42results about How to "High shear yield stress" patented technology

The invention discloses an anti-impact MPP (molypermalloy powder core) electric protection tube. The anti-impact MPP electric protection tube is prepared from the following raw materials in parts by weight: 90-110 parts of polypropylene, 5-15 parts of ethylene-propylene-diene monomer, 10-25 parts of talcum powder, 3-10 parts of brucite powder, 5-12 parts of modified micro silicon powder, 0.8-2 parts of colouring agent, 5-15 parts of nano mica, 0.5-2 parts of antioxidant, 0.5-2 parts of polytetrafluoroethylene, 10-25 parts of modified shell powder, 5-15 parts of modified hectorite, 5-25 parts of novel organic montmorillonite, 5-18 parts of melamine cyanurate, 10-25 parts of modified crystal whisker, 15-30 parts of long glass fiber, 3-8 parts of expandable graphite and 5-20 parts of intumescent flame retardants. The anti-impact MPP electric protection tube has excellent impact resistance, flame retardance, ageing resistance, cold resistance and heat resistance.

The invention discloses a high-performance magneto-rheological fluid, which comprises the following materials in percentage by weight of the magneto-rheological fluid: 50 to 80 percent of mixed magnetic granules of nano-scale carbonyl iron powder and carbonyl iron powder, 10 to 40 percent of carrier liquid, 0.5 to 2 percent of surfactant, 0.5 to 2 percent of thixotropic agent, 0.5 to 2 percent of antioxidant, 0.5 to 2 percent of solid lubricant, and 0.5 to 2 percent of dispersant. The high-performance magneto-rheological fluid of the invention has good anti-settling stability; and after the magneto-rheological fluid is stood for 1 year, the magneto-rheological fluid still has good stability and anti-settling property by observing the stability thereof. Meanwhile, the shear yield stress of the magneto-rheological fluid is obviously improved, and the shear yield stress of the high-performance magneto-rheological fluid can reach 60 kPa under an external magnetic field (1T).

The invention discloses a piezoelectric extrusion type magnetorheological clutch, which comprises a casing with a cylindrical through hole, wherein a coil is arranged in the casing, a driving disc and a driven disc are arranged in the through hole, magnetorheological fluid is arranged between the driving disc and the driven disc, the work surface of the driving disc is provided with at least two circles of concentric convex strips, the work surface of the driven disc is provided with at least two circles of grooves matched with the convex strips, a stacked piezoelectric drive used for driving the driven disc to move towards the driving disc in an axial direction is arranged on the driven disc, and a fine adjustment device used for accommodating redundant magnetorheological fluid is arranged on a driving shaft. A transfer torque calculating method of the piezoelectric extrusion type magnetorheological clutch is characterized in that the transfer torque T extrusion of the clutch is shown as the accompanying drawing. The piezoelectric extrusion type magnetorheological clutch has the advantages that a piezoelectric stacked actuator extrudes the magnetorheological fluid, and the shear yield stress of the magnetorheological fluid can be improved, so the torque transfer capability is greatly enhanced, the energy consumption is low, the transfer capability control capability of the clutch is high, and the sealing performance is good.

The invention discloses mineral oil based magnetorheological fluid for high power transmission. The mineral oil based magnetorheological fluid comprises the following components by mass percent: 60-80% of magnetic particles, 15-40% of carrier liquid and 2-5% of additives, wherein the magnetic particles are carbonyl iron powder particles and nano ferriferrous oxide particles; the carrier liquid is mineral oil; the additives comprise a surface active agent, a thixotropic agent, an antioxidant and an antiwear agent, meanwhile, the invention further provides a preparation method of the magnetorheological fluid, and the prepared magnetorheological fluid has excellent sedimentation stability, lower zero field viscosity, higher shear yield stress and long service life, and can meet the application requirements of high power transmission devices.

This invention belongs to compound material and function material technique field and in detail to light magnetic particles with magnetic rheologic liquid and its process method. The material uses nanometer tube special electromagnetism property and a layer of Fe#-[3] O#-[4] on the surface. It in detail is processed with the nanometer tube, dispersant, strong acid, trivalence iron salt, two iron salt and alkali as certain weight proportion through certain process.

The invention belongs to compound material and function material technological field, concretely are a shallow magnetic compound micro particle for magnetic rheologic liquid and its preparing method. The micro ball is formed by covering a layer of Fe3O4 on the shallow polystyrene micro ball, and it is comprised of shallow polystyrene micro ball, trivalent ferric salt, bivalent ferric salt, dispersant and alkali which are mixed by proper ratio. Through supersonic dispersion, covering micro particle and after-procession, the product is made. The product made by the invention has small density, good magnetic performance, high shearing stress and outstanding depositing stability.

The auxiliary braking device with magnetic rheological body for petroleum rig includes one cylinder of non-magnetic conductive material and two end caps of magnetic conductive material to form one sealed cylindrical cavity, two magnetic conductive columns with wound exciting coil outside the cylinder and between the two end caps, one shaft of non-magnetic conductive material with fixed magnetic conductive blades set between the two end caps, and magnetic rheological body filled in the sealed cylindrical cavity. The present invention can provide great braking moment at all rig winch speeds, and has stepless regulation of braking moment, fast response, low cost and long service life.

The invention discloses a high-performance magnetorheological fluid which comprises the following components in percentage by weight: 50-80% of mixed carbonyl iron powder, 10-40% of carrier liquid, 0.5-2% of surfactant, 0.5-2% of thixotropic agent, 0.5-2% of antioxidant, 0.5-2% of solid lubricant and 0.5-2% of dispersant. Compared with the prior art, by adding a small amount of nano carbonyl iron powder into micron carbonyl iron powder, the invention can obviously improve the sedimentation stability of the magnetorheological fluid and can improve the shear yield stress of the magnetorheological fluid under a magnetic field. After standing for 1 year, the magnetorheological fluid can still show favorable sedimentation resistance and aggregation resistance. The magnetorheological fluid disclosed by the invention can be widely used in the fields of aerospace, machinery, intelligent vibration damping of vehicles or civil building structures.

The invention discloses an anti-aging MPP (modified polypropylene) electric tube which is prepared from the following raw materials in parts by weight: 100-150 parts of polypropylene, 5-10 parts of light calcium carbonate, 1-8 parts of flake talcum powder, 2-10 parts of calcined kaolin, 1-5 parts of brucite powder, 20-40 parts of modified micro silicon powder, 0.2-3 parts of colorant, 2-10 parts of novel nucleating agent, 1-2.7 parts of antioxidant, 0.5-3 parts of polytetrafluoroethylene, 2-12 parts of master batch, 5-20 parts of melamine cyanurate and 5-15 parts of modified crystal whisker. The preparation process of the novel nucleating agent comprises the following steps: adding 150-180 parts of p-tert-butyl benzoic acid into 200-300ml of tetraisopropyl titanate, reacting at 90-130 DEG C for 3-5 hours, adding 100-150ml of silicate to obtain a solution A, adding the solution A into an ethanol-water mixture, hydrolyzing at 50-65 DEG C for 3-5 hours, filtering, and drying to obtain the novel nucleating agent. The anti-aging MPP electric tube has the advantages of high aging resistance, excellent impact resistance, excellent freezing resistance and excellent heat resistance.

The invention discloses a high flaming retarding MPP power protecting tube which comprises the following raw materials in parts by weight: 100-130 parts of polypropylene, 10-25 parts of talcum powder, 3-15 parts of brucite powder, 5-15 parts of modified silica fume, 0.3-2 parts of colorant, 5-15 parts of nano mica, 0.5-2 parts of an antioxidant, 0.5-3 parts of polytetrafluoroethylene, 15-40 parts of modified shell powder, 10-25 parts of cyanuric acid melamine, 10-25 parts of modified crystal whisker, 15-30 parts of long glass fiber, 3-8 parts of expandable graphite and 5-20 parts of inrumescent flame retardant. The high flaming retarding MPP power protecting tube disclosed by the invention is excellent in flame retardancy, impact resistance, aging resistance, cold resistance and thermal resistance.

The invention discloses an electric heating extrusion disc magneto-rheological and electromagnetic bearing bush friction combined transmission device. The electric heating extrusion disc magneto-rheological and electromagnetic bearing bush friction combined transmission device comprises a driving shaft, a driven shaft and a transmission shell, wherein the part, located in a driven shell, of the driving shaft is expanded to form a transmission section; two armature tiles are symmetrically arranged on the transmission section, and a guide column and a compression shape memory alloy spring are arranged in the middle of the inner side of each armature tile; a liquid containing groove is formed in the outer side of each armature ring, and each liquid containing groove is filled with magnetorheological fluid; extrusion discs are correspondingly arranged between two ends of the transmission section and a left end cover and between two ends of the transmission section and a right end cover, and the guide rods and the extrusion shape memory alloy springs are arranged at one sides, close to the transmission section, of the extrusion discs; a gap between the extrusion disc close to the left end cover and the left end cover and a gap between the extrusion disc close to the right end cover and the right end cover are also filled with magnetorheological fluid. According to the electric heating extrusion disc magneto-rheological and electromagnetic bearing bush friction combined transmission device, the influence of temperature on the magnetorheological fluid can be reduced, the transmission performance of the transmission device is improved, and the stability of torque transmission is ensured; and heat energy is fully converted and utilized, so that energy waste is reduced.

The invention relates to a magnetorheological-effect-based straight screwdriver with the positioning and anti-slipping functions. The magnetorheological-effect-based straight screwdriver with the positioning and anti-slipping functions is used for preventing the phenomenon that a bolt head is damaged due to the fact that relative slippage occurs between a screwdriver head and a bolt occurs when an operator overexert himself / herself to tighten or loosen the bolt through a screwdriver. The magnetorheological-effect-based straight screwdriver with the positioning and anti-slipping functions is composed of a shell, magnetorheological fluid, an isolation ring, an electromagnetic coil, a piston, a sealing ring, a piston rod, a cross bar, connecting rods, clamping rods, a straight screwdriver head, a size compensator, a sliding block, a button and a sliding groove. When the straight screwdriver head is stretched into a bolt head, a user slides the sliding block upwards to make the clamping rods clamp the bolt head tightly and then presses the button to power on the straight screwdriver, relative slippage will not be produced by the screwdriver head, the bolt head and the clamping rods when the screwdriver is rotated, and finally the bolt is tightened or loosened on the condition of guaranteeing that the bolt head is not scratched; the user presses the button again to power off the straight screwdriver and slides the sliding block downwards to make the clamping rods to loosen the bolt head, and then the whole bolt tightening or loosening process is completed.

The invention relates to a magnetorheological-effect-based hexagonal screwdriver with the positioning and anti-slipping functions. The magnetorheological-effect-based hexagonal screwdriver with the positioning and anti-slipping functions is used for preventing the phenomenon that a bolt head is damaged due to the fact that relative slippage occurs between a screwdriver head and a bolt occurs when an operator overexert himself / herself to tighten or loosen the bolt through a screwdriver. The magnetorheological-effect-based hexagonal screwdriver with the positioning and anti-slipping functions is composed of a shell, magnetorheological fluid, an isolation ring, an electromagnetic coil, a piston, a sealing ring, a piston rod, a cross bar, connecting rods, clamping rods, a hexagonal screwdriver head, a size compensator, a sliding block, a button and a sliding groove. When the hexagonal screwdriver head is stretched into a bolt head, a user slides the sliding block upwards to make the clamping rods clamp the bolt head tightly and then presses the button to power on the hexagonal screwdriver, relative slippage will not be produced by the screwdriver head, the bolt head and the clamping rods when the screwdriver is rotated, and finally the bolt is tightened or loosened on the condition of guaranteeing that the bolt head is not scratched; the user presses the button again to power off the hexagonal screwdriver and slides the sliding block downwards to make the clamping rods to loosen the bolt head, and then the whole bolt tightening or loosening process is completed.

The invention provides a magnetorheological polishing adhesive and a preparation method thereof. The magnetorheological polishing adhesive is composed of carbonyl iron powder (30%-70%), polishing powder (2%-7%), gel (0.5%-5%), gas-phase silicon dioxide (0.2%-1.5%), deionized water (10%-35%), and glycerol (15%-40%). The preparation method comprises the following steps: (1) weighing the carbonyl iron powder, the polishing powder, the gas-phase silicon dioxide, the gel, the deionized water and the glycerol according to a formula of the magnetorheological polishing adhesive; (2) putting the glycerol and the deionized water into a container, performing stirring to obtain a glycerol aqueous solution, performing heating, dissolving the gel into the glycerol aqueous solution under stirring to forma mixed solution; (3) adding the weighed carbonyl iron powder, the weighed gas-phase silicon dioxide, and the weighed polishing powder to the mixed solution in sequence, and performing stirring to obtain a magnetorheological polishing adhesive; and (4) putting the formed magnetorheological polishing adhesive into a refrigerating chamber, performing refrigeration, and taking the adhesive out whenusing. The magnetorheological polishing adhesive provided by the invention has the simple preparation method, higher stability and a higher shear yield stress, and can meet performance requirements ofprocessing.

The invention relates to a cylindrical roller thrust bearing having an integrated speed change function for a small load. The cylindrical roller thrust bearing is mainly used for adjusting the speed distribution condition of a mechanism operating in a period under the condition of the small load. The device comprises a shaft ring, a base ring, a rolling body, a holder, magnetorheological fluid, an electromagnetic coil, a separation ring, a piezoelectric ceramic and an insulation body. Two annular grooves are formed in the upper surface of the base ring; one annular groove is wound with the electromagnetic coil, and the other one is provided with the piezoelectric ceramic; the base ring and the piezoelectric ceramic are isolated by the insulation body; the shaft ring, the base ring and the separation ring are formed to a sealing cavity; the magnetorheological fluid is sealed in the sealing cavity, and is separated from the electromagnetic coil by the separation ring; a non-annular small boss is arranged on the lower surface of the shaft ring; the installation enables the small boss to periodically move in the annular groove provided with the piezoelectric ceramic; and a channel is formed between the electromagnetic coil and the piezoelectric ceramic for conducting the positive and negative poles of the piezoelectric ceramic with the two ends of the electromagnetic coil.

The invention relates to a magnetorheological-effect-based line-shaped bolt with the pretightening force adjusting function. According to the line-shaped bolt, magnetorheological intensity is regulated and controlled to regulate pretightening force so as to meet connected part occasions with specific pretightening force requirements. The line-shaped bolt comprises a bolt head, sliding grooves, a bolt bar, magnetorheological fluid, an isolation ring, a volume compensator, an electromagnetic coil, a sealing ring, a piston, a sliding gasket and a reset spring. After the optimum initial pretightening force F0 of a connected part is determined, current flowing into the electromagnetic coil is regulated so as to regulate the rheological intensity of the magnetorheological fluid, and finally the shear yield stress of the magnetorheological fluid is stabilized to be the optimum initial pretightening force F0 of the connected part; then, a nut is tightened to make the sliding gasket move slightly, and finally it is determined that the force is the optimum pretightening force F0 of the connected part. After the line-shaped bolt is connected with the connected part, pretightening force detection does not need to be carried out additionally and is completed in the pretightening process, so that operation is convenient, precision is high, and time and labor are saved.

The invention relates to a cylindrical roller bearing with an integrated speed change function for a small load. The cylindrical roller bearing is mainly used for adjusting the speed distribution condition of a mechanism during operation in a cycle under the condition of the small load. The cylindrical roller bearing comprises an outer ring, a rolling body, a retaining rack, an inner ring, magnetorheological fluid, an isolating ring, an electromagnetic coil, piezoelectric ceramics and an insulator. Two annular grooves are formed in the internal wall of the outer ring, one annular groove is wound with the electromagnetic coil, the piezoelectric ceramics are mounted in the other annular groove, and the outer ring and the piezoelectric ceramics are isolated by the insulator; a sealed chamber is formed by the inner ring, the outer ring and the isolating ring, and the magnetorheological fluid is sealed in the sealed chamber and is isolated from the electromagnetic coil by the isolating ring; the external wall of the inner ring is provided with a non-annular small boss which is mounted in a manner that the small boss does periodic motion in the annular groove with the piezoelectric ceramics; a passage is formed between the electromagnetic coil and the piezoelectric ceramics and is used for enabling the positive and negative poles of the piezoelectric ceramics to be in conduction with the two ends of the electromagnetic coil.

The invention relates to a water-based magnetorheological polishing solution for optical manufacture, which is formed by the following volume components, water-based remixed carrier liquid 25%-75% and additive component 25%-75%, wherein the additive component is dispensed by the following volume percentage, carbonyl iron powder 80%-90%, nanometer iron powder 4%-10% and polishing powder 4%-10%, the water-based remixed carrier liquid which is measured according to volume percentage comprises deionized water 85%-90%, dispersing agent 3%-5%, wetting agent 2%-5% and thixotropic agent 3%-5%, the method for preparing comprises the following steps: mixing deionized water and thixotropic agent, stirring in indoor temperature for 1-2 hours, and adding dispersing agent, stirring in indoor temperature for 0.5-1 hour, and then adding wetting agent, stirring in indoor temperature for 0.5-1 hour, getting water-based remixed carrier liquid, mixing additive component and water-based remixed carrier liquid, adding into a ball-milling tank, adding into a steel ball according to mass ratio which is 1:10, grinding for 3-5 hours in the speed which is 20-30r / m, separating out a steel ball, and getting products. The polishing solution of the invention has the advantages of excellent stability, high rheological property, excellent oxidation resistance property and simple and environmental-friendly preparation technology.

The invention discloses a high-power magnetorheological constant acceleration soft start device and a control system thereof, and belongs to the field of magnetorheological fluid transmission. The high-power magnetorheological constant acceleration soft start device and the control system thereof comprise a device part and a control part. The device part is in a double-disc magnetorheological fluid transmission mode, the working faces of two transmission discs are provided with radial strip grooves, the space between the two discs is filled with magnetorheological fluid, and a magnet exciting coil is wound around the two discs. The control part is composed of a data processor, a master controller, a sensor, a current controller and a hydraulic cylinder control valve. The largest torsional moment of the magnetorheological soft start device is improved by pressurizing the magnetorheological fluid and changing the surface structures of the inner wall faces of the two discs, and a constant acceleration soft start system is controlled in the starting process.

The present invention relates to a small load double row angular contact ball bearing with integrated speed change function. The bearing is mainly used to adjust the speed distribution of mechanism operation in one cycle in the case of small load. The apparatus includes an outer ring, a rolling element, a cage, an inner ring, a magnetorheological suspension, a spacer ring, a solenoid coil, a piezoelectric ceramic and an insulator. The inner wall of the outer ring is provided with two annular grooves; one annular groove is wound by the solenoid coil, and the other annular groove is provided with the piezoelectric ceramic; the insulator isolates the outer ring and the piezoelectric ceramic; the inner ring, outer ring and the spacer ring form a seal cavity for sealing the magnetorheological suspension therein; and the spacer ring isolates the magnetorheological suspension from the solenoid coil; outer wall of the inner ring is provided with a non-annular small projection; the small projection does periodic motion in the annular groove provided with the piezoelectric ceramic; and a channel is between the solenoid coil and the piezoelectric ceramic, and is used for conducing the positive and negative electrodes of the piezoelectric ceramic and two ends of the solenoid coil.

The present invention is an electromagnetic extruded magneto-rheological and shape-memory alloy friction composite brake, which includes a brake shaft, a brake housing and a brake base, and a brake disc is also arranged in the brake housing; the brake disc and the left An armature disc is respectively arranged between the housing and the right housing, and a squeeze disc is arranged between the armature disc and the brake disc, and magnetorheological fluid is filled between the squeeze disc and the brake disc; There are several accommodating grooves, in which a hollow liquid guide rod and a shape memory alloy spring are arranged, and a friction block is arranged at the outer end of the accommodating groove; a liquid guiding rod is arranged between the coil groove and the accommodating groove There are several through holes on the side wall of the hollow liquid guide rod, and the heat conduction liquid is filled in the liquid guide hole, the storage tank and the hollow liquid guide rod. The invention can effectively improve the braking torque of the brake, ensure the braking stability and improve the braking effect.

The invention discloses a magneto-rheological fluid pilot pressure reducing valve, which comprises a main valve body, a main valve core, a spring, a valve seat, a damping disc, a bobbin frame, a coil and a valve sleeve; the main valve includes two left and right cavities Body, the left chamber communicates with the oil outlet, the right chamber communicates with the oil inlet, and the valve port is normally open; the left chamber communicates with the front chamber of the magnetorheological pilot valve through the damping hole, and the main valve core and the inner surface of the main valve form a moving pair; In the magneto-rheological pilot valve, the liquid flow channel between the winding frame, the positioning disc and the damping disc forms an axial and radial damping gap. When the coil of the magneto-rheological pilot valve is energized, the magnetic force line passes through the damping gap vertically, and the magnetic flow Under the action of the magnetic field, the viscosity of variable fluid increases rapidly; by adjusting the magnitude of the current, the pressure difference at both ends of the damping gap can be changed; the magnetorheological pilot valve has no moving spool, simple structure, and high control precision.

The invention relates to a magnetorheological-effect-based straight screwdriver with the positioning and anti-slipping functions. The magnetorheological-effect-based straight screwdriver with the positioning and anti-slipping functions is used for preventing the phenomenon that a bolt head is damaged due to the fact that relative slippage occurs between a screwdriver head and a bolt occurs when an operator overexert himself / herself to tighten or loosen the bolt through a screwdriver. The magnetorheological-effect-based straight screwdriver with the positioning and anti-slipping functions is composed of a shell, magnetorheological fluid, an isolation ring, an electromagnetic coil, a piston, a sealing ring, a piston rod, a cross bar, connecting rods, clamping rods, a straight screwdriver head, a size compensator, a sliding block, a button and a sliding groove. When the straight screwdriver head is stretched into a bolt head, a user slides the sliding block upwards to make the clamping rods clamp the bolt head tightly and then presses the button to power on the straight screwdriver, relative slippage will not be produced by the screwdriver head, the bolt head and the clamping rods when the screwdriver is rotated, and finally the bolt is tightened or loosened on the condition of guaranteeing that the bolt head is not scratched; the user presses the button again to power off the straight screwdriver and slides the sliding block downwards to make the clamping rods to loosen the bolt head, and then the whole bolt tightening or loosening process is completed.

The invention belongs to the technical field of functional composite materials and relates to a preparation technology of a material with a shear thinning electromagnetorheological property. Comparedwith other single component materials, the prepared composite material of a core-shell structure by taking ferriferrous oxide as a core and molybdenum disulfide as a shell and modifying molybdenum disulfide with titanium dioxide has obviously excellent electrorheological and magnetorheological properties. The preparation method is simple in preparation process and convenient to operate; titanium dioxide and molybdenum disulfide have excellent electrorheological properties and can generate a relatively high shear yield stress under the action of an electric field, and meanwhile, magnetic ferriferrous oxide has a relatively high magnetizing saturated degree and can generate a relatively high shear yield stress under the action of a magnetic field. Molybdenum disulfide has an excellent lubricating property, so that the material is low in cost, clean and non-toxic and relatively short in reaction time, and has wide application value.

The invention relates to a magnetorheological-effect-based hexagonal screwdriver with the positioning and anti-slipping functions. The magnetorheological-effect-based hexagonal screwdriver with the positioning and anti-slipping functions is used for preventing the phenomenon that a bolt head is damaged due to the fact that relative slippage occurs between a screwdriver head and a bolt occurs when an operator overexert himself / herself to tighten or loosen the bolt through a screwdriver. The magnetorheological-effect-based hexagonal screwdriver with the positioning and anti-slipping functions is composed of a shell, magnetorheological fluid, an isolation ring, an electromagnetic coil, a piston, a sealing ring, a piston rod, a cross bar, connecting rods, clamping rods, a hexagonal screwdriver head, a size compensator, a sliding block, a button and a sliding groove. When the hexagonal screwdriver head is stretched into a bolt head, a user slides the sliding block upwards to make the clamping rods clamp the bolt head tightly and then presses the button to power on the hexagonal screwdriver, relative slippage will not be produced by the screwdriver head, the bolt head and the clamping rods when the screwdriver is rotated, and finally the bolt is tightened or loosened on the condition of guaranteeing that the bolt head is not scratched; the user presses the button again to power off the hexagonal screwdriver and slides the sliding block downwards to make the clamping rods to loosen the bolt head, and then the whole bolt tightening or loosening process is completed.

The invention relates to a self-aligning ball bearing for small loads and with an integrated variable speed function. The self-aligning ball bearing is mainly used under the small-load condition and adjusts the speed distribution condition of a mechanism running within one period. The ball bearing comprises an outer ring, rolling bodies, holders, an inner ring, magnetorheological fluid, an isolation ring, an electromagnetic coil, piezoelectric ceramic and an insulation body. Two annular grooves are formed in the inner wall of the outer ring, and the electromagnetic coil is wound on one annular groove; the piezoelectric ceramic is mounted on the other annular groove; and the outer ring is isolated from the piezoelectric ceramic through the insulation body. A sealed cavity is formed by the inner ring, the outer ring and the isolation ring, and the magnetorheological fluid is sealed in the sealed cavity and is isolated from the electromagnetic coil through the isolation ring; and a non-annular small boss is arranged on the outer wall of the inner ring, and the small boss does the periodic motion in the annular groove with the piezoelectric ceramic; and a channel is formed between the electromagnetic coil and the piezoelectric ceramic and is used for conducting the positive electrode and the negative electrode of the piezoelectric ceramic and the two ends of the electromagnetic coil.

The invention belongs to the technical field of functional composite materials and relates to a preparation technology of a material with a shear thinning electromagnetorheological property. Comparedwith other single component materials, the prepared composite material of a core-shell structure by taking ferriferrous oxide as a core and molybdenum disulfide as a shell and modifying molybdenum disulfide with titanium dioxide has obviously excellent electrorheological and magnetorheological properties. The preparation method is simple in preparation process and convenient to operate; titanium dioxide and molybdenum disulfide have excellent electrorheological properties and can generate a relatively high shear yield stress under the action of an electric field, and meanwhile, magnetic ferriferrous oxide has a relatively high magnetizing saturated degree and can generate a relatively high shear yield stress under the action of a magnetic field. Molybdenum disulfide has an excellent lubricating property, so that the material is low in cost, clean and non-toxic and relatively short in reaction time, and has wide application value.

The invention relates to an outer hexagonal screwdriver which is based on the magnetorheological effect and has the positioning function and the anti-slippage function. The screwdriver is used for preventing the phenomenon that when a screwdriver is used for tightening or loosening a bolt, a screwdriver blade and a bolt head have relative slippage because exerted force is too large, and the bolt head is damage is prevented. The device is composed of a shell, magnetorheological liquid, an isolating ring, an electromagnetic ring, a piston, a sealing ring, a piston rod, a transverse rod, a connecting rod, a clamping rod, an outer hexagonal screwdriver blade, a volume compensator, a slider, a button and a sliding groove. After the outer hexagonal screwdriver blade extends into the bolt head, the slider is made to slide upwards, the clamping rod is made to tightly clamp the bolt head, then, the button is pressed down and the screwdriver is powered on, no relative slippage happens to the screwdriver blade, the bolt head and the clamping rod when the screwdriver is screwed, finally, it is guaranteed that the bolt is tightened or loosened under the situation that the bolt head is not scratched, next, the button is pressed down again and the screwdriver is powered off, the slider is made to slide downwards so that the clamping rod can loosen the bolt head, and the whole process that the bolt is tightened or loosened is completed.