70 results about "Critical speed" patented technology

According to the bearing rigidity optimization and vibration reduction design method for the rotor and the bearing system, under the condition that the structural form of the rotor and the bearing system is not subversively adjusted, the elastic bearing and the extrusion oil film damper are arranged and designed, and the bearing rigidity of the rotor and the bearing system is optimized. The fulcrum rigidity is reduced to change the strain energy distribution of the rotor and adjust the critical rotating speed, and the vibration level of the rotor, especially vibration caused by sudden unbalance and transcritical of the multi-fulcrum rotor, is suppressed.

The application discloses a kind of centrifugal pump shafting critical speed calculation method, including the finite element calculation of radial roller bearing and thrust roller bearing stiffness coefficient curve, the prestressed modal analysis and critical speed calculation of centrifugal pump shafting considering different bearing stiffness coefficient.The setting of constraint condition of this method is in line with actual situation, which can realize the accurate calculation of centrifugal pump shafting critical speed, and help to improve the reliability of safety check of centrifugal pump shafting in design stage, at the same time, the calculation steps are simple, and the engineering application range is wide.

This invention provides a dual-end driven long shaft system multi-order torsional vibration test platform and a torsional vibration identification and suppression method, relating to the field of long shaft system variable frequency drive technology. The platform includes two dual-winding drive motors respectively located at both ends of the shaft system, a load motor located in the middle, and a switchable shaft system connection structure, along with a dual-master, dual-slave cooperative control system composed of four drive frequency converters. This method achieves controllable excitation of multi-order torsional vibration by superimposing the load torque step and the frequency excitation source. It utilizes differential amplification and dual-channel filtering in the signal processing module to extract speed fluctuation characteristics, accurately identifying the critical speeds of each order in the system. For the identified torsional vibration phenomenon, a speed differential negative feedback algorithm is used to correct the torque command of the frequency converter, and the torsional vibration energy of the elastic transmission chain is offset by actively enhancing the system's electrical damping. This invention solves the problem of reproducing complex torsional vibration under safe and controllable conditions and verifying suppression strategies in ultra-large generator units.

The application discloses a multi-bearing segmented flywheel energy storage device, which comprises an upper bearing, a lower bearing, a middle bearing, a shell, a rotating shaft, a first flywheel and a second flywheel. The two flywheels are arranged on the rotating shaft, the shell is arranged outside the flywheels and the rotating shaft, the upper bearing and the lower bearing are arranged at two ends of the rotating shaft, the middle bearing is arranged on the rotating shaft between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft. The first flywheel is integrally formed with the rotating shaft, and the second flywheel is detachably connected with the rotating shaft. The application is used to solve the problem of excessive radial vibration caused by the first critical speed being too low due to the large axial span of the flywheel. The flywheel body with large thickness is divided into two parts, which is beneficial to the uniformity of the heat treatment of the flywheel body. The radial strength of the rotating shaft of the flywheel body is improved by additionally arranging a bearing between the two flywheel bodies. In order to facilitate the installation of the bearing at the middle position of the flywheel, the segmented flywheel rotating shaft and the matched shell are designed.

A flexible drive shaft (10) for transmitting torque from a motor (4) to a high-speed rotor (2), particularly for a laboratory centrifuge (1), wherein the material of the drive shaft (10) has a defined yield strength and a defined modulus of elasticity. To create a new drive unit, for example for a laboratory centrifuge, that retains the necessary flexibility at critical speeds but exhibits higher strength with respect to bending stresses, it is proposed that a material be used for the drive shaft (10) in which the yield strength of the material is expressed in N / mm². 2 divided by the material's modulus of elasticity in N / mm 2 takes on a value > 0.0045.

A turbomachine engine including an engine core including a high-pressure compressor, which has an exit stage having an exit stage diameter (DCORE), a high-pressure turbine, and a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, a power turbine in flow communication with the high-pressure turbine, and a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft / sec)1 / 2 and three hundred (ft / sec)1 / 2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft / sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft. The low-pressure shaft has a length (LMSR) defined by an engine core length (LCORE) given by:LCORE=[m  (20+m)*n  (10+n)](1100)*DCORE+CIS.

The invention belongs to the field of engine design, and particularly relates to an aero-engine whole machine dynamic structure design parameter optimization method, which utilizes an APDL language of ANSYS software to carry out parametric modeling on an aero-engine whole machine (including a rotor, a support and a stator casing), and applies additional centrifugal force and additional gyroscopic moment generated by maneuvering flight. The stress level of the bearing case, the strain energy distribution of a rotor system and the rotor and stator gap change are obtained through bearing case stress analysis, critical speed analysis and unbalanced response analysis. Based on the analysis results, multi-objective optimization is carried out on complete machine dynamic design parameters, so that the stress level of a force bearing casing is lowest, rotor strain energy distribution meets rotor dynamic design requirements, rotor and stator gap changes are minimum, the rub-impact risk is reduced, optimization of the structural design parameters is completed through software, the design efficiency is improved, and the design cost is reduced. The design period is shortened.

The application discloses a robot friction parameter identification method and device, a terminal and a medium. The method comprises the following steps: acquiring a dynamic speed threshold of a robot joint; identifying a static friction coefficient, a coulomb friction coefficient and a critical speed in a low-speed section where the speed of the robot joint is lower than the dynamic speed threshold; and identifying a viscous friction coefficient in a medium-high speed section where the speed of the robot joint is higher than the dynamic speed threshold, in combination with the obtained static friction coefficient, the coulomb friction coefficient and the critical speed. The application has the advantage that higher-precision robot friction parameters can be obtained, thereby facilitating the construction of a high-precision robot friction model.

The embodiment of the invention provides an aero-engine rotor bending critical rotating speed adjusting method based on a modal shape, and relates to the field of aero-engine high-pressure rotors. The objective of the invention is to improve the problems of complex process and high cost of engine rotor bending critical speed adjustment by changing elastic support rigidity and rotor structure parameters. Comprising the steps that the bending critical rotating speed of the engine rotor is adjusted by adjusting the local mass of a deformation sensitive area of the engine rotor; wherein the deformation sensitive area refers to an area with the maximum bending mode deformation. The bending critical rotation speed of the engine rotor is controllably adjusted by adjusting the mass in a deformation sensitive area of the engine rotor, the bending critical rotation speed can be simply and efficiently adjusted and subjected to test verification through the adjusting mode, and the bending critical rotation speed design margin of the engine can be conveniently obtained.

This invention discloses a turbine testing apparatus, belonging to the technical field of turbine testing equipment. This apparatus uses a limiting unit between mounting bases. Within the limiting unit, a first directional limiting component and a second directional limiting component are mounted via a bracket. The first directional limiting component limits the connecting lug from a first direction, and the second directional limiting component limits the connecting lug from a second direction. This achieves limiting of the turbine test piece from both directions. After the turbine test piece is installed, the first and second directions are perpendicular to the axial direction of the turbine test piece. By limiting the turbine test piece from the second direction, radial vibration of the turbine test piece can be effectively restricted, reducing vibration during testing, increasing the rotor's critical speed, ensuring successful test completion, and reducing the impact of vibration on measurement results. This ensures accurate final measurement results, provides accurate and effective test data for turbine design, reduces wear on the turbine testing apparatus, lowers maintenance costs, and reduces testing risks.

The application discloses an aero-engine rotor and a checking method and checking device for a supporting assembly of the aero-engine rotor, and comprises the following steps: S1: sequentially acquiring a starting typical curve of the aero-engine rotor and rotor vibration mutation time t, and simultaneously acquiring total starting times n during the service life of the aero-engine; S2: installing the aero-engine rotor on the checking device through the rotor supporting assembly, carrying out a debugging test based on the starting typical curve, and acquiring an actual critical speed range of the aero-engine rotor; S3: adjusting the starting typical curve based on the rotor vibration mutation time t and the actual critical speed range to obtain a starting typical adjustment curve; S4: starting the aero-engine to the slow-speed state according to the starting typical adjustment curve, parking the aero-engine, and repeating the process at least n times; and S5: disassembling and checking the aero-engine rotor and the rotor supporting assembly, and judging whether the over-critical performance of the aero-engine rotor and the rotor supporting assembly meets the requirements according to the checking result.

This invention provides a technology that can suppress vibrations of the rotating shaft supported by a magnetic bearing. [Solution] A controller 700 according to one embodiment of the present disclosure includes a coil 412 that generates an electromagnetic force that attracts or repels a rotating shaft 250, and controls the output voltage from the power conversion circuit 460 to the coil 412 by operating a power conversion circuit 460 that outputs power to the coil 412 for a radial magnetic bearing 400 that supports the rotating shaft 250 in a non-contact manner. Specifically, the controller 700 includes an integral element in the transfer function from the current detection value of the coil 412 to the voltage command value Vc1, the amplitude of the open-loop transfer function including the current detection value of the coil 412 has attenuation characteristics in the frequency band above the critical speed of the rotating body RT including the rotating shaft 250, and the phase of the open-loop transfer function including the position detection value of the rotating shaft 250 is in the range of -90 degrees or more and 90 degrees or less at the critical speed of the rotating body RT.

Provided is a technology that can suppress vibration of a rotary shaft to be supported by a magnetic bearing. A controller 700 according to one embodiment of the present disclosure comprises a coil 412 for generating an electromagnetic force that attracts or repels a rotary shaft 250 and, with respect to a radial magnetic bearing 400 for supporting the rotary shaft 250 in a non-contact manner, controls an output voltage from a power conversion circuit 460 to the coil 412 by operating the power conversion circuit 460 that outputs power to the coil 412. Specifically, the controller 700 includes an integral element in a transfer function from a current detection value of the coil 412 to a voltage command value Vc1. The amplitude of an open-loop transfer function including the current detection value of the coil 412 has an attenuation characteristic in a frequency band equal to or higher than a critical speed of a rotor RT including the rotary shaft 250. The phase of the open-loop transfer function including a position detection value of the rotary shaft 250 is in the range of -90 to 90 degrees at the critical speed of the rotor RT.

The utility model provides a check ring rotating assembly which comprises a shaft and a check ring. A groove surrounding the outer wall of the shaft is formed in the end part of the shaft; the check ring is a split ring and is installed in the groove, and in the initial state, the outer circle of the check ring is located on the inner side of the groove or flush with a port of the groove. When the rotating speed of the shaft is larger than the critical rotating speed of unfolding of the check ring, the open end of the check ring is opened, so that the outer circle of the check ring protrudes out of the groove to form an effective dynamic blocking face. The invisible effect of the check ring in the non-working state is achieved, and later overhaul and maintenance of components installed on the inner side of the check ring are facilitated.

This invention relates to a variable-damping, actively controlled extrusion film damper and its variable-damping adjustment method, belonging to the technical field of extrusion film damper structural design for aero-engines. The invention addresses the problem that traditional extrusion film dampers only exhibit optimal damping characteristics at specific excitation frequencies, failing to cover all rotor operating frequencies. This results in poor stability and weak dynamic performance of the rotor system in modern aero-engines operating across multiple critical speeds. The invention comprises a damper outer ring, a cone sleeve, a squirrel cage inner ring, two servo valves, two oil film pressure sensors, and two eddy current displacement sensors. Lubricating oil enters the oil film between the cone sleeve and the squirrel cage inner ring through the two servo valves. The eddy current displacement sensors measure the change in the eddy current position of the squirrel cage inner ring, and the oil film pressure sensors measure the change in oil film pressure. The measurements from the eddy current displacement sensors and the oil film pressure sensors are used as the basis for adjusting the oil supply to the servo valves. This invention is primarily used as a structure for extrusion film dampers in aero-engines.

The application discloses a rotor supporting structure with simultaneously adjustable axial and radial stiffness, which comprises an axial weak stiffness squirrel cage, a limiting ring and a fastening screw. The axial weak stiffness squirrel cage is in a folded-back structure form, and a bearing mounting seat is arranged on the inner mounting edge of the axial weak stiffness squirrel cage; the bearing mounting seat and the limiting ring form a bearing mounting cavity, thereby achieving axial fixation of the outer ring of the bearing; and a spoke is arranged on the outer mounting edge of the axial weak stiffness squirrel cage, so as to provide smaller axial stiffness. The fastening screw is used for connecting the axial weak stiffness squirrel cage and the limiting ring. The supporting structure has the advantages that smaller radial stiffness can be achieved to reduce the critical speed of the rotor system and reduce rotor vibration, smaller axial stiffness can be achieved to ensure that the rotor system can freely expand and shrink under the action of temperature load, and the supporting structure has a large adjustable range of axial and radial stiffness.

The invention belongs to the field of fault early warning, and particularly relates to a shafting vibration real-time monitoring and early warning method and a related system.The shafting vibration real-time monitoring and early warning method comprises the steps that kinetic parameters such as critical rotation speed offset and damping ratio change rate are introduced to serve as model constraints, and self-adaptive alarm logic and high-dimensional sensitive feature weighting are combined; the technical bottlenecks of high early fault false alarm rate and high omission ratio caused by the fact that only signal processing and frequency matching are relied on and dynamic characteristics are not integrated in the prior art are overcome. The method has the outstanding beneficial effects of high fault diagnosis accuracy, low false alarm rate, low omission ratio, high adaptive capacity and the like, and the operation safety and intelligent management level of the shafting equipment are remarkably improved.

A method for operating a 6-cylinder engine connected to a driveline including a transmission. The method includes: monitoring a rotational speed of a crankshaft of the 6-cylinder engine: monitoring a gear selection of the transmission; and operating the 6-cylinder engine in one of Order 3, Order 1.5 or Order 1 based on whether the selected Order avoids operating the 6-cylinder engine at a critical speed that corresponds to a natural harmonic frequency of the driveline, wherein priority is given to operating in Order 1.5, Order 1 then Order 3, in that order.

A turbomachine engine including a high-pressure compressor, a high-pressure turbine, a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, and a power turbine in flow communication with the high-pressure turbine. At least one of the high-pressure compressor, the high-pressure turbine, and the power turbine comprises a ceramic matrix composite (CMC) material. The turbomachine engine includes a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft / sec)1 / 2 and three hundred (ft / sec)1 / 2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft / sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft.

The invention relates to a rotor system integrated topological optimization design method considering dynamic performance, and belongs to the technical field of high-performance calculation science, and the method comprises the following steps: taking statics and rotor dynamics as constraint conditions for a rotor two-dimensional structure, carrying out two-dimensional topological optimization design, and obtaining a new rotor two-dimensional structure; and on the basis of the new two-dimensional structure of the rotor, three-dimensional topological optimization design is carried out on the sector model of the rotor by taking the rotation period structure frequency and the statics property as constraint conditions, and a new three-dimensional configuration is obtained. According to the method, on the basis of traditional topological optimization which only considers the static performance, the constraint on the dynamic performance is increased, the dynamic performance requirement needed by the rotor system can be met while the maximum rigidity design is completed, the design period can be effectively shortened, and the design efficiency can be effectively improved.

A flexible membrane disc coupling for super-high-speed cryogenic bearing test and a design method thereof are disclosed. The coupling is coupled with rotors at two ends. Comprehensive design is performed from two aspects of mechanical performance and dynamic performance to ensure that additional load generated by the coupling on bearings of the rotors at two ends is minimum when the coupling is compensated. Through dynamic optimization design, mass and mass distribution characteristics of the coupling are optimized to ensure that critical speed of the whole rotor system meets rigid design principle. Through setting of a heating belt, temperature of a key part of a membrane disc curved surface of the coupling can be ensured to be in an optimal temperature range of a material when the coupling works in super-low temperature. Changes of material performance and space size caused by use of a previous coupling structure in a super-low temperature environment are overcome. The coupling always maintains an optimal working state to ensure compensation and transmission capacity of the coupling when the double-span rotor system operates at high speed.

The application discloses an engine whole machine vibration measuring point selection method and system, and the engine whole machine vibration measuring point selection method comprises the following steps: determining an engine whole machine vibration measuring point selection principle; establishing an engine whole machine finite element model; and determining an engine whole machine vibration measuring point through whole machine vibration frequency response characteristic analysis according to the engine whole machine vibration measuring point selection principle and the whole machine finite element model. The selected engine whole machine vibration measuring point can better reflect rotor vibration characteristics (critical speed, unbalanced load change), more rotor vibration characteristic information can be obtained by using less engine whole machine vibration measuring points, and the selected engine whole machine vibration measuring point is more sensitive to rotor vibration characteristic change, and is favorable for vibration safety monitoring of the engine.

This invention relates to the field of aerospace propulsion technology and discloses a gas generator circulating liquid rocket engine system with an electric bypass. This invention constructs an electric bypass supply channel by reusing the discharge pipeline, introducing the originally directly discharged high-pressure propellant into the fuel electric pump and oxidizer electric pump for secondary pressurization, and then injecting it into the main thrust chamber via a separately set bypass injector. This solves the problems of traditional open gas generator circulating liquid engines, such as the main turbopump easily entering the critical speed range and causing mechanical resonance under deep throttling conditions, and the deterioration of atomization mixing effect due to insufficient pressure drop of the main injector. It achieves stable operation of the main turbopump within the rated operating speed range and stable high-pressure atomization and combustion of propellant under extremely low thrust conditions, expands the lower limit of the engine's deep throttling capability, and improves propellant energy utilization efficiency and system operational reliability. Simultaneously, the electric bypass supply system enables rapid response and precise adjustment under low thrust conditions.

According to the rotor system and the method for changing the supporting rigidity in the operation process, a device for changing the supporting rigidity in the operation process of the rotor system mainly comprises a double-rigidity elastic support and a split type fixing ring, and the working rigidity of the double-rigidity elastic support is controlled by holding and loosening the split type fixing ring; therefore, the supporting rigidity of the rotor system in the operation process is adjusted. During working, rotor vibration is reduced by actively changing the critical rotating speed, and in the speed increasing process of a rotor system, when the rotating speed is close to 15% of the critical rotating speed, the critical rotating speed is changed under the condition that the rotating speed is not changed, and the critical rotating speed is reduced to 85% of the working rotating speed at the moment. The device is matched with the method, vibration of the rotor system in the working process is reduced, the critical speed of the rotor system is more stable, the resonance problem caused by the critical rotating speed in the follow-up speed increasing process can be avoided, and the device is suitable for large-scale industrial use and popularization.

According to the method and system for expanding the stable working range of the gas compressor, an engine signal at the current moment is collected, and the conversion rotating speed at the current moment is obtained; the conversion rotating speed is compared with the first critical rotating speed, and when the conversion rotating speed is smaller than or equal to the first critical rotating speed, a front-stage deflation valve is opened for inter-stage deflation; when the conversion rotating speed is larger than the first critical rotating speed, the conversion rotating speed and the second critical rotating speed continue to be compared, when the conversion rotating speed is smaller than or equal to the second critical rotating speed, the middle-stage deflation valve is opened to conduct interstage deflation, and when the conversion rotating speed is larger than the second critical rotating speed, the rear-stage deflation valve is opened to conduct interstage deflation, the second critical speed is greater than the first critical speed; and after the inter-stage deflation lasts for rated time, the steps are repeated, and acquisition and comparison of the rotation speed of the next turn and selection of a deflation valve are carried out. According to the method and the system, the gas compressor can keep a good stable working range in a full rotating speed range.

The invention relates to the technical field of mechanical control, in particular to a trajectory control method and system for a brushless push rod, and the method comprises the steps: generating a reference motion trajectory of the brushless push rod based on a load dynamics model of the brushless push rod; calculating a critical speed threshold value corresponding to the current load working condition according to the motor current and the external load force; comparing the reference speed curve with a critical speed threshold value, and triggering a track adjustment condition when the reference speed reaches a preset proportion of the critical speed; and after a trajectory adjustment condition is triggered, associating a critical speed threshold value with the reference speed curve to establish a dynamic speed constraint, and performing attenuation reconstruction on the reference motion trajectory based on the dynamic speed constraint to obtain a final trajectory control strategy. According to the brushless push rod, the problems of impact and unsafety caused by the fact that an existing brushless push rod still operates according to a fixed track when the load changes are effectively solved, and the control stability and the operation safety of the push rod are improved.

The present application relates to the technical field of hydraulic equipment, and discloses a critical speed determination method, device, equipment and storage medium, the present application analyzes the dynamic characteristics of the target pumped storage unit, determines the dynamic characteristic coefficient of the target pumped storage unit, constructs the unbalanced mass force model, the unbalanced magnetic pull model and the unbalanced water pressure model of the target pumped storage unit, constructs the rotor system motion model of the target pumped storage unit based on the dynamic characteristic coefficient, the unbalanced mass force model, the unbalanced magnetic pull model and the unbalanced water pressure model, determines the modal frequency corresponding to multiple rotating speeds based on the rotor system motion model, and determines the critical speed based on the modal frequency. Coupling the dynamic characteristic model of the guide bearing and the sealing, the unbalanced mass force, the unbalanced magnetic pull and the unbalanced water pressure and other excitation force models makes the rotor system motion model more practical and ensures the accuracy of the calculated critical speed.

The invention relates to the technical field of vehicle power transmission, in particular to an elastic supporting assembly, a micro-gas turbine and ultra-high-speed motor coupling system and a vehicle. The elastic supporting assembly comprises a front bearing combination body, a rear bearing combination body, a bearing body, a shaft sleeve between bearings, a front wave spring and a rear wave spring, an axially-through mounting cavity is formed in the bearing body, and the front bearing combination body and the rear bearing combination body are both arranged in the mounting cavity in a sleeved mode. A front radial gap is formed between the front bearing outer lantern ring and the bearing body, a rear radial gap is formed between the rear bearing outer lantern ring and the bearing body, the front vibration absorption ring is elastically supported in the front radial gap, and the rear vibration absorption ring is elastically supported in the rear radial gap. Through the synergistic effect of the vibration absorption ring and the wave spring, double elastic isolation of radial vibration and axial displacement is achieved, and the transmission risk of vibration of the micro-gas turbine rotor shaft to the motor rotor shaft can be reduced; the structure can reduce the dynamic load transmitted to the bearing and the foundation, and ensures that the rotor shaft of the micro-gas turbine has no critical rotating speed in the running rotating speed range.

This invention relates to the field of aero-engine transmission rod design technology, and discloses a method for designing the wall thickness of a variable cross-section transmission rod for aero-engines. By comprehensively considering the maximum speed, power, and structural parameters of the transmission rod under corresponding operating conditions, and utilizing a torsional shear stress model of the transmission rod, the minimum wall thickness parameter that prevents shear fracture of the transmission rod under operating conditions is analyzed in depth. By using the equivalent diameter of the transmission rod and combining it with a critical speed model, the maximum wall thickness parameter that meets the critical speed requirement is accurately calculated. Thus, the range of wall thicknesses for the variable cross-section section of the transmission rod that meets the requirements of torsional shear and critical speed is obtained, enabling rapid design of the transmission rod structure, significantly reducing the iterative calculation time in the design process, improving design efficiency, and providing important support for the rapid and refined design of variable cross-section transmission rods for aero-engines.

The application discloses a kind of modal optimization design methods of double-rotor system with intermediate bearing, without considering critical speed and its margin range, all modes of double-rotor system with intermediate bearing in high pressure excitation and low pressure excitation in whole speed range are optimized, all modes are evaluated using the modal tolerance evaluation function constructed in the application, the maximum of optimization objective function constructed in the application is pursued using genetic algorithm, and the final optimization result can be output after each order modal tolerance evaluation function is greater than 0.8, which makes each order mode after the modal optimization design of double-rotor system with intermediate bearing can meet the requirement of tolerance resonance, can run at critical speed, so that double-rotor system can run at any speed, without following "critical speed margin" rule, improve the high mobility of aeroengine, provide reference and thought for the design of next generation aeroengine.