214 results about "Hydrodynamic pressure" patented technology

An flame retardant, electrically-conductive EMI shielding material and method, the material being particularly adapted for use in fabric-over-foam EMI shielding gasket constructions. In construction, a generally planar, porous fabric member is provided as having at least an electrically-conductive first side and a second side defining a thickness dimension therebetween. A curable layer of a fluent, flame retardant composition is applied under a predetermined hydrodynamic pressure and viscosity to at least a portion of the second side of the fabric member. The hydrodynamic pressure and viscosity of the composition are controlled to delimit the penetration of the layer into the fabric member to a depth which is less than the thickness dimension of said fabric member. The layer then is cured to form a flame retardant surface coating on the second side of the fabric member such that the first side of said fabric member remains electrically-conductive.

The invention provides a hydrodynamic pressure scouring test method and a device of bituminous mixture. The method comprises the following steps of: disposing a bituminous mixture test piece in a closed container and soaking in water; heating the water to a temperature to be simulated, keeping the temperature, and filling compressed air in the closed container to 0.68 to 0.7 MPa, i.e. applying positive pressure to the water and the test piece; releasing the pressure of the closed container to normal pressure, pumping the closed container to -0.095 to -0.1 MPa, i.e. applying negative pressure to the water and the test piece; and repeating steps to achieve simulation process of hydrodynamic pressure scouring of the bituminous mixture. The steps are respectively used for testing the determination index of water damage resistance of the bituminous mixture test piece. The invention can acquire the attenuation law of water damage resistance performance of the bituminous mixture and the migration law of bituminous in the mixture by applying hydrodynamic pressure to the bituminous mixture test pipe, simulating the actual condition of bituminous pavement and detecting the water stability of the bituminous mixture.

The invention relates to a fluid dynamic bearing system having at least one stationary part and one rotating part that form a bearing gap filled with bearing fluid between the opposing bearing surfaces, at least one end of the bearing gap being open and sealed against the environment by a sealing means, pumping grooves being provided on at least two spatially separated bearing surfaces to generate hydrodynamic pressure and at least one supply volume connected to the bearing gap being available for the bearing fluid. The distinctive feature of the invention is that the sealing means are formed by pumping grooves that are disposed at the open end of the bearing gap on at least one of the bearing parts and designed in such a way that they generate a pumping action on the bearing fluid directed towards the interior of the bearing and, as a result, create a dynamic seal for the open end of the bearing. The bearing system itself is designed as a compact unit preferably consisting of only three parts.

The invention relates to a testing method of vibration of a structure in a flow field, in particular to the testing method of vortex-induced vibration of a cylinder. In the method, a testing device which can independently control the two-degree-of-freedom vibration along the flow direction and the transverse direction respectively is utilized for performing two-degree-of-freedom vortex-induced vibration testing and single-degree-of-freedom vortex-induced vibration testing respectively, analyzing phenomena and data of the two-degree-of-freedom vortex-induced vibration testing and the single-degree-of-freedom vortex-induced vibration testing and comparing analysis results of the single-degree-of-freedom vortex-induced vibration testing and the two-degree-of-freedom vortex-induced vibration testing. Under the same testing conditions, the single-degree-of-freedom vortex-induced vibration testing along the flow direction or the transverse direction and the two-degree-of-freedom vortex-induced vibration testing along the flow direction or the transverse direction can be completed and synchronous measurement of hydrodynamic pressure, motion parameters (displacement, speed and acceleration) of a testing model and vortex discharge can be realized.

A system to facilitate separation and concentration of particles based on centrifugal force on suspended particles, including biological matter, which are made to flow in a vortex structure is provided. The centrifugal force urges larger particles to collect along outer portions of the vortex flow. Conversely, within a vortex structure, a radial hydrodynamic pressure drop is also amplified to urge smaller particles toward inner portions of the vortex flow. This force created by the pressure can reach magnitudes that encourage a sharp cut-off and improved resolution discrimination between particle sizes. Thus, separated streams of particles can be collected with both increased concentration and purification.

A hydrodynamic bearing device which supports a relative-rotation shaft or bearing by the hydrodynamic pressure of lubricating fluid which develops in a clearance between the bearing and the shaft, wherein leakage of the lubricating fluid to the outside of the bearing is satisfactorily prevented by a simple arrangement. A fluid pressing means applying to the lubricating fluid (5) an inward pressing force directed from the opening side of the bearing clearance toward the closed side, for example, a hydrodynamic pressure producing groove (13a) in which a hydrodynamic pressure (Pa1) having an inward vector component and a hydrodynamic pressure (Pa2) having an outward vector component are simultaneously produced, the hydrodynamic pressures being unbalanced in that the hydrodynamic pressure (Pa1) having an inward vector component is prevailing, has an inward pressing force imparting action which ensures that the lubricating fluid (5) in the bearing clearance is constantly pressed toward the closed side of the bearing clearance to hold that the gas-liquid interface (6) of the lubricating fluid (5) so that it is pushed inward. By setting the filling amount of the lubricating fluid (5) at a value with which the fluid pressing means is filled with the lubricating fluid (5) even upon occurrence of relative movement of the gas-liquid interface (6) toward the bearing clearance, which relative movement takes place upon relative upward movement of a thrust plate (16) or the like in the thrust direction, leakage of the lubricating fluid (5) through a seal portion (RS) is satisfactorily prevented.

In spindle motors journaled on fluid-dynamic-pressure bearings, especially in such spindle motors employed in recording-disk drives in implementations that subject the drives to vibration and shock, sealing performance of a capillary seal formed between motor rotor-side and stator-side bearing surfaces, cohesiveness of oil-repellant on rotor-side/stator-side dry-area surfaces adjoining the capillary seal section, and motor inter-component adhesive strength are improved. The capillary-seal-constituting rotor-side/stator-side surface(s) are exposed to a plasma or to ultraviolet rays under predetermined conditions to improve the wettability of the surface(s) for the bearing fluid. The dry-area surface(s) are similarly irradiated so as to improve their wettability for the oil-repellant. Adhesively bonded component surfaces are likewise irradiated so as to improve their wettability for the adhesive, enhancing adhesive strength. Exposed surfaces may be constituted of a synthetic resin to enhance their wettability further, or may be made of metal, to yield a cleaning efficacy from the plasma/UV exposure.

The invention relates to an adjustable multiple coil extruding and expanding drilling tool, comprising a hollow connecting rod, the lower part of the lateral wall of the connecting rod is provided with a helical blade, the bottom end of the connecting rod is provided with a drill, the connecting rod is coaxially connected with a plurality of helical extruding expanding bodies, the helical extruding expanding body is arranged between the helical blades, the margin of the cross section of each helical extruding expanding body is helical line, maximum outer diameter and minimum outer diameter ofeach helical extruding expanding body are respectively constant or increased from bottom to top, and the maximum outer diameter of each helical extruding expanding body is equal to or less than the outer diameter of the helical blade. The invention aims at providing an adjustable multiple coil extruding and expanding drilling tool which can penetrate thick hard clay or dense sand soil layer, avoid collapse when drilling into finished hole in high ground eater level and high hydrodynamic pressure stratum and can implement complete extruding soil or partial extruding soil type cast-in-place pile through multiple stage extruding and expanding at different depths by freely adjusting the position of multi-stage extruding expanding body according to longitudinal distribution of stratum.

An electrochemical machining tool (1) for electrochemical machining includes an electrode body (11). The electrochemical machining tool (1) and associated method can conduct simultaneous electrochemical machining of at least two of a radial dynamic pressure generating groove (43), an axial dynamic pressure generating groove (44), and a removal of a burr (42) associated with an oil pool (41). Electrochemical machining is performed with groove machining electrodes (12, 13) and deburring electrodes (14). A sleeve (4) machined using the electrochemical machining tool (1) and associated method has the radial dynamic pressure generating groove (43), the axial dynamic pressure generating groove (44), and the deburred oil pool (41). The sleeve (4) can be used in a hydrodynamic pressure bearing for use in a spindle motor of a hard disk drive.

An electrochemical machining tool (1) for electrochemical machining includes an electrode body (11). The electrochemical machining tool (1) and associated method can conduct simultaneous electrochemical machining of at least two of a radial dynamic pressure generating groove (43), an axial dynamic pressure generating groove (44) , and a removal of a burr (42) associated with an oil pool (41). Electrochemical machining is performed with groove machining electrodes (12, 13) and deburring electrodes (14). A sleeve (4) machined using the electrochemical machining tool (1) and associated method has the radial dynamic pressure generating groove (43) , the axial dynamic pressure generating groove (44) , and the deburred oil pool (41). The sleeve (4) can be used in a hydrodynamic pressure bearing for use in a spindle motor of a hard disk drive.

A machining method for complex surfaces of liquid hybrid type mechanical seal rings belongs to the technical field of precision machining and is characterized in that a sum of the square of diameter of a cup wheel and the square of medium diameter of a sloped corrugate face is equal to a square of a doubled distance from an intersection of the end face of the wheel and a rotational axis of the wheel to a rotational axis of a rotary worktable, an inclination angle of the wheel is equal to a largest radial outline inclination angle of the sloped corrugate face, rotation of the rotary worktable, reciprocating swing of a swing worktable and periodic following are in linked control when the sloped corrugate face is ground, the end face of the wheel is used for constant micro-feed cut-in grinding in the cutting depth direction of the wheel, the rotary worktable is in constant-speed rotation when a seal dam face is ground, and the end face of the wheel is used for constant micro-speed cut-in grinding in the cutting depth direction of the wheel. The machining method has the advantages that machining high in surface shape precision and low in surface roughness for the complex surface of a hydrodynamic pressure seal ring is achieved, while the hydrodynamic pressure seal ring is composed of a flat circular dam face and a sloped corrugate face which has slight inclined linear radial outline and peripherally and periodically changing inclination.

The invention discloses a mechanical sealing structure with the end face being provided with vein-shaped grooves. The front end face, namely the sealing face, of the mechanical sealing structure is composed of an outer ring (1), an inner ring (2), a sealing weir area (3), a sealing dam area (4) and the 6-12 vein-shaped grooves (5) which are all located in the different positions of the front end face, namely the sealing face, of the mechanical sealing structure. The number of the vein-shaped grooves (5) is changed along with the size of the mechanical sealing structure. Each vein-shaped groove (5) is composed of a first branch groove body (51), a second branch groove body (52), a third branch groove body (54), a fourth branch groove body (55) and a main groove body (53). The hydrodynamic pressure effect is effectively improved, the side effect caused by unevenness of the mechanical sealing end face is reduced, and the working efficacy of mechanical sealing is improved; and the rub-impact failure under the extreme working conditions of the small film thickness and the small pressure difference can be effectively avoided, non-contact sealing is achieved, abrasion resistance is improved, the service life is prolonged, and sealing reliability is improved.

The invention relates to a method of designing a dam-reservoir water coupled dynamic model test on a vibration table, which belongs to the field of hydraulic structure engineering and model test study. A geometrical size of each part of a two-dimensional model dam section and a layout scheme for each related monitoring device are firstly designed; main physical and mechanical parameters of the model material are determined; the dam model is cast, and each test instrument is buried in advance according to the well-designed layout scheme; a water tank which simulates the reservoir is lifted to the upstream side of the model dam; a reservoir tail energy dissipation device is placed at one end, far away from the model dam, inside the water tank; and after the model dam and the water tank which simulates the reservoir are assembled and the test instruments are assembled and connected, a model dam seismic dynamic simulation test is begun. According to the method of the invention, the theory is simple and easy to understand, the construction process is simple, and hydrodynamic pressure borne by the upstream dam and influences on a dam dynamic response by the upstream reservoir water in the case of an earthquake can be accurately measured in a lab.

The invention belongs to the field of polishing of ultra-precision optical elements, and in particular discloses a magneto-rheological polishing device and method based on flow field focusing. The magneto-rheological polishing device comprises an end cover, a sleeve, a polishing head shell and a magnetic isolating rotation shaft, wherein the end cover and the polishing head shell are connected with the two ends of the sleeve, and a liquid inlet and a liquid outlet are formed in the polishing head shell; the magnetic isolating rotation shaft is arranged in the sleeve, one end of the magnetic isolating rotation shaft penetrates through the end cover to be connected with an external rotating power source, and the other end of the magnetic isolating rotation shaft is inlaid with a permanent magnet and is inserted into the polishing head shell to form a flow focusing chamber with the inner part of the polishing head shell; and the liquid outlet is positioned directly below the permanent magnet. During polishing, one part of magneto-rheological polishing fluid forms a bingham body under the action of permanent magnet at the end face of the magnetic isolating rotation shaft; and the otherpart of the magneto-rheological polishing fluid flows in the flow focusing chamber and is ejected from the liquid outlet, and the part generates hydrodynamic pressure to extrude the bingham body forshaping during flowing, so that a small bingham body polishing head with the average diameter less than the diameter of the liquid outlet is formed. The magneto-rheological polishing device and methodrealize efficient polishing of workpieces with different surface shapes.

Spindle-motor hydrodynamic bearing configuration having conical taper seals on the thrust-bearing ends. The spindle motor shaft is supported in a bore through the rotor by neighboring radial and thrust hydrodynamic bearings constituted through radial micro-gaps cylindrically between the shaft and rotor, axial micro-gaps between thrust plates on either shaft end and recesses endwise in the rotor bore, dynamic-pressure-generating grooves in the micro-gap forming surfaces, and lubricant retained continuously in the radial and axial micro-gaps. The thrust plates are at least partially conical, tapering axially outward. A ring fitted in each rotor bore recess has a conical inner peripheral surface corresponding to the opposing conical surface of the thrust plate, forming a taper seal sloped with respect to the rotational axial center of the motor. The gap clearance dimension gradually expands heading axially outward, wherein the lubricant forms an axial-end gas-liquid interface to function as a taper seal.

The invention discloses a testing device and a testing method for simulating hydrodynamic pressure action in rock fracture. A rock sample with a crack is placed into a testing water tank, the position of the rock sample is adjusted to enable a crack to directly face a rectangular hole; testing water flows are pumped into the testing water tank to be subjected to hydrodynamic pressure testing through a water injection pipe by a high-pressure water supply pump; a pressure meter, a pressure control valve and a pressure release valve are arranged on the testing water tank for controlling the flow pressure and the flow rate of the inside of the testing water tank; and an anchorage point is arranged on the testing water tank and is connected with a displacement meter and the rock sample, a pressure sensor, a flow sensor and the displacement meter are arranged on the water injection pipe and are used for transmitting the acquired data to a data acquisition instrument and are connected with a computer, and the computer is used for recording the testing data such as pressure, flow rate, the change of the diameter of the rock sample and the like. The structure is simple, the processing operation is easy and the operation is convenient.

The invention discloses a single-plate single-action rectifying-stabilizing device for planing boats. A stepping motor shaft is connected with a drive shaft; an eccentric wheel is arranged in an oil-bearing drive slider and is fixed with the drive shaft; the oil-bearing drive slider is arranged in a rectangular hole of a top corner of a rectifying plate; a base plate is fixed outside a stern sealing plate; the rectifying plate is arranged between the base plate and a cover plate; a mandrel is supported below the rectifying plate; a plurality of anti-warp pins pass through an arc-shaped groove of the rectifying plate; and a plurality of oil-bearing sliders are respectively fixed on two sides of the rectifying plate, and a plurality of pairs of flat slide rails are correspondingly arranged on the base plate and the cover plate. The device drives the rectifying plate to rotate around the center of the mandrel arranged below the rectifying plate through the eccentric wheel and the oil-bearing drive slider, which ensures that the lower edge of the rectifying plate rotates out from the bottom edge of a planing boat and cuts into water, so as to change the water flow field under the planing boat as well as the hydrodynamic pressure center and then to reduce swing. The device only adds few components to a stern of the planing boat, which solves the problem that a boat body produces great swing when the planing boat slides and sails on water surface.

The invention provides a hydrodynamic pressure suspension polishing device with a machining clearance capable of being adjusted. The polishing device comprises a lifting part and a polishing part. The lifting part mainly comprises rolling guide rails, a ball screw, a base, a middle supporting plate, an upper cover plate and a stepper motor. The stepper motor transmits torque through the ball screw to drive the middle supporting plate to go up and down. The polishing part mainly comprises a polishing disk, a ball spline shaft, springs, fine tuning knobs, a movable plate, a middle supporting plate, a guide rail, a servo motor and the like. The servo motor enables the polishing disk to rotate at a high speed through a belt wheel. The weight of the movable plate, the weight of the ball spline shaft and the weight of the polishing disk are overcome by the springs. The distance between the polishing disk and a container is adjusted through the fine tuning knobs. When the hydrodynamic pressure is increased, the polishing disk, the ball spline shaft and the movable plate float upwards overall, and when the hydrodynamic pressure is decreased, the polishing disk, the ball spline shaft and the movable plate descend overall, so that the adaptive suspension of the polishing disk during polishing is achieved. The movement of the movable plate is limited through a limiting threaded rod, and thus the fixed clearance is machined. According to the hydrodynamic pressure suspension polishing device, the machining efficiency is improved, and meanwhile the adjustability of the machining clearance is achieved.

The invention provides a hydrodynamic pressure suspension double-flow pump, relating to an impeller ultra-small pump which has no external mechanism axis and is driven magnetically. The pump comprises two mutually separate flowing channels; each flowing channel consists of an inlet, an impeller, a pressure water chamber and an outlet; and the geometrical parameters of the flowing channels are the same or different; a stator of the pump is embedded in a pump shell, a permanent magnet is embedded in a rotor; and the stator and the permanent magnet are arranged opposite along a radial direction; a radial gap is formed between the internal surface of the pump shell and the external surface of the rotor, so that liquid hydrodynamic support for restricting axial movement is formed during normal operation of the pump; an axial gap is formed between the front cover plate of each impeller and the corresponding pump cover, so that liquid hydrodynamic support for restricting rotor axial movement is formed during the normal operation of the pump. In such a way, the rotor can be suspended in the pump cavity during normal operation. The pump provided by the invention can be used for meeting double-flow use requirement of different flows and pressures, and good flowing condition can be effectively and favorably formed in the internal cavity of the pump shell, and moreover, the operation reliability of the pump can be improved.