CN201096633Y - Follow-up type air-float magnetomotive zero friction suspension device - Google Patents
Follow-up type air-float magnetomotive zero friction suspension device Download PDFInfo
- Publication number
- CN201096633Y CN201096633Y CNU200720115290XU CN200720115290U CN201096633Y CN 201096633 Y CN201096633 Y CN 201096633Y CN U200720115290X U CNU200720115290X U CN U200720115290XU CN 200720115290 U CN200720115290 U CN 200720115290U CN 201096633 Y CN201096633 Y CN 201096633Y
- Authority
- CN
- China
- Prior art keywords
- air
- cylinder
- friction
- moving
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Abstract
The utility model relates to a following type air floating magnetic-action no-friction suspension device, which comprises a mounting frame, a movable beam, a guide rod, an air floating system and a magnetic action system, wherein the air floating system comprises two no-friction cylinders, two air tanks, a no-friction cylinder connection air tube, a precision pressure reducing valve, and an air source inlet tube, the magnetic action system comprises a long travel action ring and an exciter iron core, the two no-friction cylinders are symmetrically arranged above the bottom plate of the mounting frame, the no-friction cylinder connection air tube is connected between the no-friction cylinders and the air tank, the compressed air source is connected with the air tank through the precision pressure reducing valve and the air source inlet tube, the piston rods of the no-friction cylinders are connected with the movable beam by the hinges, both ends of the movable beam is arranged on the guide rod by the air bearing, the guide rod is arranged fixedly on the mounting frame, the air channel in the movable beam is connected with the air bearing, a suspension rod is arranged fixedly below the movable beam. The utility model has the advantages of being able to meet frequency rule at ultralow frequency, adequate small additional mass, small nonlinear influence and high test precision.
Description
(1) technical field
The utility model belongs to the modal test apparatus field, relates in particular to a kind of follow-up type air-floating magneto-motive friction-free suspension device.
(2) background technology
When the modal test of space flight and some specific (special) requirements test specimen, the state of weightlessness of special low frequency suspension apparatus imitation specimen must be arranged, promptly simulate its solid propping up-freedom or freedom-free boundary condition by special suspension.
In order to reduce the influence of suspension apparatus to additional stiffness, additional mass and the additional friction power and the moment of test specimen, suspension should satisfy Nyquist criterion and stability criterion, when promptly requiring test specimen to hang, its rigid body hangs frequency should be lower than 1/3～1/5 of the own elasticity natural frequency of test specimen.
At present, domestic when carrying out ultralow frequency test specimen modal test, adopt methods such as elastic string suspention, when the fundamental frequency of test specimen is very low, as less than 0.1HZ the time, suspention highly reaches 15 meters and still can't satisfy the Nyquist criterion requirement, and at this moment additional mass, the non-linear effects of elastic string is also bigger, and the resultant error that tests out is bigger.Owing to lack necessary means, scientific research has been produced very big influence, existing means of testing can not adapt to the demand of development.
(3) summary of the invention
For overcome existing suspension can't satisfy Nyquist criterion requirement, additional mass when the ultra-low frequency, deficiency such as non-linear effects is big, measuring result error is big, the utility model provides a kind of also can satisfy Nyquist criterion when ultralow frequency, additional mass is enough little, non-linear effects is little, the follow-up type air-floating magneto-motive friction-free suspension device that measuring accuracy is high.
The technical scheme that its technical matters that solves the utility model adopts is:
A kind of follow-up type air-floating magneto-motive friction-free suspension device, described nothing friction suspension apparatus comprises that installation frame, moving beam, guide pole, synchroballistic air supply system, air-flotation system and magnetic move system, and described air-flotation system comprises that two nothing friction cylinders, two identical gas-holder, nothing friction cylinders connect tracheae, accurate reduction valve, source of the gas draft tube; The moving system of described magnetic comprises long stroke moving-coil, vibrator iron core; Two are not had the top that the friction cylinder is installed in the installation frame base plate symmetrically, do not have between friction cylinder and gas-holder by being connected the tracheae connection with the nothing friction cylinder of cylinder bore equal diameters, compressed gas source is by accurate reduction valve, the source of the gas draft tube connects gas-holder, the piston rod that does not have the friction cylinder is hinged by being connected with moving beam, the moving beam two ends are installed on the guide pole by air bearing, air bearing is connected slidably with guide pole, described guide pole is fixedly mounted on the installation frame, gas circuit in the moving beam connects air bearing, and the below of moving beam is fixed with a hanger bar that is used to hang test specimen.
Further, the endoporus of long stroke moving-coil can be enclosed within on the vibrator iron core with moving up and down, the vibrator iron core is installed between the base plate and top board of installation frame, and long stroke moving-coil that moves up and down and moving beam distance are consistent, and long stroke moving-coil endoporus is consistent with the gap between the vibrator iron core.
Further again, described synchroballistic air supply system comprises servomotor, ball-screw, synchroballistic air cylinder driven frame, synchroballistic cylinder, connects tracheae, the synchronous draft tube of air bearing; Servomotor is installed on the top board of installation frame, servomotor is fixedlyed connected with ball-screw, synchroballistic air cylinder driven frame one end be fixed on the synchronization-moving ball-screw nut of moving beam on, the other end connects the piston rod of synchroballistic cylinder, the synchroballistic cylinder is fixed on the below of installation frame top board, the epicoele of synchroballistic cylinder is connected with two gas-holder respectively by connecting tracheae, the synchronous draft tube of the air bearing that is connected with compressed air gas source is fixed on the ball-screw nut, the other end connects the air intake opening of air bearing, and the cylinder diameter sectional area of synchroballistic cylinder equals two does not have friction cylinder bore sectional area sum.
Further, described nothing friction suspension apparatus comprises the detecting sensor system, and the detecting sensor system comprises that reference gas cylinder pressure, differential pressure pickup, air bearing, displacement transducer, acceleration transducer, long stroke moving-coil force transducer, load force sensor, differential pressure pickup connect tracheae; The reference gas cylinder pressure is fixed on the base plate of installation frame, and differential pressure pickup one end is connected with nothing friction cylinder inner cavity, and the other end connects tracheae by differential pressure pickup and is connected with the reference gas cylinder pressure; The displacement transducer movable part is fixed with the support that is fixed on the moving beam, and the fixed part of displacement transducer is fixed on the top board below of installation frame; Acceleration transducer is fixed on the support on the moving beam; Long stroke moving-coil force transducer simultaneously is fixed on the side of moving beam, and another side connects long stroke moving-coil mounting bracket; The load force sensor is fixed on the moving beam hanger bar, and the other end connects the suspension wirerope.
Four air bearing are installed on the described moving beam, and the gas circuit in the moving beam connects four air bearing, and four air bearing flexibly connect two guide poles that are installed in parallel between installation frame base plate and top board.
Technical conceive of the present utility model is: be made of air-flotation system, the moving system of magnetic, synchroballistic air supply system, detecting sensor system, installation frame, moving beam, connection hinge, suspension wirerope, guide pole.Air-flotation system is called again by subsystem, and the moving system of magnetic is called initiatively subsystem again.Air-flotation system is by there not being formations such as friction cylinder-piston, outside gas-holder, accurate reduction valve.Air-flotation system provides the constant suspension force gravity with the balance test specimen, and the size of suspension force is to act on the air pressure on the piston and the product of piston area.Air pressure is regulated with accurate reduction valve.Owing to adopt there not to be friction cylinder-piston apparatus, make piston in any position of the vertical direction of cylinder, air spring power always with the test specimen gravitational equilibrium.Cylinder is connected to gas-holder by bigbore tracheae makes the volume of gas-holder become volume of cylinder.The rigidity of air spring becomes very little like this, keeps the ability of bearing big load test specimen simultaneously.Accurate reduction valve makes the mean pressure of cylinder be stabilized in setting value, makes the suspension force of not having friction cylinder-piston stablize indirectly.
Initiatively subsystem is made of long stroke moving-coil vibrator and the detecting sensor system and the controller etc. of customization.
The moving system of magnetic provides non-contacting electromagnetic force according to the information that the detecting sensor system provides under controller control.To satisfy the various demands of suspension apparatus to small power.
One of synchroballistic air supply system effect provides pressurized air for the synchronous air bearing in motion, effect two for reducing because of there not being the air pressure fluctuation that the friction cylinder piston moves and causes.
The beneficial effects of the utility model mainly show: 1, owing to adopt nothing friction cylinder and air bearing, but the state of weightlessness of imitation specimen, and because relative other the dynamic constrained power that influences vibration test of friction force is non-linear and non-repeatability, frictional resistance is minimum after adopting nothing friction cylinder and air bearing, does not therefore influence vibration mode test; 2, owing to adopt gas-holder and do not have the compressed-air actuated air spring of friction cylinder, so spring rate can be done very for a short time, to satisfy the vibration mode test of 0.1HZ with the lower frequency test specimen; 3, owing to adopted the synchroballistic air supply system, under the prerequisite that satisfies the pressure surge scope, the volume of gas-holder can be reduced greatly, obtain rigid body suspension frequency with less gas-holder and be lower than 0.03Hz; 4, owing to adopted magnetic to move system, the information that provides according to the detecting sensor system can suppress the additional mass of servomechanism under controller control, it is controlled at becomes possibility below the 600g, and can regulate suspension height and keep the vertical direction center, the compensatory pressure fluctuation; 5, owing to adopted differential pressure pickup, nothing is rubbed, and pressure reduction is controlled in the very little scope between cylinder in-cylinder pressure and reference gas cylinder pressure, thereby has improved the accuracy of detection of sensor greatly.
(4) description of drawings
Fig. 1 is the structural drawing of follow-up type air-floating magneto-motive friction-free suspension device.
Fig. 2 is the side structure synoptic diagram of Fig. 1.
(5) embodiment
Below in conjunction with accompanying drawing the utility model is further described.
With reference to Fig. 1, Fig. 2, a kind of follow-up type air-floating magneto-motive friction-free suspension device, described nothing friction suspension apparatus comprises that installation frame 4, moving beam 5, guide pole 22, air-flotation system and magnetic move system, and described air-flotation system comprises that two are not had friction cylinders 8, two identical gas-holder 12, do not have friction cylinder connection tracheae 21, accurate reduction valve 20, source of the gas draft tube 24; The moving system of described magnetic comprises long stroke moving-coil 16, vibrator iron core 17; Two are not had the top that friction cylinder 8 is installed in installation frame 4 base plates symmetrically, there are not 12 of friction cylinder 8 and gas-holder by being connected tracheae 21 connections with the nothing friction cylinder of cylinder bore equal diameters, compressed gas source is by accurate reduction valve 20, source of the gas draft tube 24 connects gas-holder 12, the piston rod that does not have friction cylinder 8 connects by being connected hinge 9 with moving beam 5, moving beam 5 two ends are installed on the guide pole 22 by air bearing 10, air bearing 10 is connected slidably with guide pole 22, described guide pole 22 is fixedly mounted on the installation frame 4, gas circuit in the moving beam 5 connects air bearing 10, and the below of moving beam 5 is fixed with a hanger bar that is used to hang test specimen.
The endoporus of long stroke moving-coil 16 can be enclosed within on the vibrator iron core 17 with moving up and down, vibrator iron core 17 is installed between the base plate and top board of installation frame 4, the long stroke moving-coil 16 that moves up and down is consistent with moving beam 5 distances, and long stroke moving-coil 16 endoporus are consistent with the gap of 17 of vibrator iron cores.
The synchroballistic air supply system comprises servomotor 2, ball-screw 25, synchroballistic air cylinder driven frame 26, synchroballistic cylinder 1, connects tracheae 11, the synchronous draft tube 3 of air bearing; Servomotor 2 is installed on the top board of installation frame 4, servomotor 2 is fixedlyed connected with ball-screw 25, synchroballistic air cylinder driven frame 26 1 ends be fixed on moving beam 5 synchronization-moving ball-screw 25 nuts on, the other end connects the piston rod of synchroballistic cylinder 1, synchroballistic cylinder 1 is fixed on the below of installation frame 4 top boards, the epicoele of synchroballistic cylinder 1 is connected with two gas-holder 12 respectively by connecting tracheae 11, the synchronous draft tube 3 of the air bearing that is connected with compressed air gas source is fixed on the ball-screw nut, the other end connects the air intake opening of air bearing 10, and the cylinder diameter sectional area of synchroballistic cylinder 1 equals two does not have friction cylinder 8 cylinder diameter sectional area sums.
Described nothing friction suspension apparatus comprises the detecting sensor system, and the detecting sensor system comprises that reference gas cylinder pressure 6, differential pressure pickup 7, displacement transducer 13, acceleration transducer 14, long stroke moving-coil force transducer 15, load force sensor 18, differential pressure pickup connect tracheae 23; Reference gas cylinder pressure 6 is fixed on the base plate of installation frame 4, and differential pressure pickup 7 one ends are connected with nothing friction cylinder 8 inner chambers, and the other end connects tracheae 23 by differential pressure pickup and is connected with reference gas cylinder pressure 6; Displacement transducer 13 movable parts are fixed with the support that is fixed on the moving beam 5, and the fixed part of displacement transducer 13 is fixed on the top board below of installation frame 4; Acceleration transducer 14 is fixed on the support on the moving beam 5; Long stroke moving-coil force transducer 15 one sides are fixed on the side of moving beam 5, and another side connects long stroke moving-coil 16 mounting brackets; Load force sensor 18 is fixed on moving beam 5 hanger bar, and the other end connects suspension wirerope 19.
Four air bearing 10 are installed on the moving beam 5 by the light alloy material manufacturing, and the gas circuit in the moving beam 5 connects 10, four air bearing of four air bearing 10 and flexibly connects two guide poles 22 that are installed in parallel between installation frame base plate and top board.
The course of work of present embodiment is: before test, feed pressurized air to air bearing 10 earlier, make 22 air films that are formed with rigidity of air bearing 10 endoporus and guide pole, thereby making guide pole 22 friction force when motion is 0 substantially, on wirerope 19, hang test specimen then, then feed pressurized air to gas-holder 12 by accurate reduction valve 20, pressurized air in the gas-holder 12 enters nothing friction cylinder 8 by being connected tracheae 21 with the nothing friction cylinder of cylinder bore equal diameters, and the cylinder compressed air passes through piston rod to the pressure that does not have the friction cylinder piston, connect hinge 9, moving beam 5, hanger bar, load force sensor 18, hang wirerope 19 and act on test specimen; Adjust accurate reduction valve 20, when making the follow-up unit gravitational equilibrium of not having friction cylinder 8 internal pressures and test specimen and air-float magneto motive friction-free suspension device, adjust electric current in the long stroke moving-coil 16 of the moving system of magnetic by control system, make test specimen be in the vibration balancing center; Because two guide poles 22 in the air bearing of being installed on the moving beam 5 have limited moving beam and can only do translation up and down, and can not rotate, long stroke moving-coil 16 is fixed on the side of moving beam by long stroke moving-coil mounting bracket, long stroke moving-coil force transducer 15, thereby as long as when guaranteeing that vibrator iron core 17 is installed with the parallel sided of moving beam 5, consistent with regard to guaranteeing that long at the volley stroke moving-coil 16 endoporus and the gap of 17 of vibrator iron cores are that magnetic gap remains; When test specimen is subjected to the external world and forces exciting force, because the power that air-flotation system provides equals gravity all the time, but so simulated weightlessness, and test specimen is suspended on the suspension wirerope 19 times, so can do the motion under the freedom-free boundary condition of three degree of freedom, carry out the vibration mode test of test specimen; The detecting sensor system comprises differential pressure pickup 7, displacement transducer 13, acceleration transducer 14, long stroke moving-coil force transducer 15, load force sensor 18; In test process, provide the displacement of air-float magneto motive friction-free suspension device follow-up unit and acceleration information, nothing friction cylinder 8 and reference gas cylinder pressure 6 pressure-difference fluctuation information, test specimens to be subjected to force information and long stroke moving-coil 16 to act on the acting force information of follow-up unit to control system respectively, so that the electric current to long stroke moving-coil 16 is adjusted, provide suitable electromagnetic force.When moving beam 5 is done translation up and down, the displacement information that control system provides according to displacement transducer 13, the control step motor is synchronized with the movement ball-screw nut and moving beam, thereby guarantee to connect tracheae and keep relative static with air bearing, elimination is by connecting the additional force fluctuation that tracheae brings, the piston that keeps simultaneously not having motion of friction cylinder piston and synchroballistic cylinder is synchronized with the movement, because the cross section of synchroballistic cylinder 1 piston equals not have 2 times of friction cylinder 8 piston cross-sections, and direction of motion is opposite, institute is not so that there be friction cylinder piston when motion, gas-holder 12, there is not friction cylinder 8, total measurement (volume) in the synchroballistic cylinder 1 remains unchanged substantially, thereby has suppressed air pressure fluctuation to greatest extent.
Claims (5)
1, a kind of follow-up type air-floating magneto-motive friction-free suspension device, it is characterized in that: described nothing friction suspension apparatus comprises that installation frame, moving beam, guide pole, synchroballistic air supply system, air-flotation system and magnetic move system, and described air-flotation system comprises that two nothing friction cylinders, two identical gas-holder, nothing friction cylinders connect tracheae, accurate reduction valve, source of the gas draft tube; The moving system of described magnetic comprises long stroke moving-coil, vibrator iron core; Two are not had the top that the friction cylinder is installed in the installation frame base plate symmetrically, do not have between friction cylinder and gas-holder by being connected the tracheae connection with the nothing friction cylinder of cylinder bore equal diameters, compressed gas source is by accurate reduction valve, the source of the gas draft tube connects gas-holder, the piston rod that does not have the friction cylinder is hinged by being connected with moving beam, the moving beam two ends are installed on the guide pole by air bearing, air bearing is connected slidably with guide pole, described guide pole is fixedly mounted on the installation frame, gas circuit in the moving beam connects air bearing, and the below of moving beam is fixed with a hanger bar that is used to hang test specimen.
2, follow-up type air-floating magneto-motive friction-free suspension device as claimed in claim 1, it is characterized in that: the endoporus of long stroke moving-coil can be enclosed within on the vibrator iron core with moving up and down, the vibrator iron core is installed between the base plate and top board of installation frame, long stroke moving-coil that moves up and down and moving beam distance are consistent, and long stroke moving-coil endoporus is consistent with the gap between the vibrator iron core.
3, follow-up type air-floating magneto-motive friction-free suspension device as claimed in claim 1 or 2 is characterized in that: described synchroballistic air supply system comprises servomotor, ball-screw, synchroballistic air cylinder driven frame, synchroballistic cylinder, connects tracheae, the synchronous draft tube of air bearing; Servomotor is installed on the top board of installation frame, servomotor is fixedlyed connected with ball-screw, synchroballistic air cylinder driven frame one end be fixed on the synchronization-moving ball-screw nut of moving beam on, the other end connects the piston rod of synchroballistic cylinder, the synchroballistic cylinder is fixed on the below of installation frame top board, the epicoele of synchroballistic cylinder is connected with two gas-holder respectively by connecting tracheae, the synchronous draft tube of the air bearing that is connected with compressed air gas source is fixed on the ball-screw nut, the other end connects the air intake opening of air bearing, and the cylinder diameter sectional area of synchroballistic cylinder equals two does not have friction cylinder bore sectional area sum.
4, follow-up type air-floating magneto-motive friction-free suspension device as claimed in claim 3, it is characterized in that: described nothing friction suspension apparatus comprises the detecting sensor system, and the detecting sensor system comprises that reference gas cylinder pressure, differential pressure pickup, air bearing, displacement transducer, acceleration transducer, long stroke moving-coil force transducer, load force sensor, differential pressure pickup connect tracheae; The reference gas cylinder pressure is fixed on the base plate of installation frame, and differential pressure pickup one end is connected with nothing friction cylinder inner cavity, and the other end connects tracheae by differential pressure pickup and is connected with the reference gas cylinder pressure; The displacement transducer movable part is fixed with the support that is fixed on the moving beam, and the fixed part of displacement transducer is fixed on the top board below of installation frame; Acceleration transducer is fixed on the support on the moving beam; Long stroke moving-coil force transducer simultaneously is fixed on the side of moving beam, and another side connects long stroke moving-coil mounting bracket; The load force sensor is fixed on the moving beam hanger bar, and the other end connects the suspension wirerope.
5, follow-up type air-floating magneto-motive friction-free suspension device as claimed in claim 4, it is characterized in that: four air bearing are installed on the described moving beam, gas circuit in the moving beam connects four air bearing, and four air bearing flexibly connect two guide poles that are installed in parallel between installation frame base plate and top board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200720115290XU CN201096633Y (en) | 2007-09-21 | 2007-09-21 | Follow-up type air-float magnetomotive zero friction suspension device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200720115290XU CN201096633Y (en) | 2007-09-21 | 2007-09-21 | Follow-up type air-float magnetomotive zero friction suspension device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201096633Y true CN201096633Y (en) | 2008-08-06 |
Family
ID=39923686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU200720115290XU Expired - Lifetime CN201096633Y (en) | 2007-09-21 | 2007-09-21 | Follow-up type air-float magnetomotive zero friction suspension device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201096633Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100535632C (en) * | 2007-09-21 | 2009-09-02 | 浙江工业大学 | Follow-up type air-floating magneto-motive friction-free suspension device |
| CN108444737A (en) * | 2018-06-21 | 2018-08-24 | 湖南科技大学 | A kind of half vehicle floating installation of energy storage type and its control method |
-
2007
- 2007-09-21 CN CNU200720115290XU patent/CN201096633Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100535632C (en) * | 2007-09-21 | 2009-09-02 | 浙江工业大学 | Follow-up type air-floating magneto-motive friction-free suspension device |
| CN108444737A (en) * | 2018-06-21 | 2018-08-24 | 湖南科技大学 | A kind of half vehicle floating installation of energy storage type and its control method |
| CN108444737B (en) * | 2018-06-21 | 2023-09-05 | 湖南科技大学 | Energy storage type half-vehicle floating device and control method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100535632C (en) | Follow-up type air-floating magneto-motive friction-free suspension device | |
| CN100535631C (en) | Air-float magneto motive friction-free suspension device | |
| CN103063392B (en) | Ultra-low frequency modal test gravitational equilibrium system | |
| CN103063390B (en) | Hoisting device of horizontal modality test | |
| CN104216024B (en) | Active damping positioning device for dynamic gravity meter | |
| CN103063515B (en) | Tensile creep test device for cement-based materials | |
| CN106769036B (en) | A kind of static air thrust bearing bearing test device and method | |
| CN102331332B (en) | Test device with controllable vibrational degrees of freedom for vortex-induced vibration of cylinders | |
| CN103512740A (en) | Device for carrying out static-dynamic force multifunction testing on support | |
| CN101261259A (en) | Pressurized type confined pressure three axis rheogeniometer for low modulus materials | |
| CN202693287U (en) | Test complex for parallel coupled actuator | |
| CN201096633Y (en) | Follow-up type air-float magnetomotive zero friction suspension device | |
| CN201096632Y (en) | Air-floating magnetomotive zero friction suspension device | |
| CN113740929B (en) | Ground testing device and method for space inertial sensor | |
| CN102944347A (en) | Multistage small-displacement down force tester for testing static characteristics of direct current solenoid electromagnet | |
| CN203534808U (en) | Device for static and dynamic multifunctional test of supporting seat | |
| CN1987391B (en) | Negative valence jump dynamic torsion corrector | |
| CN203275069U (en) | Test device for testing lateral force resistance of frictionless cylinder | |
| CN113942667B (en) | Micro-low gravity environment simulation method and device | |
| CN113942666B (en) | Near-zero stiffness supporting device for zero gravity environment simulation | |
| CN101839731B (en) | Undisturbed air-flotation magnetomotive suspension device based on double electromagnetic forces | |
| CN113306749B (en) | Weighing air floatation device for simulating weightlessness | |
| CN201844846U (en) | Double electromagnetic force-based undisturbed air flotation magnetomotive suspension apparatus | |
| CN209647227U (en) | Strip-mill strip hydraulic roller-bending device simulation loading and integrated test system | |
| CN209372612U (en) | A kind of small-sized high frequency and low stress width soil dynamic triaxial apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Effective date of abandoning: 20070921 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |