209results about How to "Reduce fatigue damage" patented technology

The present invention discloses a double-annular strong magnetic array nonlinear dynamic vibration absorber and design method for suspension vibration reduction, which belongs to the field of structural vibration control. The installation position and quantity are designed according to the vibration reduction requirements, and one is usually installed at the midpoint of the suspension. The vibration absorber comprises inner and outer magnetic ring arrays, counterweights, universal wheels and a base. It feeds back the control force in the opposite direction of the suspension vibration during movement, so that the suspension vibration energy is transferred to the vibration absorber and then less returned to the suspension, and the energy is dissipated through friction between the universal wheel and the base, the installation of air dampers and other measures. It introduces nonlinear stiffness, so that the optimal parameter domain range is expanded from the line domain to the surface domain, and thus has the outstanding advantages of easy parameter tuning and high vibration reduction robustness, and is easy to install, durable, and requires no or less maintenance. It is applicable to single, double and four-cable suspensions, and is expected to achieve the goal of good vibration reduction effect throughout the life cycle of the suspension, which has positive significance for ensuring driving and bridge safety and extending the service life of the suspension.

The invention provides an active load shedding optimization control method, system and device of a wind power plant and a storage medium, and belongs to the technical field of active power control of the wind power plant, and the method comprises the steps: constructing and training an SAC intelligent agent through an SAC algorithm; acquiring a wind power plant state quantity; inputting the state quantity of the wind power plant into the SAC intelligent agent to obtain a vector # imgabs0 # composed of active power initial reference values of all wind turbine generators; inputting the # imgabs 1 # into a constraint controller for secondary calculation to obtain a vector # imgabs 2 # composed of active power optimization reference values of the wind turbine generators; the wind power plant executes # imgabs3 #; and repeating the steps, and adjusting the active power of each wind turbine generator in real time. The model is high in generalization, stability, reliability and learning efficiency, real-time online calculation of the equivalent fatigue load can be achieved, reasonable distribution of the active power of the wind power plant can be achieved under the condition that the active power constraint of the wind power plant is met, the equivalent fatigue load of the whole wind power plant can be reduced, and the maintenance cost can be reduced.

The invention discloses a wear-resistant hard alloy and a preparation method and application thereof, and belongs to the technical field of hard alloys, and the wear-resistant hard alloy comprises the following components in parts by weight: 78.4-87.9 parts of tungsten carbide powder, 4-12 parts of high-entropy alloy powder, 2-8 parts of carbon nanotubes, 1-6 parts of titanium aluminum carbide and 0.1-0.6 part of tantalum carbide. The high-entropy alloy powder comprises, by weight, 1-3 parts of manganese powder, 2-5 parts of silicon powder, 5-12 parts of chromium powder, 10-15 parts of carbon powder, 10-15 parts of cobalt powder, 10-18 parts of molybdenum powder and 40-50 parts of nickel powder. The tungsten carbide powder comprises first tungsten carbide powder and second tungsten carbide powder in a weight ratio of (2-4): 1. The tungsten carbide powder serves as a matrix, under the combined action of the high-entropy alloy powder, the carbon nanotubes, the titanium aluminum carbide and the tantalum carbide, the wear resistance and the mechanical property of the hard alloy are remarkably improved, and the hard alloy can be well applied to preparation of cutting tools and drill bits and has wide application prospects.

The invention relates to the technical field of hydropower station water turbine joint optimization control, and discloses a cascade scheduling joint curve optimization control method and system, and the method comprises the steps: building a hydropower station water turbine full-flow-channel physical model through a field scanning method, and carrying out the construction of a model grid; calculating an optimal joint point and obtaining a double-regulation unit joint curve; the full-head and full-opening water turbine efficiency and output database of the hydropower station water turbine is studied, and the optimal operation efficiency characteristic of the unit is obtained; analyzing the design association relationship of the hydropower station water turbine, calculating the association relationship, comparing the association relationship with historical operation data, and proposing the optimal association relationship of the water turbine; and obtaining a hydropower station water turbine joint optimization control strategy and an operation scheme according to the optimal joint relation of the water turbine. Efficient operation of the water turbine under various working conditions is ensured, and the energy conversion efficiency is improved. The optimal combination curve is provided, and the optimal performance of the water turbine under different working conditions is ensured. And according to the real-time water regimen and load requirements, efficient scheduling of the cascade power stations is realized.

The invention discloses a suspended ballast floating type offshore wind power foundation suitable for water depth and a using method, and belongs to the technical field of floating type offshore wind power generation. The wind power foundation comprises a three-stand-column semi-submersible foundation, a mooring system and a control system, and the three-stand-column semi-submersible foundation comprises three vertical stand columns, a supporting rod and a ballast caisson; the ballast caisson is connected with a sliding rail arranged on the side wall of the vertical stand column through a sliding rope, so that the ballast caisson moves up and down relative to the vertical stand column, the position of the ballast caisson is adjusted through a control system, and then the gravity center position and the draft depth of the foundation are adjusted so as to adapt to different environmental conditions, and the stability and the anti-overturning capacity are ensured. The use method comprises the steps of monitoring environmental conditions, calculating overturning moment, calculating anti-overturning moment, adjusting the depth of the ballast caisson and recording and analyzing data, the required moving depth of the ballast caisson is reversely deduced by calculating the overturning moment to ensure that the gravity center and the buoyancy center of the foundation are kept at proper positions, and the risk of overturning of the foundation is reduced.

The invention discloses an aero-engine thrust bearing buffering and damping structure which comprises a thrust bearing, a bearing ring cavity structure and a bearing buffering structure, a bearing outer ring is installed in a ring cavity of a fixed supporting frame, a bearing inner ring is installed on a fan rotating shaft, and a buffering body is arranged between the bearing outer ring and the ring cavity. And the bearing outer ring is provided with an instantaneous breaking boss which is radially positioned with the ring cavity. When fan blades of an aero-engine fly to lose a limit load similar to that of the aero-engine, an impact load is transmitted to the force bearing structure from the fan rotor through the bearing, the load is fused after exceeding the bearing limit of the boss, the outer ring of the bearing is allowed to move relative to the ring cavity in the radial direction, and the buffering and damping effects of a fan rotor system are achieved by extruding the buffering body. Meanwhile, due to the design of the damping structure, the critical rotating speed of the fan rotor is reduced, and the load on the bearing when the rotor passes through the critical rotating speed is further reduced. In the windmill state, the structure can effectively reduce the vibration level of the rotor, and stable operation of the bearing under the non-power condition is ensured.

The present invention provides a vibration suppression system for a photovoltaic bracket and a single-axis photovoltaic bracket. The vibration suppression system includes a constraint protection unit, and the constraint protection unit includes a force transmission component, a vibration displacement amplification component, an eddy current energy dissipation component, and a high wind protection component. The input end of the force transmission component is connected to the two ends of the photovoltaic bracket in the rotation direction; the high wind protection component includes a magnetic conductor arranged on the outside of the transmission shaft, and the magnetic conductor has a magnetic attraction with the transmission shaft when the wind speed reaches the critical wind speed of static wind instability of the bracket. The single-axis photovoltaic bracket includes a photovoltaic panel, a photovoltaic panel rotating beam, and a vibration suppression system. The constraint protection unit of the vibration suppression system is divided into two groups, and the two groups of constraint protection units are respectively arranged at the two ends of the photovoltaic panel along the length direction; the force transmission component of the constraint protection unit is arranged parallel to the torsion surface of the photovoltaic panel, and the transmission shaft is arranged horizontally. The present invention has the advantages of avoiding damage to the bracket during wind vibration and improving the safety and reliability of the bracket.

The invention provides a vibration suppression system of a photovoltaic support and a single-shaft photovoltaic support, the vibration suppression system comprises a constraint protection unit, the constraint protection unit comprises a force transmission assembly, a vibration displacement amplification assembly, an eddy current energy consumption assembly and a strong wind protection assembly, and the input end of the force transmission assembly is connected to the two ends of the photovoltaic support in the rotation direction; the strong wind protection assembly comprises a magnetizer arranged on the outer side of the transmission shaft, and a magnetic attraction force exists between the magnetizer and the transmission shaft when the wind speed reaches the static wind instability critical wind speed of the support. The single-shaft photovoltaic support comprises a photovoltaic panel, a photovoltaic panel rotating beam and a vibration suppression system, the vibration suppression system is provided with two sets of constraint protection units, and the two sets of constraint protection units are arranged at the two ends, in the length direction, of the photovoltaic panel respectively; the force transmission assembly of the constraint protection unit is parallel to the torsion surface of the photovoltaic panel, and the transmission shaft is horizontally arranged. The invention has the advantages of avoiding bracket damage during wind vibration, improving the safety and reliability of the bracket and the like.

The invention provides an intelligent active suspension system of a centrifugal machine, which belongs to the technical field of centrifugal machines and comprises an air spring mechanism, an actuating mechanism arranged beside the air spring mechanism, a control mechanism arranged beside the actuating mechanism, and an air supply mechanism arranged beside the spring mechanism. An anti-toppling structure is arranged inside or outside the air spring mechanism, a sensor body is arranged inside the air spring mechanism, the air spring mechanism is composed of an air spring body, a spring upper mounting plate and a spring lower mounting plate, and the spring upper mounting plate is fixed to the top of the air spring body. The advantages can be fully exerted, the problems existing in an existing centrifugal machine vibration isolation technology are effectively solved, the overall performance and reliability of the centrifugal machine are improved, and more stable, efficient and safe technical support is provided for the centrifugal separation process in industrial production; and the use height and the vibration isolation effect of the intelligent active suspension of the centrifugal machine can be adjusted according to use requirements.

The invention provides a tower wind load model test device and test method, the device comprises a tower simulation piece and a damping adjustment unit, the damping adjustment unit comprises an eddy current conductor assembly and an electromagnetic assembly, the eddy current conductor assembly comprises an eddy current conductor and a magnetic back plate, and an air gap is reserved between the electromagnetic assembly and the eddy current conductor. The method comprises the following steps: constructing a tower simulation piece according to a scale ratio, and determining the thickness of a longitudinal main tower rod of the tower simulation piece according to the thickness and the elastic modulus of the longitudinal main tower rod of the tower and the elastic modulus of the tower simulation piece; the critical vortex vibration initial wind speed, smaller than the preset safe wind speed, of the tower is screened out from the vortex vibration initial wind speeds of the tower during vibration of all orders; determining the optimal test simulation wind speed of the tower simulation part according to the critical vortex vibration initial wind speed and the wind speed ratio; and the electromagnetic assembly adjusts the initial damping force of the damping adjusting unit to the target damping force. The method has the advantages of improving accuracy and reliability of test results, reducing potential safety hazards of the tower and the like.

The invention discloses a solid waste-based multifunctional tailing asphalt pavement material and a preparation method thereof, and the pavement material comprises the following components in parts by mass: 4.5-5.5 parts of polyurethane modified asphalt, 45-60 parts of titanate modified iron tailings, 2-5 parts of surface activated copper tailing powder, 20-35 parts of copper tailing sand and 0.5-1.0 part of acetic anhydride modified wollastonite fiber. The high and low temperature performance, the durability and the self-healing performance of the asphalt mixture are comprehensively improved by modifying the solid waste tailing material and the asphalt, and the application range of the asphalt mixture is effectively widened.

The invention belongs to the technical field of new energy automobiles, and discloses an anti-seismic chassis for a new energy automobile, which comprises an automobile chassis, a battery pack is mounted in the automobile chassis, through the arrangement of a buffer mechanism, when a bearing plate vibrates along with the chassis, a moving column can slide up and down in a sliding groove of a fixed plate, and when the moving column moves downwards due to vibration, the moving column can move up and down. The telescopic spring is compressed to play a preliminary buffering and damping role, meanwhile, the lantern ring moves downwards along with the moving column, the rotating blocks on the two sides of the lantern ring rotate to drive the connecting rod and the auxiliary rod to move, the buffering rod slides in the lantern ring, the reset spring is stretched, and vibration energy is further absorbed and dispersed; the influence of vibration on the battery pack is effectively relieved, the automobile chassis and the battery pack can be built, the overall stability of the chassis is enhanced, the impact of vibration on key components of the chassis is effectively relieved through the buffering mechanism, and chassis structure stress concentration and fatigue damage caused by local strong vibration are reduced.

The invention belongs to the technical field of building structure monitoring, and particularly relates to an intelligent monitoring system and method for a prestressed cable structure, the system comprises a cable body and an intelligent monitoring module for monitoring the stress change in the cable body, the cable body comprises a steel strand with a center steel wire removed and an optical fiber, and the optical fiber is connected with the intelligent monitoring module. The optical fiber is installed at the position of a center steel wire of the steel strand through the optical fiber protection shell, a buffer layer is arranged between the optical fiber and the inner wall of the optical fiber protection shell, the optical fiber is installed in the optical fiber protection shell through the elastic clamp, and the data collector is connected to a tail fiber of the cable body through the tail fiber leading-out component and used for receiving optical signals transmitted by the optical fiber. The optical fiber embedded in the central position in the cable body instead of a central steel wire of a steel strand is used as a sensing element, tiny stress changes can be more accurately captured, and high-precision monitoring of the stress state of the cable body is achieved.

The invention belongs to the technical field of robots, and discloses a decoupling control method and system for a two-degree-of-freedom vibration suppressor of a robot, and the method comprises the steps: analyzing the structural characteristics of a robot system, and designing a decoupling control strategy through a structural invariance principle; coupled vibration of force applied in the X direction in the Y direction and coupled vibration of force applied in the Y direction in the X direction are effectively eliminated. Compared with a traditional vibration control method, the multi-degree-of-freedom vibration suppression method has the advantages that the influence of a pose related mode and a coupling mode of the robot is fully considered, multi-degree-of-freedom vibration suppression can be efficiently realized in real time in a complex load and dynamic environment, and the adaptability and the control precision are relatively high. The technology has wide application prospects in the fields of robot precision machining, assembling, carrying and the like, and the stability, precision and working efficiency of a robot system can be remarkably improved.

The invention discloses a self-adaptive settlement photovoltaic support structure and method, and relates to the technical field of photovoltaic support. The self-adaptive settlement photovoltaic support structure comprises a stand column; the hoops are arranged in a split mode and connected through connecting pieces, and the split positions of the hoops extend outwards to form first mounting positions; the oblique beam is located on the upper side of the stand column, and the bottom side of the oblique beam extends outwards to form a second mounting position; the supporting part comprises a first supporting rod and a second supporting rod; the connecting assembly extends into the first mounting position and the second mounting position and is connected with the hoop or the oblique beam, and the first supporting rod and the second supporting rod are hinged to the connecting assembly. Passive or semi-active compensation is achieved when a stand column is subjected to differential settlement or relative displacement caused by temperature and wind load through hinge and deformation design of a hoop-supporting rod-connecting assembly, resistance control of a nested sliding piece and an adjustable embedded block and a force transmission path of a traction piece and a flexible cable.

The utility model discloses a diamond roller for lead screw finishing, which comprises two driving rods, the diamond roller is arranged between the driving rods on the two sides, and the diamond roller is spiral; the device further comprises a limiting groove formed in the driving rod, a limiting block is arranged in the limiting groove, and the limiting block extends to the side, close to the diamond roller, of the driving rod. And when the diamond roller is replaced after the surface of the diamond roller is abraded after being used for a long time, the whole fixing structure needs to be dismantled, heat dissipation of the diamond roller is insufficient, and a large amount of heat is accumulated on the diamond roller after the diamond roller is used for a long time.

The invention relates to the technical field of wind power generation, in particular to a vertical axis wind turbine with blades rotating in a self-adaptive mode along with wind speed changes. The two vertical main shafts are arranged at the upper end and the lower end of the supporting cylinder; the base is arranged at the bottom end of the vertical main shaft located at the bottom; the turning system is arranged in an inner cavity of the supporting cylinder; one ends of the two sets of supporting shafts are connected with the two sides of the turning system correspondingly, and the other ends of the supporting shafts extend out of the supporting cylinders; the blade is arranged at the other end of the supporting shaft; when the turning system is started, the supporting shafts on the two sides can be driven to drive the blades to rotate and adjust in the same direction at 0-90 degrees. By means of the direction changing system, the blades can automatically adjust the rotation angle and change the blade load according to the wind speed change, safe shutdown of the wind turbine is ensured, the risk that the supporting arms deform or are damaged due to overload is reduced, the overall structural safety is improved, and the service life is prolonged.

The present invention belongs to the technical field of elevator products, and specifically discloses an escalator device for a shopping cart, including an escalator truss and an escalator track, wherein an upward / downward running device is respectively installed on the escalator truss, and the running device includes a driving device, and a lower horizontal conveying chain, an inclined conveying chain, and an upper horizontal conveying chain that are symmetrically arranged with the escalator truss as the center and driven by the driving device, and each chain of the conveying chain is connected with a push rod structure that forms a conflicting contact with the upright column at the rear side of the shopping cart and can drive the shopping cart to move when the elevator goes up or down, and the horizontal projection of the inclined conveying chain partially overlaps with the end positions of the upper horizontal conveying chain and the lower horizontal conveying chain adjacent thereto, and the bottoms of the lower horizontal conveying chain, the inclined conveying chain, and the upper horizontal conveying chain are all provided with a rolling support structure supported on the escalator truss. The escalator device can effectively reduce the pressure generated by the conveying chain at the bending part, ensure the stable performance during chain transmission, and effectively improve its service life. At the same time, it is easy to disassemble and assemble, which is convenient for the maintenance and maintenance of the escalator.

The utility model discloses a kind of damping device of unmanned plane rotating shaft, it is related to unmanned plane technical field, including: unmanned plane body and damping protection piece, unmanned plane body has rotor support, the end of rotor support is equipped with rotor drive structure, the end of rotor support is located below rotor drive structure and is equipped with through mounting hole;Damping protection piece is connected in the outside of rotor drive structure by mounting rod through mounting hole, the connecting place of mounting rod and mounting hole has elastic damping part, the outside of mounting rod is formed with damping and protection structure.The utility model sets up mounting hole by being arranged at the end of rotor support, connects damping protection piece in the outside of rotor drive structure, and sets up elastic damping part at the connecting place of mounting rod and mounting hole, can effectively buffer the vibration and impact of rotor rotating shaft, improve the flight stability and reliability of unmanned plane under complex environment.

The invention discloses a transmission conductor damping device and method, and the device comprises a fixed part which is disposed on a transmission conductor; the rotating part is arranged outside the fixed part in a sleeving manner and is rotationally connected with the fixed part; the driving part is rotationally arranged at the end, away from the power transmission line, of the fixing part; the limiting part is arranged on the driving part; the telescopic rotating part is arranged on the driving part, the telescopic rotating part is separated from limiting of the limiting part in the plumb bob direction under the action of wind power and rotates to droop, so that the telescopic rotating part abuts against the rotating part to drive the rotating part to rotate, and then the rotating part generates upward acting force to balance vibration force; and the telescopic rotating piece is separated from the rotating part. The telescopic rotating part drives the rotating part to rotate to generate upward acting force by utilizing vertically downward vibration force of the power transmission conductor, so that the vibration force of the conductor is balanced, and the vibration of the conductor in the vertical direction can be effectively inhibited.

The invention discloses a wear-resistant high-speed deep groove ball bearing and a retainer, and belongs to the technical field of bearings. The device comprises a bearing inner ring; a bearing outer ring; the retainer is positioned between the bearing inner ring and the bearing outer ring; the holder is provided with an elliptical pocket with a vertical section with a notch; the balls are installed in the pockets, the balls are half-wrapped by the pockets, and the size of the balls is smaller than that of the pockets; when the high-speed ball bearing operates, only part of the balls abut against the inner walls of the pockets. The pockets with the oval vertical sections are formed in the retainers, when the high-speed ball bearing operates, only parts of the balls make contact with the inner walls of the pockets, the contact area of the pockets of the retainers and the balls is small, abrasion between the retainers and the balls can be reduced, reduction of the inner diameter of the parts, making contact with the balls, of the retainers is avoided, and fatigue damage of the bearing is reduced; and the long-time normal use of the bearing is ensured.

The invention relates to the technical field of packers, in particular to an anti-falling packer for oil production engineering, which comprises a packer, a rubber sleeve is fixedly connected to the middle position of the packer, a plugging and limiting mechanism capable of providing protection for the rubber sleeve is arranged on the packer, and the plugging and limiting mechanism comprises a plurality of sliding chutes, a guide groove and a limiting seat. Sliding grooves are formed in the top end and the bottom end of the limiting seat, movable plates are slidably connected to the interiors of the sliding grooves, symmetrically-arranged guide strips are fixedly connected to the movable plates, first supports are fixedly connected to the positions, in the sliding grooves, of the movable plates, linkage blocks are rotatably connected to the first supports, and two symmetrically-arranged supports are fixedly connected to the top end and the bottom end of the limiting seat; the packer has the beneficial effects that excessive radial expansion of the rubber sleeve can be limited, plastic deformation or tearing of the rubber sleeve due to high pressure is prevented, meanwhile, pressure borne by the rubber sleeve is evenly dispersed, the overall structural stability is improved, and the sealing reliability and the structural stability of the packer are further improved.

The utility model discloses a stainless steel flange plate which comprises two stainless steel plates and an elastic buffer plate, the elastic buffer plate is fixedly adhered between the two stainless steel plates, storage cavities are arranged in the stainless steel plates, damping liquid is stored in the storage cavities, a plurality of blocking holes are arranged on the elastic buffer plate, and the blocking holes are communicated with the elastic buffer plate. And the retarding holes are hexagonal. The shock-absorbing bolt is good in shock-absorbing performance, reduces fatigue damage caused by shock, and can prevent the bolt from loosening caused by shock.

The invention relates to the technical field of bridge engineering, and discloses a novel damping vibration attenuation intelligent bridge support which comprises a bottom plate, a top plate is arranged at the top of the bottom plate, and the bottom plate is connected with the top plate through a connecting rod; the damping assembly is arranged between the bottom plate and the top plate and used for conducting damping operation when the damping assembly is stressed; the extrusion plate is fixed at the bottom of the top plate and is used for generating a force effect on the damping assembly; the limiting frame is fixed to the top of the bottom plate and used for limiting the force application direction of the extrusion plate; the sensing assemblies are arranged in the limiting frame in an annular array mode and used for monitoring the state of the equipment in a multi-azimuth mode when the equipment is stressed. External impact force is effectively absorbed and dissipated layer by layer, the top plate is buffered for the first time, and then the extrusion plate and the damping assembly are used for buffering for the second time and the third time, so that equipment still keeps stable when bearing large loads and vibration, the overall damping effect of the bridge support is improved, the service life of the structure is prolonged, and the service life of the bridge support is prolonged. And the possibility of fatigue damage is reduced.

The invention provides an efficient and energy-saving magnetic suspension fan and an operation method, and relates to the field of magnetic suspension fans, the efficient and energy-saving magnetic suspension fan comprises a double-end impeller driving part, a first-stage air inlet pipe orifice, a positioning mounting plate, a first-stage air outlet volute, a second-stage air inlet pipe orifice, a second-stage air outlet volute and a shunt connecting pipeline; the primary air inlet pipe orifice is in bolted connection with the left side of the double-end impeller driving part; the first-stage air outlet volute is in bolted connection with the left side of the double-end impeller driving part; the secondary air inlet pipe orifice is in bolted connection with the right side of the double-end impeller driving part; the second-stage air outlet volute is in bolted connection with the right side of the double-end impeller driving part; the positioning mounting plate is fixedly connected to the inner side of the primary air inlet pipe orifice; the flow dividing connecting pipeline is fixedly connected to the front side of the second-stage air outlet volute. The occurrence probability of fan surge faults caused by filter element blockage is reduced, and the problem that fan surge is triggered after the air inlet density and the effective air inlet amount are easily affected by filter element blockage is solved.

The invention discloses an environment-friendly range hood based on a dynamic smoke dust separation technology, and belongs to the technical field of oil smoke separation. Comprising a shell, a motor, an impeller, a smoke exhaust mechanism, a dust removal mechanism, a sensor and a controller, the impeller is rotationally installed in the shell and driven by the motor, the smoke exhaust mechanism comprises a filter screen and a connecting assembly, the filter screen and the impeller are coaxially and rotationally installed through the connecting assembly, and the filter screen is a diamond mesh oil filter screen formed by interweaving multiple sets of curves; the dust removal mechanism comprises a brush and an opening and closing mechanism, the opening and closing mechanism is arranged on the shell and used for adjusting the working angle of the brush, and the sensor is used for detecting the smoke concentration around the range hood. The smoke and dust separation of the smoke exhaust ventilator is realized, dust in the smoke is effectively separated, the exhausted gas is purified, the pollution to outdoor air is reduced, the accumulation speed of the smoke and dust on the filter screen is reduced through the arrangement of the brush, and the cleaning and maintenance cost of the smoke exhaust ventilator is further reduced.

The utility model belongs to the technical field of unmanned plane, concretely relates to a retractable landing gear, including containing frame, landing support, limiting component and telescopic push rod. The utility model discloses the rotation direction adjustment is toward the advancing direction of unmanned plane when the landing support is stored in the internal storage cavity of containing frame, and when the landing support rotates to the vertical state, limiting support is realized by utilizing limiting component, so that in the ground taxiing stage of unmanned plane, the reverse torque borne by the landing support will not be transmitted to the telescopic push rod, effectively reduces the abrasion and fatigue damage of telescopic push rod, guarantees its stability in the long -term use process, and then prolongs the service life, and reduces maintenance cost and replacement frequency.

The invention provides a thread design method and device based on a load distribution factor under an axial load, and relates to the field of thread stress calculation. The method comprises the following steps: calculating axial load coefficients of different positions of a bolt meshing thread area, and correcting the axial load coefficient of each position; calculating the axial load of the bolt meshing thread area at the corresponding position by using the corrected axial load coefficient of each position; calculating a load distribution factor of the corresponding position based on the axial load of each position and the axial load coefficient of the corresponding position; and according to the load distribution factor of each position, generating a design scheme of a bolt meshing thread. According to the method, the distribution condition of the axial load in the thread meshing area can be evaluated more accurately, and optimization of thread design and nut selection is facilitated, so that the bolt connection strength is improved.

This utility model discloses an automatic centering ball-distributing oscillator structure, belonging to the field of bearing assembly. The automatic centering ball-distributing oscillator structure includes an upper connecting seat, with a lower connecting seat at the bottom of the upper connecting seat. The upper and lower connecting seats are interconnected by a centering structure. This utility model solves the problems of traditional oscillating ball-distributing mechanisms, where a single soft rubber body directly connects to the ball distributor for rotational oscillation, or directly connects to an object for rotational oscillation. These mechanisms are prone to breakage of the connecting rubber body, resulting in a short service life, frequent replacement of parts, low production efficiency, and increased operating costs. More critically, when using a single soft rubber body structure, the concentricity of the oscillating component is poor, preventing automatic centering. When used in bearing production equipment, the poor concentricity of the oscillating component frequently causes it to bump against the bearing edge. This utility model patent solves all these problems, resulting in significant economic benefits.

The invention discloses a multi-head embroidery machine and a dual-drive-shaft clutch mechanism thereof, and belongs to the technical field of embroidery, an axial clutch piece moves in the axial direction in the clutch process so as to realize transmission separation of one of a first drive shaft and a second drive shaft and transmission connection of the other one; the driving shaft positioning structure is used for achieving circumferential positioning of the first driving shaft and the second driving shaft after transmission separation with the axial clutch piece so as to limit rotation of the first driving shaft or the second driving shaft. Therefore, one of the first driving shaft and the second driving shaft which are separated from the axial clutch piece can be circumferentially positioned, so as to ensure that convex teeth and tooth grooves between the axial clutch piece and the first driving shaft and between the axial clutch piece and the second driving shaft are meshed again during next clutch.