CN115539144A - Elastic strip staggered axial force measurement integrated elastic support and measurement method - Google Patents
Elastic strip staggered axial force measurement integrated elastic support and measurement method Download PDFInfo
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- CN115539144A CN115539144A CN202211016834.2A CN202211016834A CN115539144A CN 115539144 A CN115539144 A CN 115539144A CN 202211016834 A CN202211016834 A CN 202211016834A CN 115539144 A CN115539144 A CN 115539144A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/28—Supporting or mounting arrangements, e.g. for turbine casing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/28—Supporting or mounting arrangements, e.g. for turbine casing
- F01D25/285—Temporary support structures, e.g. for testing, assembling, installing, repairing; Assembly methods using such structures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L25/00—Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/12—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring axial thrust in a rotary shaft, e.g. of propulsion plants
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- General Engineering & Computer Science (AREA)
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- Combustion & Propulsion (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
Abstract
The invention discloses an elastic strip staggered axial force measurement integrated elastic support which comprises a mounting edge, a plurality of elastic strips I, a plurality of elastic strips II, an integrated bearing outer ring and a deformation ring, wherein the deformation ring is arranged between a cylinder where the elastic strips I are located and a cylinder where the elastic strips II are located; the invention also comprises an axial force measuring method. The invention can solve the technical problems that the integrated elastic support cannot use the existing axial force measuring method to measure the axial force and the existing axial force measuring method has low sensitivity.
Description
Technical Field
The invention relates to the technical field of elastic supports of engine rotors, in particular to an elastic strip staggered axial force measurement integrated elastic support. In addition, the invention also relates to an axial force measuring method of the elastic strip staggered axial force measuring integrated elastic support.
Background
The elastic support is widely used in a rotor support system of a small and medium-sized aircraft engine, can effectively reduce the vibration amplitude when the rotor crosses the critical rotating speed, and ensures the safe and reliable work of the rotor. The compressor rotor generates a forward axial force when in operation, and the turbine rotor generates a backward axial force when in operation. The axial force must be kept in a proper range, the excessive axial force can cause overload damage of the bearing, and the insufficient axial force can cause light-load slipping and abrasion failure of the bearing. Therefore, during the operation of the engine, the rotor is monitored for vibration, and the axial force of the rotor is often measured to ensure the safe and reliable operation of the rotor.
In order to meet the design requirements of weight reduction, unit bodies and the like of an aero-engine, an integrated supporting structure of a bearing outer ring and an elastic support is gradually applied. For the integrated elastic supporting structure, because the bearing outer ring can not move independently, and no bearing cavity is arranged on the elastic supporting for placing the force measuring ring (the bearing outer ring can not compress the force measuring ring to cause elastic deformation), the scheme that the traditional bearing outer ring is combined with the force measuring ring to measure the axial force can not be implemented. For the mode of directly pasting the strain gauge on the elastic strip of the elastic support to measure the axial force, the axial rigidity of the elastic strip is large, and the axial deformation of the elastic strip is very small under the action of the axial force of the rotor, so that the measurement error of the method for measuring the axial force is large, and the engineering requirement can not be well met.
The existing rotor axial force measurement mainly aims at the situation that a bearing outer ring and an elastic support are of a split structure, a bearing is installed in a bearing cavity of the elastic support, a bearing inner ring is tightly matched with a rotor shaft neck, the bearing outer ring is in clearance fit with the inner wall of the bearing cavity, the bearing outer ring is attached to one side of a force measuring ring, the other side of the force measuring ring is attached to the bottom of the bearing cavity, bosses which are arranged in a staggered mode are arranged on two sides of the force measuring ring, and a strain gauge is attached to one side of the force measuring ring to form a test bridge circuit. The axial force of the rotor acts on the force measuring ring through the bearing, so that the elastic deformation of the force measuring ring is caused, and the axial force of the rotor is obtained through conversion of output strain when the elastic deformation of the force measuring ring is measured. Therefore, the existing method for measuring the axial force of the rotor by using the force measuring ring is only suitable for the condition that the outer ring of the bearing and the elastic support are in a split structure, but not suitable for the condition that the outer ring of the bearing and the elastic support are in an integrated structure (because the outer ring of the bearing of the integrated elastic support cannot move independently, the force measuring ring cannot be placed on the integrated elastic support). All axial force measuring solutions involving the placement of a force ring in the bearing cavity of an elastic bearing in abutment with the outer ring of the bearing are no longer suitable for rotor axial force measuring situations with integrated elastic bearings.
For the method of measuring the axial force of the rotor by sticking the strain gauge on the elastic strip of the elastic support and connecting the strain gauge in series into the test bridge circuit, because the axial rigidity of the elastic strip is large, the axial deformation of the elastic strip is small under the action of the axial force of the rotor, the output strain of the bridge circuit is small, and the conversion coefficient of the output strain and the axial force is small. The method is low in sensitivity of axial force measurement when the method is used for measuring the axial force, large errors exist in the axial force measurement, and particularly under the condition of small-magnitude axial force measurement, so that the practical engineering application of the method is limited.
Disclosure of Invention
The invention provides an elastic strip staggered axial force measurement integrated elastic support and a measurement method, and aims to solve the technical problems that the integrated elastic support cannot be used for measuring an axial force by using the conventional axial force measurement method and the conventional axial force measurement method is low in sensitivity.
According to one aspect of the invention, the elastic strip staggered axial force measurement integrated elastic support comprises a mounting edge, a plurality of elastic strips I, a plurality of elastic strips II, an integrated bearing outer ring and a deformation ring, wherein the mounting edge, the plurality of elastic strips I, the plurality of elastic strips II, the integrated bearing outer ring and the deformation ring form an integrated structure, the mounting edge and the integrated bearing outer ring are respectively arranged at two end parts of the integrated structure, a ball track is arranged on the inner wall of the integrated bearing outer ring, the plurality of elastic strips I are annularly arranged to form a cylinder structure, the plurality of elastic strips II are annularly arranged to form a cylinder structure, the deformation ring is arranged between the cylinder where the elastic strips I are located and the cylinder where the elastic strips II are located, the other end of the cylinder where the elastic strips I are located is connected with the integrated bearing outer ring, the other end of the cylinder where the elastic strips II are located is connected with the mounting edge, the elastic strips I and the elastic strips II are staggered with respect to the deformation ring, and are used for extruding the elastic deformation ring to enable the deformation ring to generate elastic deformation under the axial strain measurement of a plurality of integrated strain sheets, and the integrated strain gauge can be respectively sensed at the axial strain gauge.
As a further improvement of the above technical solution: the foil gage includes four foil gages one and four foil gage two, the position of foil gage one is close to on the terminal surface of the deformation ring of deformation ring and bullet strip junction, the position of foil gage two is close to on the terminal surface of the deformation ring that deformation ring and two junctions of bullet strip are relative, four foil gage one and two respectively evenly distributed of four foil gages are on the circumference that the deformation ring formed, and on two adjacent bridge arms of foil gage one and foil gage two, the strain direction that foil gage one and two were experienced is opposite, and two series connections of foil gage form two foil gage groups, and two liang of series connections of foil gage form two foil gage groups, and two foil gage groups form the full bridge with two foil gage two groups series connections respectively and draw forth four measuring lines and be used for the axial force measurement.
Furthermore, two first strain gauges in the first strain gauge group are two strain gauges at opposite positions on the deformation ring, and two second strain gauges in the second strain gauge group are two strain gauges at opposite positions on the deformation ring.
Furthermore, the number of the elastic strips I is the same as that of the elastic strips II.
Further, the width and the thickness of the first elastic strip and the second elastic strip are the same, and the length of the first elastic strip and the length of the second elastic strip can be different.
Furthermore, the elastic strips I and the elastic strips II are uniformly arranged along the circumferential direction of the cylinder where the elastic strips I and the elastic strips II are respectively arranged.
Furthermore, the outer diameter of the cylinder where the first elastic strip is located is equal to the outer diameter of the cylinder where the second elastic strip and the deformation ring are located, and the centers of the first elastic strip, the second elastic strip and the deformation ring are all located on the central line of the integrated elastic support integrated structure.
Further, the radial rigidity of the elastic strip staggered axial force measurement integrated elastic support is
The radial rigidity of the elastic strip I is K 1 ＝nEb 2 h 2 /l 1 3 The radial rigidity of the second elastic strip is K 2 ＝nEb 2 h 2 /l 2 3 Wherein n is the number of the elastic strips I or the elastic strips II, E is the elastic modulus of the material, b is the width of the elastic strips I or the elastic strips II, h is the thickness of the elastic strips I or the elastic strips II, and l 1 Is the length of the elastic strip I 2 The length of the elastic strip II.
Further, the outer diameter of the cylinder where the first elastic strip is located is equal to the outer diameter of the outer ring of the integrated bearing, and the centers of the first elastic strip and the outer ring of the integrated bearing are located on the central line of the integrated elastic support integrated structure.
Furthermore, the deformation ring is provided with a wire binding hole for binding the measuring wire, and the measuring wire is bound and fixed on the deformation ring through the wire binding hole.
According to another aspect of the present invention, there is also provided an axial force measuring method for an elastic strip staggered axial force measuring integrated elastic support, including the above elastic strip staggered axial force measuring integrated elastic support, and including the following steps:
s1, adhering a plurality of strain gauges to corresponding positions on a deformation ring, forming the plurality of strain gauges into a full bridge, leading out a measuring line, and connecting the measuring line into a dynamic strain measuring instrument;
s2, carrying out axial force measurement calibration on the elastic strip staggered axial force measurement integrated elastic support, fixing the elastic strip staggered axial force measurement integrated elastic support on a calibration platform, applying axial loads F with equal load intervals on an integrated bearing outer ring, recording an output strain value epsilon in a dynamic strain measuring instrument, obtaining an axial force calibration formula F = k epsilon + b through linear fitting, wherein b is a constant, solving a calibration coefficient k, and when the square of a linear correlation coefficient is greater than 0.99, the obtained k value meets the requirement;
s3, mounting the integrated elastic bearing capable of testing the axial load of the rotor on a mounting seat for supporting the rotor through a mounting edge, sleeving a ball track of an integrated bearing outer ring on a bearing inner ring through balls and a retainer, and when the axial force borne by a rotor shaft is F ', under the action of the axial force F', a strain gauge senses the compressive strain and the tensile strain at the corresponding position on a deformation ring, and forward axial force and backward axial force are distinguished by positive signs and negative signs respectively;
and S4, judging the direction of the axial force F ' of the rotor through the sign of the full-bridge output strain of the strain gauge, and accurately obtaining the magnitude of the axial force F ' of the rotor through the magnitude of the full-bridge output strain epsilon ' of the strain gauge and the conversion of F ' = k epsilon '.
The invention has the following beneficial effects:
(1) The integrated elastic support for measuring the staggered axial force of the elastic strips solves the problem of measuring the axial load of the rotor with the integrated elastic support by skillfully designing the elastic strip I, the elastic strip II and the deformation ring arranged between the elastic strip I and the elastic strip II in the elastic support, can effectively solve the technical problem that the axial force measuring method disclosed in the prior art is not suitable for the integrated elastic support by sticking a plurality of strain gauges on the deformation ring for measuring the axial force, can respectively stick a plurality of strain gauges on the deformation ring at different positions close to the end surface of one side of the elastic strip I or the elastic strip II to sense the tensile strain and the compressive strain under the action of the axial force of the rotor by mutually staggering the elastic strip I and the elastic strip II relative to the deformation ring, the strain gauges are arranged on the deformation ring between the elastic strip I and the elastic strip II, and the bridge circuit has larger output strain, the conversion coefficient of the output strain and the axial force is larger, which is beneficial to improving the sensitivity of the axial force measurement (the sensitivity of the axial force measurement is closely related to the number of the elastic strips I and II and the thickness of the deformation ring, the number of the elastic strips I and II determines the length of the annular beam of the deformation ring between the elastic strips I and II, the longer the length of the annular beam is, the smaller the thickness of the deformation ring is, the higher the sensitivity of the axial force measurement is, and the lower the sensitivity of the axial force measurement is on the contrary, the thickness of the deformation ring can not be too small, the axial deformation of the integrated elastic support under the expected maximum axial force action meets the design requirement, the rotor friction fault can not be caused due to the overlarge axial deformation, according to the calculation formula of the radial rigidity of the elastic strips I and II, under the condition of ensuring that the thickness and the length parameters of the elastic strips I and II are not changed, along with the reduction of the number of the elastic strips I and the elastic strips II, the radial rigidity of the elastic strips I and the elastic strips II can be ensured to meet the design requirement by increasing the width parameters of the elastic strips I and the elastic strips II, and finally, the axial force measurement sensitivity of the integrated elastic support is improved on the premise that the radial rigidity of the integrated elastic support meets the design requirement;
(2) The elastic strip staggered axial force measurement integrated elastic support has the advantages that the elastic strip I and the elastic strip II in the elastic strip staggered axial force measurement integrated elastic support, the deformation ring arranged between the elastic strip I and the elastic strip II and the strain gauge are pasted on the deformation ring, the interference of radial force can be effectively eliminated when the axial force is measured, the accuracy of axial force measurement is ensured, the strain gauge full bridge can also effectively eliminate the adverse effect of the temperature effect of the strain gauge on the axial force measurement (because the strain gauges are full bridge connection wires, all the strain gauges are connected into the bridge circuit, the temperature of each strain gauge is always the same, and the temperature is the working environment temperature of the integrated elastic support, so the resistance value change caused by the temperature change is the same, and because the strain gauges are mutually positioned on the adjacent bridge arms of the bridge circuit, the output voltage of the bridge circuit is not generated, so that the influence of the temperature effect is eliminated), and the sensitivity of the axial force measurement is favorably improved, the linear relation between the axial force sensed by the deformation ring and the output strain is good (when the rotor is subjected to radial force, the strain directions on the same bridge arm are opposite, the strains sensed by strain gauges on the same bridge arm are mutually offset, if R50 and R51 on the same bridge arm are subjected to the axial force, the strain directions are the same, and are both compressive strain or tensile strain, and when the rotor is subjected to the radial force, the strain directions sensed by the two are opposite, one is compressive strain and the other is tensile strain, and the two are mutually offset, and no strain output is caused by the radial force on the bridge arm, so that the influence of the radial force can be eliminated when the axial force is measured, therefore, the magnitude of the output strain of the deformation ring (force measuring unit) completely reflects the magnitude of the axial force, and simultaneously, the axial force sensed by the deformation ring (force measuring unit) is in a linear relation with the deformation (output strain), the sensitivity of axial force measurement is high;
(3) According to the elastic strip staggered axial force measurement integrated elastic support axial force measurement method, the strain gauge is pasted on the deformation ring between the elastic strip I and the elastic strip II and is close to one side end face of the elastic strip I or the elastic strip II, the position of the strain gauge is reasonably arranged, and a strain gauge full-bridge form is adopted, so that the adverse effect of the temperature effect of the strain gauge on the axial force measurement can be effectively eliminated, the improvement of the sensitivity of the axial force measurement is facilitated, the linear relation between the axial force sensed by the deformation ring and the output strain is good, the sensitivity of the axial force measurement is high, the high sensitivity and the high accuracy of the measurement result can be ensured.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic structural diagram of an elastic strip staggered axial force measurement integrated elastic support according to a preferred embodiment of the invention;
FIG. 2 isbase:Sub>A sectional view A-A of FIG. 1;
FIG. 3 is a cross-sectional view B-B of FIG. 1;
fig. 4 is a schematic diagram of a full bridge structure composed of a first strain gauge and a second strain gauge in the preferred embodiment of the present invention.
Illustration of the drawings:
1. installing edges; 2. a first elastic strip; 3. a second elastic strip; 4. an integrated bearing outer ring; 41. a ball race; 5. a deformable ring; 52. a wire binding hole; 6. a strain gauge; 61. a first strain gauge; 62. a second strain gauge; 7. and measuring the line.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the accompanying drawings, but the invention can be embodied in many different forms, which are defined and covered by the following description.
As shown in fig. 1 to 4, the elastic strip staggered axial force measurement integrated elastic support of the embodiment includes an integrated structure composed of a mounting edge 1, a plurality of elastic strips one 2, a plurality of elastic strips two 3, an integrated bearing outer ring 4, a deformation ring 5, the mounting edge 1, the plurality of elastic strips one 2, the plurality of elastic strips two 3, the integrated bearing outer ring 4, and the deformation ring 5, the mounting edge 1 and the integrated bearing outer ring 4 are respectively disposed at two ends of the integrated structure, the inner wall of the integrated bearing outer ring 4 is provided with a ball track 41, the plurality of elastic strips one 2 are annularly arranged to enclose a cylindrical structure, the plurality of elastic strips two 3 are annularly arranged to enclose a cylindrical structure, the deformation ring 5 is disposed between the cylinder where the elastic strips one 2 is located and the cylinder where the elastic strips two 3 are located, the other end of the drum where the elastic strip I2 is located is connected with an integrated bearing outer ring 4, the other end of the drum where the elastic strip II 3 is located is connected with a mounting edge 1, the elastic strip I2 and the elastic strip II 3 are arranged in a staggered mode relative to a deformation ring 5, the elastic strip I2 and the elastic strip II 3 are used for extruding the deformation ring 5 to enable the deformation ring to generate elastic deformation under the action of rotor axial force, a plurality of strain gages 6 capable of respectively sensing tensile strain and compressive strain are pasted at different positions on the end face, close to the elastic strip I2, of the deformation ring 5, the strain gages 6 form a full bridge and are led out through measuring lines 7 to be used for measuring the axial force on the integrated elastic support under the action of the rotor axial force, and the positive and negative values of the full bridge output strain of the strain gages 6 on the deformation ring 5 can be used for judging the direction of the rotor axial force.
In this embodiment, the strain gage 6 includes 4 strain gages one 61 and 4 strain gages two 62, the position of the strain gage one 61 is close to the end face of the deformation ring 5 at the connection position of the deformation ring 5 and the elastic strip one 2, the strain gage one 61 includes R50, R51, R52 and R53, the R50, R51, R52 and R53 are pasted at the root position where the elastic strip one 2 is connected with the deformation ring 5, the position of the strain gage two 62 is close to the end face of the deformation ring 5 opposite to the connection position of the deformation ring 5 and the elastic strip two 3, the strain gage two 62 includes R54, R55, R56 and R57, the R54, R55, R56 and R57 are pasted at the end face of the deformation ring 5 opposite to the connection position of the elastic strip two 3 and the deformation ring 5, the first 4 strain gauges 61 and the second 4 strain gauges 62 are respectively and uniformly distributed on a circumference formed by the deformation ring 5, the first strain gauges 61 and the second strain gauges 62 are respectively arranged on two adjacent bridge arms, strain directions sensed by the first strain gauges 61 and the second strain gauges 62 are opposite, the first strain gauges 61 are connected in series in pairs to form a first group of two strain gauges (R50 and R51 are connected in series, R52 and R53 are connected in series), the second strain gauges 62 are connected in series in pairs to form a second group of two strain gauges (R54 and R55 are connected in series, R56 and R57 are connected in series), the first group of two strain gauges are respectively connected in series with the second group of two strain gauges (R50 and R57 are connected in series, R51 and R54 are connected in series, R52 and R55 are connected in series, R53 and R56 are connected in series) to form a full bridge, and four measuring lines 7 are led out for measuring axial force. The arrangement of the first strain gauge 61 and the second strain gauge 62 on the deformation ring 5 can ensure that the strain gauges can respectively sense larger compressive strain/tensile strain under the action of axial force, so that a bridge circuit formed by the first strain gauge 61 and the second strain gauge 62 has larger output strain, the conversion coefficient of the output strain and the axial force is larger, and the sensitivity of axial force measurement is favorably improved.
In this embodiment, the deformation ring 5 can effectively eliminate the interference of the radial force when measuring the axial force, and ensure the accuracy of the axial force measurement. The full bridge of the strain gauge 6 can also effectively eliminate the adverse effect of the temperature effect of the strain gauge 6 on the axial force measurement, and improve the axial force measurement sensitivity of the deformation ring 5. The linear relation between the axial force sensed by the deformation ring 5 and the output strain is good, and the sensitivity of axial force measurement is high.
In the present embodiment, as shown in fig. 2 and 4, after theoretical analysis and finite element calculation, 8 positions of the strain gauge attached are determined, R50, R51, R52, and R53 in the strain gauge one 61 are symmetrically attached to the end surface of the deformation ring 5 near the elastic strip one 2 at intervals of 90 °, R54, R55, R56, and R57 in the strain gauge two 62 are attached to the end surface of the deformation ring 5 near the connection between the elastic strip two 3 and the deformation ring 5, and the compressive strain/tensile strain of the deformation ring 5 under the action of the axial force of the rotor is measured. As shown in fig. 4, R50 and R51 are connected in series, and R52 and R53 are connected in series with the strain gauge one 61 that induces compressive strain/tensile strain on the end face of the deformation ring 5 near the elastic strip one 2; and the strain gauge II 62 which is used for inducing tensile strain/compressive strain on the end face of the deformation ring 5 opposite to the joint of the elastic strip II 3 and the deformation ring 5 is connected with R54 and R55 in series and R56 and R57 in series. The strain gauges R50 and R57 are connected in series, the strain gauges R51 and R54 are connected in series, the strain gauges R52 and R55 are connected in series, and the strain gauges R53 and R56 are connected in series to form a full bridge, then 4 measuring wires 7 are respectively led out, and the 4 measuring wires 7 are bundled by using a heat shrink tube and then are bound and fixed on the deformation ring 5 through the binding hole 51.
In this embodiment, be equipped with on the ring of warping 5 and be used for binding up the line hole of tying up measuring wire 7, measuring wire 7 binds through line hole 51 and fixes on ring of warping 5, can be convenient for the collection of measuring wire, avoids measuring wire to receive rotor shaft pivoted influence and endanger rotor operation safety or influence the accuracy nature of measuring result.
In this embodiment, the resistance of a single strain gauge 6 forming the full bridge is 120 Ω, the resistance between every two output four measurement lines 7 is 180 Ω (corresponding to AB, BC, CD, DA in fig. 4) or 240 Ω (corresponding to AC, BD in fig. 4), it can be determined by testing the resistance value whether there is any phenomena such as actual series connection, disconnection of the measurement lines 7, short circuit, etc. due to poor contact of the series lines, so that it can be ensured that the reliability of the connection lines between the measurement lines 7 and the eight strain gauges 6 is high when the axial force measurement is performed, and the axial force measurement cannot be performed normally or the accuracy of the measurement result cannot be affected due to the phenomena such as poor contact, disconnection, short circuit, etc.
In this embodiment, the two first strain gauges 61 in the first set of strain gauges are the first strain gauges 61 at two opposite positions on the deformation ring 5, and the two second strain gauges 62 in the second set of strain gauges are the second strain gauges 62 at two opposite positions on the deformation ring 5. Under the action of radial force, the strains sensed by the strain gauges R50 and R51 are opposite in direction and same in magnitude, the strains sensed by the strain gauges R52 and R53 are opposite in direction and same in magnitude, the strains sensed by the strain gauges R54 and R55 are opposite in direction and same in magnitude, and the strains sensed by the strain gauges R56 and R57 are opposite in direction and same in magnitude.
Because the first strain gauge 61 and the second strain gauge 62 on the same bridge arm forming the full bridge of the strain gauges are respectively adhered to the symmetrical positions of the central axis of the deformation ring 5, both sense compressive strain/tensile strain simultaneously under the action of axial force, the strain directions sensed by the first strain gauge 61 and the second strain gauge 62 are opposite, when one senses compressive strain, the other senses tensile strain, and vice versa, so that the full bridge of the strain gauges 6 can normally output strain values under the action of axial force of the rotor. When the integrated elastic support is subjected to radial force, one of the two strain gauges on the same bridge arm of the full bridge of the strain gauge 6 senses tensile strain, and the other one senses compressive strain, so that the strain output caused by the radial force on the same bridge wall of the full bridge of the strain gauge 6 is 0, the effect of no radial force output is realized, the interference of the radial force can be effectively eliminated when the deformation ring 5 (force measuring unit) measures the axial force of the rotor, and the accuracy of the measurement of the axial force of the rotor is ensured. The strain gauge full bridge can also effectively eliminate the adverse effect of the temperature effect of the strain gauge 6 on the measurement of the axial force of the rotor, and improve the measurement sensitivity of the axial force of the rotor of the deformation ring 5 (force measuring unit).
In the embodiment, four measuring lines are connected into the dynamic strain measuring instrument, the axial force measurement calibration is carried out on the integrated elastic support, the calibration coefficient related to the axial force and the strain is obtained, and the axial force in the actual working of the rotor can be obtained through the calibration coefficient and the strain measurement. When the rotor is subjected to forward/backward axial force, R50, R51, R52 and R53 in the first strain gauge 61 sense compressive strain and R54, R55, R56 and R57 in the second strain gauge 62 sense tensile strain and compressive strain, and the full bridge of the strain gauge 6 outputs a positive/negative strain value. And judging the direction of the axial force of the rotor according to the signs of the full-bridge output strain of the strain gauge 6, and accurately obtaining the magnitude of the axial force of the rotor after conversion of the magnitude of the full-bridge output strain of the strain gauge 6.
In this embodiment, the number of the first elastic strips 2 is the same as that of the second elastic strips 3. The elastic strips I2 and the elastic strips II 3 determine the radial rigidity of the elastic support, the number, the width and the thickness of the elastic support are required to be consistent, the length can be different (the axial position of the deformation ring can be properly changed and is not limited at the midpoint), in order to ensure the consistency of the radial rigidity of the elastic strips at two sides of the deformation ring 5, the most important point is the requirement of the structural symmetry of the elastic strips, and the elastic strips need to be staggered to generate equal deformation at the circumferentially symmetrical position of the deformation ring 5.
In this embodiment, the widths of the first elastic strip 2 and the second elastic strip 3 are the same, and the uniformity and the strength of the elastic strips are ensured to be consistent.
In this embodiment, the elastic strips one 2 and two 3 are respectively and uniformly arranged along the circumferential direction of the cylinder where the elastic strips are located, so that the improvement of the uniformity of the elastic support and the convenience of the adhesion of the strain gauge 6 are facilitated, and the improvement of the accuracy of the axial force measurement is facilitated.
In this embodiment, the outer diameter of the cylinder in which the elastic strip one 2 is located is equal to the outer diameter of the cylinder in which the elastic strip two 3 and the deformation ring 5 are located, and the centers of the elastic strip one 2, the elastic strip two 3 and the deformation ring 5 are all located on the central line of the integrated elastic support structure, so that the consistency of the size of the outer surface of the elastic support is maintained.
In the embodiment, the radial rigidity of the elastic strip staggered axial force measurement integrated elastic support is
The radial rigidity of the elastic strip I2 is K 1 ＝nEb 2 h 2 /l 1 3 The radial rigidity of the second elastic strip 3 is K 2 ＝nEb 2 h 2 /l 2 3 Wherein n is the number of the first elastic strip 2 or the second elastic strip 3, E is the elastic modulus of the material, b is the width of the first elastic strip 2 or the second elastic strip 3, h is the thickness of the first elastic strip 2 or the second elastic strip 3, and l 1 Length of the elastic strip 2, /) 2 The length of the elastic strip two 3.
In the embodiment, the outer diameter of the cylinder where the elastic strip I2 is located is equal to the outer diameter of the integrated bearing outer ring 4, and the centers of the elastic strip I2 and the integrated bearing outer ring are both located on the central line of the integrated elastic support integrated structure, so that the consistency of the size of the outer surface of the elastic support is maintained.
The integrated elastic support for measuring the elastic strip staggered axial force is subjected to simulation analysis and verification, and the result shows that the strength of the integrated elastic support with the deformation ring 5 meets the design requirement, the deformation ring 5 has small influence on the radial rigidity of the integrated elastic support, and the radial rigidity of the integrated elastic support with the deformation ring 5 can meet the design requirement by adjusting the parameters such as the length, the width, the thickness, the number and the like of the elastic strip I2 and the elastic strip II 3. The deformation ring 5 has high axial force measurement sensitivity and good radial rigidity, and provides an effective solution for the problem of measurement of the axial force of the rotor of the integrated elastic support.
The method for measuring the axial force of the elastic strip staggered axial force measurement integrated elastic support comprises the elastic strip staggered axial force measurement integrated elastic support and comprises the following steps:
s1, adhering a plurality of strain gauges 6 to corresponding positions on a deformation ring 5, forming the plurality of strain gauges 6 into a full bridge, leading out a measuring wire 7, and connecting the measuring wire 7 into a dynamic strain measuring instrument;
s2, carrying out axial force measurement calibration on the elastic strip staggered axial force measurement integrated elastic support, fixing the elastic strip staggered axial force measurement integrated elastic support on a calibration platform, applying axial loads F with equal load intervals on an integrated bearing outer ring 4, recording an output strain value epsilon in a dynamic strain measuring instrument, and obtaining an axial force calibration formula F = k epsilon + b through linear fitting, wherein b is a constant, solving a calibration coefficient k, and when the square of a linear correlation coefficient is greater than 0.99, the obtained k value meets the requirement;
s3, installing the elastic strip staggered axial force measurement integrated elastic support on an installation seat for supporting a rotor through the installation edge 1, enabling a ball runway 41 of an integrated bearing outer ring 4 to be sleeved on a bearing inner ring through balls and a retainer, and when the axial force borne by a rotor shaft is F ', under the action of the axial force F', a strain gauge 6 senses the compressive strain and the tensile strain at the corresponding position on a deformation ring 5, and distinguishing the forward axial force and the backward axial force by positive and negative signs respectively;
and S4, judging the direction of the axial force F ' of the rotor through the sign of the full-bridge output strain of the strain gauge, and accurately obtaining the magnitude of the axial force F ' of the rotor through the magnitude of the full-bridge output strain epsilon ' of the strain gauge and the conversion of F ' = k epsilon '.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The elastic strip staggered axial force measurement integrated elastic support is characterized by comprising an installation edge (1), a plurality of elastic strips I (2), a plurality of elastic strips II (3), an integrated bearing outer ring (4) and a deformation ring (5), wherein the installation edge (1), the plurality of elastic strips I (2), the plurality of elastic strips II (3), the integrated bearing outer ring (4) and the deformation ring (5) form an integrated structure, the installation edge (1) and the integrated bearing outer ring (4) are respectively arranged at two end parts of the integrated structure, a ball track (41) is arranged on the inner wall of the integrated bearing outer ring (4),
a plurality of elastic strips I (2) are annularly arranged and enclosed to form a cylinder structure, a plurality of elastic strips II (3) are annularly arranged and enclosed to form a cylinder structure, the deformation ring (5) is arranged between the cylinder where the elastic strips I (2) are located and the cylinder where the elastic strips II (3) are located, the other end of the cylinder where the elastic strips I (2) are located is connected with the integrated bearing outer ring (4), the other end of the cylinder where the elastic strips II (3) are located is connected with the mounting edge (1),
the elastic strip I (2) and the elastic strip II (3) are arranged in a staggered manner relative to the deformation ring (5) and are used for extruding the deformation ring (5) to enable the deformation ring (5) to generate elastic deformation under the action of the axial force of the rotor,
deformation ring (5) are close to on the lateral surface of bullet strip (2) or bullet strip two (3) different positions department paste have a plurality of can feel respectively strain gauge (6) of drawing strain and compressive strain a plurality of strain gauge (6) constitute the full-bridge and draw forth through measuring wire (7) and are used for rotor axial force to exert oneself the axial force measurement on the integrated elastic support down.
2. The integrated elastic support for measuring elastic strip staggered axial force according to claim 1,
the strain gauge (6) comprises four strain gauges one (61) and four strain gauges two (62), the position of the strain gauge one (61) is close to the end face of the deformation ring (5) at the joint of the deformation ring (5) and the elastic strip one (2), the position of the strain gauge two (62) is close to the end face of the deformation ring (5) opposite to the joint of the deformation ring (5) and the elastic strip two (3), the four strain gauges one (61) and the four strain gauges two (62) are respectively and evenly distributed on the circumference formed by the deformation ring (5),
the strain gauge I (61) and the strain gauge II (62) are respectively arranged on two adjacent bridge arms, the strain directions sensed by the strain gauge I (61) and the strain gauge II (62) are opposite, the strain gauge I (61) is connected in series two by two to form a strain gauge group, the strain gauge II (62) is connected in series two by two to form two strain gauge groups, the two strain gauge groups are respectively connected in series with the two strain gauge groups to form a full bridge, and four measuring lines (7) are led out for measuring the axial force.
3. The integrated elastic support for measuring elastic strip staggered axial force according to claim 2,
two first strain gauges (61) in the strain gauge group are first strain gauges (61) at two opposite positions on the deformation ring (5), and two second strain gauges (62) in the strain gauge group are second strain gauges (62) at two opposite positions on the deformation ring (5).
4. The integrated elastic support for alternate elastic strip axial force measurement according to any one of claims 1 to 3,
the number of the elastic strips I (2) is the same as that of the elastic strips II (3).
5. The integrated elastic support for measuring elastic strip alternate axial force according to any one of claims 1 to 3,
the width and the thickness of the elastic strip I (2) and the elastic strip II (3) are the same.
6. The integrated elastic support for measuring elastic strip alternate axial force according to any one of claims 1 to 3,
the elastic strips I (2) and the elastic strips II (3) are respectively and uniformly arranged along the circumferential direction of the cylinder where the elastic strips I and the elastic strips II are respectively arranged.
7. The integrated elastic support for measuring elastic strip alternate axial force according to any one of claims 1 to 3,
the outer diameter of the cylinder where the elastic strip I (2) is located is equal to the outer diameter of the cylinder where the elastic strip II (3) and the deformation ring (5) are located, and the centers of the elastic strip I (2), the elastic strip II (3) and the deformation ring (5) are all located on the central line of the integrated elastic support integrated structure.
8. The integrated elastic support for alternate elastic strip axial force measurement according to any one of claims 1 to 3,
the radial rigidity of the elastic strip staggered axial force measurement integrated elastic support is
The radial rigidity of the elastic strip I (2) is K 1 ＝nEb 2 h 2 /l 1 3 The radial rigidity of the elastic strip II (3) is K 2 ＝nEb 2 h 2 /l 2 3 Wherein n is the number of the first elastic strip (2) or the second elastic strip (3), E is the elastic modulus of the material, b is the width of the first elastic strip (2) or the second elastic strip (3), h is the thickness of the first elastic strip (2) or the second elastic strip (3), and l 1 Is the length of the elastic strip one (2) | 2 The length of the elastic strip II (3).
9. The integrated elastic support for alternate elastic strip axial force measurement according to any one of claims 1 to 3,
the deformation ring (5) is provided with a wire binding hole for binding the measuring wire (7), and the measuring wire (7) is bound and fixed on the deformation ring (5) through the wire binding hole (51).
10. A method for measuring an elastic support integrating measurement of elastic strip staggered axial force, which is characterized by comprising the elastic support integrating measurement of elastic strip staggered axial force of any one of claims 1-9, and comprising the following steps:
s1, sticking a plurality of strain gauges (6) to corresponding positions on a deformation ring (5), forming the plurality of strain gauges (6) into a full bridge, leading out a measuring line (7), and connecting the measuring line (7) into a dynamic strain measuring instrument;
s2, carrying out axial force measurement calibration on the elastic strip staggered axial force measurement integrated elastic support, fixing the elastic strip staggered axial force measurement integrated elastic support on a calibration platform, applying axial loads F with equal load intervals on an integrated bearing outer ring (4), recording an output strain value epsilon in a dynamic strain measuring instrument, obtaining an axial force calibration formula F = k epsilon + b through linear fitting, wherein b is a constant, solving a calibration coefficient k, and when the square of a linear correlation coefficient is greater than 0.99, obtaining a k value meeting the requirement;
s3, mounting the integrated elastic support capable of testing the axial load of the rotor on a mounting seat for supporting the rotor through a mounting edge (1), sleeving a ball track (41) of an integrated bearing outer ring (4) on a bearing inner ring through balls and a retainer, and when the axial force borne by a rotor shaft is F ', under the action of the axial force F', a strain gauge (6) senses the compressive strain and the tensile strain at the corresponding position on a deformation ring (5) and distinguishes forward axial force and backward axial force by positive and negative signs respectively;
and S4, judging the direction of the axial force F ' of the rotor through the positive sign and the negative sign of the full-bridge output strain of the strain gauge, and accurately obtaining the magnitude of the axial force F ' of the rotor through the magnitude of the full-bridge output strain epsilon ' of the strain gauge and the conversion of F ' = k epsilon '.
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