrically arranged. The inner nesting includes a first insert and a second insert assembled together, the first insert and the second insert being respectively inserted into the first recessed platform and the second recessed platform; the first insert and the second insert both abut against the limiting step, confining the separator within the blind hole.

[0013] By setting a mating surface and a first mating part on the outer surface of the separator, and setting a limiting step between the mating surface and the first mating part; the mating surface abuts against the inner wall of the blind hole to achieve flow channel sealing and separation; the first mating part is set in the limiting groove to achieve circumferential positioning and axial guidance; the limiting step provides an axial abutment positioning surface for the inner nest, realizing the multi-functional integration of circumferential positioning, radial sealing and axial limiting of the separator. By setting an eccentric first countersunk platform and a second countersunk platform at the ends of the shaft corresponding to the blind hole opening, an installation positioning reference is provided for the double-block inner nest; the eccentric setting makes the two countersunk platforms staggered in the circumferential direction, providing independent installation space for the double blocks of the inner nest, and at the same time, the eccentric structure is used to transfer circumferential load, improving the torsional resistance of the inner nest. By designing the inner nest as a spliced ​​first and second insert, which are respectively installed into the first and second recessed platforms; both the first and second inserts abut against the limiting steps, jointly confining the separator within the blind hole; the double-insert spliced ​​design solves the assembly problem of the integral inner nest being difficult to install into the eccentric recessed platform, and realizes the precise fit between the inner nest and the eccentric recessed platform and the reliable axial limiting function.

[0014] Preferably, the step of installing the first insert and the second insert into the first sink and the second sink respectively adopts an ultrasonic vibration-assisted assembly process, wherein the ultrasonic vibration is a high-frequency vibration composed of axial vibration component and circumferential vibration component. During the assembly process, the high-frequency vibration generates nonlinear acoustic radiation pressure and dynamic deflection of friction vector in the assembly micro-gap between the inner wall of the first insert and the first sinking platform and between the inner wall of the second insert and the second sinking platform. This drives the first insert and the second insert to generate suspension micro-movement and self-alignment within the first sinking platform and the second sinking platform, converting axial sliding friction into circumferential high-frequency sliding, thus preventing skewing and jamming during deep hole assembly. After the separator and the inner nest are assembled in place, a thermosensitive expansion crosslinking adhesive is injected into the assembly gap between the limiting groove and the first mating part through the limiting groove, and a thermosetting treatment is performed under the condition of continuing to apply the high-frequency vibration. The nonlinear acoustic radiation pressure generated by the high-frequency vibration in the thermosensitive expanding crosslinking adhesive drives the molecular chains of the thermosensitive expanding crosslinking adhesive to be oriented along the acoustic flow direction, so that the thermosensitive expanding crosslinking adhesive forms a fibrous oriented network crosslinking structure after thermal curing. The main direction of the fibrous orientation is at an angle to the circumferential direction of the shaft to resist the circumferential shearing action transmitted to the assembly gap through the sealing sheet and the inner nest when the sealing screw is tightened. The cured network cross-linked structure forms an oriented cross-linked adhesive layer that fills the assembly gap. The oriented cross-linked adhesive layer constitutes an intermediate interface that has both directional shear resistance, torsional damping and secondary static sealing functions.

[0015] By employing high-frequency ultrasonic vibration-assisted assembly with a combination of axial and circumferential vibration components, nonlinear acoustic radiation pressure and dynamic deflection of friction vectors are generated in the assembly micro-gap between the first insert and the inner wall of the first sinker, and between the second insert and the inner wall of the second sinker. This drives the first and second inserts to produce suspension micro-movements and self-alignment, converting axial sliding friction into circumferential high-frequency sliding, preventing skewness and jamming during deep hole assembly, and significantly improving the assembly accuracy and efficiency of nested deep holes. Thermosensitive expanding crosslinked adhesive is injected into the assembly gap between the limiting groove and the first mating part, and then thermosetting is performed under the condition of continued high-frequency vibration. The nonlinear acoustic radiation pressure generated by the high-frequency vibration in the thermosensitive expanding crosslinked adhesive drives the crosslinked adhesive molecular chains to oriented along the acoustic flow direction, so that the thermosensitive expanding crosslinked adhesive forms a fibrous oriented network crosslinked structure after thermosetting. The main direction of the fibrous orientation is at an angle to the circumferential direction of the shaft, which effectively resists the circumferential shearing action transmitted to the assembly gap through the sealing sheet and inner nest when the sealing screw is tightened. The cured oriented crosslinked adhesive layer fills the assembly gap and has the triple functions of directional shear resistance, torsional damping and secondary static sealing, which further improves the reliability and sealing performance of the assembly structure.

[0016] Preferably, the anti-rotation structure includes an anti-rotation boss or anti-rotation pin that protrudes axially inward on the sealing sheet, and an anti-rotation positioning groove on the first insert and the second insert; The anti-rotation boss or the anti-rotation pin is fitted into the anti-rotation positioning groove to prevent the sealing sheet from circumferentially deflecting during the tightening process of the sealing screw sleeve, so that the through hole and the second flow channel always remain axially aligned.

[0017] By setting an anti-rotation boss or anti-rotation pin that protrudes inward along the axial direction on the sealing sheet, and setting an anti-rotation positioning groove on the first and second inserts; the anti-rotation boss or anti-rotation pin is fitted into the anti-rotation positioning groove to form a circumferential locking structure with concave and convex engagement, which effectively prevents the sealing sheet from circumferentially deflecting during the tightening and pressing process of the sealing screw sleeve, ensuring that the through hole on the sealing sheet and the second flow channel always remain axially aligned, thus ensuring the stability of the flow channel area and the operational reliability of the cooling system.

[0018] Preferably, the through holes on the sealing sheet are a plurality of small circular holes arranged in an eccentric region. The sum of the flow cross-sectional area of ​​the first flow guide and the flow cross-sectional area of ​​the second flow guide is the total inflow cross-sectional area. The total flow cross-sectional area of ​​the plurality of small circular holes is smaller than the total inflow cross-sectional area, and the ratio of the total inflow cross-sectional area to the total flow cross-sectional area is in the range of 1.3-2.1. By asymmetrically reducing the flow area, a local throttling damping is constructed at the return end of the second flow channel, converting the fluid dynamic pressure of the coolant into static pressure, thereby establishing a reverse back pressure gradient in the second flow channel, keeping the coolant operating pressure in the first flow channel above the critical vaporization pressure of the coolant; at the same time, a secondary disturbance vortex is induced at the outlet end of the second flow channel near the sealing plate, eliminating the thermal dead zone at the sealing end; The static pressure established by the reverse back pressure gradient is matched with the capillary suction pressure of the capillary microporous layer: the reverse back pressure gradient inhibits the macroscopic boiling of the coolant and prevents local vapor film from blocking the micropores of the capillary microporous layer; the capillary microporous layer maintains continuous wetting of the wall surface of the first flow channel through capillary wicking; the reverse back pressure gradient and the capillary microporous layer work together to inhibit local film boiling and wall drying.

[0019] By designing the through holes on the sealing plate as multiple small circular holes concentrated in the eccentric region, and controlling the ratio of the total inlet cross-sectional area to the total outlet cross-sectional area within the range of 1.3-2.1, local throttling damping is constructed at the return end of the second flow channel. Through the asymmetric reduction design of the flow area, the fluid dynamic pressure of the coolant is converted into static pressure, and a reverse back pressure gradient is established in the second flow channel, so that the operating pressure of the coolant in the first flow channel is kept above the critical vaporization pressure of the coolant, thus suppressing the macroscopic boiling of the coolant. At the same time, secondary disturbance eddies are induced at the outlet end of the second flow channel near the sealing plate, eliminating the thermal dead zone at the sealing end and improving the heat exchange effect in the end region. The static pressure established by the reverse back pressure gradient is matched with the capillary suction pressure of the capillary microporous layer; the reverse back pressure gradient inhibits macroscopic boiling of the coolant and prevents local vapor film from blocking the micropores of the capillary microporous layer; the capillary microporous layer maintains continuous wetting of the wall of the first flow channel through capillary wicking, and continuously provides coolant to the heat exchange interface; the reverse back pressure gradient and the capillary microporous layer work together to inhibit local film boiling and wall drying, achieving better phase change cooling stability and heat exchange efficiency than a single mechanism.

[0020] Preferably, the sealing sheet is provided with a variable cross-section throttling tongue that deforms with temperature at the edge region of at least one of the plurality of small round holes. The variable cross-section throttling tongue is a bimetallic sheet or a shape memory alloy sheet. The variable cross-section throttling tongue is fixedly connected to or embedded in the sealing sheet. When the coolant temperature at the outlet of the second flow channel rises, the variable cross-section throttling tongue deflects inward toward the inner side of the corresponding small circular hole, reducing the effective flow cross-sectional area of ​​the corresponding small circular hole, thereby increasing the reverse back pressure gradient. At the same time, the static pressure of the coolant in the first and second flow channels increases, suppressing the local boiling of the coolant under high heat load, and keeping the heat exchange in the first flow channel within the nucleus boiling range, thus forming a self-reinforcing negative feedback protection loop that increases with heat load. When the temperature of the coolant drops, the variable cross-section throttling tongue resets, and the effective flow cross-sectional area of ​​the corresponding small circular orifice recovers. The ratio of the thickness of the variable cross-section throttling tongue to the average diameter of the plurality of small circular holes is in the range of 0.04-0.09.

[0021] By setting a variable cross-section throttling tongue that deforms with temperature in the edge region of at least one small circular hole in the sealing plate, when the coolant temperature at the outlet end of the second flow channel rises, the variable cross-section throttling tongue deflects inward towards the small circular hole, reducing the effective flow cross-sectional area of ​​the small circular hole, increasing the reverse back pressure gradient, and raising the static pressure of the coolant in the first and second flow channels. This suppresses local boiling of the coolant under high heat load, keeping the heat exchange in the first flow channel within the nucleation boiling range, thus forming a self-reinforcing negative feedback protection loop that depends on the heat load. When the coolant temperature drops, the variable cross-section throttling tongue resets, and the effective flow cross-sectional area recovers. By controlling the ratio of the variable cross-section throttling tongue thickness to the average hole diameter within the range of 0.04-0.09, the tongue has sufficient deformation sensitivity and structural strength.

[0022] Preferably, the outer surface of the separator is provided with a microrib array structure, the microrib array structure including a plurality of microribs obliquely distributed along the outer surface of the separator, and two adjacent microribs are arranged in an alternating pattern where one end converges and approaches each other, and the other end diverges and opens outward, forming a periodic flow guiding unit continuously arranged on the outer surface of the separator. The tilt angle of the microribs relative to the axis of the separator, the axial arrangement period of the periodic flow guiding unit, and the liquid supply phase difference form a linked limiting relationship, specifically: Under accelerated cooling conditions, the coolant jet entering the first flow channel through the second guide port falls into the fluid reattachment zone defined by the periodic guide unit at the boundary layer peeling point induced on the wall of the first flow channel. This allows the micro-rib array to receive and amplify the disturbance energy of the coolant jet, triggering localized boundary layer peeling and turbulent abrupt changes in the coolant, thereby reducing fluid friction resistance and improving the solid-liquid interface heat transfer efficiency.

[0023] By setting multiple inclined microribs on the outer surface of the separator, adjacent microribs are arranged in an alternating pattern with one end converging towards each other and the other end diverging outwards, forming a periodic flow guiding unit. The convergent-divergent microrib array generates periodic contraction-expansion disturbances in the fluid, triggering local stripping and reattachment of the fluid boundary layer, enhancing the turbulent mixing degree of the fluid, and improving the heat transfer efficiency of the solid-liquid interface while reducing fluid friction resistance. By linking the tilt angle of the microribs, the axial arrangement period of the periodic flow guiding unit, and the liquid supply phase difference, under accelerated cooling conditions, the coolant jet entering the first flow channel through the second guide port falls into the fluid reattachment zone defined by the periodic flow guiding unit at the boundary layer stripping point induced on the first flow channel wall. The microrib array receives and amplifies the disturbance energy of the coolant jet, triggering local stripping and turbulent change of the coolant boundary layer, realizing the synergistic enhancement of heat transfer by jet disturbance and microrib structure.

[0024] Preferably, under basic cooling conditions, coolant is supplied to the first flow channel only through the second liquid guiding channel and the second flow guide port, and the coolant in the first flow channel maintains a first flow state; Under accelerated cooling conditions, coolant is simultaneously supplied to the first flow channel through the first and second liquid guiding channels. The two coolant streams converge and interfere within the axial section defined by the supply phase difference, triggering a nonlinear transition of the coolant in the first flow channel from the first flow state to the second flow state. The turbulence intensity of the second flow state is higher than that of the first flow state, resulting in an increase in the interface heat transfer coefficient greater than the increase in the total coolant flow rate. The coolant in the first flow channel is discharged through the second flow channel and the through hole, constructing an adjustable cooling circulation channel. The ratio of the liquid supply phase difference to the hydraulic diameter of the first flow channel is in the range of 0.8-2.4, so that the convergence interference intensity of the two coolant streams in the axial section is sufficient to trigger a nonlinear transition from the first flow state to the second flow state.

[0025] By supplying coolant to the first flow channel only through the second liquid guiding channel and the second guide port under basic cooling conditions, the coolant in the first flow channel maintains the first flow state, meeting conventional cooling requirements and reducing pumping energy consumption. Under accelerated cooling conditions, coolant is supplied to the first flow channel simultaneously through the first and second liquid guiding channels. The two coolant streams converge and interfere within the axial section limited by the phase difference of the supply, triggering a nonlinear transition of the coolant in the first flow channel from the first flow state to the second flow state. The turbulence intensity of the second flow state is higher than that of the first flow state, resulting in an increase in the interfacial heat transfer coefficient greater than the increase in the total coolant flow rate, thus achieving highly efficient and enhanced heat transfer. The coolant in the first flow channel is discharged through the second flow channel and the guide hole, constructing an adjustable cooling circulation channel, realizing on-demand adjustment of cooling intensity. By controlling the ratio of the liquid supply phase difference to the hydraulic diameter of the first flow channel within the range of 0.8-2.4, the convergence interference intensity of the two coolant streams in the axial section is sufficient to trigger the nonlinear transition from the first flow state to the second flow state, ensuring the reliable triggering of the flow state transition mechanism and the stable realization of the enhanced heat transfer effect.

[0026] The beneficial effects of the present invention include at least the following: (1) By staggering the first and second guide ports along the axial direction to form a liquid supply phase difference, the two coolants converge and interfere in the staggered section under the cooling condition, triggering the nonlinear transition of the flow state in the first flow channel. The increase in heat transfer coefficient is greater than the increase in flow rate, breaking the inherent understanding in the field that "enhancing heat transfer must proportionally increase flow rate and pump power consumption", realizing the reconfigurable control of cooling intensity according to the working condition and reducing the energy consumption of the circulating pump.

[0027] (2) By degreasing micro-nano channels in the flow channel wall through metal injection molding process, the process pores that are considered defects in the field are transformed into functional capillary micropore layers, which form a symbiotic relationship with the reverse back pressure gradient established by the sealing sheet throttling: the reverse back pressure gradient prevents the vapor film from blocking the micropores, and the capillary micropore layer maintains the wall wetting through wicking. The two work together to significantly increase the initial heat flux density of local film boiling, and the other element will fail when either element is missing.

[0028] (3) The radial temperature gradient driven by the aging heat treatment strengthens the precipitation of the phase gradient, with high thermal conductivity in the near-wall region and high toughness in the core region. This achieves radial decoupling of heat transfer performance and torsional mechanical properties within a single material system, thus breaking the long-standing contradiction between heat transfer and load bearing in this field.

[0029] (4) By using composite ultrasonic vibration to assist assembly and sonic orientation curing of thermosensitive expansion crosslinking adhesive, the assembly process parameters directly determine the micro-orientation of the adhesive layer, and the micro-orientation of the adhesive layer directly determines the anti-torsion sealing performance, forming a three-scale causal chain of process, microstructure and macro performance, so that the adhesive interface, which is considered to inevitably fail under rotating conditions, becomes a controlled damping energy dissipation sealing element.

[0030] 5) By forming a negative feedback protection loop that is self-reinforcing with the heat load through the variable cross-section throttling tongue, it can automatically increase the static pressure of the flow channel and suppress the boiling crisis under high heat load without the need for external sensors and controllers. Together with the dual-channel active switching, it forms a dual-loop thermal management that combines active and passive functions.

[0031] (6) By interlocking the parameters of the tilt angle, arrangement period and liquid supply phase difference of the micro-rib array, the jet boundary layer stripping point falls into the reattachment zone of the guide unit, thereby reducing frictional resistance and further improving the interface heat transfer efficiency.

[0032] (7) By resisting the frictional torque when the sealing threaded sleeve is tightened through the anti-rotation structure, the axial alignment accuracy between the through hole and the second flow channel is guaranteed, and the reliability of the end seal can be repeatedly assembled is improved. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the exploded structure of the present invention.

[0034] Figure 2 This is a schematic diagram of the structure of the present invention.

[0035] Figure 3 This is a schematic diagram of the structure of the shaft of the present invention.

[0036] Figure 4 This is a schematic diagram of the structure of the separator of the present invention.

[0037] Figure 5 This is a schematic diagram of the nested structure of the present invention.

[0038] Figure 6 This is a schematic diagram of the structure of the sealing sheet of the present invention.

[0039] The reference numerals in the figures include: 1. Shaft; 11. Blind hole; 12. Limiting groove; 14. First recessed platform; 15. Second recessed platform; 2. Separator; 21. First flow channel; 22. Second flow channel; 23. First liquid guiding channel; 24. Second liquid guiding channel; 25. First guide port; 26. Second guide port; 27. Mating surface; 28. First mating part; 29. ​​Limiting step; 3. Inner nesting; 31. First insert; 32. Second insert; 33. Anti-rotation positioning groove; 4. Sealing plate; 41. Through hole; 42. Anti-rotation boss; 43. Variable cross-section throttling tongue; 5. Sealing screw sleeve. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0043] like Figures 1 to 6 As shown, Example 1: Basic manufacturing process of microchannel cooling drive shaft.

[0044] Step 1: Manufacturing shaft 1. A blank for shaft 1 is prepared by machining. Shaft 1 has a total length of 280mm and an outer diameter of 28mm. A blind hole 11 is drilled axially from one end of shaft 1. The diameter of the blind hole 11 is 8mm and the depth is 240mm. Two symmetrically spaced grooves 12 are machined axially on the inner wall of the blind hole 11. The grooves 12 have a width of 2mm, a depth of 1mm, and a length of 210mm. A first countersunk platform 14 and a second countersunk platform 15, eccentrically arranged, are milled at the ends of shaft 1 corresponding to the openings of the blind hole 11. The first countersunk platform 14 and the second countersunk platform 15 are symmetrically and eccentrically arranged with respect to the axis of the blind hole 11. By machining a blind hole 11 inward at the end of the solid shaft 1, an internal cavity space for the cooling medium to be contained and flow is formed; by machining a limiting groove 12 along the axial direction on the inner wall of the blind hole 11, a circumferential positioning reference and an axial guide track are provided for the subsequent separator 2, so that the separator 2 can automatically complete the circumferential positioning simply by pushing it in along the axial direction, thereby achieving high-precision assembly positioning of the flow channel separation structure and avoiding the problem of uneven flow channel cross-sectional area caused by the skewness of the traditional central tube insertion method.

[0045] Step 2: Assemble the separator 2 and the inner nest 3. The separator 2 is a semi-cylindrical stainless steel insert with an outer diameter of 7.8 mm and a length of 215 mm. The plane side of the separator 2 is provided with a mating surface 27 and a first mating part 28. A limiting step 29 is provided between the mating surface 27 and the first mating part 28. The separator 2 is pushed axially into the blind hole 11 along the limiting groove 12. The first mating part 28 slides in the limiting groove 12. The mating surface 27 abuts against the inner wall of the blind hole 11. The separator 2 divides the blind hole 11 into a first flow channel 21 and a second flow channel 22. The first flow channel 21 and the second flow channel 22 are connected at the bottom of the blind hole 11 to form a connection. Then, the first insert 31 and the second insert 32 are respectively installed into the first recess 14 and the second recess 15. The first insert 31 and the second insert 32 abut against the limiting step 29, thus confining the separator 2 within the blind hole 11. The outer wall of the separator 2 and the inner wall of the blind hole 11 are in contact and fit together to form a sealed and reliable flow channel interface, dividing the inner cavity of the blind hole 11 into two independent flow channels 21 and 22 along the axial direction. The two flow channels are connected at the bottom of the blind hole 11 to form a U-shaped cooling circuit, which extends the flow path of the coolant in the blind hole 11 to nearly twice the depth of the blind hole 11, so as to achieve uniform heat exchange throughout the entire axial section of the shaft 1. The inner nest 3 is inserted from the end of the shaft 1 and abuts against the end of the separator 2, clamping the separator 2 from both ends with the bottom of the blind hole 11, restricting the axial movement of the separator 2 under the pressure impact of the coolant, and ensuring that the cross-sectional area of ​​the first flow channel 21 and the second flow channel 22 is constant.

[0046] The separator 2 has a first liquid guiding channel 23 and a second liquid guiding channel 24 inside. The side wall of the separator 2 has a first flow port 25 communicating with the first liquid guiding channel 23 and a second flow port 26 communicating with the second liquid guiding channel 24. The first flow port 25 and the second flow port 26 are arranged axially offset to form a liquid supply phase difference: the distance from the center of the first flow port 25 to the connection point is 35mm, the distance from the center of the second flow port 26 to the connection point is 41.6mm, and the liquid supply phase difference is 6.6mm. The cross-section of the first flow channel 21 is semi-circular, the hydraulic diameter is 4.1mm, and the ratio of the liquid supply phase difference to the hydraulic diameter is 1.6, which is within the range of 0.8-2.4. By integrating the first liquid guiding channel 23 and the second liquid guiding channel 24 inside the separator 2, the inlet and outlet channels are built into the separator 2, making the cooling structure of the drive shaft highly integrated; by setting the first flow port 25 near the bottom connection of the blind hole 11 and the second flow port 26 away from the connection and near the end of the shaft 1, the inlet and outlet are made to form a phase difference in the axial direction, and the coolant flow path covers the entire axial length of the blind hole 11, so as to achieve sufficient and uniform heat exchange in each section of the shaft 1.

[0047] Step 3, sealing assembly. Place the sealing plate 4 with the through hole 41 at the end of the shaft 1 and abut against the inner nest 3. The anti-rotation boss 42 protruding inward along the axial direction on the sealing plate 4 is fitted into the anti-rotation positioning groove 33 on the first insert 31 and the second insert 32, locking the sealing plate 4 and the inner nest 3 into abutment state. The through hole 41 and the second flow channel 22 are axially aligned and connected. Tighten the sealing sleeve 5 that is threaded to the shaft 1. The sealing sleeve 5 is pressed against the outside of the sealing plate 4. The engagement of the anti-rotation boss 42 and the anti-rotation positioning groove 33 resists the frictional torque applied to the sealing plate 4 during tightening, preventing the sealing plate 4 from circumferentially deflecting, and ensuring that the through hole 41 and the second flow channel 22 remain axially aligned throughout the tightening process. The end opening of the blind hole 11 is blocked by the sealing plate 4, and the through hole 41 on the sealing plate 4 is connected to the second flow channel 22 to realize the flow of coolant. The anti-rotation structure locks the circumferential relative position of the sealing plate 4 and the inner nest 3 in a concave-convex meshing manner. The axial clamping force is provided by the threaded connection between the sealing sleeve 5 and the shaft 1 to ensure the reliability of the end seal. The anti-rotation structure resists the circumferential friction torque during the tightening process, prevents the sealing plate 4 from circumferentially deflecting, and ensures that the through hole 41 and the second flow channel 22 are always accurately aligned.

[0048] During cooling operation, under basic cooling conditions, coolant (in this embodiment, a 50% volume fraction ethylene glycol aqueous solution) is supplied to the first flow channel 21 only through the second liquid guiding channel 24 and the second flow guide port 26. The coolant maintains a gentle first flow state, meeting the heat dissipation requirements below the rated operating conditions of the motor. Under accelerated cooling conditions (when the motor is overloaded or the ambient temperature exceeds the threshold), coolant is supplied to the first flow channel 21 simultaneously through the first liquid guiding channel 23 and the second liquid guiding channel 24. The two coolants converge and interfere in the axial section (the section from 35mm to 41.6mm upstream of the connection point) defined by the phase difference of the supply, triggering a nonlinear transition of the coolant in the first flow channel 21 from the first flow state to the second flow state. The turbulence intensity of the second flow state is higher than that of the first flow state. The coolant in the first flow channel 21 is discharged through the second flow channel 22 and the through hole 41, forming an adjustable cooling circulation channel. By maintaining the first flow state under basic operating conditions with single-channel liquid supply to meet conventional cooling requirements and reduce pumping energy consumption, and accelerating the nonlinear transition of the flow state triggered by the convergence and interference of dual-channel liquid supply in the liquid supply phase difference section under accelerated operating conditions, the increase in interface heat transfer coefficient is greater than the increase in total coolant flow rate, thereby achieving on-demand adjustment of efficient heat transfer and cooling intensity.

[0049] Example 2: Metal injection molding integrally prepares shafts and retains the orientation of the capillary micropore layer.

[0050] The first step is mixing and granulation. Spherical metal powder with an average particle size of 12 micrometers (within the range of 5-18 micrometers) is prepared by high-purity argon atomization. The powder formulation by mass percentage is: Cr 14.5%, Ni 7.0%, Al 3.0%, Mo 1.6%, Cu 2.0%, Nb and Ti total 0.45%, Si 0.6%, and the balance Fe. The metal powder is then mixed with a binder at a mass ratio of 90:10. The binder formulation by mass percentage is: oligoisobutylene 40%, cyclic olefin copolymer 28%, amphiphilic microcrystalline beeswax 15%, fatty alcohol polyoxyethylene ether phosphate 6%, and azobisisobutyronitrile 1%. The mixture is preheated and stirred in a closed mixer at a mixing temperature of 150℃, a rotation speed of 55 r / min, and a mixing time of 3 hours. After cooling, the mixture is crushed to obtain the metal feedstock. By using gas atomization to prepare spherical metal powder, the powder is guaranteed to have good flowability and filling density. By designing a multi-element iron-based alloy formula, the sintered material has both high strength, corrosion resistance and aging strengthening potential. By mixing the metal powder with a specific ratio of binder at a set temperature, the binder can uniformly coat the metal powder particles, resulting in a uniform metal feed.

[0051] The second step is injection molding. Metal feedstock is injected into the barrel of a precision injection molding machine. The barrel injection temperature is 170℃, the injection pressure is 110MPa, and the mold temperature is controlled at 55℃. After pressure holding and cooling, a green shaft blank with blind holes 11 and limiting grooves 12 is integrally formed. By injecting metal feedstock into the mold cavity under set temperature and pressure, the feedstock fills the mold and cools and solidifies, resulting in a green shaft blank containing blind holes 11 and limiting grooves 12. This achieves near-net-shape forming of complex internal hole structures, avoiding the process difficulties and material waste associated with traditional machining methods for deep holes and internal grooves.

[0052] The third step involves in-situ micro-foaming and water-based extraction degreasing. The green shaft blank is immersed in a slightly alkaline aqueous washing solution (pH 8.5-9.5) at 70°C. The azobisisobutyronitrile decomposes upon heating, releasing nitrogen gas and forming directional micro / nano exhaust channels in situ within the blank. The aqueous slightly alkaline washing solution is then introduced into blind holes 11 through their openings, resulting in a higher degree of extraction and degreasing in the surface region of the inner wall of blind holes 11 (depth range 0-200 micrometers) and a higher distribution density of directional micro / nano exhaust channels compared to the core region of the shaft. After 110 minutes of washing and extraction degreasing, approximately 72% of the oligomeric isobutylene and amphiphilic microcrystalline beeswax are dissolved and removed, yielding a porous shaft blank. Inert gases are released by the thermal decomposition of azobisisobutyronitrile (AIBN), forming directional micro-nano exhaust channels in situ inside the green body. An aqueous slightly alkaline washing solution is then immersed into the inner wall of blind hole 11 through the opening, making the extraction and degreasing degree of the surface area of ​​the inner wall of blind hole 11 and the distribution density of directional micro-nano exhaust channels greater than those in the core area of ​​shaft 1. This achieves the prefabrication of the surface-core gradient pore structure, laying the foundation for the subsequent sintering to directionally retain the capillary micropore layer.

[0053] The fourth step involves slightly positive pressure hot degreasing and pre-sintering. In a furnace with a slightly positive pressure argon atmosphere (furnace pressure 1.05-1.10 times atmospheric pressure), the dried shaft blank is hot-degreased at 450℃ at a rate of 2℃ / min and held for 120 minutes; then, it is heated to 850℃ at a rate of 10℃ / min for dense pre-sintering for 90 minutes to obtain a high-strength pre-sintered blank. Slow heating under slightly positive pressure for hot degreasing removes residual binder gradually and prevents cracking and deformation of the green blank; rapid heating for dense pre-sintering allows the powder particles to initially metallurgically bond, forming a high-strength pre-sintered blank with a certain strength, providing structural support for subsequent high-temperature sintering and preventing deformation and collapse of the blank during the high-temperature sintering process.

[0054] The fifth step involves high-temperature densification sintering and toughening aging. This is done in a vacuum sintering furnace (vacuum degree better than 5×10⁻⁶). - 3In the process of sintering, the high-strength pre-sintered blank is heated to 1310℃ at a rate of 6℃ / min and held for 170 minutes; then, aging heat treatment is completed at 490℃. Since the distribution density of directional micro-nano exhaust channels in the surface region of the inner wall of blind hole 11 is greater than that in the core region, the core region achieves full densification during the sintering densification process (measured relative density 98.6%), while the directional micro-nano exhaust channels in the surface region of the inner wall of blind hole 11 are directionally retained, forming a capillary microporous layer with a thickness of about 80-150 micrometers and a porosity of about 15%. The capillary microporous layer covers the wall surface of the first flow channel 21 and the wall surface of the second flow channel 22, and its porosity decreases to zero along the radial direction of the shaft from the inner wall of blind hole 11 to the core region. High-temperature sintering achieves complete densification of the core region, while the directional micro-nano exhaust channels in the inner wall surface region of the blind hole 11 are directionally preserved, forming a capillary microporous layer covering the walls of the first flow channel 21 and the second flow channel 22. Aging heat treatment causes in-situ precipitation of nano-sized nickel-aluminum intermetallic compounds and nano-copper-containing reinforcing phases in the matrix, achieving material toughness. The capillary microporous layer maintains continuous wetting of the flow channel walls through capillary wicking, further enhancing the heat transfer effect.

[0055] During the aging heat treatment, a resistance heating mandrel was inserted into the blind hole 11 to assist heating the surface region of the inner wall of the blind hole, making the aging temperature of the surface region 25-40℃ higher than that of the core region. Due to the radial difference in aging temperature, nano-sized nickel-aluminum intermetallic compounds (Ni3Al, average particle size 18nm) and nano-sized copper-containing reinforcing phases (ε-Cu, average particle size 9nm) were enriched and precipitated in the surface region of the inner wall of the blind hole, while being depleted and precipitated in the core region. Energy dispersive spectroscopy (EDS) characterization showed that the enrichment of Ni and Al elements in the near-wall region (0-1mm) was 1.8 times that in the core region. The measured thermal conductivity of the surface region of the inner wall of the blind hole was 27.5 W / (m·K), while that of the core region was 21.0 W / (m·K). The impact toughness of the core region remained at 62 J / cm². 2 The overall torsional yield strength of the shaft reaches 1120 MPa, achieving radial decoupling of heat transfer performance and torsional mechanical properties. A radial temperature gradient is created by auxiliary heating of the inner wall surface region of the blind hole 11 during aging, driving the enrichment of the nano-reinforcing phase on the surface and its depletion in the core, forming a reinforcing phase structure with a radial gradient distribution. The enrichment of the surface reinforcing phase improves the thermal conductivity, while the depletion of the core reinforcing phase preserves the matrix toughness, achieving radial decoupling of the heat transfer performance and torsional mechanical properties of the shaft 1.

[0056] The through holes 41 on the sealing sheet 4 consist of six small circular holes arranged in an eccentric region. The diameter of each small circular hole is 1.2 mm, and the total flow cross-sectional area is 6.8 mm². 2 The sum of the cross-sectional areas of the first guide port 25 and the second guide port 26 (total inlet cross-sectional area) is 11.5 mm. 2The ratio of the total inlet cross-sectional area to the total flow cross-sectional area is 1.7, falling within the range of 1.3-2.1. When the coolant flows through the small circular hole, the flow area decreases asymmetrically, creating local throttling damping at the return end of the second flow channel 22. The fluid dynamic pressure is converted into static pressure, establishing a reverse back pressure gradient within the second flow channel 22, keeping the coolant operating pressure in the first flow channel 21 above the critical vaporization pressure. The reverse back pressure gradient inhibits macroscopic boiling of the coolant, preventing local vapor film from blocking the micropores of the capillary micropore layer. The capillary micropore layer maintains continuous wetting of the wall surface of the first flow channel 21 through capillary wicking (measured capillary suction pressure of approximately 3.2 kPa). The two work together to inhibit local film boiling and wall drying, while simultaneously inducing secondary turbulent eddies at the outlet end of the second flow channel 22 near the sealing plate 4, eliminating the thermal dead zone at the sealing end. A reverse back pressure gradient is established by asymmetrically reducing the flow area to suppress macroscopic boiling of the coolant. The reverse back pressure gradient is matched with the capillary suction pressure of the capillary micropore layer to synergistically suppress local film boiling and wall drying, achieving better phase change cooling stability and heat transfer efficiency than a single mechanism.

[0057] As a preferred embodiment of Example 2, the metal powder formulation and process parameters are further optimized within the parameter range defined in Example 2 to obtain higher capillary microporous layer porosity and better corrosion resistance. In the first sub-step, spherical metal powder is prepared by high-purity argon atomization, with an average particle size of 8 micrometers (fineer than 12 micrometers in Example 2, resulting in higher sintering activity); the powder formulation by mass percentage is: Cr 15.2%, Ni 7.8%, Al 2.5%, Mo 1.9%, Cu 2.4%, total Nb and Ti 0.55%, Si 0.7%, and the balance being Fe. Compared to Example 2, this preferred embodiment increases the Cr content to near the upper limit (15.2% vs 14.5%), the Ni content to 7.8% (vs 7.0%), the Cu content to 2.4% (vs 2.0%), and decreases the Al content to 2.5% (vs 3.0%). Increasing the Cr and Ni content enhances the matrix's resistance to pitting and general corrosion, increasing the Cu content provides more ε-Cu precipitation sources during the aging stage to reduce the interphase spacing, and decreasing the Al content avoids the toughness degradation caused by excessive brittle Ni3Al precipitation. The metal powder and binder are blended at a mass ratio of 88:12 (90:10 in Example 2). The binder formulation, by mass percentage, is: 44% oligoisobutylene, 26% cyclic olefin copolymer, 13% amphiphilic microcrystalline beeswax, 7.5% fatty alcohol polyoxyethylene ether phosphate, and 1.5% azobisisobutyronitrile. Compared to Example 2, this preferred embodiment increases the azobisisobutyronitrile (AIB) content to the upper limit of 1.5% (vs. 1.0%), resulting in denser directional micro / nano exhaust channels during the foaming stage; increases the oligomeric isobutylene content to 44% (vs. 40%), resulting in a faster surface dissolution rate during the extraction stage and a more significant degreasing gradient between the surface and the core; and increases the fatty alcohol polyoxyethylene ether phosphate content to 7.5% (vs. 6%), improving the interfacial wetting uniformity between the metal powder and the binder. The mixing temperature is 140°C, the rotation speed is 48 r / min, and the mixing time is 3.2 hours.

[0058] In the second step, the injection temperature was 162℃, the injection pressure was 135MPa (higher than 110MPa in Example 2), and the mold control temperature was 45℃. The higher injection pressure resulted in a higher initial packing density of the green shaft blank, which is beneficial for obtaining a higher core density during subsequent sintering. In the third step, the green shaft blank was immersed in an aqueous slightly alkaline washing solution (pH 8.5-9.5) at 78℃ for 90 minutes for cleaning, extraction, and degreasing (70℃ and 110 minutes in Example 2). The higher extraction temperature combined with the shorter extraction time made the degreasing reaction in the surface area of ​​the inner wall of the blind hole 11 more intense, further widening the difference in the degree of extraction and degreasing between the surface and the core, and further increasing the distribution density of directional micro-nano exhaust channels in the surface area. After leaching and removing approximately 75% of the oligomeric isobutylene and amphiphilic microcrystalline beeswax, a shaft brown blank with a more significant pore gradient was obtained. In the fourth step, in a furnace with a slightly positive pressure argon atmosphere, the dried shaft blank is heated to 465℃ at 1.8℃ / min for hot degreasing and held for 110 minutes; then heated to 870℃ at 11℃ / min for dense pre-sintering for 75 minutes to obtain a high-strength pre-sintered blank.

[0059] In the fifth sub-step, in a vacuum sintering furnace (vacuum degree better than 5×10⁻⁶), -3In the process of sintering, the high-strength pre-sintered blank was heated to 1340℃ at a rate of 5℃ / min and held for 190 minutes; subsequently, aging heat treatment was performed at 510℃. The higher sintering temperature (1340℃ vs. 1310℃ in Example 2) combined with a longer holding time (190 minutes vs. 170 minutes) resulted in more thorough densification of the core region, with a measured core relative density of 99.2% (98.6% in Example 2). Due to the higher density of directional micro-nano exhaust channels and the higher azobisisobutyronitrile content (1.5% vs. 1.0%) in the surface region of the inner wall of blind hole 11, more directional micro-nano exhaust channels were retained during the sintering densification process, forming a capillary microporous layer with a thickness of approximately 100-180 micrometers (80-150 micrometers in Example 2) and a porosity of approximately 22% (approximately 15% in Example 2). The measured capillary suction pressure was approximately 5.1 kPa (approximately 3.2 kPa in Example 2). During the aging heat treatment, a resistance heating mandrel is inserted into the blind hole 11 to provide auxiliary heating to the surface region of the inner wall of the blind hole, making the aging temperature of the surface region of the inner wall of the blind hole 25-40℃ higher than that of the core region. The higher content of Ni and Al causes the nano-sized nickel-aluminum intermetallic compound (Ni3Al, average particle size 14nm, 18nm in Example 2) to be more densely enriched and precipitated in the surface region of the inner wall of the blind hole; the higher content of Cu causes the precipitation density of the nano-copper-containing reinforcing phase (ε-Cu, average particle size 7nm, 9nm in Example 2) to be higher. Energy dispersive spectroscopy (EDS) characterization showed that the enrichment of Ni and Al elements in the near-wall region (0-1 mm) was 2.1 times that in the core region (1.8 times in Example 2). The measured thermal conductivity of the surface region of the blind hole inner wall was 29.8 W / (m·K) (27.5 W / (m·K) in Example 2), and the thermal conductivity of the core region was 22.5 W / (m·K) (21.0 W / (m·K) in Example 2). The impact toughness of the core region remained at 65 J / cm. 2 The above (62 J / cm² in Example 2) 2 The overall torsional yield strength of the shaft reaches 1185MPa (1120MPa in Example 2).

[0060] Compared with Example 2, the differentiated technical effects of this preferred embodiment are mainly reflected in the following aspects: First, the porosity of the capillary microporous layer is increased from 15% to 22%, the capillary suction pressure is increased from 3.2 kPa to 5.1 kPa, and the wall wetting maintenance ability is significantly enhanced at 22 W / cm². 2 The initial heat flux density for film boiling under high heat load is further increased to 31 W / cm². 2 (Example 2 is 26W / cm) 2First, the phase change cooling safety margin is increased by 19%. Second, due to the increase in Cr content to 15.2%, Ni content to 7.8%, and Mo content to 1.9%, the corrosion resistance of the matrix is ​​significantly improved. In the accelerated corrosion test (85°C, 500 hours) by immersion in 50% ethylene glycol aqueous solution, the annual corrosion rate of the sample of this preferred scheme is 0.008 mm / year, which is 47% lower than that of the sample of Example 2 (0.015 mm / year), making it more suitable for long-term coolant immersion conditions. Third, the powder particle size is refined from 12 micrometers to 8 micrometers, the sintering temperature is increased from 1310°C to 1340°C, and the core relative density is increased from 98.6% to 99.2%. Combined with finer Ni3Al (14nm vs 18nm) and ε-Cu (7nm vs 9nm) precipitates, the torsional yield strength is increased from 1120MPa to 1185MPa, while the impact toughness is increased from 62J / cm. 2 Increased to 65J / cm 2 This achieves a simultaneous improvement in both strength and toughness.

[0061] Example 3: Ultrasonic vibration-assisted assembly and acoustic orientation curing of thermosensitive expansion crosslinking adhesive.

[0062] The step of installing the first insert 31 and the second insert 32 into the first sinker 14 and the second sinker 15 respectively adopts an ultrasonic vibration-assisted assembly process: the assembly tool head applies high-frequency vibration to the insert, which is composed of a 20kHz axial vibration component (amplitude 12 micrometers) and a 35kHz circumferential vibration component (amplitude 8 micrometers); during the assembly process, the high-frequency vibration generates nonlinear acoustic radiation pressure and dynamic deflection of friction vector in the assembly micro-gap (designed fit gap 0.02-0.04mm) between the insert and the inner wall of the sinker, driving the first insert 31 and the second insert 32 to produce suspension micro-movement and self-alignment within the sinker, converting axial sliding friction into circumferential high-frequency sliding. The assembly thrust is reduced from 850N in conventional press fitting to about 120N, without any skewing or jamming. By employing high-frequency ultrasonic vibration-assisted assembly with a combination of axial and circumferential vibration components, nonlinear acoustic radiation pressure and dynamic deflection of friction vectors are generated within the assembly gaps. This drives the insert to generate suspended micro-motion and self-alignment, converting axial sliding friction into circumferential high-frequency sliding. This prevents skewness and jamming during deep hole assembly, significantly improving the assembly accuracy and efficiency of nested deep holes.

[0063] After the separator 2 and the inner nest 3 are assembled in place, a thermosensitive expansion crosslinking adhesive (epoxy-carboxyl-terminated butadiene-acrylonitrile rubber system containing 8% thermal expansion microspheres by volume) is injected into the assembly gap between the limiting groove 12 and the first mating part 28 through the limiting groove 12. Under the condition of continuing to apply the above-mentioned high-frequency vibration, it is heat-cured at 120°C for 30 minutes. The nonlinear acoustic radiation pressure generated by the high-frequency vibration in the adhesive drives the adhesive molecular chains to be oriented along the acoustic flow direction. After heat curing, a fibrous oriented network crosslinking structure is formed. The main direction of the fibrous orientation forms an angle of 45°-90° with the circumference of the shaft 1. After curing, an oriented crosslinking adhesive layer is formed to fill the assembly gap (curing volume expansion rate of about 6%, which just fills the gap), forming an intermediate interface with directional shear resistance, torsional damping and secondary static sealing functions. By injecting thermosensitive expansion crosslinking adhesive into the assembly gap and curing it under high-frequency vibration, the crosslinking adhesive molecular chains are oriented along the direction of acoustic flow, forming a fibrous oriented network crosslinking structure, which effectively resists the circumferential shearing force transmitted to the assembly gap when the sealing sleeve 5 is tightened; the cured oriented crosslinking adhesive layer has three functions: directional shear resistance, torsional damping and secondary static sealing, further improving the reliability and sealing performance of the assembly structure.

[0064] Comparative tests show that the same formulation adhesive layer (with isotropic random orientation of molecular chains) without ultrasonic vibration curing only retains 54% of its shear strength after 100 circumferential shear cycles simulating the tightening of the sealing sleeve; while the orientation cross-linked adhesive layer in this embodiment retains 93% of its shear strength after the same cycle, and the damping loss factor increases from 0.08 to 0.21, verifying the three-scale causal chain between assembly process parameters, micro-orientation of the adhesive layer, and macroscopic torsional sealing performance.

[0065] Example 4: Negative feedback protection circuit composed of variable cross-section throttling tongue.

[0066] The sealing plate 4 has two small circular holes arranged opposite each other on the edge area of ​​the sealing plate 4, which are respectively fitted with variable cross-section throttling tongues 43 that deform with temperature. The variable cross-section throttling tongues 43 are bimetallic sheets, with the active layer material being Mn75Ni15Cu10 high expansion alloy and the passive layer material being Ni36 Invar alloy. The tongue thickness is 0.08 mm and the cantilever length is 3.5 mm. The average diameter of the multiple small circular holes is 1.2 mm, and the ratio of the tongue thickness to the average diameter is 0.067, which is in the range of 0.04-0.09.

[0067] When the coolant temperature at the outlet of the second flow channel 22 rises from 60°C to 95°C, the variable cross-section throttling tongue 43 deflects inward by about 0.35 mm towards the inner side of the corresponding small circular hole, reducing the effective flow cross-sectional area of ​​the corresponding small circular hole by about 40%, increasing the reverse back pressure gradient, and raising the static pressure of the coolant in the first flow channel 21 and the second flow channel 22 by about 1.8 kPa. This suppresses local boiling of the coolant under high heat load, keeping the heat exchange in the first flow channel 21 within the nucleus boiling range, thus forming a self-reinforcing negative feedback protection loop that increases with heat load. When the coolant temperature drops back to 60°C, the variable cross-section throttling tongue 43 resets, the effective flow cross-sectional area of ​​the corresponding small circular hole recovers, the flow resistance of the flow channel decreases, and pump power consumption loss is avoided under normal operating conditions. The temperature-responsive variable cross-section throttling tongue 43 automatically reduces the effective flow cross-sectional area of ​​the small circular orifice, increases the reverse back pressure gradient, and improves the static pressure of the flow channel under high heat load, thus suppressing local boiling. When the temperature drops, the tongue resets and the flow cross-sectional area recovers, avoiding pump power consumption loss under normal operating conditions, thus forming a self-reinforcing negative feedback protection loop that follows the heat load.

[0068] It should be noted that in this embodiment, the variable cross-section throttling tongue 43 does not enhance heat transfer by increasing the coolant flow rate: reducing the outlet cross-sectional area under constant pressure supply conditions will reduce the flow rate; the physical path of negative feedback is to increase static pressure to suppress boiling and prevent the heat transfer coefficient from dropping sharply due to deviation from the bubble nucleus boiling. It belongs to a self-protective thermal management loop, which together with the dual-channel active switching constitutes a dual-loop thermal management system that combines active and passive coordination.

[0069] Specifically, the connection structure between the variable cross-section throttling tongue 43 and the sealing plate 4 is an embedded cantilever beam structure: the variable cross-section throttling tongue 43 is set in the edge area of ​​the small round hole, the root end of the variable cross-section throttling tongue 43 is embedded in the base of the sealing plate 4 and forms an integral part with the sealing plate 4, the cantilever section of the variable cross-section throttling tongue 43 extends from the edge of the small round hole toward the center of the small round hole, and the free end of the cantilever section extends into the inside of the small round hole; The specific method for the connection structure of the variable cross-section throttling tongue 43 and the sealing plate 4 is as follows: During the manufacturing process of the sealing plate 4, the root end of the variable cross-section throttling tongue 43 is pre-placed in the mold cavity. The base material of the sealing plate 4 covers the root end of the variable cross-section throttling tongue 43 during injection molding or powder metallurgy sintering, and forms an integrated connection after cooling. The cantilever length of the variable cross-section throttling tongue 43 is 3.5mm, the width of the variable cross-section throttling tongue 43 is less than or equal to the diameter of the small round hole, and the thickness of the variable cross-section throttling tongue 43 is 0.08mm.

[0070] The thermally induced deflection principle of the variable cross-section throttling tongue 43 is as follows: The variable cross-section throttling tongue 43 is a bimetallic strip with a double-layer composite structure, including an active layer with a higher coefficient of thermal expansion and a passive layer with a lower coefficient of thermal expansion. When the coolant temperature rises, the thermal expansion of the active layer is greater than that of the passive layer. The expansion difference between the two layers generates an internal bending moment at the interface, driving the variable cross-section throttling tongue 43 to bend towards the passive layer, that is, the free end of the variable cross-section throttling tongue 43 deflects towards the center of the small circular hole. The variable cross-section throttling tongue 43 adopts a variable cross-section design with a thicker root and a gradually thinner free end. Since the bending moment of inertia is proportional to the cube of the thickness, the bending stiffness of the free end is much smaller than that of the root end, so that the same bimetallic bending moment produces a larger deflection at the free end. The variable cross-section design amplifies the deflection of the basic bimetallic strip by about 2.5-3.5 times. The radial distance between the superimposed active layer and the passive layer... The combined effect of temperature gradient effect and incremental pre-bending curvature during manufacturing results in a total deflection amplification factor of approximately 5 times. Taking the parameters of this embodiment as an example, the root thickness of the variable cross-section throttling tongue 43 is 0.08 mm, the thickness at the free end gradually decreases to approximately 0.04 mm, and the cantilever length is 3.5 mm. Under the condition of a temperature difference of 35 °C from 60 °C to 95 °C, after the basic bimetallic deflection is amplified by the variable cross-section and the superposition of multiple factors, the deflection at the free end of the variable cross-section throttling tongue 43 reaches approximately 0.35 mm. The free end of the variable cross-section throttling tongue 43 deflects by 0.35 mm and penetrates into the small circular hole, reducing the effective flow cross-sectional area of ​​the small circular hole in an arc-shaped blocking manner. Under the condition that the width of the variable cross-section throttling tongue 43 is approximately 0.8-1.0 mm and the average diameter of the small circular hole is 1.2 mm, the effective flow cross-sectional area is reduced by approximately 35%-42%, which is consistent with approximately 40% as described in Example 4.

[0071] Example 5: Parameter interlocking between micro-rib array and liquid supply phase difference.

[0072] The outer surface of the mating surface 27 of the separator 2 is provided with a micro-rib array structure. The micro-rib array structure includes multiple micro-ribs that are inclinedly distributed along the outer surface of the separator 2. The height of the micro-ribs is 0.15 mm (about 3.7% of the hydraulic diameter of the first flow channel 21). The inclination angle of the micro-ribs relative to the axis of the separator 2 is 35°. Adjacent two micro-ribs are arranged in an alternating pattern with one end close to the other end open, forming a periodic flow guiding unit with an arrangement period of 2.5 mm.

[0073] The tilt angle of the microribs relative to the axis of the separator 2, the arrangement period of the periodic flow guiding units, and the liquid supply phase difference are mutually constrained: In this embodiment, the liquid supply phase difference is 6.6 mm. The jet from the second flow guide 26 enters the first flow channel 21 at about 2.1 m / s. The boundary layer peeling point induced by the jet on the wall of the first flow channel 21 is located in the section about 8-11 mm downstream of the second flow guide 26. This peeling point falls exactly within the reattachment zone defined by the 3rd-4th periodic flow guiding unit. The microrib array receives and amplifies the disturbance of the coolant jet, triggering local peeling of the coolant boundary layer and turbulent change. Under actual accelerated cooling conditions, the scheme with the microrib array reduces the friction coefficient by about 14% compared to the scheme with the smooth wall separator, and further increases the interface heat transfer coefficient by about 11%. By linking the convergence-divergence microrib array with the liquid supply phase difference, the jet boundary layer stripping point falls precisely within the reattachment zone of the guide unit. The microrib array receives and amplifies the jet disturbance energy, triggering local boundary layer stripping and turbulent abrupt change, thereby reducing frictional resistance and improving the heat transfer efficiency at the solid-liquid interface.

[0074] Experimental and control examples: full-range scanning of key parameters and destructive control.

[0075] Experimental Example 1: Full-range scanning of the ratio of supply phase difference to hydraulic diameter. Eight sets of samples with supply phase difference to hydraulic diameter ratios of 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, and 3.2 were prepared according to the structure of Example 1. Under the same accelerated cooling conditions (dual-channel total flow rate 2.4 L / min, inlet temperature 60 °C, wall heat flux density 18 W / cm²), the samples were tested. 2 The test measured the gain of the heat transfer coefficient at the interface relative to the basic cooling condition. The results showed that when the ratio was between 0.8 and 2.4, the heat transfer coefficient gain reached 118%-146%, with the gain curve peaking at approximately 1.6. When the ratio was less than 0.8, the interference of the two coolant streams was insufficient to trigger a flow transition, and the gain was only 42%-55% (comparable to the flow rate increase, exhibiting a linear response). When the ratio was greater than 2.4, the two coolant streams mixed and attenuated along the flow path, the flow transition disappeared, and the gain dropped back to 58%-70%. The gain curve exhibited a discontinuous step-like jump at the two endpoints of 0.8 and 2.4, indicating that this range has a specificity that cannot be linearly predicted by existing technologies.

[0076] Experimental Example 2: Full-range scan of the ratio of total inlet cross-sectional area to total outflow cross-sectional area. Five sets of samples with ratios of 1.0, 1.3, 1.7, 2.1, and 2.5 were prepared, with a wall heat flux density of 22 W / cm². 2 The initial heat flux density and maximum wall temperature of local film boiling were tested under high heat load. The test results show that when the ratio is in the range of 1.3-2.1, the reverse back pressure gradient is stably established, and the initial heat flux density of film boiling increases to 26-29 W / cm².2 When the ratio is 1.0 (without throttling), the initial heat flux density is only 19 W / cm³. 2 This is accompanied by a rapid increase in wall temperature; when the ratio reaches 2.5, excessive throttling leads to a decrease in total flow rate of more than 25%, the heat transfer coefficient decreases instead, and the steady-state noise increases significantly.

[0077] Experimental Example 3: Full-range scanning of the ratio of thickness to average aperture of the variable cross-section throttling tongue 43. Five sets of samples with ratios of 0.02, 0.04, 0.067, 0.09, and 0.12 were prepared and subjected to temperature cycling tests from 60℃ to 95℃. The test results showed that when the ratio was in the range of 0.04-0.09, the deflection of the variable cross-section throttling tongue 43 showed a stable and monotonic relationship with the temperature, and the negative feedback loop did not oscillate or fail hysteresis within 1000 cycles; when the ratio was 0.02, the stiffness of the variable cross-section throttling tongue 43 was insufficient, and self-excited oscillation (oscillation frequency of about 18Hz) occurred under hydrodynamic action, resulting in uncontrolled fluctuations in the flow cross-section; when the ratio was 0.12, the deflection hysteresis of the variable cross-section throttling tongue 43 exceeded 15℃, and the negative feedback basically failed.

[0078] Comparative Example 1 (Removal of the capillary microporous layer): The process of Example 2 was followed, but the extraction time in the third sub-step was extended to 240 minutes, and the inner wall of the blind pores was densified by glass shot peening before the fifth sub-step to obtain a sample without a capillary microporous layer; under the same high heat load as in Experimental Example 2, even if the reverse back pressure gradient was established normally, wall wetting could not be maintained, and the initial heat flux density of film boiling dropped to 20 W / cm². 2 Furthermore, the wall temperature of the thermal dead zone at the liquid outlet is 14°C higher than that of the sample in Example 2.

[0079] Comparative Example 2 (removal of reverse back pressure gradient): The structure of Example 2 is followed, but the total cross-sectional area of ​​the small circular holes of the sealing sheet 4 is increased to be equal to the total cross-sectional area of ​​the inlet flow, while the capillary micropore layer is retained; under high heat load, the local vapor film rapidly blocks the micropores of the capillary micropore layer, the capillary wicking effect fails, and the initial heat flux density of film boiling is only 21 W / cm². 2 Comparative Examples 1 and 2 together demonstrate that the reverse backpressure gradient and the capillary micropore layer are mutually dependent prerequisites for each other's existence. If either element is missing, the other element will fail to function independently. The two constitute an inseparable synergistic whole.

[0080] Comparative Example 3 (liquid supply phase difference is zero): A sample with the first guide port 25 and the second guide port 26 axially aligned (liquid supply phase difference is zero) was prepared, and the rest of the structure was the same as in Example 1; the heat transfer coefficient gain under accelerated cooling conditions was only 48%, which was comparable to the flow rate increase, and no flow regime transition or superlinear gain was observed.

[0081] Comparative Example 4 (adhesive layer without ultrasonic orientation): This is the control sample in Example 3 that was not cured by ultrasonic vibration. The shear strength retention rate was only 54%, which verifies the causal chain between the ultrasonic process, adhesive layer orientation and torsional sealing performance.

[0082] The above experimental and control examples show that the parameter ranges defined in the claims of this invention are all nonlinear abrupt change ranges of the performance curves. When the endpoints of the ranges deviate by only about 1% (such as hydraulic diameter ratios of 2.4 and 2.42, and thickness ratios of 0.09 and 0.091), the technical effect deteriorates measurably. The relevant ranges have a specificity that cannot be expected based on the evolution law of existing technology. Moreover, the technical features are mutually dependent and synergistic rather than simply superimposed.

[0083] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a robot motor microchannel cooling drive shaft, characterized in that, Includes the following steps: Step 1: Manufacturing a shaft with a blind hole inside, and at least one limiting groove machined along the axial direction on the inner wall of the blind hole; Step 2: Push the separator along the axial direction of the limiting groove into the blind hole, so that the outer wall of the separator abuts against the inner wall of the blind hole and divides the blind hole into a first flow channel and a second flow channel. The first flow channel and the second flow channel are connected at the bottom of the blind hole to form a communication point. Then, insert the inner nest into the end of the shaft and abut against the separator to confine the separator within the blind hole. The separator has a first liquid guiding channel and a second liquid guiding channel. The side wall of the separator has a first flow port communicating with the first liquid guiding channel and a second flow port communicating with the second liquid guiding channel. The first flow port and the second flow port are arranged axially offset to form a liquid supply phase difference, and the distance from the first flow port to the communication point is less than the distance from the second flow port to the communication point. Step 3: Place the sealing sheet with the through hole at the end of the shaft and abut against the inner nest. The sealing sheet and the inner nest are provided with an anti-rotation structure in a locked abutment state. The through hole is connected to the second flow channel. Tighten the sealing sleeve that is threaded to the shaft. The sealing sleeve is pressed against the outside of the sealing sheet. The anti-rotation structure resists the frictional torque applied to the sealing sheet when tightening, preventing the sealing sheet from circumferentially deflecting.

2. The manufacturing method of a robot motor microchannel cooling transmission shaft according to claim 1, characterized in that, The shaft is integrally manufactured using a metal injection molding process, comprising the following steps: The first step, mixing and granulation: Metal powder is produced using a pure gas atomization method. The metal powder is spherical with an average particle size of 5-18 micrometers. The metal powder formulation, by mass percentage, includes: Cr 13.5%-15.5%, Ni 6.0%-8.0%, Al 2.2%-3.8%, Mo 1.2%-2.0%, Cu 1.5%-2.5%, Nb and Ti total 0.3%-0.6%, Si 0.4%-0.8%, with the balance being Fe; the metal powder and binder are blended at a mass ratio of 88:12 to 93:7; wherein the binder comprises the following components by mass percentage: 35%-45% oligomeric isobutylene, 25%-32% cyclic olefin copolymer, 12%-18% amphiphilic microcrystalline beeswax, 4%-8% fatty alcohol polyoxyethylene ether phosphate, and 0.5%-1.5% azobisisobutyronitrile; the metal powder and the binder are preheated and stirred in a closed mixer at a mixing temperature of 135-165℃, a mixer speed of 45-65 r / min, and a mixing time of 2.5-3.5 hours; after cooling, the mixture is crushed to obtain metal feedstock; The second step, injection molding: The prepared metal feedstock is added into the barrel of a precision injection molding machine. The barrel injection temperature is set to 155-185℃, the injection pressure is 80-140MPa, and the mold temperature is controlled at 40-68℃. After holding pressure and cooling, the green shaft blank is integrally formed. The third step, in-situ micro-foaming and water-based extraction degreasing: The green shaft blank is immersed in an aqueous slightly alkaline washing solution at a temperature of 60-80℃. The azobisisobutyronitrile in the green shaft blank decomposes and releases inert gas, forming directional micro-nano exhaust channels in situ inside the green shaft blank. The aqueous slightly alkaline washing solution enters the blind holes through the openings of the blind holes, making the degree of extraction degreasing in the surface area of ​​the inner wall of the blind holes and the distribution density of the directional micro-nano exhaust channels greater than those in the core area of ​​the shaft. After 80-140 minutes of washing and extraction degreasing, the oligomeric isobutylene and amphiphilic microcrystalline beeswax in the green shaft blank are partially dissolved and removed, resulting in a porous shaft blank. The fourth step, micro-positive pressure hot degreasing and pre-sintering: In a furnace with a micro-positive pressure argon or argon-hydrogen mixture, the dried shaft blank is first hot-degreased at a slow rate of 1.5-3℃ / min to 420-480℃ and held for 90-150 minutes; then it is rapidly heated to 820-880℃ at a rate of 8-12℃ / min for a dense pre-sintering time of 60-120 minutes to obtain a high-strength pre-sintered blank; The fifth step, high-temperature densification sintering and toughening aging: In a fully sealed hydrogen atmosphere sintering furnace or vacuum sintering furnace, the high-strength pre-sintered billet is heated to 1280-1350℃ at a heating rate of 4-8℃ / min and held for sintering for 140-200 minutes; finally, aging heat treatment is completed at 460-520℃ to induce in-situ precipitation of nano-sized nickel-aluminum intermetallic compounds and nano-sized copper-containing reinforcing phases in the matrix; In this process, since the distribution density of the directional micro-nano exhaust channels in the surface region of the inner wall of the blind hole is greater than that in the core region, the core region achieves full densification during the sintering densification process, while the directional micro-nano exhaust channels in the surface region of the inner wall of the blind hole are retained in a directional manner, forming a capillary microporous layer covering the first flow channel wall and the second flow channel wall. The porosity of the capillary microporous layer decreases to zero along the radial direction of the shaft from the inner wall of the blind hole to the core region.

3. The manufacturing method of a robot motor microchannel cooling transmission shaft according to claim 2, characterized in that, In the fifth step of the aging heat treatment process, auxiliary heating is applied to the surface region of the inner wall of the blind hole, so that the aging temperature of the surface region of the inner wall of the blind hole is higher than that of the core region. Due to the radial difference in aging temperature, the nano-sized nickel-aluminum intermetallic compound and the nano-sized copper-containing reinforcing phase are enriched and precipitated in the surface region of the inner wall of the blind hole, while being depleted and precipitated in the core region, forming a reinforcing phase structure with a radial gradient distribution. The thermal conductivity of the surface region of the inner wall of the blind hole is higher than that of the core region. The core region maintains the toughness of the matrix, thereby decoupling the heat transfer performance and torsional mechanical properties of the shaft radially.

4. A method for manufacturing a robot motor microchannel cooling drive shaft according to claim 1 or 2, characterized in that, The outer surface of the separator is provided with a mating surface and a first mating part. A limiting step is provided between the mating surface and the first mating part. The mating surface abuts against the inner wall of the blind hole. The first mating part is disposed in the limiting groove. In step one, a first recessed platform and a second recessed platform are respectively provided at the end of the shaft corresponding to the blind hole opening end, and both the first recessed platform and the second recessed platform are eccentrically arranged. The inner nesting includes a first insert and a second insert assembled together, the first insert and the second insert being respectively inserted into the first recessed platform and the second recessed platform; the first insert and the second insert both abut against the limiting step, confining the separator within the blind hole.

5. The manufacturing method of a robot motor microchannel cooling transmission shaft according to claim 4, characterized in that, The step of installing the first insert and the second insert into the first sink and the second sink respectively adopts an ultrasonic vibration-assisted assembly process, wherein the ultrasonic vibration is a high-frequency vibration composed of axial vibration component and circumferential vibration component. During the assembly process, the high-frequency vibration generates nonlinear acoustic radiation pressure and dynamic deflection of friction vector in the assembly micro-gap between the inner wall of the first insert and the first sinking platform and between the inner wall of the second insert and the second sinking platform. This drives the first insert and the second insert to generate suspension micro-movement and self-alignment within the first sinking platform and the second sinking platform, converting axial sliding friction into circumferential high-frequency sliding, thus preventing skewing and jamming during deep hole assembly. After the separator and the inner nest are assembled in place, a thermosensitive expansion crosslinking adhesive is injected into the assembly gap between the limiting groove and the first mating part through the limiting groove, and a thermosetting treatment is performed under the condition of continuing to apply the high-frequency vibration. The nonlinear acoustic radiation pressure generated by the high-frequency vibration in the thermosensitive expanding crosslinking adhesive drives the molecular chains of the thermosensitive expanding crosslinking adhesive to be oriented along the acoustic flow direction, so that the thermosensitive expanding crosslinking adhesive forms a fibrous oriented network crosslinking structure after thermal curing. The main direction of the fibrous orientation is at an angle to the circumferential direction of the shaft to resist the circumferential shearing action transmitted to the assembly gap through the sealing sheet and the inner nest when the sealing screw is tightened. The cured network cross-linked structure forms an oriented cross-linked adhesive layer that fills the assembly gap. The oriented cross-linked adhesive layer constitutes an intermediate interface that has both directional shear resistance, torsional damping and secondary static sealing functions.

6. The manufacturing method of a robot motor microchannel cooling transmission shaft according to claim 4, characterized in that, The anti-rotation structure includes an anti-rotation boss or anti-rotation pin that protrudes inward along the axial direction on the sealing sheet, and an anti-rotation positioning groove on the first insert and the second insert. The anti-rotation boss or the anti-rotation pin is fitted into the anti-rotation positioning groove to prevent the sealing sheet from circumferentially deflecting during the tightening process of the sealing screw sleeve, so that the through hole and the second flow channel always remain axially aligned.

7. The manufacturing method of a robot motor microchannel cooling transmission shaft according to claim 2, characterized in that, The through holes on the sealing sheet are a plurality of small circular holes arranged in an eccentric region. The sum of the flow cross-sectional area of ​​the first flow guide and the flow cross-sectional area of ​​the second flow guide is the total inflow cross-sectional area. The total flow cross-sectional area of ​​the plurality of small circular holes is smaller than the total inflow cross-sectional area, and the ratio of the total inflow cross-sectional area to the total flow cross-sectional area is in the range of 1.3-2.

1. By asymmetrically reducing the flow area, a local throttling damping is constructed at the return end of the second flow channel, converting the fluid dynamic pressure of the coolant into static pressure, thereby establishing a reverse back pressure gradient in the second flow channel, keeping the coolant operating pressure in the first flow channel above the critical vaporization pressure of the coolant; at the same time, a secondary disturbance vortex is induced at the outlet end of the second flow channel near the sealing plate, eliminating the thermal dead zone at the sealing end; The static pressure established by the reverse back pressure gradient is matched with the capillary suction pressure of the capillary microporous layer: the reverse back pressure gradient inhibits the macroscopic boiling of the coolant and prevents local vapor film from blocking the micropores of the capillary microporous layer; the capillary microporous layer maintains continuous wetting of the wall surface of the first flow channel through capillary wicking; the reverse back pressure gradient and the capillary microporous layer work together to inhibit local film boiling and wall drying.

8. A method for manufacturing a robot motor microchannel cooling transmission shaft according to claim 7, characterized in that, The sealing sheet is provided with a variable cross-section throttling tongue that deforms with temperature at the edge region of at least one of the multiple small round holes. The variable cross-section throttling tongue is a bimetallic sheet or a shape memory alloy sheet. The variable cross-section throttling tongue is fixedly connected to or embedded in the sealing sheet. When the coolant temperature at the outlet of the second flow channel rises, the variable cross-section throttling tongue deflects inward toward the inner side of the corresponding small circular hole, reducing the effective flow cross-sectional area of ​​the corresponding small circular hole, thereby increasing the reverse back pressure gradient. At the same time, the static pressure of the coolant in the first and second flow channels increases, suppressing the local boiling of the coolant under high heat load, and keeping the heat exchange in the first flow channel within the nucleus boiling range, thus forming a self-reinforcing negative feedback protection loop that increases with heat load. When the temperature of the coolant drops, the variable cross-section throttling tongue resets, and the effective flow cross-sectional area of ​​the corresponding small circular orifice recovers. The ratio of the thickness of the variable cross-section throttling tongue to the average diameter of the plurality of small circular holes is in the range of 0.04-0.

09.

9. A method for manufacturing a robot motor microchannel cooling transmission shaft according to claim 1, characterized in that, The outer surface of the separator is provided with a micro-rib array structure, which includes a plurality of micro-ribs that are inclinedly distributed along the outer surface of the separator. Two adjacent micro-ribs are arranged in an alternating pattern with one end converging and approaching each other and the other end diverging outward, forming a periodic flow guiding unit on the outer surface of the separator. The tilt angle of the microribs relative to the axis of the separator, the axial arrangement period of the periodic flow guiding unit, and the liquid supply phase difference form a linked limiting relationship, specifically: Under accelerated cooling conditions, the coolant jet entering the first flow channel through the second guide port falls into the fluid reattachment zone defined by the periodic guide unit at the boundary layer peeling point induced on the wall of the first flow channel. This allows the micro-rib array to receive and amplify the disturbance energy of the coolant jet, triggering localized boundary layer peeling and turbulent abrupt changes in the coolant, thereby reducing fluid friction resistance and improving the solid-liquid interface heat transfer efficiency.

10. A method for manufacturing a robot motor microchannel cooling transmission shaft according to claim 1, characterized in that, Under basic cooling conditions, coolant is delivered to the first flow channel only through the second liquid guiding channel and the second flow guide port, and the coolant in the first flow channel maintains the first flow state. Under accelerated cooling conditions, coolant is simultaneously supplied to the first flow channel through the first and second liquid guiding channels. The two coolant streams converge and interfere within the axial section defined by the supply phase difference, triggering a nonlinear transition of the coolant in the first flow channel from the first flow state to the second flow state. The turbulence intensity of the second flow state is higher than that of the first flow state, resulting in an increase in the interface heat transfer coefficient greater than the increase in the total coolant flow rate. The coolant in the first flow channel is discharged through the second flow channel and the through hole, constructing an adjustable cooling circulation channel. The ratio of the liquid supply phase difference to the hydraulic diameter of the first flow channel is in the range of 0.8-2.4, so that the convergence interference intensity of the two coolant streams in the axial section is sufficient to trigger a nonlinear transition from the first flow state to the second flow state.

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