Bearing load testing method and bearing load testing device

Abstract

The application discloses a bearing load testing method and a bearing load testing device, and comprises the following steps: a simulation stage: a radial load and / or an axial load are loaded on one end of a squirrel cage spring support, a response value of a strain gauge located on the squirrel cage spring support is acquired, a load-strain relationship equation is obtained by substituting the radial load and the response value into a load-strain coefficient matrix; a test stage: a load result is obtained through the load-strain relationship equation according to strain data measured in the test. The bearing load data obtained through the method can effectively avoid the influence of coupling effects among various loads on the test result and reduce the detection error.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and in particular to a bearing load testing method and a bearing load testing device. Background Technology

[0002] Aero engines operate over a wide range of speeds and have numerous operating points. To ensure optimal bearing conditions and prevent slippage under light loads, it is typically necessary to monitor the axial force at the bearing. Traditional methods for monitoring bearing axial force use force rings. However, this method requires pre-allocated space on the device for the force ring. Given the need for compact designs, it is often difficult to provide such space in engines. Modifying the product structure to accommodate the force ring is also costly. Therefore, axial force measurement methods based on force rings are sometimes unusable.

[0003] Currently, there are patented technologies for axial force testing based on squirrel cage spring supports (squirrel cage elastic supports) both domestically and internationally. However, analysis and research on these technologies have revealed that their measurement accuracy is still relatively low and needs further improvement.

[0004] Currently, Chinese patent application CN111238711A discloses a method for mechanical analysis of a mouse cage spring. However, as... Figure 1 As shown, the squirrel cage spring support 1' bears the axial load F transmitted from the outer ring 2' of the bearing. A and radial load F r Among them, the axial load F A The equivalent axial load F borne by each cage bar 11' in the squirrel cage spring support 1' is... Ai and bending moment M Ai F on each cage bar 11' Ai They are equal in size and have the same direction. And as... Figure 2 As shown: M on each cage bar 11' Ai They are of equal size but different orientations. The cross-sections and stress relationships of each 11' cage bar are as follows: Figure 3 As shown, because the radius R2 of the outer circle of the cage bar 11' is different from the radius R1 of the inner circle, the bending moment M Ai Under the influence of the force, the strain magnitude at the midpoint A of the outer circular surface of the cage bar 11' differs from the strain magnitude at the midpoint B of the inner circular surface. Therefore, averaging the measured strain at the midpoints A and B of the outer and inner circular surfaces cannot eliminate the bending moment M. Ai For axial force F A Due to the influence of measurement, the measurement method disclosed in Chinese patent application number CN111238711A has certain deviations.

[0005] In addition to the axial load F analyzed above AThe squirrel cage spring support 1' also bears the radial load F transmitted from the outer ring 2' of the bearing. r The force distribution is as follows: Figure 4 As shown: Radial load F r Equivalent to the radial load F on each cage bar 11' ri The bending moment M shared by all cage bars 11' r Among them, bending moment M r The stress field distribution is simple, and the bending moment M can be eliminated by summing the strains of the two cage bars 11' at 180 degrees to each other on the circumference of the squirrel cage spring support 1'. r The effect on axial force measurement. However, the radial load F ri The effects are quite complex. The radial load F on each cage bar 11' is... ri They are in the same direction but different sizes. Therefore, cage bars 11' under radial load F ri Under the influence of the radial force and the deformation restriction at the ends, a complex strain field will be generated on the cage bar 11'. Although the stress field of the cage bar 11' has a certain stress distribution law, for example, the stress is smaller near the middle section of the cage bar 11', while the strain increases rapidly away from the middle section, the radial force inevitably affects the measurement of the axial force. That is, the coupling effect between loads affects the load measurement. If this effect is not considered, it will inevitably cause a large error in the measurement of the axial force. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defect of large measurement error in the existing bearing load testing methods, and to provide a bearing load testing method and bearing load testing device.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] A bearing load testing method, the testing method comprising the following steps:

[0009] Simulation phase: Apply radial and / or axial loads to one end of the squirrel cage spring support, obtain the response values ​​of the strain gauges located on the squirrel cage spring support, and substitute the radial load and the response values ​​into the coefficient matrix from load to strain to obtain the equation relating load and strain.

[0010] Experimental phase: Based on the strain data measured in the experiment, the load result is obtained through the relationship equation between load and strain.

[0011] This bearing load testing method applies a radial or axial load to one end of the squirrel cage spring during the simulation stage before using the squirrel cage spring to test the radial and axial forces of the bearing. By substituting the load and the response value measured on the squirrel cage spring into the coefficient matrix from load to strain, the radial and axial forces of the bearing are calculated based on the relationship equation between load and strain. The bearing axial force and other data obtained in this way can effectively avoid the influence of radial force on the axial force test results and reduce the detection error.

[0012] Preferably, a preparation stage is included before the simulation stage: establishing a coordinate system composed of the X-axis, Y-axis and Z-axis, setting the axis of the squirrel cage spring as the X-axis, and setting the radial plane of the squirrel cage spring as the YZ plane composed of the Y-axis and Z-axis.

[0013] Preferably, in the simulation phase, applying a radial load to one end of the squirrel cage spring support and obtaining the response values ​​of the strain gauges located on the squirrel cage spring support includes:

[0014] A force along the X-axis is applied to the squirrel cage spring support, and the response value of the strain gauge is measured.

[0015] A force along the Y-axis is applied to the squirrel cage spring support, and the response value of the strain gauge is measured.

[0016] A force along the Z-axis is applied to the squirrel cage spring support, and the response value of the strain gauge is measured.

[0017] During the simulation phase, loads are applied to the squirrel cage spring support along the relatively perpendicular X, Y, and Z directions to obtain the corresponding strain gauge response values. This is to improve the accuracy of the calculated load-strain relationship equation by acquiring more data.

[0018] The radial force Fr is decomposed into Fy and Fz, plus the axial force Fx, resulting in a total of 3 unknowns. Therefore, the number of strain gauges should be greater than or equal to 3.

[0019] Preferably, the number of strain gauges on the squirrel cage spring support is four, and in the simulation stage, the coefficient matrix from load to strain is [k], and the formula for solving [k] is:

[0020]

[0021] In the formula: F x0 ε is the force applied to the squirrel cage spring along the X-axis direction. x1 ε x2 ε x3 ε x4 The four strain gauges are under load F x0 The response value at time F y0ε is the force applied to the squirrel cage spring along the Y-axis. y1 ε y2 ε y3 ε y4 The four strain gauges are under load F y0 The response value at time F z0 ε is the force applied to the squirrel cage spring along the Z-axis direction. z1 ε z2 ε z3 ε z4 The four strain gauges are under load F z0 The response value at that time.

[0022] Preferably, when the mounting flange of the squirrel cage spring support is thick (highly rigid) and the spring support fixing bolts are evenly distributed around the circumference, it is possible to choose not to apply an axial force F. x0 Without applying an axial force, [k] is:

[0023]

[0024] In the formula: E is the elastic modulus of the rat cage spring support, and S is the total cross-sectional area of ​​all the cage bars of the rat cage spring support.

[0025] The above method provides a preferred coefficient matrix.

[0026] Preferably, during the test phase, the load results include axial force and radial force.

[0027] A bearing load testing device is provided for use in the bearing load testing method described above. The bearing load testing device includes a squirrel cage spring support, a strain gauge, and a strain measurement system. The squirrel cage spring support includes a plurality of cage bars arranged circumferentially around the squirrel cage spring support. The strain gauge is electrically connected to the strain measurement system. The strain gauge is disposed in the middle layer of the cage bars and is arranged along the axial direction of the squirrel cage spring support. The midpoint of the strain gauge is located on the mid-section of the cage bar in the length direction.

[0028] This bearing load testing device sets strain at the middle position (on the mid-section) of the middle layer of the cage bar to minimize the difference in strain measured by strain gauges at different positions of the cage bar due to bending moment and radial load. This allows the strain gauges to measure relatively accurate strain data, thereby obtaining more accurate load data.

[0029] Preferably, the strain gauge is electrically connected to the strain measurement system in a quarter-bridge configuration.

[0030] The above structural design can reduce the error caused by the measurement of corresponding variables in the measurement system.

[0031] Preferably, the angle between the cage bars containing two of the strain gauges and the circumference of the cage spring is 90 degrees.

[0032] The above structural design can reduce the error caused by the strain gauge placement position in strain measurement.

[0033] Preferably, the number of strain gauges is four, and the four strain gauges are evenly distributed around the circumference of the squirrel cage spring.

[0034] The above-mentioned structural design, by uniformly distributing strain gauges, enables these strain gauges to more comprehensively reflect the overall strain of the squirrel cage spring support.

[0035] Preferably, the bearing load testing device further includes a temperature compensation plate, which, together with the strain gauge, forms an adjacent half-bridge and is electrically connected to the strain measurement system.

[0036] The above-described structural design directly compensates for the strain measurement system by setting a temperature compensation plate, thus achieving the purpose of temperature compensation through a relatively simple structural design.

[0037] Preferably, the temperature compensation plate is disposed on the cage bar, the cage bar where the temperature compensation plate is located is adjacent to the cage bar where the strain gauge is located, and the position of the temperature compensation plate on the cage bar is the same as the position of the strain gauge on the cage bar.

[0038] The above structural setup, by placing the temperature compensation element at a position corresponding to the strain gauge, ensures that the temperature compensation data measured by the temperature compensation element matches the strain variable data measured by the strain gauge as closely as possible, avoiding data errors caused by mismatched placement.

[0039] Preferably, the bearing load testing device further includes a spacer, the temperature compensation piece is attached to the outside of the spacer, the spacer is attached to the cage bar by a heat-transferring but force-transferring connection, and the spacer is made of the same material as the squirrel cage spring support.

[0040] The above structural design, while obtaining temperature data through the temperature compensation plate, completely avoids the influence of stress data on the measurement results of the temperature compensation plate.

[0041] Preferably, the spacer is attached to the cage bars by means of an adhesive layer.

[0042] The above structural design provides a relatively better connection method, enabling the spacer to be connected to the cage bars in a way that transfers heat but not force.

[0043] Preferably, the temperature compensation sheet is attached to the connecting rib between adjacent cage bars.

[0044] The positive and progressive effects of this invention are as follows:

[0045] This bearing load testing method and apparatus, before using a squirrel cage spring to detect the radial and axial forces of the bearing, applies radial and axial loads to one end of the squirrel cage spring during the simulation stage. By substituting the radial load and the response value measured on the squirrel cage spring into the coefficient matrix from load to strain, the axial and radial forces of the bearing are calculated based on the relationship equation between load and strain. The bearing load data obtained in this way can effectively avoid the influence of the coupling effect between various loads on the test results and reduce the detection error. Attached Figure Description

[0046] Figure 1 A schematic diagram of the force relationship of the rat cage spring support (I).

[0047] Figure 2 Schematic diagram of the force relationship of the rat cage spring support (II).

[0048] Figure 3 This is a schematic diagram of the cross-sectional structure of the cage bars of a rat cage spring support.

[0049] Figure 4 Schematic diagram of the force relationship of the rat cage spring support (III).

[0050] Figure 5 This is a perspective sectional view of the mouse cage spring support according to an embodiment of the present invention.

[0051] Figure 6 This is a schematic flowchart of a bearing load testing method according to an embodiment of the present invention.

[0052] Figure 7 This is a schematic diagram showing the layout of strain gauges on a squirrel cage spring support according to an embodiment of the present invention.

[0053] Figure 8 This is a schematic diagram showing the layout of the strain gauges and temperature compensation gauges on the squirrel cage spring support according to an embodiment of the present invention.

[0054] Figure 9 for Figure 8 A magnified view of part E in the middle.

[0055] Figure 10 for Figure 8 A magnified view of part F in the middle.

[0056] Figure 11 This is a schematic diagram of the specific process of the bearing load testing method in the simulation stage according to an embodiment of the present invention.

[0057] Figure 12 This is a schematic diagram of the measurement deviation of each algorithm in an embodiment of the present invention.

[0058] Figure 13 for Figure 8 A partial sectional view of section G in the middle.

[0059] Explanation of reference numerals in the attached figures:

[0060] Existing technology

[0061] Mouse cage spring 1'

[0062] Cage bar 11'

[0063] Bearing outer ring 2'

[0064] This invention

[0065] Mouse cage spring 1

[0066] Cage bars 11

[0067] Install flange 2

[0068] Cylindrical surface 3, boss 3a

[0069] Strain gauge 4

[0070] Temperature compensation plate 5

[0071] Spacer 6 Detailed Implementation

[0072] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0073] Example 1

[0074] This invention provides a bearing load testing method, which measures and calculates the axial and radial forces of the bearing using a squirrel cage spring support 1. The structure of the squirrel cage spring support 1 used in this bearing load testing method is as follows:

[0075] like Figure 5 As shown, it is a three-dimensional sectional view of the squirrel cage spring support 1. The cage bars 11 of the squirrel cage spring support 1 are arranged around the perimeter. The outer end face of the squirrel cage spring support 1 on one side is the mounting flange edge, while the inner end face of the squirrel cage spring support 1 on the other side is a cylindrical surface for mounting the outer ring of the bearing. The surface of the cylindrical surface is provided with a boss for positioning the outer ring of the bearing.

[0076] like Figure 6 As shown, the bearing load testing method includes two stages: a simulation stage and a test stage. In the simulation stage: a radial load is applied to one end of the squirrel cage spring support 1, and the response value of the strain gauge 4 located on the squirrel cage spring support 1 is obtained. Based on the radial load and the response value, the coefficient matrix from load to strain is substituted to obtain the equation relating load and strain.

[0077] During the experimental phase: based on the strain data measured in the experiment, the load result is obtained through the relationship equation between load and strain.

[0078] This bearing load testing method applies a radial load to one end of the squirrel cage spring support 1 during the simulation stage before using the squirrel cage spring support 1 to detect the axial force of the bearing. The radial load and the response value measured on the squirrel cage spring support 1 are substituted into the coefficient matrix from load to strain to calculate the axial force of the bearing based on the relationship equation between load and strain. The bearing axial force and other data obtained in this way can effectively avoid the influence of other influencing factors on the test results and reduce the detection error.

[0079] Specifically, this embodiment provides a detailed process for implementing the simulation phase in a bearing load testing method:

[0080] First, an XYZ three-axis coordinate system is established on the squirrel cage spring support 1, and the placement position and measurement direction of the strain gauge 4 attached to the cage bars 11 are determined. In this embodiment, the placement position of the strain gauge 4 on the cage bars 11 of the squirrel cage spring support 1 is as follows: Figure 7 There are four strain gauges in total, numbered A, B, C, and D. Strain gauges A and B are at a 90° angle to each other in the circumferential direction, A and C are at a 180° angle to each other in the circumferential direction, and B and D are at a 180° angle to each other in the circumferential direction. For example... Figures 8-10 As shown, 11a is the intermediate layer between the inner and outer cylindrical surfaces of the cage bar 11, 11b is the mid-section along the length of the cage bar 11, and 11c is the starting and ending surfaces of the strain gauge 4. Figure 9 and Figure 10 As can be seen, the starting and ending surfaces of strain gauge 4 are symmetrical about the mid-section of cage bar 11, meaning the midpoint of strain gauge 4 lies on mid-section 11b, and the strain measurement direction is axial. Figure 8 In the X direction, each strain gauge 4 is connected to the strain measurement system via a quarter bridge.

[0081] After that, as Figure 11 As shown, the mounting flange of the fixed squirrel cage spring support is thick and rigid. Therefore, with the fixing bolts evenly distributed on the mounting flange, it is not necessary to apply an axial force to the squirrel cage spring support. Instead, the bearing load is simulated by applying a force F in the Y direction on the bearing mounting cylindrical surface. y0 The response values ​​of the four strain gauges 4 (A, B, C, and D) are measured, and these are respectively ε. y1 ε y2 ε y3 ε y4 Uninstalling F y0 Then, a bearing load force F in the Z direction is simulated on the bearing mounting cylindrical surface. z0 Then measure the response values ​​of the four strain gauges 4, which are ε.z1 ε z2 ε z3 ε z4 Let the elastic modulus of the cage spring support 1 be E, and the total area at the cross-section of all cage bars 11 be S. The coefficient matrix [k] from load to strain can be obtained as follows:

[0082]

[0083] The calibration is completed after the coefficient matrix [k].

[0084] Of course, in other embodiments, an axial load can also be applied to the squirrel cage spring support, and the applied axial load is F. x0 The measured response values ​​of the four strain gauges 4 were ε x1 ε x2 ε x3 ε x4 Then, the coefficient matrix [k] from load to strain can be obtained:

[0085]

[0086] The coefficient matrix [k] is calculated using the above method, and then the relationship equation between strain and load is obtained. In this embodiment, whether the Y-axis load is applied to the squirrel cage spring support 1 first or first does not affect the accuracy of the measured data. Similarly, in other embodiments, whether the X-axis load is applied to the squirrel cage spring support 1 first or last does not affect the accuracy of the measured data. Therefore, the order of load application can be determined based on the actual experimental conditions.

[0087] After obtaining the equation relating load and strain, the experimental phase of the bearing load testing method includes the following specific steps:

[0088] The aforementioned squirrel cage spring support 1 was used in a bearing test. The data ε1, ε2, ε3, and ε4 measured from four strain gauges 4, and the two components Fy and Fz of the axial force Fx and radial force Fr to be determined, are used to establish the relationship between strain and load as follows:

[0089]

[0090] Based on the above relationships, the formulas for calculating axial and radial forces are as follows:

[0091]

[0092] There are three unknowns, so theoretically, they can be solved using three equations. In this embodiment, by setting four strain gauges 4 to obtain the strain at four different locations, the accuracy of the results can be improved.

[0093] Example 2

[0094] This embodiment also provides a bearing load testing method, the process of which is largely the same as the bearing load testing method provided in Embodiment 1. The difference lies in that, in this embodiment, during the experimental stage of the bearing load testing method, the calculation formulas for the axial force and radial force are one of the following four:

[0095] Formula 2: Based on three measured strain data ε1, ε2, ε3 (corresponding to strain gauges A, B, and C);

[0096]

[0097] Formula 3: Based on the three measured strain data ε1, ε2, ε4 (corresponding to strain gauges A, B, and D);

[0098]

[0099] Formula 4: Based on the three measured strain data ε1, ε3, ε4 (corresponding to strain gauges A, C, and D);

[0100]

[0101] Formula 5: Based on the three measured strain data ε2, ε3, ε4 (corresponding to strain gauges B, C, and D);

[0102]

[0103] In fact, formulas 2, 3, 4 and 5 above only require attaching three strain gauges 4 to the squirrel cage spring support 1 to measure the axial force and radial force.

[0104] The data processing and calculation methods corresponding to Formula 1 in Example 1, and Formulas 2, 3, 4, and 5 in Example 2 are applied. The deviations of the measured values ​​from the theoretical values ​​under these five algorithms are as follows: Figure 12 As shown, where, Figure 12 The “four-point algorithm 1234” indicated in the text refers to the result calculated from the data ε1, ε2, ε3, and ε4 of four strain gauges, while the “three-point algorithm 123” refers to the result calculated from the data ε1, ε2, and ε3 of three strain gauges, and so on.

[0105] from Figure 12 It can be seen that the measurement accuracy of the data obtained by each calculation method is within 5%, and the measurement accuracy is relatively high.

[0106] Example 3

[0107] This embodiment also provides a bearing load testing method, the process of which is largely the same as the bearing load testing method provided in Embodiment 1. The difference is that, in this embodiment, the bearing load testing device used in the bearing load testing method further includes a temperature compensation plate 5. The temperature compensation plate 5 and the strain gauge 4 form an adjacent half-bridge and are electrically connected to the strain measurement system. This structural arrangement directly compensates the strain measurement system by setting the temperature compensation plate 5, achieving the purpose of temperature compensation with a relatively simple structural arrangement.

[0108] Among them, such as Figure 8 As shown, in this embodiment, temperature compensation plates 5 are provided at at least two locations on the mouse cage spring support 1. Figure 8 As shown, the temperature compensation piece 5 is attached to the connecting rib between adjacent cage bars 11. The adhesive used for the pasting method is thermally conductive adhesive to achieve the connection between the temperature compensation piece 5 and the cage bar 11. The thermally conductive adhesive connects the temperature compensation piece 5 and the cage bar 11, enabling the cage bar 11 to transfer heat to the temperature compensation piece 5, but it does not transfer strain force.

[0109] In addition, such as Figure 8 As shown, the temperature compensation gauge 5 is also disposed on the cage bar 11. The cage bar 11 where the temperature compensation gauge 5 is located is adjacent to the cage bar 11 where the strain gauge 4 is located, and the position of the temperature compensation gauge 5 on the cage bar 11 is the same as the position of the strain gauge 4 on the cage bar 11. This structural arrangement, by placing the temperature compensation gauge 5 at a position corresponding to the strain gauge 4, makes the temperature compensation data measured by the temperature compensation gauge 5 match the strain data measured by the strain gauge 4 as closely as possible, avoiding data errors caused by mismatched placement positions.

[0110] In addition, such as Figure 13 As shown, in this embodiment, the connection scheme between the temperature compensation piece 5 and the surface of the cage spring support 1 is as follows: a spacer 6 is provided between the temperature compensation piece 5 and the surface of the cage spring support 1. The temperature compensation piece 5 is attached to the outside of the spacer 6 with thermally conductive adhesive, and the spacer 6 is attached to the cage bar 11 with thermally conductive adhesive. The spacer 6 and the cage spring support 1 are made of the same material. With this structural arrangement, the spacer 6 is made of the same material as the cage spring support 1, avoiding errors caused by material differences when temperature is transferred from the cage spring support 1 to the spacer 6. Simultaneously, the spacer 6 is bonded to the cage spring support 1 and to the temperature compensation piece 5 with thermally conductive adhesive, thus avoiding stress transmission while ensuring effective heat transfer. In other embodiments, the spacer 6 can be bonded only to the cage spring support 1 using an adhesive method to prevent the force of the cage spring support 1 from being transmitted to the spacer 6.

[0111] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A bearing load testing method, characterized in that, The test method includes the following steps: Simulation stage: Apply radial load and / or axial load to one end of the squirrel cage spring support, obtain the response value of the strain gauge located on the squirrel cage spring support, and substitute the radial load and the response value into the coefficient matrix from load to strain to obtain the relationship equation between load and strain. Experimental phase: Based on the strain data measured in the experiment, the load result is obtained through the relationship equation between load and strain; Before the simulation stage, there is also a preparation stage: establishing a coordinate system composed of the X-axis, Y-axis and Z-axis, setting the axis of the squirrel cage spring as the X-axis, and setting the radial plane of the squirrel cage spring as the YZ plane composed of the Y-axis and Z-axis; During the simulation phase, a radial load is applied to one end of the squirrel cage spring support, and the response values ​​of the strain gauges located on the squirrel cage spring support are obtained, including: A force along the Y-axis is applied to the squirrel cage spring support, and the response value of the strain gauge is measured. A force along the Z-axis is applied to the squirrel cage spring support, and the response value of the strain gauge is measured. The number of strain gauges on the squirrel cage spring support is four. In the simulation stage, the coefficient matrix from load to strain is [k], and the formula for solving [k] is: In the formula: Fx0 is the force applied to the squirrel cage spring along the X-axis direction, ε x1 ε x2 ε x3 ε x4 These are the response values ​​of the four strain gauges under load Fx0, where Fy0 is the force applied to the squirrel cage spring along the Y-axis, and ε y1 ε y2 ε y3 ε y4 These are the response values ​​of the four strain gauges under load Fy0, where Fz0 is the force applied to the squirrel cage spring along the Z-axis, and ε z1 ε z2 ε z3 ε z4 These are the response values ​​of the four strain gauges when Fz0 is applied.

2. The bearing load testing method as described in claim 1, characterized in that, During the test phase, the load results include axial force and radial force.

3. A bearing load testing device, characterized in that, It is applied in the bearing load testing method as described in any one of claims 1-2, wherein the bearing load testing device includes: a squirrel cage spring support, a strain gauge and a strain measurement system, the squirrel cage spring support includes a plurality of cage bars, the plurality of cage bars are arranged around the circumference of the squirrel cage spring support, the strain gauge is electrically connected to the strain measurement system, the strain gauge is disposed on the middle layer of the cage bar, and the strain gauge is arranged along the axial direction of the squirrel cage spring support, and the midpoint of the strain gauge is located on the mid-section of the cage bar in the length direction; The bearing load testing device also includes a temperature compensation plate, which, together with the strain gauge, forms an adjacent half-bridge and is electrically connected to the strain measurement system. The temperature compensation plate is disposed on the cage bar, the cage bar where the temperature compensation plate is located is adjacent to the cage bar where the strain gauge is located, and the position of the temperature compensation plate on the cage bar is the same as the position of the strain gauge on the cage bar. The temperature compensation plate is attached to the connecting rib between adjacent cage bars.

4. The bearing load testing device as described in claim 3, characterized in that, The strain gauge is electrically connected to the strain measurement system using a quarter-bridge configuration.

5. The bearing load testing device as described in claim 3, characterized in that, The angle between the cage bars containing two of the strain gauges and the circumference of the rat cage spring is 90 degrees.

6. The bearing load testing device as described in claim 3, characterized in that, The number of strain gauges is four, and the four strain gauges are evenly distributed around the circumference of the squirrel cage spring.

7. The bearing load testing device as described in claim 3, characterized in that, The bearing load testing device also includes a spacer, and the temperature compensation piece is attached to the outside of the spacer. The spacer is attached to the cage bar through a heat-transferring but force-transferring connection method. The spacer is made of the same material as the squirrel cage spring support.

8. The bearing load testing device as described in claim 7, characterized in that, The spacer is attached to the cage bars by means of an adhesive layer.

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