539 results about "Solid structure" patented technology

A solid structure deformation and damage analysis method based on a quasi-bond finite element method comprises: carrying out geometric modeling on a target structure body, and distribution and subdivision to generate a grid of a traditional finite element method; dividing the target structure body into a finite element region and a quasi-bond region, and calculating a finite element region system stiffness matrix and a quasi-bond region system stiffness matrix to obtain an overall stiffness matrix of the target structure body; setting a boundary condition for the target structure body, applying an external load, and calculating a system force matrix under current load and boundary state; and judging a quasi-bond breakage condition according to a node trial displacement, then calculating a node displacement of the structure body and an equivalent damage parameter at each node, and outputting cloud charts of a displacement field and an equivalent damage field.

The invention provides a self-adaptive optimization method and device for control parameters of a gantry machine tool, and relates to the technical field of gantry machine tools. A control parameter sequence is obtained according to processing design and processing quality analysis; the gantry machine tool is operated through the control parameter sequence to process the machining raw materials, and production of the solid structural part of the structural part is executed; and monitoring the gantry machine tool based on the control deviation window, generating a process self-adaptive compensation parameter, and performing compensation control on the operation process of the gantry machine tool by adopting the process self-adaptive compensation parameter. The technical problem that in the prior art, the automation degree of the production process of the complex structural parts is low due to the fact that the dependence on manual operation is high in the machining process of producing the complex structural parts through a gantry machine tool is solved. The gantry machine tool achieves the technical effects that the gantry machine tool is automatic and intelligent in the machining process of complex structural parts, and the production efficiency and quality control quality of the structural parts are improved.

The invention relates to a method for predicting the bearing capacity of a concrete-filled steel tube yielding lagging jack, and belongs to the technical field of artificial intelligence and data processing. The method comprises the following steps: acquiring stress data at a key stress position of a concrete filled steel tube arch solid structure; stress data screening is carried out, and a screened data set is stored in an HDF5 hierarchical format; denoising the stored stress data by adopting a self-adaptive normalization method and a wavelet threshold function; time domain-frequency domain feature fusion is carried out on the stress data after denoising normalization through dynamic time segmentation and short-time Fourier transform; constructing a concrete-filled steel tube yielding arch bearing capacity prediction model, inputting the fusion feature vector into the model, and training the model to obtain a trained model; and processing the collected data, inputting the processed data into the trained model to obtain a predicted value of the bearing capacity, and triggering early warning when the predicted value exceeds 90% of the designed bearing capacity for three continuous times. The prediction capability of the model can be improved.

The invention discloses a double-injection rubber-coated product assembled in a super-thick plastic part cavity structure mold and a production process of the double-injection rubber-coated product. A molten plastic material is injected into a first injection mold cavity through a first gun barrel of a double-injection injection molding machine to form a first injection molding part and a second injection molding part which are integrated; then the six-axis robot is controlled to drive the part taking and mounting tool to move to grab the insert and fix the insert to the second injection molding part, and at the moment, a closed assembly part with a cavity structure is formed between the second injection molding part and the insert; finally, a molten plastic material is injected to the outer surface of the assembly part of the second injection mold through a second gun barrel of the double-injection injection molding machine to form a third injection molding part; according to the technology, the overall weight of a solid structure product can be greatly reduced, the material use is reduced, the material cost is reduced, the product cooling time is shortened through the design of the cavity structure, the production efficiency is improved, and the product defects such as surface shrinkage marks and internal irregular cavities caused by excessive shrinkage of a plastic material in the cooling and curing process are thoroughly eradicated.

The present disclosure relates to embodiments of a method for manufacturing a ceramic material comprising the steps of (a) homogenizing aluminum oxide, niobium pentoxide and solvent; (b) ultrasonicating the blend obtained in step (a); (c) adding an aliquot of the prepared suspension to the empty cavity of a mold, particularly between the polymeric mold and the metal mold; (d) immersing the mold into a coolant liquid-containing bath for sufficient time to ensure that all parts are completely frozen; (e) removing the ceramic body from the mold; (f) removing the solidified phase by means of sublimation hence obtaining a green tube; and (g) sintering the green tube, so as to obtain a solid structure. The present disclosure further relates to embodiments of a ceramic material and its use to manufacture a microfiltration membrane and / or a membrane support for fluid separation.

A user support includes a hood structure that is supported by a back frame structure of the user support. The hood structure may comprise a one-piece homogeneous polymer structure that is formed by an additive process. The hood structure may include solid structures and at least one porous lattice matrix that is integrally formed with the solid structures.

The invention discloses a reaction cavity and a multi-stage series micro-channel reactor. The reaction cavity comprises a water-drop-shaped cavity shell and a built-in octopus-like shunting baffle, and a four-section type mixing flow channel is formed between the water-drop-shaped cavity shell and the built-in octopus-like shunting baffle; in the collision shearing section, fluid at a feeding hole impacts the head of the baffle at a high speed to realize forced shunting and primary shearing; according to the deceleration recombination section, a waist expansion flow channel reduces the flow speed and promotes fluid recombination and interface fusion. In the acceleration section, narrow channels between tentacles extrude and accelerate the fluid to enhance permeation and mixing; and in the mixing section, vortex breaking sharp corners are arranged at the tail parts of the baffles to eliminate vortexes and guide the vortexes to a discharge port. The multi-stage reactor is composed of a three-split-flow inlet unit, N reaction cavities connected in series and an outlet unit, and reverse parallel arrangement is achieved through a U-shaped pipe. Except for the reaction cavity, the interior of the reactor is of a solid structure, and the three-flow-dividing inlet adopts the design that a central pipeline is embedded into a peripheral pipeline, so that graded feeding control is realized. The structure has the characteristics of efficient microcosmic forced mixing and low flow resistance.

Disclosed is a granule made of biocompatible metallic material, in particular made of titanium or titanium alloys, for vertebroplasty operations. The granule has a spherical shape and includes a central core with a solid structure, also spherical, having an outer surface from which a first diametrical rib and a second diametrical rib also having a solid structure, protrude. The ribs are advantageously arranged according to two diameters orthogonal to each other. The granule also includes a portion having a trabeculated structure which extends between the outer surface of the central core and the outer surface of the granule itself.

Methods and apparatuses for utilizing triply periodic minimal surface structures for additive manufacturing of a thermal management system are disclosed, wherein the thermal management system comprises: a solid structure; a triply periodic minimal surface structure within the solid structure, wherein the triply periodic minimal surface structure comprises a first fluid channel and a second fluid channel; a first inlet coupled to the solid structure and configured to pass a first fluid into the first fluid channel; a second inlet coupled to the solid structure and configured to pass a second fluid into the second fluid channel; a first outlet coupled to the solid structure and configured to pass the first fluid out of the first fluid channel; and a second outlet coupled to the solid structure and configured to pass the second fluid out of the second fluid channel. Other embodiments are described and claimed.

The invention discloses a method for preparing an aluminum alloy capillary structure based on a selective laser melting technology, which comprises the following steps of: comprehensively regulating and controlling technological parameters of selective laser melting according to laser energy density by utilizing the forming principle of'incomplete melting pores' and'keyhole pores' in a selective laser melting forming process; and the porosity-adjustable aluminum alloy capillary structure is prepared. The method mainly comprises the following steps that firstly, aluminum alloy spherical powder with the particle size range suitable for the selective laser melting process is selected; secondly, a laser energy density reference value is selected according to the optimal technological parameters of selective laser melting forming of the aluminum alloy solid structure; then, according to the laser energy density, the laser power, the scanning rate, the scanning interval and other technological parameters are comprehensively regulated and controlled, the powder laying layer thickness is set, and the aluminum alloy capillary structure is prepared; and finally, the porosity of the capillary structure is measured, the correlation between the technological parameters and the porosity is established, a technological window is determined, and the aluminum alloy capillary structure with the adjustable porosity is prepared.

A method for detecting a sound field in an outside environment of a solid structure is provided. The solid structure comprises at least one sound transducing element, which is a part of the solid structure and forms a part of an outer surface of the solid structure, wherein the incident sound falls at least partly onto the sound transducing element. The method comprises obtaining sensor data from at least one vibration sensor, which is mounted onto a mounting surface of the at least one sound transducing element, wherein the at least one vibration sensor detects vibrations in the at least one sound transducing element, which are induced into the at least one sound transducing element by the incident sound field, processing the sensor data to generate output data, and providing the output data.

The invention discloses a fluid-solid-sound coupling calculation and noise reduction method for a bent pipe, and belongs to the technical field of pipeline testing. According to the method, the three-dimensional physical model of the bent pipe is constructed, the bent pipe fluid-solid coupling model is established, and the dynamic correlation between the flowing characteristics of fluid in the bent pipe and the response of a solid structure is accurately reflected; the method can capture flow field disturbance caused by inertia, centrifugal force and geometric changes of the elbow pipe in the flowing process, quantitatively describes a dynamic load change rule applied by fluid to the pipe wall, effectively improves understanding of complex elbow pipe flow field behaviors, extracts wall surface pressure distribution data, generates fluid disturbance data, and improves the flow field performance of the elbow pipe. According to the method, the distribution characteristics of noise sources generated by flow-induced vibration can be accurately predicted, the problem that a traditional single-field modeling method cannot fully describe actual working conditions is solved on the whole, the physical authenticity and prediction precision of simulation are greatly improved, and the problems of high cost and low efficiency caused by a traditional trial and error method are effectively avoided.

The invention relates to the technical field of aerospace, in particular to a ceramic 3D printing A sandwich structure with a broadband wave-transparent characteristic. According to the ceramic 3D printing A sandwich structure with the broadband wave transmission characteristic, good compatibility of broadband wave transmission, strength-structure accuracy and reliability is achieved, an obvious effect on broadband wave transmission of 1 GHz to 18 GHz is achieved, the dielectric constant and the tangent loss are in a reduction trend under the same frequency band, excellent stability is shown, and the dielectric constant and the tangent loss are reduced under 10 GHz. The dielectric constant of the ceramic 3D printing A sandwich structure with the broadband wave transmission characteristic is reduced by 40% or above compared with that of a full solid structure, the wave transmission rate is increased by 50% or above, the ceramic 3D printing A sandwich structure has excellent electromagnetic performance and mechanical performance, and support is provided for implementation of reliable service application targets such as diversion, heat protection, wave transmission, bearing and rain erosion resistance of hypersonic aircrafts.

The present invention discloses a welding positioning tool for steel structure bridge components, which relates to the technical field of bridge construction; it is characterized in that a welding platform is rotatably installed on a base, and a guardrail column is placed in the central area of ​​the welding platform; both ends of the welding platform are respectively provided with a top fixing structure against the outside of a support plate; both sides of the support frame are respectively provided with a lifting structure, and the lifting structure is connected to a tilting structure; an axial lock is connected to a telescopic structure, and the telescopic structure is connected to a clamping structure, the clamping structure is inserted between two support plates, the clamping structure is clamped on an auxiliary plate, and the tilting structure is used to coordinate and adjust the position of the clamping structure according to the tilting direction of the guardrail column. The device can splice and fix the guardrail column, and can flip the guardrail column in an upright state, which greatly facilitates the welding work.

The application discloses a heat pipe structure based on metamaterial and a processing method, relates to the technical field of lightweight multifunctional structures, and the heat pipe structure comprises a metal structure, a sealed cavity is arranged in the metal structure, a filling lattice is arranged in the sealed cavity, and an unfilled area is arranged in the middle of the filling lattice; the filling lattice comprises at least two lattice layers with different porosities, and the porosity of the filling lattice decreases from the unfilled area to the edge of the sealed cavity. The integration of the metal solid structure or the honeycomb sandwich structure and the specific heat pipe structure is realized, the number of heat transfer interfaces is greatly reduced, and the heat transfer efficiency is greatly improved.

A dome cover and a gas uniformizing disc are relatively and fixedly assembled to form a gas uniformizing cavity, one or more heat conduction columns are installed in the gas uniformizing cavity, the two ends of each heat conduction column make contact with the dome cover and the gas uniformizing disc in a heat conduction mode respectively, and on one hand, the heat conduction columns can play a supporting role; the supporting strength between the dome cover and the gas uniformizing disc is enhanced; on the other hand, the heat conduction columns can play a role in heat conduction and are used for conducting heat between the dome cover and the gas uniformizing disc, and deformation caused by uneven temperature can be reduced; as the second end of the heat conduction column is provided with the hollow gap along the radial direction, and the hollow gap has no solid structure so as to allow the airflow to pass through, the interference to the airflow flowing state can be greatly reduced compared with a complete solid structure; besides, due to the existence of the hollowed-out notches, the contact area between the second ends of the heat conduction columns and the gas uniformizing disc is reduced, gas uniformizing channels can be arranged within the projection range of the heat conduction columns, and the gas uniformizing channels are distributed on the gas uniformizing disc in a more uniform and consistent density mode.

The invention relates to the technical field of industrial dust removal and environmental protection, in particular to a novel gas-solid ejector capable of preventing dust accumulation, which mainly comprises a nozzle, a receiving chamber, a mixing pipe and a diffuser pipe. On one hand, the speed of working fluid sprayed out of the nozzle can be remarkably increased, the pressure difference in a receiving chamber is increased, an ejection working medium falling from a feeding port obtains higher driving force, and it is ensured that the substances can completely flow into a mixing chamber along with the working fluid as much as possible; on the other hand, due to the special inclination angle design of the reducing pipeline, the materials falling on the pipeline naturally flow to the mixing chamber under the traction of gravity, accumulation of the materials in the mixing chamber is effectively avoided, in addition, the area where the lower wall of the inner cavity of the receiving chamber is connected with the reducing pipeline and the lower edge of the nozzle is designed to be of a solid structure, and the structure is simple. And dust particles are ingeniously prevented from being deposited in the region.

The utility model provides a feed mixing device capable of reducing stirring time, which comprises a device main body, a crushing bin and an upper cover mechanism, and a stirring barrel body used for mixing and stirring feed is arranged at the central position of the device main body. The upper cover mechanism and the device body are connected and fixed, raw materials in different states are fed from different feeding guide pipes according to use, raw materials of large-particle or large-block solid structures are fed into different crushing bins to be processed at the same time, the raw materials are crushed through crushing rollers, and then the crushed raw materials are guided into the stirring barrel through the feeding guide pipes. Liquid or powdery raw materials are guided into the stirring barrel body from the feeding port through the feeding guide pipe, the stirring motor is started to drive the stirring frame to conduct mixing operation, and therefore the stirring time can be shortened, and the device body and the upper cover mechanism are conveniently disassembled and assembled by additionally arranging the device body and the upper cover mechanism.

The present invention discloses a structural crack control measurement device and a measurement method. The device is composed of a first steel pipe and a second steel pipe, both of which are internally provided with vibrating wire strain gauges; elastic linings are arranged in a fitting manner on the inner walls of the first steel pipe and the second steel pipe; the two vibrating wire strain gauges are coaxially arranged with the first steel pipe and the second steel pipe where they are respectively located; the opening directions of the first steel pipe and the second steel pipe point to the principal stress of the concrete; the signal cables of the vibrating wire strain gauges are led out of the cast solid structure; the concrete in the cast solid structure is poured to ensure that the concrete in the first steel pipe and the second steel pipe is filled completely; the data of the two vibrating wire strain gauges during the monitoring and measurement are collected, analyzed and crack controlled in real time. The device provided by the present invention has a simple structure and low cost, truly realizes the stress measurement inside the structure, and the measurement process is easier to implement, strengthens the credibility of the crack measurement data, reduces the error range, and can achieve good prevention and control of cracks caused by temperature stress and the like.

The invention discloses a method for measuring the surface temperature of a high-temperature solid structure based on ultrasonic evanescent wave amplitudes, which belongs to the field of nondestructive measurement and comprises the following steps: under different surface temperature conditions, exciting ultrasonic waves above the high-temperature solid structure, and measuring the ultrasonic evanescent wave amplitudes under different surface temperatures; determining the incidence relation between the ultrasonic evanescent wave amplitude and the temperature; and after the incidence relation between the amplitude of the ultrasonic evanescent wave and the temperature is determined, in subsequent ultrasonic detection, the temperature of the surface of the high-temperature solid structure is calculated by combining the measured amplitude of the ultrasonic evanescent wave with a predetermined incidence relation between the amplitude of the ultrasonic evanescent wave and the temperature. The method does not depend on radiation emitted by the surface of the measured material, can stably measure in a high-temperature or extremely-high-temperature environment, and is good in real-time performance.

The invention discloses a super-flexible high-strength cable based on a topological optimization structure and a preparation method of the super-flexible high-strength cable. The cable comprises a conductor, an insulating layer, a reinforcing structure layer, a shielding layer and an outer sheath which are sequentially arranged from inside to outside. The conductor adopts a single-strand solid structure or a multi-strand stranded structure; the insulating layer coats the outer side of the conductor through an extrusion process; the reinforced structure layer adopts a topological optimization design and is formed by compounding a high-strength fiber material and a matrix material, and the fiber material is arranged according to the direction and distribution determined by topological optimization; the shielding layer is of a metal woven mesh or metal foil tape wrapping structure; and the outer sheath coats the outer side of the shielding layer. The reinforced structure layer is designed through the topological optimization technology, so that the cable can maintain super flexibility, and meanwhile, the stretching resistance, the bending resistance and the extrusion resistance are remarkably improved, and the problem that the flexibility and the strength of a traditional cable are difficult to consider at the same time is solved.

A user support includes a hood structure that is supported by a back frame structure of the user support. The hood structure may comprise a one-piece homogeneous polymer structure that is formed by an additive process. The hood structure may include solid structures and at least one porous lattice matrix that is integrally formed with the solid structures.

The utility model discloses an anti-misplug power socket, which comprises a mounting rack, a gland arranged in the mounting rack, and a panel arranged on one side of the mounting rack, a conductive piece is arranged in the mounting rack, one side of the conductive piece is provided with a binding post, a safety door is movably arranged between the mounting rack and the gland, a vertical rod is arranged on the safety door, and the vertical rod is provided with an anti-misplug power supply. Through holes are formed in the installation frame and the gland, the vertical rods are installed in the through holes in a sliding mode, a threaded column is integrally formed on the inner side wall of the gland, the outer side of the threaded column is in threaded connection with an adjusting disc, and a limiting groove is formed in the safety door. The safety door is prevented from deflecting in the moving process and being clamped, even if the safety door is clamped, the safety door can be driven to move through the vertical rods, the safety door can move smoothly, the situation that a plug is difficult to insert is avoided, the mounting frame is of a thickened solid structure, and the structural strength of the mounting frame is improved.

The utility model relates to the technical field of plastic steel sheet piles, in particular to a hollow reinforced plastic steel sheet pile which comprises sheet pile bodies, C-shaped lock catch parts and T-shaped lock catch parts are arranged on the two opposite sides of the sheet pile bodies correspondingly, and the adjacent sheet pile bodies are detachably assembled through the C-shaped lock catch parts and the T-shaped lock catch parts. The cross section of the sheet pile body is of a nonlinear bent structure, a plurality of reinforcing structures are integrally formed in the sheet pile body in a continuous co-extrusion mode, the thickness of materials located on the surfaces of the two opposite sides of each reinforcing structure is at least 2 mm, and a plurality of micro hollow holes formed in the width direction of each reinforcing structure at intervals are formed in each reinforcing structure. The reinforcing structure can obviously improve the tensile strength and bending strength of the plastic steel sheet pile, the plastic steel sheet pile is not prone to being extruded and deformed, and due to the fact that the multiple micro hollow holes are formed in the reinforcing structure, compared with a solid structure, the reinforcing structure can improve the deformation resistance and the bearing capacity of the plastic steel sheet pile to a certain degree.

The utility model discloses a powder sampler which comprises a hollow pipe and a sampling rod, the hollow pipe comprises two layers, an inner-layer hollow pipe is rotatably connected in an outer-layer hollow pipe, and the sampling rod is rotatably connected in the inner-layer hollow pipe; the sampling rod is of a solid structure, and a plurality of sampling grooves for quantitative sampling are formed in the sampling rod; corresponding outer sampling holes are formed in the positions, at the same height as the sampling groove, of the outer-layer hollow pipe, a plurality of inner sampling holes used for fixed-point sampling are formed in the positions, at the same height as the sampling groove, of the inner-layer hollow pipe, and the inner sampling holes are spirally formed in the axial direction of the inner-layer hollow pipe. The sampling rod is of a solid structure and is provided with sampling grooves at intervals, so that quantitative sampling at different positions is realized; the inner sampling holes axially formed in the inner hollow layer at intervals are matched with the sampling grooves, so that quantitative sampling at a specific position is realized; the sampler is made of rubber, so that samples are prevented from being polluted due to long-term abrasion; the tip and the thread of the outer hollow pipe are beneficial for the sampler to go deep into a sample.

The invention provides a coated window frame and a manufacturing method thereof, the coated window frame is used for manufacturing a window, the window frame is formed by splicing sectional materials, the sectional materials comprise sectional material bodies and metal coated sectional materials, the sectional material bodies are provided with notches, the metal coated sectional materials are rolling sectional materials and are coated on the sectional material bodies, and the notches are formed in the sectional material bodies. The two sides of the metal-coated section bar are provided with hooks, the hooks are matched with the notches in shape, and after the window frame is manufactured into a window, the section bar body is invisible. The cladding material of the window frame is formed through a rolling forming technology, the bonding strength between the cladding material and a composite interface of a main body material can be improved, the structural strength and durability of the window frame are enhanced, a high-grade and fire-resistant material is used as the cladding material, the fire resistance of the window frame is enhanced, a traditional window frame and a manufacturing method of the traditional window frame are remarkably improved, and the application range is wide. The novel window frame which is firm in structure, good in fire resistance, attractive in appearance and high-grade in texture and the manufacturing method of the novel window frame are provided by combining various materials and utilizing the advantages of each material.

The utility model discloses an assembly type tunnel subgrade connection structure and tunnel portal subgrade project, including prefabricated subgrade block, prefabricated subgrade block includes the solid waste bulk solid structure and light plate that overlap mutually, the light plate is provided with a plurality of functional holes along the length direction, at least one functional hole is used as the connecting hole, the light plate is used as the connecting hole, and the connecting hole is used for connecting the solid waste bulk solid structure and the light plate. The connecting structure further comprises connecting anchor rods penetrating through the tunnel portal slope, and the connecting holes of the prefabricated roadbed blocks located on the tunnel portal slope are connected with the connecting anchor rods in a matched mode. The prefabricated roadbed blocks located outside the tunnel portal slope are laid in a layered mode in the transverse direction.

The invention discloses a supercavitation navigation body cross-medium static stability margin integrated evaluation method, which comprises the following steps: (1) establishing a fluid domain and solid domain model, dividing grids, requiring good matching of a solid wall surface in contact with a fluid, setting initial and boundary conditions of the fluid domain, setting material attributes of a solid structure and endowing the solid structure with an initial working condition; (2) monitoring a pitching moment and a pitching force value in the air, calculating an aerodynamic center of the supercavitation navigation body in the air, and obtaining a static stability margin of the supercavitation navigation body in a flight state; (3) according to an empirical cavitation contour formula and the underwater characteristics of the supercavitation navigation body, the wetting volume and the equivalent buoyancy center position of the navigation body are obtained, and the static stability margin after complete development of the cavitation in water is calculated; and (4) carrying out weighted average by integrating the air static stability margin and the underwater static stability margin so as to obtain the static stability margin for judging the super-cavitation navigation body in the cross-medium water entry process. And help can be provided for judging the static stability of the navigation map entering water.

The utility model discloses a waterproof pressing rivet nut structure, which comprises a main body, a flange seat and a convex eave, the main body is provided with a central shaft hole, the central shaft hole is provided with an internal thread, the bottom of the central shaft hole is of a solid structure, the flange seat extends outwards from the middle of the main body, the inner side of the flange seat is provided with a limiting groove which is concavely arranged, and the convex eave is arranged in the limiting groove. The convex eaves are arranged on the peripheral wall of the upper end of the main body, the convex eaves are arranged above the limiting groove and are oppositely arranged, and a pressing interval is defined by the limiting groove and the convex eaves. In actual installation, the main body is placed in a riveting hole of a plate, then the plate is extruded and deformed through a riveting press and pressed between the limiting groove and the convex eave, and through the staggered pressing intervals, after the pressing rivet nut is fixed to the plate, a stepped staggered waterproof structure can be formed, firm combination is guaranteed, and the waterproof effect is improved. The water tightness of the pressing rivet nut after the pressing rivet nut is mounted on the plate is also ensured; the structure is simple and stable.

The near-end supporting structure of the blood pump is high in abrasion resistance, good in lubricity and small in resistance, the near-end supporting structure of the blood pump comprises an impeller and a driving unit which are axially arranged and connected in a magnetic coupling mode, and the far end of a shell of the driving unit is provided with a connecting shaft in a protruding and extending mode in the direction of the impeller. The far end of the connecting shaft abuts against the near end of the impeller shaft to form axial limiting and circumferential running fit, the connecting shaft comprises a metal shaft, a blind hole is formed in a shaft core of the metal shaft, a ceramic column is inserted into the blind hole, and the far end surface of the ceramic column is smoothly connected with the far end surface of the metal shaft. The connecting shaft is arranged to be of a structure with the ceramic column in the middle and the metal shaft on the outer ring, the whole connecting shaft is still of a solid structure, and the overall strength meets the requirement. Wherein the ceramic material is high in hardness and abrasion resistance and can reduce abrasion, meanwhile, the metal material located on the outer ring has the good self-lubricating characteristic, rotation resistance is reduced, and rotation smoothness of the impeller is guaranteed.