Integrated squirrel cage elastic support and rotor axial force measurement method

Abstract

The application discloses an integrated squirrel-cage elastic support and a rotor axial force measuring method, and the integrated squirrel-cage elastic support comprises a connecting cylinder and a bearing outer ring which are integrally connected, and a plurality of elastic strips are connected between the connecting cylinder and the bearing outer ring; a base is arranged below the connecting cylinder; the base comprises a plurality of mounting blocks which are uniformly distributed in a circumferential direction and a plurality of arc-shaped beams which are arranged in a circumferential direction and are uniformly segmented; the arc-shaped beams are connected with the bottom wall of the connecting cylinder, there is a gap space between the top end of the mounting block and the bottom end of the connecting cylinder, and the mounting block is connected with the outer side wall of the connecting cylinder; and a force measuring unit is arranged on the bottom surface of the arc-shaped beam. Since the gap space exists between the top end of the mounting block and the bottom end of the connecting cylinder and the mounting block is connected with the outer side wall of the connecting cylinder, the force measuring unit of the arc-shaped beam does not affect the lateral stiffness and structural strength of the application, the dynamics and vibration characteristics of the traditional squirrel-cage elastic support are not changed, and the rotor axial force measuring can be satisfied.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine rotor axial force measurement, and particularly relates to an integrated squirrel-cage elastic support and a rotor axial force measurement method. BACKGROUND

[0002] The squirrel-cage elastic support is widely used in the rotor support system of a medium or small aero-engine, and can effectively reduce the vibration of the rotor when the rotor passes through the critical speed, and ensure normal operation of the rotor. When the engine is working, the compressor rotor generates forward axial force, and the turbine rotor generates backward axial force. Excessive axial force can overload the bearing and cause damage, and insufficient axial force can cause the bearing to slip under light load. Therefore, the rotor axial force must be kept within a suitable range. During engine operation, the rotor axial force needs to be measured to ensure safe and reliable operation of the engine.

[0003] The existing aero-engine rotor axial force measurement needs to use a load cell ring. The load cell ring is installed in the bearing cavity of the squirrel-cage elastic support, and one side of the load cell ring abuts against the bearing cavity stop edge of the squirrel-cage elastic support, and the other side abuts against the bearing outer ring. There is a gap between the bearing outer ring and the inner wall of the bearing cavity of the squirrel-cage elastic support, so under the action of the rotor axial force, the bearing and the squirrel-cage elastic support can move relatively, so that the load cell ring is deformed to realize the measurement of the axial force. Therefore, the rotor axial force measurement method based on the load cell ring is only suitable for the rotor axial force measurement of the squirrel-cage elastic support and the bearing in a split structure, and is not suitable for the rotor axial force measurement of the squirrel-cage elastic support and the bearing in an integrated structure.

[0004] The existing rotor axial force measurement method based on the load cell ring is only suitable for the rotor axial force measurement of the squirrel-cage elastic support and the bearing in a split structure, and is not suitable for the rotor axial force measurement of the squirrel-cage elastic support and the bearing in an integrated structure. For the rotor axial force measurement of the squirrel-cage elastic support and the bearing in an integrated structure, there are reported methods such as pasting strain gauges on the elastic strips, machining a load cell ring unit on the connecting cylinder of the squirrel-cage elastic support, changing the layout of the elastic strips of the squirrel-cage elastic support, and using L-shaped elastic strips for the squirrel-cage elastic support. However, they all have their own characteristics and application scope. Among them, the method of pasting strain gauges on the elastic strips has a lower axial force measurement sensitivity, and especially has a larger measurement error under a small axial force state. The method of machining a load cell ring unit on the connecting cylinder of the squirrel-cage elastic support is prone to cause weak nonlinearity of the lateral stiffness of the squirrel-cage elastic support due to the load cell ring unit. The width of the upper and lower bosses of the load cell ring is not very wide, the number of the bosses is less than that of the elastic strips, and the bosses are sparsely distributed. The gap space between the upper and lower bosses will affect the linearity of the lateral stiffness of the squirrel-cage elastic support to some extent, which may bring risks and adverse effects to the vibration stability and operation reliability of the rotor.

[0005] The way of changing the layout of the elastic supporting spring strips of the squirrel cage adopts a spring strip staggered layout form, and since the arc length of the deformation beam between the upper and lower spring strips is smaller than the arc length of the deformation beam between the upper and lower convexes of the load cell, the sensitivity of the way of changing the layout of the elastic supporting spring strips of the squirrel cage when measuring the axial force is not as good as that of using the load cell to measure the axial force, and under the condition of meeting the lateral stiffness of the squirrel cage elastic support, the structure parameters of the spring strips need to be further optimized to improve the axial force measurement sensitivity. The squirrel cage elastic support adopts the way of L-shaped spring strips, which can ensure that the squirrel cage elastic support has high axial force measurement sensitivity, but the L-shaped spring strips can easily cause the lateral stiffness and axial stiffness of the squirrel cage elastic support to be weak, especially the linearity of the lateral stiffness is poor, which needs to be further improved to improve the lateral stiffness and axial stiffness and ensure that it has good stiffness measurement linearity. SUMMARY

[0006] Therefore, the technical problem to be solved by the present application is to overcome the defects of the existing rotor axial force measurement method based on the load cell, which is not suitable for integrated structure, and other methods or problems that can easily cause the lateral stiffness of the squirrel cage elastic support to be weak and nonlinear or the axial force measurement sensitivity to be poor, so as to provide an integrated squirrel cage elastic support and a rotor axial force measurement method.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0008] The integrated squirrel cage elastic support comprises a connecting cylinder and a bearing outer ring which are integrally connected, and a plurality of spring strips are connected between the connecting cylinder and the bearing outer ring.

[0009] The bottom of the connecting cylinder is provided with a base; the base comprises a plurality of mounting blocks which are uniformly distributed in the circumferential direction and a plurality of arc-shaped beams which are arranged in the circumferential direction; the mounting blocks and the arc-shaped beams are arranged in an alternating and spaced manner; the arc-shaped beams are connected with the bottom wall of the connecting cylinder, there is a gap space between the top end of the mounting block and the bottom end of the connecting cylinder, and the mounting block is connected with the outer side wall of the connecting cylinder.

[0010] The bottom surface of the arc-shaped beam is provided with a load cell; the load cell comprises a plurality of strain gauge groups, each strain gauge group comprises two strain gauges which are symmetric about the center axis of the connecting cylinder, the two strain gauges in each strain gauge group are connected in series to form a bridge arm, and the bridge arms are connected in series to form a full bridge and lead out test lines.

[0011] The two strain gauges on the same bridge arm of the full bridge are adapted to feel opposite strain directions when subjected to lateral load, and the felt strain cancels each other out; the two strain gauges on the same bridge arm of the full bridge are adapted to feel the same strain direction when subjected to axial load.

[0012] Further optimize the technical scheme, the bottom surface of the mounting block is uniformly distributed with a plurality of bosses in the circumferential direction, and two ends of the arc-shaped beam are respectively connected with a boss;

[0013] The position where the mounting block intersects with the arc-shaped beam is cut with an arc-shaped groove, and the two sides of the arc-shaped groove stop at the bosses, so that the position where the arc-shaped beam is connected with the bosses can be deformed under the action of the rotor axial force.

[0014] Further optimize the technical scheme, each strain gauge is arranged in the position where the bottom surface of the arc-shaped beam is connected with the boss and the middle part of the bottom surface of the arc-shaped beam.

[0015] Further optimize the technical scheme, the arc-shaped beam and the bottom wall of the connecting cylinder are connected through a plurality of circumferentially uniformly distributed connecting columns.

[0016] Further optimize the technical scheme, the mounting block and the outer side wall of the connecting cylinder are connected through a plurality of circumferentially uniformly distributed reinforcing ribs, so as not to affect the lateral rigidity and structural strength of the device as a whole, and so that the lateral rigidity of the device as a whole is mainly determined by the structural size of the elastic strip.

[0017] Further optimize the technical scheme, the number of the reinforcing ribs, the connecting columns and the bosses is the same, and the reinforcing ribs, the connecting columns and the bosses are in a staggered distribution state.

[0018] Further optimize the technical scheme, a binding hole is formed in the arc-shaped beam, and the test wire is positioned on the arc-shaped beam through the binding hole.

[0019] Further optimize the technical scheme, the rigidity between the base and the connecting cylinder is enhanced as the number of the arc-shaped beams and the mounting blocks decreases.

[0020] The rotor axial force measurement method comprises the following steps:

[0021] S1. Each test wire is connected to a strain measuring instrument, and the axial force measurement calibration of the integrated squirrel-cage elastic support is carried out, and the integrated squirrel-cage elastic support is fixed on a calibration platform;

[0022] S2. An equal-load-interval axial load F is applied on the bearing outer ring, and the output strain value ε in the strain measuring instrument is recorded, and the axial force calibration formula F=kε+b is obtained through linear fitting, k is the conversion coefficient of the axial force in the arc-shaped beam and the output strain, b is a constant, and ε is the output strain value in the strain measuring instrument;

[0023] S3. During the operation of the engine, the output strain value ε' of the arc-shaped beam is monitored through the strain measuring instrument, and the conversion coefficient k in step S2 is combined, so that the axial force F' in the working process of the rotor can be obtained in real time.

[0024] The direction of the axial force of the rotor is judged by the positive and negative values of the strain output by the strain gauge full bridge.

[0025] The step S3 is further optimized, when the rotor is subjected to the forward axial force, the strain gauge full bridge outputs the positive strain value, when the rotor is subjected to the backward axial force, the strain gauge full bridge outputs the negative strain value, and then the direction of the axial force of the rotor is judged by the positive and negative values of the strain output by the strain gauge full bridge.

[0026] The technical scheme has the following advantages:

[0027] 1. The integrated squirrel cage elastic support provided by the application has the functions of adjusting the critical speed of the rotor system and measuring the axial load of the rotor, and the lateral stiffness of the integrated squirrel cage elastic support with the segmented arc-shaped beam of the base is still the size of the elastic strip structure compared with the traditional squirrel cage elastic support structure.

[0028] Compared with the mode of processing the force ring unit on the connecting cylinder of the squirrel cage elastic support, the integrated squirrel cage elastic support with the segmented arc-shaped beam of the base processes the segmented arc-shaped beam on the base to measure the axial force.

[0029] 2. The integrated squirrel cage elastic support provided by the application integrates the force measuring unit in the base, and the arc-shaped beam and the uncut mounting block are staggered and connected to form the base.

[0030] 3. The integrated squirrel cage elastic support and rotor axial force measuring method provided by the application adopts the mode of full-bridge strain gauge patch and lead wire on the arc beam, so that the positive and negative signs of the output strain can be used to determine the direction of the rotor axial force. The arc beam can effectively eliminate the interference of the rotor unbalance and other transverse loads when measuring the rotor axial force, and ensure the accuracy of the rotor axial force measurement. When the rotor is subjected to a transverse load, the strain directions on the same bridge arm are opposite, and the sensed strains cancel each other out. For example, when the strain gauges on the same bridge arm are subjected to an axial load, they sense the same strain, which is either compressive strain or tensile strain. When subjected to a transverse load, the strain directions sensed by the two strain gauges are opposite, one is in compression and the other is in tension, and the two cancel each other out, so there is no strain output on the bridge arm affected by the transverse load, and thus the influence of the transverse load can be eliminated.

[0031] The full-bridge strain gauge can also effectively eliminate the adverse effects of strain gauge temperature effects on rotor axial force measurement, and improve the accuracy of rotor axial force measurement of the arc beam. The rotor axial force and the measured strain have a good linear relationship, and the rotor axial force measurement sensitivity is high. Since the strain gauges pasted on the bottom surface of the arc beam are full-bridge wired, all strain gauges are connected to the bridge, and the temperature of each strain gauge is always the same as the working environment temperature of the base with the segmented arc beam of the integrated squirrel cage elastic support, so the changes in resistance value caused by temperature changes are also the same. Since they are adjacent to each other in the bridge, no output voltage of the bridge is generated, so that the influence of temperature effects is eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0033] Figure 1 The bottom view of the first form of the integrated squirrel cage elastic support of the application;

[0034] Figure 2 The bottom view of the second form of the integrated squirrel cage elastic support of the application; Figure 1 The transverse sectional view along the line A-A in the application;

[0035] Figure 3 The transverse sectional view along the line B-B in the application; Figure 2 The transverse sectional view along the line B-B in the application;

[0036] Figure 4 The bottom view of the second form of the integrated squirrel cage elastic support of the application;

[0037] Figure 5Figure 1 is a perspective view of a first form of integrated squirrel cage elastic support according to the present application; Figure 4 Figure 2 is a transverse sectional view along the line A-A in the first form of integrated squirrel cage elastic support according to the present application;

[0038] Figure 6 Figure 3 is a perspective view of a second form of integrated squirrel cage elastic support according to the present application; Figure 5 Figure 4 is a transverse sectional view along the line B-B in the second form of integrated squirrel cage elastic support according to the present application;

[0039] Figure 7 Figure 5 is a bottom view of a third form of integrated squirrel cage elastic support according to the present application;

[0040] Figure 8 Figure 6 is a perspective view of a fourth form of integrated squirrel cage elastic support according to the present application; Figure 7 Figure 7 is a transverse sectional view along the line A-A in the fourth form of integrated squirrel cage elastic support according to the present application;

[0041] Figure 9 Figure 8 is a perspective view of a fifth form of integrated squirrel cage elastic support according to the present application; Figure 8 Figure 9 is a transverse sectional view along the line B-B in the fifth form of integrated squirrel cage elastic support according to the present application;

[0042] Figure 10 Figure 10 is a full bridge connection diagram of a strain gauge for measuring the axial force of a rotor according to the present application.

[0043] Reference signs:

[0044] 1, base; 10, reinforcing rib; 11, boss; 12, connecting column; 13, arc-shaped beam; 2, elastic strip; 3, bearing outer ring; 4, connecting cylinder; 50, first strain gauge; 51, second strain gauge; 52, third strain gauge; 53, fourth strain gauge; 54, fifth strain gauge; 55, sixth strain gauge; 56, seventh strain gauge; 57, eighth strain gauge; 6, binding hole. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0046] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "mounting", "connected", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict between them.

[0049] In order to solve the problem that the integrated squirrel cage elastic support cannot be matched with the force ring for rotor axial force measurement, it is necessary to improve the design of the integrated squirrel cage elastic support structure for rotor axial force measurement. While realizing the rotor axial force measurement of the integrated squirrel cage elastic support, it is necessary to avoid introducing rotor dynamics and vibration problems, avoiding the structural modification of the traditional squirrel cage elastic support which has a great influence on the lateral stiffness and vibration characteristics of the squirrel cage elastic support, and also ensuring high sensitivity of the rotor axial force measurement. The present application aims to design and propose an integrated squirrel cage elastic support with segmented arc-shaped beams on the base and a rotor axial force measurement method, to provide a reliable solution for rotor axial force measurement of the integrated squirrel cage elastic support with segmented arc-shaped beams on the base, without changing the stiffness and strength characteristics of the squirrel cage elastic support, and improving the feasibility of rotor axial force measurement of the integrated squirrel cage elastic support.

[0050] Embodiment 1

[0051] As shown in Figures 1 to 10 The embodiment discloses an integrated squirrel cage elastic support, which comprises a connecting cylinder 4, a bearing outer ring 3, a spring strip 2, a base 1 and a strain gauge group.

[0052] The connecting cylinder 4 and the bearing outer ring 3 are integrally connected, the bearing outer ring 3 is at the outermost end of the squirrel cage elastic support, and the inner wall of the bearing outer ring 3 is a rolling body track. The rotor is supported on the integrated squirrel cage elastic support with segmented arc-shaped beams on the base through the bearing inner ring, the rolling body, the retainer and the bearing outer ring 3.

[0053] The connecting cylinder 4 is connected with the spring strip 2, and the spring strip 2 is connected with the bearing outer ring 3.

[0054] The lower part of the connecting cylinder 4 is provided with a base 1. The base 1 comprises a plurality of mounting blocks distributed uniformly in the circumferential direction and a plurality of arc-shaped beams 13 arranged in the circumferential direction in segments, and the mounting blocks and the arc-shaped beams 13 are arranged alternately and spaced apart. The arc-shaped beams 13 are coaxial with the connecting cylinder 4, the arc-shaped beams 13 are connected with the bottom wall of the connecting cylinder 4, and there is a gap space between the top end of the mounting block and the bottom end of the connecting cylinder 4, and the mounting block is connected with the outer side wall of the connecting cylinder 4.

[0055] The bottom surface of the arc-shaped beam 13 is provided with a force measuring unit. The force measuring unit comprises a plurality of strain gauge groups, each strain gauge group comprises two strain gauges which are symmetrical about the center axis of the connecting cylinder 4, the two strain gauges in each strain gauge group are connected in series to form a bridge arm, and the bridge arms are connected in series to form a full bridge and lead out test lines.

[0056] The two strain gauges on the same bridge arm of the full bridge are adapted to feel opposite strain directions when subjected to a transverse load, and the felt strain cancels each other out; the two strain gauges on the same bridge arm of the full bridge are adapted to feel the same strain direction when subjected to an axial load.

[0057] The integrated squirrel-cage elastic support has the functions of adjusting the critical speed of the rotor system of the traditional squirrel-cage elastic support, and can also measure the axial load of the rotor. Compared with the traditional squirrel-cage elastic support structure, the transverse stiffness of the integrated squirrel-cage elastic support with the segmented arc-shaped beams of the base is still determined by the structure size of the elastic strip. Because there is a gap space between the top end of the mounting block and the bottom end of the connecting cylinder 4, and the mounting block is connected with the outer side wall of the connecting cylinder 4, the force measuring unit of the arc-shaped beam does not affect the transverse stiffness and structural strength of the integrated squirrel-cage elastic support with the segmented arc-shaped beams of the base, and does not change the dynamics and vibration characteristics of the traditional squirrel-cage elastic support, but can meet the function of measuring the axial force of the rotor.

[0058] The integrated squirrel-cage elastic support with the segmented arc-shaped beams of the base is still determined by the structure size of the elastic strip. Because there is a gap space between the top end of the mounting block and the bottom end of the connecting cylinder 4, and the mounting block is connected with the outer side wall of the connecting cylinder 4, the force measuring unit of the arc-shaped beam does not affect the transverse stiffness and structural strength of the integrated squirrel-cage elastic support with the segmented arc-shaped beams of the base, and does not change the dynamics and vibration characteristics of the traditional squirrel-cage elastic support, but can meet the function of measuring the axial force of the rotor.

[0059] The strain gauge full bridge can effectively eliminate the adverse effects of strain gauge temperature effect on rotor axial force measurement, and improve the rotor axial force measurement accuracy of the arc-shaped beam. The rotor axial force borne by the arc-shaped beam has a good linear relationship with the measured strain, and the rotor axial force measurement sensitivity is high. Since the strain gauges pasted on the bottom surface of the arc-shaped beam are full bridge wiring, all strain gauges are connected to the bridge circuit, and the temperature of each strain gauge is always the same as the working environment temperature of the integrated squirrel-cage elastic support with the segmented arc-shaped beam on the base. Therefore, the changes in resistance value caused by temperature changes are also the same, and since they are adjacent to each other in the bridge, they do not produce output voltage of the bridge, so that the influence of temperature effect is eliminated.

[0060] The arc-shaped beam 13 is connected to the bottom wall of the connecting cylinder 4 through a plurality of circumferentially uniformly distributed connecting columns 12. There are gap spaces between the connecting cylinder 4 and the uncut mounting block, and between the connecting cylinder 4 and the arc-shaped beam 13, and the height of the gap space is the height of the connecting column 12.

[0061] The mounting block and the outer side wall of the connecting cylinder 4 are connected through a plurality of circumferentially uniformly distributed reinforcing ribs 10, so as not to affect the lateral stiffness and structural strength of the device as a whole, and the reinforcing ribs 10 ensure that the connecting cylinder 4 is firmly connected to the base 1.

[0062] The lateral stiffness k of the squirrel-cage elastic support is nEb 2 h 2 / l 3 , n is the number of elastic strips 2, E is the elastic modulus of the material, b is the width of the elastic strip 2, h is the thickness of the elastic strip 2, and l is the length of the elastic strip 2. Thus, the lateral stiffness of the device as a whole is mainly determined by the structural dimensions of the elastic strip 2.

[0063] The number of reinforcing ribs 10, connecting columns 12 and bosses 11 is the same, the reinforcing ribs 10 and the connecting columns 12 are circumferentially uniformly distributed, and the reinforcing ribs 10, the connecting columns 12 and the bosses 11 are in a staggered distribution state.

[0064] In particular, compared with the method of machining the force ring unit on the squirrel-cage elastic support connecting cylinder, the integrated squirrel-cage elastic support with segmented arc-shaped beam on the base machines the segmented arc-shaped beam to measure the axial force. The base and the connecting cylinder are connected through the connecting columns in the middle of the arc-shaped beam and the reinforcing ribs on the uncut mounting block, which greatly enhances the rigidity between the base and the connecting cylinder.

[0065] The rigidity between the base 1 and the connecting cylinder 4 increases as the number of arc beams 13 and mounting blocks decreases. The fewer the number of arc beams and uncut mounting blocks, the stronger the rigidity between the base and the connecting cylinder. This ensures that the arc beam force measuring unit for measuring axial force will not affect the linearity of the lateral stiffness of the squirrel cage elastic support due to the way force measuring rings are machined between the connecting cylinders and on the connecting cylinder of the squirrel cage elastic support. This ensures that the lateral stiffness linearity of the integrated squirrel cage elastic support with segmented arc beams on the base is very good (almost 1).

[0066] The mounting block has several protrusions 11 evenly distributed around its bottom surface, and each end of the arc-shaped beam 13 is connected to a protrusion 11. An arc-shaped groove is cut at the intersection of the mounting block and the arc-shaped beam 13, and the two sides of the arc-shaped groove stop at the protrusion 11, so that the position where the arc-shaped beam 13 and the protrusion 11 meet can undergo large deformation under the action of the rotor axial force.

[0067] Meanwhile, complete mounting holes can be retained on the uncut mounting block, making it easy to use bolts to fix the base 1 of the integrated squirrel cage elastic support with segmented arc beams to the mounting base.

[0068] Strain gauges are sequentially installed at the junction of the bottom surface of the arc-shaped beam 13 and the boss 11, as well as at the center of the bottom surface of the arc-shaped beam 13. The first strain gauge 50, the second strain gauge 51, the third strain gauge 52, and the fourth strain gauge 53 are attached to the center of the bottom surface of the arc-shaped beam 13, opposite the connecting column 12, to measure the tensile / compressive strain of the arc-shaped beam 13 under the axial force of the rotor. The fifth strain gauge 54, the sixth strain gauge 55, the seventh strain gauge 56, and the eighth strain gauge 57 are attached to the junction of the bottom surface of the arc-shaped beam 13 and the boss 11 to measure the compressive / tensile strain of the arc-shaped beam 13 under the axial force of the rotor.

[0069] like Figure 10 As shown, eight strain gauges measuring tensile and compressive strain are connected in pairs to form a full-bridge output. The binding hole 6 is located on the arc-shaped beam 13 between the boss 11 and the connecting column 12. The four test leads output from the eight strain gauges are fixed to the arc-shaped beam 13 through the binding hole 6. The resistance of a single strain gauge is 120Ω, and the resistance between any two pairs of the four output test leads is either 180Ω or 240Ω. When the resistance between any two pairs of the four output test leads is 180Ω, the corresponding... Figure 10 Between AB, BC, CD, and DA; when the resistance between any two of the four output test leads is 240Ω, the corresponding... Figure 10 Between AC and BD in the equation.

[0070] Figures 1 to 3 This is a schematic diagram of the first form of the integrated squirrel cage elastic support of the present invention. Figures 4 to 6 This is a schematic diagram of the second type of integrated squirrel cage elastic support of the present invention. Figures 7 to 9The third form of the integrated squirrel-cage elastic support of the application is shown in the structural schematic diagram, wherein the second form is different from the first form in the arrangement of the strain gauges, the number of the reinforcing ribs, the mounting blocks and the arc-shaped beams, and the third form is different from the first form in the number of the bosses and the connecting columns, the arrangement of the strain gauges, the number of the mounting blocks and the arc-shaped beams.

[0071] The integrated squirrel-cage elastic support of the above base with segmented arc-shaped beams is only an example of the structure, which illustrates the specific design and implementation process of the application, and is not limited to the specific structures of the elastic strips, the arc-shaped beam force measuring unit, the base, the uncut mounting blocks, the reinforcing ribs, the connecting columns and the positions of the strain gauges. The positions of the strain gauges on the roots of the bosses of the arc-shaped beams can be changed, and can be attached to adjacent bosses or non-adjacent bosses to form a full-bridge measuring circuit. The number of the arc-shaped beams and the uncut mounting blocks can be 4 or 2. The distribution and number of the bosses on the base, the positions and number of the reinforcing ribs, the number of the connecting columns, and the positions of the gap spaces between the connecting cylinders, the uncut mounting blocks and the arc-shaped beams can be changed. For those skilled in the art, the number, length, width and thickness of the elastic strips, the number of the arc-shaped beams and the uncut mounting blocks, the number and positions of the bosses on the base, the number and positions of the connecting columns, the number and positions of the reinforcing ribs, the positions of the strain gauges, and the full-bridge lead way can be changed.

[0072] Example 2

[0073] The rotor axial force measuring method disclosed in the embodiment comprises the following steps:

[0074] S1. Four test wires are connected to the strain measuring instrument, and the integrated squirrel-cage elastic support in Example 1 is subjected to axial force measurement calibration. The integrated squirrel-cage elastic support in Example 1 is fixed on the calibration platform.

[0075] S2. Equal load intervals of axial load F are applied to the bearing outer ring 3, and the output strain value ε in the strain measuring instrument is recorded. The axial force calibration formula F=kε+b is obtained by linear fitting, wherein k is the conversion coefficient of the axial force in the arc-shaped beam 13 and the output strain, ε is the output strain value in the strain measuring instrument, and b is a constant. The correlation coefficient R 2 >0.99.

[0076] S3. During the operation of the engine, the output strain value ε' of the arc-shaped beam 13 is monitored by the strain measuring instrument, and the conversion coefficient k in step S2 is combined, so that the axial force F' in the working process of the rotor can be obtained in real time.

[0077] When the axial force is 0, the full-bridge output strain value is 0 after the bridge circuit of the strain gauge is balanced and zeroed. When the rotor is subjected to the forward axial force, the first strain gauge 50, the second strain gauge 51, the third strain gauge 52 and the fourth strain gauge 53 measure the tensile strain, the fifth strain gauge 54, the sixth strain gauge 55, the seventh strain gauge 56 and the eighth strain gauge 57 measure the compressive strain, and the full-bridge output of the strain gauges is the positive strain value.

[0078] When the rotor is subjected to the backward axial force, the first strain gauge 50, the second strain gauge 51, the third strain gauge 52 and the fourth strain gauge 53 measure the compressive strain, the fifth strain gauge 54, the sixth strain gauge 55, the seventh strain gauge 56 and the eighth strain gauge 57 measure the tensile strain, and the full-bridge output of the strain gauges is the negative strain value.

[0079] Therefore, the direction of the rotor axial force can be determined by the positive and negative values of the full-bridge output strain.

[0080] Since the two strain gauges on the same bridge arm of the full-bridge are pasted on the center axis symmetrical positions of the arc-shaped beam 13, they both simultaneously sense the tensile / compressive strain under the action of the axial force, so the full-bridge can output the corresponding strain value under the action of the axial force. When the integrated squirrel-cage elastic support with the segmented arc-shaped beam is subjected to the transverse load, one of the two strain gauges on the same bridge arm of the full-bridge senses the tensile strain and the other senses the compressive strain, so the output strain of the full-bridge on the same bridge arm caused by the transverse load is 0, that is, the arc-shaped beam 13 can effectively eliminate the interference of the transverse load when measuring the axial force, and ensure the accuracy of the axial force measurement.

[0081] According to Figure 1 , Figure 4 , Figure 7 and Figure 10 , when the rotor is subjected to the transverse load, the strain directions on the same bridge arm are opposite, and the sensed strains are mutually cancelled out. For example, R50 and R51 on the same bridge arm sense the same strain, which is the compressive strain or the tensile strain when subjected to the axial load, but when subjected to the transverse load, the strain directions sensed by the two are opposite, one is compressed and the other is tensile, and the two are mutually cancelled out, so there is no strain output on the bridge arm affected by the transverse load, and thus the influence of the transverse load can be eliminated. The full-bridge of the strain gauges can also effectively eliminate the adverse effects of the temperature effect of the strain gauges on the axial force measurement, and improve the axial force measurement accuracy of the arc-shaped beam 13. Since the eight strain gauges pasted on the bottom surface of the arc-shaped beam 13 are full-bridge wiring, all the strain gauges are connected to the bridge circuit, the temperature of each strain gauge is always the same, which is the working environment temperature of the integrated squirrel-cage elastic support, so the changes in the resistance values caused by the temperature changes of the strain gauges are also the same, and since they are in the adjacent two arms of the bridge, no output voltage of the bridge is generated, so that the influence of the temperature effect is eliminated.

[0082] The simulation analysis and experimental verification show that the measured lateral stiffness of the integrated squirrel-cage elastic support with the segmented arc-shaped beam of the base is 3.96x10 6 N / m, has similar lateral stiffness characteristics as the squirrel-cage elastic support with the same spring strip structure parameters (the calculated lateral stiffness is 4.05x10 6 N / m), and has the function of adjusting the critical speed of the rotor system, and has high strain-axial force measurement sensitivity due to the segmented arc-shaped beam as the force measuring unit, the axial force calibration coefficient is 1.40 N / με, and can meet the rotor axial force measurement requirements of the integrated squirrel-cage elastic support base with the segmented arc-shaped beam.

[0083] Obviously, the above embodiments are only examples for clearly illustrating, but not limit the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An integrated squirrel-cage elastic support, comprising an integrated connecting cylinder (4) and a bearing outer ring (3), and a plurality of elastic strips (2) connected between the connecting cylinder (4) and the bearing outer ring (3); characterized in that A base (1) is arranged below the connecting cylinder (4); the base (1) comprises a plurality of circumferentially uniformly distributed mounting blocks and a plurality of circumferentially uniformly segmented arc-shaped beams (13), the mounting blocks and the arc-shaped beams (13) are arranged in an interlaced and spaced manner; the arc-shaped beams (13) are connected with the bottom wall of the connecting cylinder (4), and there is a gap space between the top end of the mounting block and the bottom end of the connecting cylinder (4); the mounting block is connected with the outer side wall of the connecting cylinder (4); A force measuring unit is arranged on the bottom surface of the arc-shaped beam (13); the force measuring unit comprises a plurality of strain gauge groups, each strain gauge group comprises two strain gauges which are symmetric about the central axis of the connecting cylinder (4), the two strain gauges in each strain gauge group are connected in series to form a bridge arm, and the bridge arms are connected in series to form a full bridge and lead out test lines; A plurality of bosses (11) are circumferentially and uniformly distributed on the bottom surface of the mounting block, and the two ends of the arc-shaped beam (13) are respectively connected with a boss (11); An arc-shaped groove is cut at the position where the mounting block intersects with the arc-shaped beam (13), and the arc-shaped groove stops at the bosses (11) on both sides, so that the position where the arc-shaped beam (13) and the boss (11) are connected can be deformed under the action of the axial force of the rotor; The two strain gauges on the same bridge arm of the full bridge are adapted to feel opposite strain directions when subjected to a transverse load, and the felt strain cancels each other out; The two strain gauges on the same bridge arm of the full bridge are adapted to feel the same strain direction when subjected to an axial load.

2. The integrated squirrel-cage elastic support according to claim 1, characterized in that, Each of the strain gauges is arranged at the position where the bottom surface of the arc-shaped beam (13) and the boss (11) are connected and at the middle part of the bottom surface of the arc-shaped beam (13) in turn.

3. The integrated squirrel cage elastomeric bearing of claim 1, wherein, The arc-shaped beam (13) and the bottom wall of the connecting cylinder (4) are connected through a plurality of circumferentially uniformly distributed connecting columns (12).

4. The integrated squirrel-cage elastic support according to claim 3, characterized in that, The mounting block and the outer side wall of the connecting cylinder (4) are connected through a plurality of circumferentially uniformly distributed reinforcing ribs (10) so as not to affect the transverse rigidity and structural strength of the device as a whole, and so that the transverse rigidity of the device as a whole is mainly determined by the structural size of the elastic strip (2).

5. The integrated squirrel cage spring of claim 4, wherein, The number of the reinforcing ribs (10), the connecting columns (12) and the bosses (11) is the same, and the reinforcing ribs (10), the connecting columns (12) and the bosses (11) are in an interlaced distribution state.

6. The integrated squirrel cage elastomeric bearing of claim 1, wherein, A binding hole (6) is formed on the arc-shaped beam (13), and the test line is positioned on the arc-shaped beam (13) through the binding hole (6).

7. The integrated squirrel cage elastomeric bearing of claim 1, wherein, The rigidity between the base (1) and the connecting cylinder (4) is enhanced as the number of the arc-shaped beams (13) and the mounting blocks decreases.

8. A method of measuring axial forces on a rotor, characterized by, The method comprises the following steps: S1. Connect each test line to a strain measuring instrument, calibrate the axial force of the integrated squirrel-cage elastic support according to any one of claims 1 to 7, and fix the integrated squirrel-cage elastic support on a calibration platform. S2. Apply equal load interval axial load F on the bearing outer ring (3), record the output strain value ε in the strain gauge, and obtain the axial force calibration formula F=kε+b through linear fitting, k is the conversion coefficient of axial force and output strain in the arc beam (13), b is a constant, and ε is the output strain value in the strain gauge; S3. In the working process of the engine, the output strain value ε' of the arc beam (13) is monitored through the strain gauge, and the conversion coefficient k in step S2 is combined, so that the axial force F' of the rotor in the working process can be obtained in real time, that is, F'=kε'; The positive and negative values of the output strain of the strain gauge full bridge are used to judge the direction of the axial force of the rotor.

9. The rotor axial force measurement method of claim 8, wherein, In the step S3, when the rotor is subjected to the forward axial force, the strain gauge full bridge outputs the positive strain value, when the rotor is subjected to the backward axial force, the strain gauge full bridge outputs the negative strain value, and then the positive and negative values of the output strain of the strain gauge full bridge are used to judge the direction of the axial force of the rotor.

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