3271 results about "Axial force" patented technology

The invention discloses a deep foundation pit stability deformation control method and device based on digital twinning. The method comprises the steps that monitoring time sequence data of a deep foundation pit are collected and obtained; constructing a deep foundation pit deformation control digital twin platform; constructing a CNN-LSTM composite neural network based on an Adam optimization algorithm through a foundation pit deformation prediction module, and performing model training / verification on the CNN-LSTM composite neural network through the data training set and the data verification set to obtain an optimized CNN-LSTM composite neural network; based on the optimized CNN-LSTM composite neural network, performing time sequence change prediction on the axial force of the steel support according to the data test set to obtain a prediction result; the steel support servo module realizes servo control on the axial force of the steel support according to a prediction result on the basis of a constructed servo control strategy; and the foundation pit BIM module is used for constructing a deep foundation pit BIM model based on a Revit modeling technology and interacting with the deep foundation pit BIM model in real time through a RevitAPI data interface according to the output of the steel support servo module so as to realize visualization of deformation control of the deep foundation pit. The problems that in the deep foundation pit construction process, due to the fact that complex geological conditions are involved, the surrounding environment and an existing building are affected to a certain degree, and deformation and stability of the deep foundation pit cannot be accurately controlled are solved.

The invention is suitable for the technical field of reliability test of numerical control machine tools, and provides a ball screw pair comprehensive performance test device and method for simulating real working conditions. The device comprises a ball screw pair, a test device base, a rolling guide rail pair, a grating ruler integrated installation unit, two sets of support driving units, a loading workbench, an axial force simulation loading unit, a tested workbench and a comprehensive performance detection unit. The two sets of supporting and driving units are distributed on the test device base in a staggered alignment manner and are respectively connected with the loading workbench and the tested workbench, and synchronous driving of the loading workbench and the tested workbench is realized through synchronous control; and the axial force simulation loading unit realizes static and dynamic simulation loading of the axial force through electro-hydraulic servo control. According to the invention, a test device and technical support are provided for carrying out the reliable comprehensive performance bench test of the ball screw pair, and the problems of the ball screw pair in the aspects of high-frequency dynamic load simulation loading, comprehensive performance test and motion tracking loading are solved.

The invention discloses a grinding force online detection control device and method, and relates to the technical field of precision grinding machining force measurement, a spring chuck is arranged in a containing cavity, and the outer wall of a detection shaft section is a tapered conical surface; the threaded gland is connected with the connecting shaft section to axially limit the spring chuck, the mounting handle is provided with a first conical cavity, the threaded gland is provided with an avoiding hole, the piezoelectric sensors are mounted on the detection shaft section, the grinding wheel spindle acts on the piezoelectric sensors through the detection shaft section, and the piezoelectric sensors are used for detecting tangential force, normal force and axial force. The signal amplification processing module can convert charge signals output by the piezoelectric sensor into digital signals and output the digital signals to the terminal, and the terminal can control logic to control the grinding head to maintain constant-force grinding according to a preset grinding force target value. According to the method, all-directional real-time detection and control over the grinding force are achieved, the accuracy and the real-time performance are improved, and a new control method is provided for low-damage machining of hard and brittle materials.

The invention relates to the technical field of bolt tightening, and provides an intelligent bolt tightening control method and system based on axial force measurement. Comprising the steps of collecting bolt identification and process parameter data, collecting temperature measurement data, and obtaining sound velocity compensation parameters and elastic modulus compensation parameters. And zero-load preloading data are collected and processed to generate zero-load baseline data, and a self-calibration model is obtained. Axial force data and ultrasonic echo data are collected, and an axial force fusion estimation result is obtained. And comparing an axial force fusion estimation result with target axial force data. And when in the target interval, fine twisting control is carried out based on model predictive control and a micro-stepping strategy, and the controllable damping unit is driven to carry out energy absorption and stopping. And acquiring an axial force fusion estimation result when the target axial force is reached, processing the data in the holding stage to obtain an axial force rebound check result, and if the axial force rebound check result exceeds the limit, performing secondary twisting control. According to the scheme, refinement and traceability of the bolt tightening process are achieved.

The invention belongs to the technical field of supporting structure performance evaluation, and particularly discloses and provides an NT-CEP pile wall anchor foundation pit supporting structure anti-overturning evaluation method which comprises the steps that in the whole construction period, the construction process is divided into a plurality of continuous load steps based on excavation and supporting procedures; under each load step, pile body strain, arc-shaped wall stress, anchor rod axial force and deep soil displacement are synchronously collected, and a multi-source response data set is constructed; constructing an NT-CEP pile-arc wall-anchor rod coupling model based on the design drawing; carrying out inversion analysis through the model, and solving the load sharing proportion and the overall anti-overturning safety coefficient of each component under each load step; and continuously identifying the abnormal component based on the load sharing proportion, and dynamically analyzing and outputting an anti-overturning capability evaluation index based on the change trend of the safety coefficient. According to the method, dynamic refined evaluation of the construction process is realized, and the authenticity and perspectiveness of an evaluation result are remarkably improved.

The invention discloses a state transition pump shaft simulation load run-out detection system which comprises a pump, a dial indicator and a pull and push dynamometer. The pump shaft is provided with a driving disc and a stress disc, and the driving disc, the pump shaft and the stress disc are located on the same central axis. The dial indicator can be selectively configured in a radial run-out detection state by adjusting the position of the dial indicator and the direction of a measuring head, wherein the measuring head is perpendicular to the central axis and abuts against the outer circumferential surface of the pump shaft; in the axial run-out detection state, the measuring head is overlapped or parallel to the central axis and abuts against the axial end face of the pump shaft; the push-pull dynamometer can be selectively configured in a radial force application state by adjusting the position of the push-pull dynamometer and the direction of a force application end, wherein the force application end is perpendicular to the central axis and abuts against the outer circumferential surface of the stress disc, and a radial simulation load is applied; in the axial force application state, the force application end is parallel to the central axis and abuts against the disc end face of the stress disc, and an axial simulation load is applied. Through the state conversion of the same detection and force application device, the radial and axial runout integrated detection of the pump shaft under the simulated load is realized.

The invention relates to an air blower based on magnetic and gas combination axial force balance and a control method of the air blower, and belongs to the technical field of axial force regulation and control of air blowers. An axial air suspension bearing and an axial magnetic bearing are arranged in a main machine of the air blower, the axial magnetic bearing is connected with a magnetic bearing controller, and the magnetic bearing controller controls the axial position of a rotor by controlling the current of the axial magnetic bearing; an axial displacement sensor and a radial displacement sensor are arranged to detect the displacement of the rotor; and the main controller is used for controlling the starting and stopping of the axial magnetic bearing and the main machine based on the axial displacement and the radial displacement of the rotor, and sending out early warning. According to the magnetic and air combined axial force balance device, the axial magnetic bearing is used for providing active control force, the air bearing is used for providing passive support, the stability and reliability of a system are improved, and an important protection effect is achieved on core parts of an air blower.

The invention discloses a follow-up type superhard grinding wheel outer circle reciprocating grinding force measuring device and method, relates to the technical field of grinding machining, and solves the problem that grinding force follow-up measurement in a reciprocating grinding mode cannot be achieved in grinding force measurement in the prior art. The device comprises a driving tool, wherein the driving tool is used for clamping one end of a workpiece and driving the workpiece to rotate; a Z-axis moving assembly is fixedly arranged on the driving tool, a moving supporting table is arranged at the moving end of the Z-axis moving assembly, and the Z-axis moving assembly can drive the moving supporting table to move in the axial direction of the workpiece. A tangential telescopic measuring mechanism and a normal telescopic measuring mechanism which are perpendicular to each other are arranged on the movable supporting table, and the tangential telescopic measuring mechanism and the normal telescopic measuring mechanism can be in contact with the outer wall of the workpiece on the same normal plane perpendicular to the axis of the workpiece to measure force; the driving tool is adjustably provided with a Z-axis force measurement supporting tip, and the Z-axis force measurement supporting tip can be matched with the other end of the workpiece. Grinding force measurement in the reciprocating grinding machining process is achieved, and the grinding process can be monitored timely and accurately.

The invention belongs to the technical field of electric digital data processing and foundation engineering, and discloses a method for calculating stress and displacement of a foundation pile in a soil body under the action of a pile top axial load, which comprises the following steps of: taking the pile top as an origin of coordinates, and taking the downward direction of the longitudinal axis of a pile body as a z axis; according to the basic mechanical equilibrium condition of an infinitesimal body formed by the micro-section length randomly selected in the axial direction of the pile body, the boundary condition of the force at the top end of the pile and the deformation coordination relation between the bottom end of the pile and the foundation, characteristic variables reflecting the pile body stress and displacement distribution mode are solved; and according to the basic mechanical equilibrium condition of the infinitesimal body, the boundary condition of the force at the top end of the pile and the characteristic variables, the pile body axial displacement, the pile body axial force and the pile side surface friction resistance at different depths in the axial direction of the pile body are solved. The rapid and effective method and scientific basis are provided for design calculation and analysis of the foundation pile in the soil body under the action of the axial load of the pile top, and the method has important technical method significance and engineering application value.

The invention relates to the technical field of aero-engines, in particular to a sealing and cooling structure and method for adjusting the axial force of an aero-engine rotor, which comprises a turbine disc provided with a rear baffle, and further comprises a low-pressure turbine guide vane arranged opposite to the turbine disc, a low guide front inner supporting ring and a low guide rear inner supporting ring are arranged in the middle of the low-pressure turbine guide vane; labyrinth teeth correspondingly matched with the low-guide front inner supporting plate are formed on the rear baffle, radial labyrinth tooth gaps are formed, and when airflow in an air collection cavity enters a rotor cavity from a low-pressure pre-rotation nozzle, the airflow is embedded into an air supply channel from a front pre-rotation hole at the same time; one part of airflow entering the air supply channel enters the disc rear cavity, and the other part of airflow enters the rotor cavity. By adjusting the sealing labyrinth structure, it is ensured that the axial force of the rotor does not exceed the allowable maximum value in the large-state working process and is not subjected to light load in the small-state working process, meanwhile, sealing gas used behind a turbine disc is ensured, turbine hot gas is prevented from flowing into an inner disc cavity from a main channel, and it is ensured that an engine works reliably.

The present invention provides a steel support system for foundation pit support, belonging to the field of foundation pit support, and is used to support the foundation pit in foundation pit engineering. Foundation pit construction is extremely likely to cause damage such as settlement of surrounding buildings and municipal pipelines, so there are very high requirements for construction quality and deformation control. In the prior art, the steel supports that can achieve axial force compensation have problems of high cost and weak structure. This steel support system includes a plurality of steel supports, and both ends of the steel supports are respectively connected to the foundation pit side through quick-installation and quick-disassembly structures. The steel support includes a flexible section and an adjustment section. Two flexible sections are respectively arranged at both ends of the steel support. The flexible section includes a flexible head and a fixed head that are slidably matched, and the adjustment section is arranged inside the steel support. With the cooperation of the sliding function of the flexible section and the telescopic function of the adjustment section, the overall length of the steel support can be adjusted. In the present invention, the entire steel support system only requires a set of servo adjustment mechanisms, having the effects of low cost and high reliability.

The invention discloses a rigid rod frequency ratio method axial force identification method. The method comprises the following steps: (1) according to engineering data, obtaining whether a rigid rod is a pressure rod or a pull rod, and obtaining related parameters of the rigid rod: the linear density m of the rigid rod, the length L of the rigid rod and the flexural rigidity EI of the rigid rod; (2) vibration signals of the rigid rod are collected on site through a vibration sensor, and multi-order frequency of the rigid rod is obtained through analysis; (3) selecting a corresponding method to calculate the frequency ratio of the rigid rod according to whether the rigid rod is a compression rod or a pull rod and boundary conditions, and calculating the axial force of the rigid rod through a frequency ratio method; and (4) checking the relative flexural rigidity xi of the rigid rod, and evaluating the axial force identification precision of the rigid rod. According to the method, a unified calculation method for identifying the axial force of the rigid pull rod and the pressing rod is established through a frequency ratio method, the method is easy to use and has good precision, and a practical new method is provided for identifying the axial force of the rigid rod.

The magnetic suspension motor comprises annular rotors and a stator assembly, the two annular rotors are coaxial and arranged in the vertical direction, the number of magnetic poles of the two annular rotors is the same, the arrangement directions of the magnetic poles of the two annular rotors are the same or opposite, and the relative positions of the two annular rotors are fixed; the two annular rotors are arranged on the outer side of the stator assembly in a sleeving mode, and the stator assembly drives the two annular rotors to suspend and rotate through magnetic force. The axial driving assembly can provide additional axial force for the rotating cylinder, and after the rotating cylinder axially deviates, the rotating cylinder is driven to return to the normal position; the stator assembly is isolated from the outside by the mounting cavity, and the annular rotor is isolated from the outside by the rotating cylinder, so that external media are prevented from being polluted, and the stator assembly and the annular rotor are also prevented from being corroded by the external media.

The invention discloses a surrounding rock deformation treatment method which comprises the following steps: determining the range of a strong influence area in a fault through advanced geological detection, and adopting a graded support strategy for different influence areas: when the width of the strong influence area in the fault is three times greater than the span of a tunnel, arranging an NPR anchor cable group on the ground surface to form a pre-reinforcement system; during benching, NPR anchor rods and steel arches are combined for supporting in a fault non-weak-influence area, and long and short NPR anchor cables are additionally arranged in a fault weak-medium-influence area for collaborative supporting; double-gradient grouting is implemented in front of the boundary of the moderately strong affected zone, a peripheral reinforcing shell is formed by grouting at the first gradient of 2-3 MPa, and an internal permeation network is formed by grouting at the second gradient of 3.5-4.5 MPa; through real-time monitoring of the axial force of the steel arch, a linkage response mechanism of anchor cable secondary tensioning and grouting and supplementing is established. According to the method, through combination of advanced pre-reinforcement, graded support and dynamic regulation, active control over tunnel surrounding rock deformation of the fault fracture zone is achieved, and the collapse risk and the support structure damage risk are effectively restrained.

The invention discloses a non-contact monitoring method for the axial force of an end anchoring anchor rod, and relates to the technical field of anchor rod axial force measurement. The monitoring method comprises the steps that firstly, relevant parameters of surrounding rock, relevant parameters of an anchor rod in the anchoring process and relevant parameters of an anchoring agent are obtained; acquiring strain data of an anchor rod tray in the anchoring system by adopting a full-field strain measurement system, transmitting the strain data to a data processing module of the full-field strain measurement system, and acquiring anchor supporting force by virtue of a stress-strain relationship of the anchor rod tray; finally, a calculation analysis formula of the mechanical relation between the anchor supporting force Ft generated by the anchor rod tray and the anchor rod axial force F is constructed in a computer; and inputting the values of the related parameters obtained in the step 1 and the step 2 into a calculation analysis formula, and calculating to obtain the axial force of the end anchoring anchor rod. By means of the method, non-contact measurement of the anchor supporting force of the anchor rod can be achieved, and the integrity of an anchoring system is further protected.

The invention discloses a foundation pit deformation prediction and control method based on a graph neural network, and relates to the technical field of civil engineering, and the method comprises the steps: employing a space-time diagram attention network model, and employing a graph attention mechanism to capture spatial features between monitoring points around a steel support; inputting spatial features extracted by the time-space diagram attention network model into a gating circulation unit, extracting single representation of the whole diagram, and obtaining a monitoring point deformation prediction value; the method has the advantages that the space-time diagram attention network is used for analyzing and weighting the space relation among the multiple monitoring points, the importance of supporting axial force near all the monitoring points is distinguished, the model more accurately captures the spatial heterogeneity of soil deformation, and the deformation prediction accuracy is improved. Therefore, the accuracy of foundation pit deformation prediction is obviously improved.

The invention relates to a drive device (2) for a robot (1), comprising a worm drive (3) having a rotatable worm shaft (4) and a worm wheel (10) meshing therewith, wherein the worm shaft (4) is supported by a bearing element (5) transmitting at least one axial force, characterized in that the bearing element (5) transmitting at least one axial force is axially supported at least indirectly on an axial force measuring device (6), wherein the axial force measuring device (6) is configured to detect an axial force when a torque is transmitted to the worm shaft (4) via the worm wheel (5). The invention further relates to a robot (1) comprising such a drive device (2).

Disclosed in the present invention are high-rise pile cap equipment under a horizontal load and a centrifuge test method for foundation bearing characteristics thereof. The equipment comprises a model box, a sand layer, a model pile cap, at least eight model piles, a horizontal loading device, at least two laser displacement sensors, an axial force sensor, and a plurality of strain gauges. The method comprises: S1, performing one-way horizontal loading on high-rise pile cap equipment under a horizontal load to obtain an ultimate foundation bearing capacity situation, a model pile body axial force distribution situation, a pile foundation axial force comparison situation, a model pile body bending moment distribution situation, and a model pile body bending moment comparison situation of the equipment; and S2, performing one-way variable amplitude cyclic loading on the high-rise pile cap equipment under the horizontal load to obtain a foundation displacement situation, an effect of the number of cycles on foundation stiffness, an effect of a cyclic load amplitude on the foundation stiffness, and a foundation inclination situation. In this way, the foundation design of the high-rise pile cap can be optimized, and a basis and a reference for evaluating safety of foundation long-term service are provided.

The invention relates to the technical field of turbo molecular pump magnetic bearing dynamic performance testing, in particular to a gas loading simulation turbo molecular pump magnetic bearing dynamic performance testing device which comprises a frame, an upper three-axis moving platform is arranged on the top of the frame, and a side three-axis moving platform is arranged on one side of the frame. The upper three-axis moving platform and the side three-axis moving platform are respectively and fixedly connected with a pressure applying assembly, the pressure applying assembly is detachably connected with a simulation rotor, the simulation rotor is detachably connected with a bottom plate, the bottom plate is fixedly connected to the bottom of the frame, and one side of the top surface of the frame is fixedly connected with a visual detection assembly. Axial force and radial force are applied to the molecular pump through the upper three-axis moving platform and the side three-axis moving platform respectively, moments in different directions are applied, and the static and dynamic load performance of the molecular pump under different axial force, radial force and moment combinations can be measured.

The invention relates to the technical field of petrochemical equipment sealing, in particular to a flange sealing performance evaluation method based on bolt axial stress, which comprises the following steps: establishing a nonlinear stress relationship between a gasket and bolt axial force; establishing a relationship between the axial stress of the bolt and the sealing contact stress of the contact surface of the gasket under different working pressures; constructing a three-dimensional model of a real sealing surface; establishing a three-dimensional model of the sealing surface contact process; obtaining the change of a leakage gap between the contact surfaces under different contact stresses, and establishing a relation model of the leakage gap of the contact interface and the sealing contact stress; establishing a quantitative evaluation model among the sealing contact stress, the leakage clearance and the leakage rate; obtaining the contact stress under the actual working condition, and calculating whether the corresponding leakage rate meets the tightness judgment standard or not so as to judge the sealing state of the flange. The invention aims to solve the technical problem that the metal sealing performance of in-service flange connection cannot be quantitatively and online evaluated in the prior art.

The invention discloses a quasi-static loading system for plane local loading and a loading method of the quasi-static loading system, and aims to solve the problem that a processing method for accurately simulating a complex stress state of a shear wall under an equipment anchoring effect does not exist at present. A bottom-arranged boundary fixing piece is arranged at the bottom of a counter-force portal, and an out-of-plane local load loading assembly is arranged on the top surface of the bottom-arranged boundary fixing piece; the vertical loading piece and the in-plane horizontal transverse loading assembly are arranged in the counter-force portal frame, a placing part matched with a test piece is formed between the bottom side of the loading beam and the top surface of the bottom boundary fixing piece, the two horizontal actuators are arranged at the two ends of the loading beam respectively, one end of each horizontal actuator is connected with the loading beam, and the other end of each horizontal actuator is connected with the in-plane horizontal transverse loading assembly. The other end of each horizontal actuator is arranged on the inner wall of the side part of the counter-force gantry; the quasi-static force loading method comprises the following steps: performing preset vertical axial force application, prestress tension grading and / or supplementary tension treatment on a test piece according to preset requirements, and then performing horizontal cyclic loading until the bearing capacity of the test piece is reduced to 85% of a peak load, and terminating the loading process.

The invention relates to a method for optimizing a newly-built anchor rod supporting system for slope expanding excavation by using residual anchor rods. The method comprises the following steps: preliminarily selecting a plurality of excavation schemes of different excavation slope angles according to the geometrical morphology of the side slope and the layout of anchor rods; calculating the excavation area and the residual length of the anchor rod of each scheme; calculating the theoretical ultimate uplift bearing capacity of the residual anchor rod based on the soil nail theory; midas GTS NX software is used for establishing a slope stability numerical simulation model considering and not considering the influence of residual anchor rod reinforcement, and a safety coefficient and anchor rod axial force distribution are calculated; by comparing the maximum axial force of the residual anchor rod obtained through numerical simulation calculation with the ultimate uplift bearing capacity obtained through theoretical calculation, the authenticity of the numerical simulation calculation safety coefficient is judged, and the true safety coefficient is sought; calculating a rock-soil body shear strength parameter adjustment coefficient according to the true safety coefficient to obtain an enhanced rock-soil body shear strength parameter, inputting the enhanced rock-soil body shear strength parameter into geotechnical engineering design software, and designing a newly-built support structure; and finally, technical and economic comparison and selection are carried out on the schemes, and the optimal scheme is selected.

The invention relates to the technical field of pile foundation tests, in particular to a pile-soil interaction simulation test system and method.The pile-soil interaction simulation test system comprises a vibration table and a test piece placed on the vibration table, and a plurality of pile-soil interaction loading mechanisms are arranged on the vibration table; the pile-soil interaction loading mechanisms are sequentially mounted on the vibration table in the extension direction of a test piece pile shaft, and each pile-soil interaction loading mechanism comprises an arc-shaped component, a spring, a component force plate and a lower sealing plate; the bottom surface of the pile foundation in the test piece abuts against the steel plate; a force sensor is mounted between the steel plate and the pile bottom; a pile end anchoring part is arranged at the end part of the pile foundation in the test piece; a pile axial force loading mechanism is arranged between the steel plate and the bearing platform; the device is simple in structure, ingenious in construction, small in size and easy to install and operate, and the vibration table test of the large-size pile foundation test piece can be completed. And the economic benefit is high.

The utility model belongs to the technical field of bearing testing, and relates to an oversize turntable bearing rigidity testing device. The related testing device is provided with a testing platform. A driving assembly which is connected with the test bearing inner ring and drives the test bearing inner ring to rotate is placed on the test platform; the driving assembly is provided with a transition flange connected with the inner ring of the test bearing; the transition flange plate is supported on the test platform through a driving bearing; a loading arm is arranged above the transition flange plate; the loading arm is connected with the outer ring of the test bearing; a radial oil cylinder is arranged at one end of the loading arm; and an axial oil cylinder and an overturning oil cylinder are also arranged corresponding to the loading arm. According to the utility model, the rigidity of the bearing can be tested under the action of different axial forces, radial forces and overturning moments, so that the change of the rigidity of the bearing can be analyzed and tested under the influence of various working conditions.

The invention discloses a B-axis power knife rest simulation loading test bench which comprises a B-axis power knife rest, an up-down radial force loading module, a left-right radial force loading module, an axial force loading module, an axial torque loading module, a rotary loading module, a combined knife handle and horizon iron. The B-axis power tool rest and the rotary loading module are both arranged on the horizontal iron; the up-down radial force loading module, the left-right radial force loading module, the axial force loading module and the axial torque loading module are all arranged on the rotary loading module; one end of the combined knife handle is connected with an electric main shaft of the B-axis power knife rest, and the other end of the combined knife handle is connected with the torque loading module. Through cooperation of the up-down radial force loading module, the left-right radial force loading module, the axial force loading module, the axial torque loading module and the rotary loading module, comprehensive simulation dynamic loading of the radial force, the axial force and the reverse torque of the main shaft can be realized, so that the test period can be shortened, and the test cost can be reduced.

The invention relates to the technical field of multi-stage pumps, and particularly discloses a multi-stage pump axial force balancing system which comprises a water inlet section, a water outlet section and a water outlet section. The water outlet section is provided with a pressure relief cavity; two ends of the balance pipe are respectively communicated with the water inlet section and the pressure relief cavity; the two ends of the middle section are communicated with the water inlet section and the water outlet section respectively, an impeller is arranged on the inner wall of the middle section in a matched mode, a flow blocking cavity and a cover plate cavity are formed in the two sides of the impeller, and when the impeller rotates, hydraulic pressure generated by media in the flow blocking cavity to the impeller and hydraulic pressure generated by media in the cover plate cavity to the impeller are balanced; a balancing drum mounted on the pump shaft; the balance rings are mounted on the water outlet section, and the outer wall of the balance drum is sleeved with the balance rings at intervals; wherein the impellers comprise a plurality of first impellers and a plurality of second impellers, and the cover plate cavity corresponding to the second impellers is communicated with the pressure relief cavity through a gap between the balancing drum and the balancing ring. According to the axial force balancing system of the multi-stage pump, the balancing effect of axial force can be improved, and it is ensured that the multi-stage pump runs safely.

The invention discloses a method and system for analyzing the rolling resistance of a concrete-filled steel tube combined pier column, and the method comprises the steps: applying an axial compression load to the concrete-filled steel tube combined pier column, and dividing the cross section of the concrete-filled steel tube combined pier column into three layers of regions along a radial material change part; according to corresponding total cross-section average axial strain generated by the steel pipe concrete combined pier column when different axial compression loads are applied, equivalent stress corresponding to each layer of area is calculated, total axial force corresponding to each total cross-section average axial strain is calculated, and a total cross-section average axial strain-total axial force curve is formed; searching a first total cross-section average axial strain corresponding to the maximum value of the total axial force in the total cross-section average axial strain-total axial force curve and a second total cross-section average axial strain corresponding to a first obvious inflection point of the total cross-section average axial strain-total axial force curve, and calculating a ductility coefficient, and judging whether the concrete-filled steel tube composite pier column meets the ductility design requirement or not.

The invention relates to the technical field of multi-stage centrifugal pumps, and discloses an axial balance assembly which comprises a balance shaft sleeve, a pump shaft and a high-pressure throttling ring connected to a water inlet and outlet section, the balance shaft sleeve is connected to the pump shaft and arranged on the periphery of the pump shaft in a sleeving mode, and the high-pressure throttling ring is arranged on the periphery of the balance shaft sleeve in a sleeving mode. The high-pressure throttling ring and the periphery of the balance shaft sleeve are limited to form a flow blocking cavity, the flow blocking cavity is provided with a high-pressure flow blocking inlet and a high-pressure flow blocking outlet, the high-pressure flow blocking inlet and the high-pressure flow blocking outlet are oppositely arranged at the two ends of the flow blocking cavity in the axial direction of the balance shaft sleeve, and the high-pressure throttling ring is provided with a high-pressure ring end face. The balance shaft sleeve is provided with a high-pressure shaft end face, and the high-pressure choke flow inlet is located between the high-pressure ring end face and the high-pressure shaft end face. According to the axial balance assembly, generation of residual axial force from the high-pressure section to the low-pressure section is reduced, the service life of the water pump is prolonged, and the operation reliability of the water pump is improved.

The motorized spindle comprises a machine body assembly, a spindle core, a pulling claw assembly and a tool loosening and broaching mechanism, the pulling claw assembly comprises a sliding core, a clamping head is arranged at the rear end of the sliding core, the tool loosening and broaching mechanism comprises a first driving cylinder, a second driving cylinder and a pull rod, and the first driving cylinder is arranged at the rear end of the machine body assembly; the second driving cylinder is arranged at the rear end of the first driving cylinder, an axial connecting rod for transmitting axial force is arranged between a piston of the first driving cylinder and a piston of the second driving cylinder, the rear end of the pull rod is connected to the piston of the first driving cylinder, the front end of the pull rod extends into an inner hole of the shaft core, a clamping groove is formed in the front end of the pull rod, and the clamping connector is connected to the clamping groove. The clamping groove is provided with a clamping face capable of pulling the clamping head from the front side and an abutting face capable of abutting against the clamping head from the rear side, and an axial interval allowing the clamping head to move in the axial direction is formed between the abutting face and the clamping face. By adopting a disc-spring-free type locking structure, the problem of cutter loosening caused by failure of a disc spring is solved.

The invention relates to a device (19) for a muscle-powered vehicle (20), comprising an electric machine (8) with a rotor shaft (8.1), a gear (4) with at least one first helical gear (5) and a second helical gear (7) which mesh with one another, a pedal crankshaft (9) and a housing (10) for accommodating the electric machine (8), the gear (4) and essentially also the pedal crankshaft (9), wherein the first gear (5) is arranged on the pedal crankshaft (9) in a torque-transmitting manner, wherein the second gear (7) is arranged on the rotor shaft (8.1) in a torque-transmitting manner.1), wherein one of the two gearwheels (5, 7) is arranged to be axially displaceable and the other of the two gearwheels (7, 5) is arranged to support axial force, wherein at least one first friction surface (3) is arranged on at least one end face of the axially displaceable gearwheel (5), which is assigned to at least one second, stationary friction surface (2), so that when the pedal crankshaft (9) is driven in the direction of travel of the vehicle (20), the axially displaceable gearwheel (5) is displaced axially in such a way that the two friction surfaces (3, 2) come into contact and generate a friction torque.