CN1456824A - Rigidity variable bellows coupling - Google Patents

Abstract

A bellows-type shaft coupler whose torsional and bending rigidity can be controlled by external magnetic field features that it is based on the characteristic of magnetic rheopectic material that its rheopectic properties can be greatly changed under the action of external magnetic field and on the principle that the bellows has high flexibility and shift compensating performance. It can be used in multi-rotor coupling system to prevent vibration addition and poor centerization. Its advantages are high load-bearing power, response speed, flexibility and shift compensating power, and controllable rigidity.

Description

Become the rigidity bellows coupling

Technical field: the present invention is intended to solve many rotors of unit coupling link balance and rotor system stability control problem.

Background technique: rotating machinery is widely used in and comprises gas turbine, aeroengine, and in the mechanical device such as various motor, at electric power, aviation, chemical industry plays important effect in the national economy such as weaving.Generally speaking, influence the reason that unit vibration has following several aspects.1) imbalance of axle system, the size of rotor unbalance value is directly proportional with the peak value of vibration, reduces the peak value that amount of unbalance can significantly reduce vibration, and improving the rotor dynamic balancing precision as far as possible is the effective measures that reduce rotor oscillation.But, present large-scale unit generally adopts the plural serial stage method of operation, four units of the compressor of using as petrochemical industry, steam turbine, gas turbine and motor series connection, even each rotor is through the dynamic balancing of strictness, and it is good that centering is installed, but get into smooth strong vibration may take place, this is the common technical barrier of manufactory and user.Theory analysis thinks, this is owing to ignored due to the remaining unbalanced coupling connection of each rotor during centering.If can in depth study remaining unbalanced phase place of each rotor and their lotus root connection relation, and can be in unit running process dynamic control phase.Reduce even elimination imbalance fully, be expected to replace the complete machine full speed dynamic balance method that generally adopts now both at home and abroad and eliminate this rotor axial system imbalance and guarantee that the unit one-shot is successful.The vibration that is that die misalignment causes also can appear in 2) centering problem in unit running process.Traditional method must be shut down maintenance both at home and abroad, looks for centering again." self-healing system " of this vibration can be in time eliminated in discussion voluntarily in unit operation, developing a kind of new " autonomous control technique " is an important topic of mechanical engineering subject.It has important value to the rotor dynamics Study on Theory, has great importance too for solving the Important Project key problem in technology and improving the business economic benefit.3) compensation ability of coupling is poor, the unit of some frequent conversion operating modes, and its coupling should have compensation ability preferably.For example, unit produces very big vibration under indivedual loads or sub load, but operation is very steady under other loads, this is because unit is when moving under different operating modes, axle is different with the side-play amount between the axle, yet can both accomplish that axle system is a smooth curve can not take into account under each operating mode operation during centering fully the time, and deviation partly can only compensate with coupling, therefore for the frequent unit of variable working condition, the compensating action of coupling is very important.

Based on above-mentioned engineering reality, design this change rigidity bellows coupling, making to address the above problem simultaneously becomes possibility.According to hophornbeam Xin Ke (Timoshenko) beam theory in the elastokinetics, the Young's modulus of beam influences wave propagation in it.If the rigidity of adjusting axle system dynamically, the phase place that just can regulate the rotor-support-foundation system medium wave dynamically makes each vibration weakening mutually, so just can weaken even eliminate fully the imbalance of the rotor-support-foundation system that the remaining amount of unbalance of above-mentioned rotor causes.

Magnetic flow liquid is that material jumpy takes place rheological properties under the effect of externally-applied magnetic field.Its essential characteristic is can change semisolid into from free-pouring liquid at moment (Millisecond) under the effect of high magnetic fields, embody controllable-viscosity, plasticity and characteristics such as viscoelasticity and yield strength, and this variation is reversible.Rabinow had invented magnetic flow liquid and application apparatus (clutch) the earliest in 1948.Holding of electrorheological fluid and magnetic flow liquid seminar promoted the research and development of magnetic flow liquid in the world, and each key industry developed country is competitively developing this technology.The Shtarkman of U.S. TRW Ltd. (US) One Space Park, Redondo Beach CA 90278 U.S.A. just developed the rotary bump leveller of magnetic flow liquid in 1991, and was applied to automotive suspension ACTIVE CONTROL system.People such as the Carlson of U.S. Lord company and Weiss are since nineteen ninety-three obtaining outstanding achievement aspect magnetic flow liquid and the application study thereof, the existing many kinds of commercial prods of Lord company appear on the market.People such as the Dyke of U.S. Notre Dame university and Spencer also are one of application of absorbing magnetic flow liquid with the control that MR damper is used for the large scale structure seismic response.The people such as Ginder of U.S. Ford Motor Company study the finite element analysis of magnetic flow liquid yield stress and the raising of performance.People such as Foister of General Motors Overseas Corporation and Gophalswamy have developed magnetic flow liquid and magnetic rheological clutch.People such as the Zhu of California, USA state university and Liu have carried out more research to the rheology, particularly microstructure of magnetic flow liquid.People such as the Kordonski of Byelorussia Study on Heat and Mass Transfer institute are obtaining major progress aspect the application studies such as the performance of magnetic flow liquid and magnetorheological polishing, sealing.China starts late to the research of magnetic flow liquid, just has relevant document to deliver after 1996.China Science ﹠ Technology University is studied the mechanism of magnetic flow liquid and the performance of damper; Jin Yun has developed two cover magnetic flow liquid yield stress test systems, and people such as the Pan Sheng of Fudan University have developed magnetic flow liquid and surveying instrument.The unit of domestic research magnetic flow liquid also has University of Electronic Science and Technology, HarBin Building University, Northwestern Polytechnical University, University Of Chongqing, Shanghai Communications University, ray machine research institute of the Chinese Academy of Sciences etc.Totally it seems, China at present aspect the development of magnetic flow liquid and the performance study with a certain distance is still arranged abroad, application product still belongs to blank.

Bellows as a kind of can freely stretch the elastic compensating element, the history in more than 100 year arranged, in World War II, begin to be widely used, mainly as the elastic sensing element of instrument, instrument and the functional element of connection, absorbing, sealing, compensation and media isolated.The bellows that adopts in equipment has many kinds of structural types, and with regard to the shape of ripple, with being most widely used of U type bellows, next has Ω type, C type, square type etc.For improving the service behaviour of bellows, improve its bearing capacity, occurred again later on multilayer with the band stiffening ring bellows.Because characteristics such as reliable operation, compact structure now have been widely used in each industrial department,, and still constantly enlarging its use field as temperature compensation, vibration isolation, absorption relative displacement, movable sealing and the instrument spring etc. of pipeline and equipment.The characteristics of this type of coupling are: in light weight, volume is little, large deflection, and good displacement compensation capability, inertial force is little, thereby characteristics such as spring-back force is little, at a high speed, is widely used in the rotating machinery of underloading.The more important thing is that its inner cavity makes us apply control unit and become possibility for controlling its crooked and torsional stiffness.

Summary of the invention: comprehensive above affiliated various characteristics at this, can charge into magnetic rheological body in the bellows coupling, like this under the situation of externally-applied magnetic field.We can control the magnetic field that adds by control circuit, thereby the rigidity of control coupling reaches the purpose of the whole rotor system stability of control with this.For example, under the certain situation of transmitted power, the moment of torsion that axle system transmits and the rotating speed of rotor are inversely proportional to.Because the moment of torsion that bellows coupling can bear is less relatively, at this moment can apply high magnetic fields to bellows coupling, make inner magnetic rheological body solidify, participate in the transmission of moment of torsion.When rotor-support-foundation system reaches working speed, need to reduce the rigidity that whole axle is, thereby reduce the natural frequency of rotor-support-foundation system, utilize the rotor-support-foundation system gyroscopic action like this, can be so that rotor-support-foundation system be more stable.

And, according to thinking,, be to cause large-scale many rotors of unit lotus root contact system that the main cause of judder takes place in the running through the superposition of dynamically balanced each rotor oscillation of strictness.If can regulate the vibration phase of each rotor in this case dynamically, make their vibration cancel out each other, will bring huge economic benefit like this, the development of promotion rotor dynamics theory that simultaneously also can be strong.Developing this change rigidity bellows coupling just can be so that this imagination be achieved.In the process of rotor running, can impose on the intensity in the magnetic field of this coupling by change, changing the mechanical property of magnetic rheological body, thereby reach the purpose with flexural rigidity reversed that changes this coupling.By elastodynamic theory as can be known, the phase place of its internal wave of deflection of beam stiffness effect so just might be regulated the phase place of ripple dynamically in the process of rotor running, thereby the vibration of each rotor is weakened mutually even offsets.

In sum, this change rigidity coupling has the compensation performance preferably of traditional bellows coupling, vibration isolation, outside the characteristics such as compact structure, the rigidity that mainly is it can be regulated dynamically, under different rotating speeds, perhaps different vibrational state lower rotor part systems reaches the rigidity that needed rigidity that is of stable operation is regulated coupling.This change rigidity stability control method is with respect to having many good qualities with electromagnetic bearing and squeeze film bearing control rotor system stability.At first, its compact structure, simple, be suitable for transformation to original equipment.Such as, with original flange coupling of equipment or rubbercushioned sleeve bearing coupling etc., change this change rigidity bellows coupling into, do not need to change the structure at other position of rotor-bearing system.Yet if the repacking electromagnetic bearing, perhaps squeeze film bearing is because the complexity of its structure almost is impossible to original rotor-support-foundation system.Next is a performance, though electromagnetic bearing and squeeze film bearing can be controlled rotor stability, but it can not weaken the remaining uneven influence to vibration of rotor-support-foundation system, more the judder of the rotor-support-foundation system that can not cause the compensation ability difference owing to coupling acts on to some extent, and this change rigidity bellows coupling can satisfy above requirement simultaneously.

Therefore, promoting the use of of this change rigidity bellows coupling will be brought considerable economic benefit.

Description of drawings: Fig. 1, this change rigidity bellows coupling schematic representation, wherein 1 is bellows, and 2 is magnetic rheological body, and 3 is baffle plate.

Fig. 2, baffle edge partial enlarged drawing.

Fig. 3, the bent limit partial cross section figure of bellows.

Embodiment: bellows is the critical piece that bears moment of torsion, and its straight section has the spline keyway, to connect with the required shaft part that is connected, can reduce the stress of bellows straight section like this and concentrate and the weakening degree of keyway to bellows.Charge into magnetic rheological body in bellows, this is the core component that bellows coupling is become rigidity control.Magnetic rheological body can be magnetic rheological liquid, magnetorheological foamed material and magnetorheological man made rubber, and their common trait is a mechanical property, changes with the variation of externally-applied magnetic field as cutting performance, Young's modulus.Baffle plate is used for limiting the magnetic rheological body working space, for baffle plate being fixed in the bellows straight section, the edge of baffle plate is processed into zigzag fashion, as shown in Figure 2.When assembling, in bellows, insert magnetic rheological body earlier, and then baffle plate is filled in the bellows straight section, magnetic rheological body is compressed, and then the outside of roll extrusion straight section, make baffle plate and bellows be connected, reach the effect of sealing simultaneously.In the process of transmitting torque, bellows will deform, in order better to allow magnetic rheological body participate in the transmission of moment of torsion, the position internal surface that magnetic rheological body is housed in the bent limit of bellows section is pressed with decorative pattern, as shown in Figure 3, like this after magnetic rheological body solidifies, can be better and bellows be coupled transmitting torque jointly.For the mode that applies in concrete magnetic field, present patent application is not done requirement.

Claims (4)

1. one kind can change its coupling crooked and torsional stiffness by externally-applied magnetic field, this coupling is by bellows [1], magnetic rheological body [2], and baffle plate [3] is formed, its characteristics are to fill magnetic rheological body in bellows, be used for transmitting torque, utilize its rigidity, the stability of rotor is controlled dynamically with the characteristics that the variation of externally-applied magnetic field changes.

2. the magnetic rheological body described in the claim 1 [2] is meant magneto-rheological fluid, magnetorheological foamed material and magnetorheological man made rubber; Magneto-rheological fluid is a kind of liquid, it is characterized in that its mobile and cutting performance can be controlled by the magnetic field that adds, thereby changes the ability of its transmitting torque or the control of vibrating; Magnetorheological foamed material is to be to absorb matrix with the foamed material, and magneto-rheological fluid is being adsorbed in its inside, saves the consumption of magneto-rheological fluid with this, the same magneto-rheological fluid of its feature; Magnetorheological man made rubber is a kind of rubberlike solid, it is characterized in that controlling its Young's modulus by the magnetic field that adds, thereby reaches the purpose of vibration control.

3. the baffle plate in the claim 1 [3] is used for limiting the working space of magnetic rheological body, its essential characteristic is its edge engrail, outside that can roll extrusion bellows straight section in the manufacture process of coupling realizes and being connected of bellows, with the damage to magnetic rheological body of the high temperature avoiding welding.

4. the bellows in the claim 1 [1] is main torque transfer member, is primarily characterized in that section inboard, bent limit is pressed with decorative pattern, thereby improves the degree of coupling of magneto-rheological fluid and bellows; Have the spline keyway at straight section, concentrate, reduce weakening degree bellows to reduce stress, thus improve change the rigidity bellows coupling anti-twisting property.

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