CN102759450B - Bearing load recognition method based on coupler opening and height difference - Google Patents

Abstract

A bearing load recognition method based on coupler opening and height difference is provided by the invention, and includes the following two steps: load recognition of bearings based on the given openings and height difference values at couplers, installation instruction for a machine set, and failure control; and acquisition of the openings and the height difference values at the couplers during the machine set installation based on the given load of bearings, and design instruction for the machine set. The method provided by the invention also takes the influence of bending deformation of a rotator on the openings and the height difference values of the couplers into consideration.

Description

A kind ofly to dehisce and the bearing load recognition methods of difference of height based on shaft coupling

Technical field

The present invention relates to a kind of multispan, the bearing load recognition methods of branched support statically indeterminate shaft system, help technician to analyze the load condition that in multispan statically indeterminate shaft system, each bearing bears.Main application fields comprises: the large rotating machinery such as electric power, metallurgy, petrochemical industry, aviation, as bearing load recognition methods technical fields such as steam turbine, compressor, generator, gas turbine, pump, blower fans.

Background technology

Although all kinds of rotating machinery principle of work such as Turbo-generator Set, gas turbine generator group, large-scale compressor are different with the course of work, they all have a common feature, that is: axle system is made up of many transfers axle and multiple bearing.This is a statically indeterminate system.Bearing is the critical component of this type systematic, for ensureing that the safe and stable operation of unit is most important.From lubrication theory, bearing load determines bearing working state, and bearing load depends on that axle fastens the centering situation between multiple-rotor.High-speed rotating machine is higher for the requirement of accuracy of alignment between rotating shaft.When centre deviation between rotating shaft is larger, be easy to produce the faults such as the stone roller that causes because bearing load is overweight watt, the fault such as broken watt and the bearing unstability that causes because bearing load kicks the beam.These all can cause unit to produce larger vibration, and fault caused thus is of common occurrence in engineering.Adjusted by axial center and optimize the Main Means that bearing load distribution is also unit vibration fault treatment.Therefore, bearing load identification and method of adjustment, for the large rotating machinery such as steam turbine, compressor, have important application value.Along with unit to maximization future development and the requirement of modern electric power industry to unit safety operation more and more higher, identify bearing load, analyze bearing working condition, and shaft center is optimized adjustment and just seems more and more important on this basis.

Early stage people identify bearing load by punching at bearing inner surface and installing pressure transducer additional.This method not only destroys bearing inner surface and oil film, and identification error is larger.The method adding dynamometer bottom bearing seat not only workload is large, and changes bearing seat supporting form.When adopting jacking process to measure bearing load, if institute's reinforcing is too light, then axle jack-up cannot be come; If institute's reinforcing is too heavy, because bearing clearance is less, be then easy to touch watt, produce an additional force downward.Both can produce comparatively big error.Said method is all difficult to accurately identify bearing load.

The axle system of large rotating machinery comprises the bearing of more than 3 or 3 usually, and this is a statically indeterminate system, and bearing load directly cannot be obtained by force and moment balance equation.In engineering, bearing load adjustment looks for middle technology to carry out by axle system, and be dehisce to carry out with difference of height according to shaft coupling mostly in looking for, and these two values can be measured more exactly by dial gauge or high-precision laser centering instrument.Although dehisce and difference of height can measure more easily, people and do not know bearing the actual load condition born.

Summary of the invention

The present invention proposes the bearing load recognition methods of a kind of branched support statically indeterminate shaft system.The method that this invention provides comprises two aspects: dehisced and each bearing load of difference of height identification by given each shaft coupling, instruct units' installation, fault treatment; When obtaining units' installation by given bearing load, each shaft coupling is dehisced and difference of height, instructs unit design.Method proposed by the invention can also consider that shaft bending distortion to be dehisced on shaft coupling and the impact of difference of height.

The present invention adopts following technical scheme:

Dehisce and the bearing load recognition methods of difference of height based on shaft coupling, the present invention is characterised in that:

Axle system is considered as nonprismatic continuous beam by this method, each shaft part deadweight is as uniform quality, bearing, as the centre-point load be carried on continuous beam, is considered as rigid support by shaft coupling, thrust disc, blade and wheel disc, is in concentric for initial baseline with each bearing of axle system.Calculation procedure is:

First, at bearing place, axle system is disconnected and form multiple shaft part, for each shaft part, utilize theory of mechanics of materials, set up state parameter relation between top and clearing end.Wherein, state parameter comprises: flexure, corner, shearing and moment of flexure.Utilize known boundary condition, two ends, left and right, bearing place state parameter relation, known bearing height, set up the known variables solving equation groups such as bearing load, shaft bending distortion, corner, shearing, moment of flexure, obtain the sensitivity matrix that initial baseline lower bearing load distribution and bearing load divide the change of pairing bearing height.

Secondly, at shaft coupling place, axle system is disconnected and form multiple shaft part, for each shaft part, utilize theory of mechanics of materials, set up state parameter relation between top and clearing end; Wherein, state parameter comprises: flexure, corner, shearing and moment of flexure; Utilize known boundary condition, two ends, left and right, bearing place state parameter relation, shaft part inner bearing height, set up the known variables solving equation group of rotating shaft deflection deformation in shaft part, under obtaining initial baseline each shaft coupling dehisce, difference of height and to bearing height change sensitivity matrix.

Again, realize each bearing load in axle system and distribute the two-way calculating between each shaft coupling state (dehiscing and difference of height).

The present invention sets up axle system mechanics analysis model, solve each bearing load to bearing height changing sensitivity matrix and initial straight normal condition lower bearing load distribution, solve shaft coupling and dehisce to dehisce and difference of height to bearing height changing sensitivity matrix and initial straight normal condition lower coupler with difference of height; Dehisced and the load distribution identification bearing load under difference of height, two sensitivity matrix and initial baseline by actual measurement shaft coupling, dehisced and difference of height by given bearing load, two sensitivity matrix and initial baseline lower coupler, when design and installation and maintenance, shaft coupling is dehisced and difference of height standard value.

Compared with prior art, tool of the present invention has the following advantages in the present invention:

(1) achieve the two-way calculating between bearing load and shaft coupling state: measure shaft coupling dehisce and difference of height after, bearing load can be obtained rapidly, this is very important for large rotating machinery, can instruct units' installation, fault diagnosis and improvement; During unit design, given bearing load distributes, and can design shaft coupling easily and dehisce and difference of height installation code value.

(2), when adjusting axial center traditionally, rotating shaft is regarded as straight line, does not consider the deflection deformation of rotating shaft itself.When rotating shaft deflection deformation is larger, this method has certain error.The method that the present invention proposes considers the impact of rotating shaft deflection deformation.

Accompanying drawing explanation

Fig. 1 is multispan statically indeterminate shaft system model sketch;

Fig. 2 is each shaft part force analysis schematic diagram after rotating shaft being disconnected at bearing place;

Fig. 3 is each shaft bending distortion schematic diagram after rotating shaft being disconnected at shaft coupling place;

Fig. 4 considers and does not consider that shaft bending distortion affects schematic diagram to shaft coupling opening and difference of height;

Fig. 5 is method flow diagram of the present invention.

Embodiment

Dehisce and the bearing load recognition methods of difference of height based on shaft coupling, the present invention is characterised in that:

Axle system is considered as nonprismatic continuous beam by this method, each shaft part deadweight is as uniform quality, bearing, as the centre-point load be carried on continuous beam, is considered as rigid support by shaft coupling, thrust disc, blade and wheel disc, is in concentric for initial baseline with each bearing of axle system.Calculation procedure is:

First, at bearing place, axle system is disconnected and form multiple shaft part, for each shaft part, utilize theory of mechanics of materials, set up state parameter relation between top and clearing end.Wherein, state parameter comprises: flexure, corner, shearing and moment of flexure.Utilize known boundary condition, two ends, left and right, bearing place state parameter relation, known bearing height, set up the known variables solving equation groups such as bearing load, shaft bending distortion, corner, shearing, moment of flexure, obtain the sensitivity matrix that initial baseline lower bearing load distribution and bearing load divide the change of pairing bearing height.

Secondly, at shaft coupling place, axle system is disconnected and form multiple shaft part, for each shaft part, utilize theory of mechanics of materials, set up state parameter relation between top and clearing end; Wherein, state parameter comprises: flexure, corner, shearing and moment of flexure; Utilize known boundary condition, two ends, left and right, bearing place state parameter relation, shaft part inner bearing height, set up the known variables solving equation group of rotating shaft deflection deformation in shaft part, under obtaining initial baseline each shaft coupling dehisce, difference of height and to bearing height change sensitivity matrix.

Again, realize each bearing load in axle system and distribute the two-way calculating between each shaft coupling state (dehiscing and difference of height).

The present embodiment analyzes for the multispan statically indeterminate system shown in Fig. 1, with reference to Fig. 2 ~ 5.As shown in Figure 1, axle is fastened and is provided with rotating shaft 1, bearing 2, shaft coupling 3.Proposed by the invention dehisces to comprise the following steps with the bearing load recognition methods of difference of height data based on shaft coupling:

(1) set up computational analysis model: axle system is considered as nonprismatic continuous beam, each shaft part deadweight is as uniform quality, and bearing, as the centre-point load be carried on continuous beam, is considered as rigid support by shaft coupling, thrust disc, blade and impeller, as shown in Figure 2.

(2) at n-1 bearing surface place, axle system is broken into n elementary section, first segment unit is made up of initial cross section and the 1st bearing sections, rear unit is by last bearing sections and stop cross section and form, and remaining element is made up of any two adjacent bearing sections, as shown in Figure 2; The unknown number of each unit is left and right end state parameter (displacement, corner, shearing and moment of flexure) and bearing reaction.It is individual that n unit unknown state parameter adds up to (9n-1).Be in concentric for initial baseline with bearing each in axle system, in each elementary section, set up initial cross section by theory of mechanics of materials and stop state parameter relationship analysis model between cross section.Be described for unit i a certain shown in Fig. 2:

${\left\{\begin{array}{c}y\\ \mathrm{\θ}\\ M\\ Q\\ 1\end{array}\right\}}_i^R=\left\{\begin{array}{ccccc}1& L& \frac{L^2}{2\mathrm{EI}}& \frac{L^3}{3\mathrm{EI}}& -\frac{q{L}^4}{24\mathrm{EI}}\\ 0& 1& \frac{L}{\mathrm{EI}}& \frac{L^2}{2\mathrm{EI}}& -\frac{q{L}^3}{6\mathrm{EI}}\\ 0& 0& 1& L& -\frac{q{L}^2}{2}\\ 0& 0& 0& 1& -\mathrm{qL}\\ 0& 0& 0& 0& 1\end{array}\right\}{\left\{\begin{array}{c}y\\ \mathrm{\θ}\\ M\\ Q\\ 1\end{array}\right\}}_i^L$

In formula, L is length, is known quantity; Q is the uniform quality of axle unit length, is known quantity; Subscript L and R be representative unit left end and right-hand member respectively; E is shaft part elasticity modulus of materials, is known quantity; I is shaft part cross sectional moment of inertia, is known quantity.

If shaft section diameter is not etc. in unit, then can set up the relation between the state parameter of two ends in each uniform cross section shaft part, be multiplied multiple relational matrix the relation that can obtain between the state parameter of non-constant section shaft part two ends:

${\left\{\begin{array}{c}y\\ \mathrm{\θ}\\ M\\ Q\\ 1\end{array}\right\}}_i^R=\left[A\right]{\left\{\begin{array}{c}y\\ \mathrm{\θ}\\ M\\ Q\\ 1\end{array}\right\}}_i^L$

Above formula can obtain 4 equations after launching, and n unit can obtain 4n solving equation.Following relation is had between i-th-1 unit right-end state parameter and the i-th unit left-end state parameter:

${\left\{\begin{array}{c}y\\ \mathrm{\θ}\\ M\\ Q\\ 1\end{array}\right\}}_i^L=\left\{\begin{array}{ccccc}1& 0& 0& 0& 0\\ 0& 1& 0& 0& 0\\ 0& 0& 1& 0& 0\\ 0& 0& 0& 1& -F_{i-1}\\ 0& 0& 0& 0& 1\end{array}\right\}{\left\{\begin{array}{c}y\\ \mathrm{\θ}\\ M\\ Q\\ 1\end{array}\right\}}_{i-1}^R$

Wherein F _i-1it is the support reaction at the i-th-1 bearing place.4 (n-1) individual equation can be listed at n-1 bearing place.Axle system initiating terminal and clearing end place shearing and moment of flexure are 0, can list 4 equations.If the height of a known n-1 bearing, n-1 system of equations can be listed.Solving equation group formed thus adds up to 4n+4 (n-1)+4+ (n-1)=9n-1.System of equations number is equal with unknown number number, can solve.On this basis, each bearing load { F of initial baseline lower shaft system is calculated ₀and bearing load sensitivity matrix [A that bearing height is changed _f].The load that arbitrary height distribution lower bearing bears is:

{F}＝{F ₀}+[A _F]{Y}

(3) at shaft coupling place, each rotating shaft is disconnected, as shown in Figure 3, adopt above-mentioned identical method to calculate and disconnect rear each shaft bending deformation curve.Calculate that dehisce in each shaft coupling place under initial baseline, difference of height { C ₀and shaft coupling is dehisced and the sensitivity matrix [A that changes bearing dynamical height of difference of height _c]:

$\left\{C_0\right\}=\left\{\begin{array}{c}{\mathrm{\Δ}}_1\\ {\mathrm{\Φ}}_1\\ \·\\ \·\\ \·\\ \·\\ \·\\ \·\\ {\mathrm{\Δ}}_n\\ {\mathrm{\Φ}}_n\end{array}\right\}$

In formula, Δ, Φ is respectively shaft coupling difference of height and dehisces.This method considers the impact of shaft bending distortion.Fig. 4 gives consideration (solid line) and does not consider that (dotted line) rotating shaft deflection deformation is dehisced on shaft coupling and the impact of difference of height.When rotating shaft deflection deformation is larger, its impact be can not ignore.

(4) the two-way calculating solving equation group between bearing load and shaft coupling state is set up:

By design bearing load Load} solve each shaft coupling of axle system dehisce and difference of height Coupling}:

{Coupling}＝{C ₀}+[A _C][A _F] ^-1({Load}-{F ₀})

By shaft coupling dehisce and difference of height Coupling} solve bearing load Load}:

{Load}＝{F ₀}+[A _F][A _C] ^-1({Coupling}-{C ₀})。

Claims (1)

1. dehisce, with a bearing load recognition methods for difference of height, to it is characterized in that based on shaft coupling:

Axle system is considered as nonprismatic continuous beam by this method, each shaft part deadweight is as uniform quality, bearing, as the centre-point load be carried on continuous beam, is considered as rigid support by shaft coupling, thrust disc, blade and wheel disc, is in concentric for initial baseline with each bearing of axle system; Calculation procedure is:

First, at bearing place, axle system is disconnected and form multiple shaft part, for each shaft part, utilize theory of mechanics of materials, set up state parameter relation between top and clearing end; Wherein, state parameter comprises: flexure, corner, shearing and moment of flexure; Utilize known boundary condition, two ends, left and right, bearing place state parameter relation, known bearing height, set up bearing load known variables solving equation group, obtain the sensitivity matrix that initial baseline lower bearing load distribution and bearing load divide the change of pairing bearing height;

Secondly, at shaft coupling place, axle system is disconnected and form multiple shaft part, for each shaft part, utilize theory of mechanics of materials, set up state parameter relation between top and clearing end; Wherein, state parameter comprises: flexure, corner, shearing and moment of flexure; Utilize known boundary condition, two ends, left and right, bearing place state parameter relation, shaft part inner bearing height, set up the known variables solving equation group of rotating shaft deflection deformation in shaft part, under obtaining initial baseline each shaft coupling dehisce, difference of height and to bearing height change sensitivity matrix;

Again, realize each bearing load in axle system and distribute the two-way calculating between each shaft coupling state.