Bearing rigidity indirect measurement method and system based on system error compensation

Abstract

The invention discloses a bearing rigidity indirect measurement method and system based on system error compensation, and the method comprises the following steps: installing a standard sample block in a test system, applying an axial load, measuring a first deformation amount of the standard sample block under each stage of load, and recording the first deformation amount as a system deformation amount; installing a measured bearing, applying axial loads of all levels which are the same as the axial loads of the step S1, measuring a second deformation amount of the measured bearing, and recording the second deformation amount as a total deformation amount; according to the obtained total deformation amount and the system deformation amount, calculating the real deformation amount of the measured bearing under each level of load; and determining a load-deformation function relationship based on a corresponding relationship between each stage of axial load and the real deformation amount, and obtaining the rigidity of the measured bearing. Compared with the prior art, the standard sample block is introduced for comparison testing, a system error compensation mechanism is innovatively provided, errors caused by self deformation of a testing system can be accurately eliminated, the real deformation amount of the bearing is obtained, the rigidity measurement precision is greatly improved, and the method is particularly suitable for accurate calibration of the high-rigidity bearing.

Description

Technical Field

[0001] This invention relates to the field of bearing performance testing technology, specifically to an indirect method and system for measuring bearing stiffness based on system error compensation. Background Technology

[0002] As is well known, the axial stiffness of precision bearings such as rotary table bearings and machine tool spindle bearings is a key parameter affecting the rotational accuracy, dynamic performance, and reliability of the entire equipment. Currently, bearing stiffness is typically measured by directly loading and measuring its deformation. However, the deformation measured by dial indicators or displacement sensors includes not only the bearing's own elastic deformation but also the deformation of the entire testing system, including the test bench and loading screws, under load (i.e., systematic error). For high-stiffness bearings, this systematic error can be on the same scale as the bearing's own deformation, causing the measurement results to deviate significantly from the true value, resulting in low measurement accuracy and failing to provide reliable data support for the design and fault diagnosis of precision equipment. Furthermore, existing technologies lack effective, economical, and easily implemented solutions to eliminate this systematic error. Therefore, the industry urgently needs a method that can achieve high-precision, low-cost measurement of bearing stiffness. Summary of the Invention

[0003] The purpose of this invention is to provide an indirect measurement method and system for bearing stiffness based on systematic error compensation, which aims to solve the technical problem in existing bearing stiffness measurement methods that result in low measurement accuracy and inability to truly reflect the stiffness characteristics of the bearing itself due to the inability to eliminate the deformation (systematic error) of the test system itself. In particular, this invention solves the problem of measurement inaccuracy caused by an excessive proportion of systematic error in the axial stiffness test of high-stiffness turntable bearings.

[0004] The technical solution adopted in this invention is: an indirect method for measuring bearing stiffness based on system error compensation, comprising the following steps: S1. Install the standard sample block on the test system, apply axial load and measure the first deformation of the standard sample block under each load level, which is recorded as the system deformation. S2. Install the bearing under test on the test system, apply the same axial loads as in step S1, and measure the second deformation of the bearing under test under each load, which is recorded as the total deformation. S3. Based on the obtained total deformation and system deformation, calculate the actual deformation of the tested bearing under each load level. The actual deformation is the difference between the total deformation and the system deformation. S4. Based on the correspondence between the axial loads at each level and the actual deformation, determine the load-deformation function relationship and obtain the stiffness of the tested bearing.

[0005] As a preferred embodiment, in step S1, the stiffness of the standard sample block is greater than that of the bearing under test, and the shape and installation connection dimensions of the standard sample block are consistent with the corresponding dimensions of the bearing under test.

[0006] As a preferred option, the standard sample block is made of high-strength alloy steel.

[0007] As a preferred embodiment, in step S4, determining the load-deformation function relationship specifically involves: Curve fitting is performed on the data sets of the axial loads at each level and the actual deformation to obtain the fitting equation.

[0008] As a preferred option, the curve fitting uses a nonlinear function model.

[0009] As a preferred embodiment, the nonlinear function model is a power function model.

[0010] As a preferred embodiment, the bearing under test is a turntable bearing.

[0011] This solution also includes a bearing stiffness testing system for implementing the method described above, comprising: a rigid testing platform, which serves as the load-bearing base for the entire testing system; The standard sample block has the same shape and size as the corresponding size of the bearing being tested; A loading device, installed on the rigid test platform, is used to apply different axial loads to the standard sample block or the bearing under test. A displacement measuring device, mounted on the rigid test platform, is used to measure the deformation of a standard sample block or the bearing under test under various load levels. The data processing unit is used to acquire data from the displacement measuring device and calculate the stiffness value of the bearing under test.

[0012] As a preferred embodiment, the loading device includes a loading rod and weights mounted on the loading rod. The loading rod is connected to a standard sample block or the bearing under test via a locking element, and different axial loads are applied by adjusting different weights.

[0013] As a preferred embodiment, the displacement measuring device includes a magnetic frame fixed on a rigid test platform and a dial indicator mounted on the magnetic frame.

[0014] The beneficial effects of this invention are: This invention provides an indirect method for measuring bearing stiffness based on systematic error compensation. By comparing tests and data fitting, the axial stiffness of the bearing can be obtained with high precision, achieving the following technical effects: Firstly, it has high measurement accuracy: by introducing standard sample blocks for comparative testing, an innovative system error compensation mechanism is proposed, which can accurately eliminate the error caused by the deformation of the test system itself, thereby obtaining the true deformation of the bearing, which greatly improves the accuracy of stiffness measurement, and is especially suitable for the precise calibration of high stiffness bearings.

[0015] Secondly, the method has strong universality: the principle of the method described in this invention is clear and does not rely on an extremely expensive high-rigidity testing platform. By introducing a "sample calibration" step into an ordinary testing system, high-precision measurement can be achieved, which lowers the threshold for high-precision testing and has high engineering application value and universality.

[0016] Thirdly, the results are highly reliable: by fitting data based on the actual deformation and obtaining the stiffness by differentiating the fitted equation, the nonlinear characteristics of bearing stiffness as a function of load can be accurately reflected. The obtained stiffness value is more consistent with the actual mechanical behavior of the bearing, providing more reliable data input for the design and simulation of precision equipment.

[0017] Fourth, this solution also includes an indirect bearing stiffness measurement system based on system error compensation. The test system mainly consists of a test platform, a standard sample block, a loading device, and a displacement measuring device. Its structure is simple, the standard sample block is inexpensive to manufacture, and the absolute accuracy requirements of the displacement measuring device are relatively relaxed because it focuses more on the relative difference between two measurements, making the solution easy to implement and promote. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the bearing stiffness testing system; Figure 2 This is a flowchart of the bearing stiffness testing method; Figure 3 This is a schematic diagram of the standard sample block; Figure 4 This is a structural schematic diagram of the YRT turntable bearing; Figure 5 This is a diagram showing the comparison of deformation amounts; Figure 6 It is the load-actual deformation curve; Figure 7 This is a graph showing the change in bearing stiffness versus load.

[0020] Reference numerals in the attached figures: 1. Test frame, 2. Bearing under test, 3. Standard sample block, 4. Loading rod, 5. Weight, 6. Magnetic frame, 7. Dial indicator. Detailed Implementation

[0021] The present invention will now be described in detail through exemplary embodiments and in conjunction with the accompanying drawings.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains; the words "a," "an," or "the" and similar terms used in the patent application specification and claims of this invention do not express a quantity limitation, but rather indicate the presence of at least one; the words "comprising" or "including" and similar terms indicate that the elements or objects preceding "comprising" or "including" cover the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function; A bearing stiffness indirect measurement system based on system error compensation mainly consists of a test frame 1, a bearing under test 2, a standard sample block 3, a loading rod 4, weights 5, a magnetic frame 6, and a dial indicator 7. The test frame 1 serves as a rigid test platform supporting the entire system. The standard sample block 3 has the same shape and dimensions as the bearing under test 2. The loading rod 4 and weights 5 constitute a loading device for applying different axial loads to the standard sample block or the bearing under test. The magnetic frame 6 and dial indicator 7 constitute a displacement measuring device for measuring the deformation of the standard sample block or the bearing under test under various load levels. The system also includes a data processing unit for acquiring data from the displacement measuring device and calculating the stiffness value of the bearing under test. In this system, the loading rod 4 is connected to the standard sample block or the bearing under test via a locking device, and the weights 5 are mounted on the loading rod 4. Different axial loads are applied by adjusting different weights.

[0023] In this system, the dial indicator 7 is mounted on the test frame 1 via a magnetic frame 6, and the measuring position of the dial indicator can be adjusted via the magnetic frame.

[0024] An indirect method for measuring bearing stiffness based on system error compensation includes the following steps: Step 1: System Error Calibration Steps: Install the standard sample block into the measurement system described above, apply an axial load, and measure the first deformation of the standard sample block under each load level, denoted as the system deformation δ. system ; Step 2: Total Deformation Measurement: Remove the standard sample block, install the bearing to be tested into the measurement system, apply the same axial loads as in the previous step, and measure the second deformation of the bearing under each load level. This deformation is recorded as the total deformation δ. total ; Step 3: Calculation of Actual Deformation: Based on the total deformation δ total and the system deformation δ system The actual deformation δ of the tested bearing under various load levels was calculated. bearing , where δ bearing = δ total -δ system ; Step 4: Stiffness Calculation Steps: Based on the axial loads at each level and the actual deformation δ bearing The corresponding relationship is used to determine the load-deformation function relationship F = f(δ), and the derivative of this function relationship is taken to obtain the stiffness K = dF / dδ of the tested bearing.

[0025] In the stiffness calculation step, determining the load-deformation function relationship F = f(δ) specifically involves: for each level of axial load and the actual deformation δ bearing The data set was subjected to curve fitting to obtain the fitting equation.

[0026] In this scheme, the curve fitting uses a nonlinear function model.

[0027] In this scheme, the nonlinear function model is a power function model F = A×δ^B.

[0028] In this scheme, the stiffness of the standard sample block is greater than the stiffness of the bearing under test.

[0029] In this scheme, the standard sample block is made of high-strength alloy steel, and its shape and installation connection dimensions are consistent with the corresponding dimensions of the bearing being tested.

[0030] In this scheme, the bearing under test is a turntable bearing, and the obtained stiffness K is the axial stiffness.

[0031] Example 1 This embodiment uses the YRT120 rotary table bearing as an example. Figure 4 As shown in Table 1, the bearing parameters are not limited to this.

[0032] Reference Figure 1 The schematic diagram of the bearing stiffness testing system shown includes a test frame 1 serving as a rigid testing platform, a loading device, and a displacement measuring device; the complete testing method is as follows: Figure 2 As shown, the specific test process is described in detail: First, the system error is calibrated: the deformation of the high-rigidity bearing sample is taken as the deformation generated by the test system; Figure 3The standard sample block shown is mounted on the test platform. This sample block has the same dimensional parameters as the bearing but has higher rigidity. Axial loads (including eccentric conditions) are applied in stages using a loading rod, and the dial gauge readings are recorded at each load level. The test is performed three times, and the average value is taken as the system deformation δ at the corresponding load level. system The deformation of the test system under different load levels is as follows: Figure 5 The deformation amounts of the samples were 0.0005 mm, 0.004 mm, 0.026 mm, 0.045 mm, 0.062 mm, 0.081 mm, and 0.104 mm, respectively. After the systematic error measurement was completed, the standard sample block was removed and replaced with a YRT120 rotary table bearing. Under the same installation conditions, the load was reapplied according to the same load sequence described above, and the deformation under each load level was recorded as the total deformation δ of the bearing and the test system. total The total deformation of the bearing and system under different load levels is as follows: Figure 5 The total deformation of the bearings in the test were 0.001 mm, 0.0047 mm, 0.027 mm, 0.0465 mm, 0.064 mm, 0.0833 mm, 0.0965 mm, and 0.107 mm, respectively. According to δ bearing =δ total -δ system The actual deformation of the YRT120 turntable bearing under various load levels can be calculated; Figure 5 The actual bearing deformation is obtained by removing errors caused by the testing system, representing the deformation occurring solely by the YRT120 rotary table bearing under load. Figure 5 It can be clearly seen that the system generates a very large error during the YRT120 turntable bearing deformation test. Only by eliminating the system error can we obtain a value closer to the true deformation of the bearing. The true deformation of the bearing under different load levels is 0.0005mm, 0.0007mm, 0.001mm, 0.0015mm, 0.002mm, 0.0023mm, 0.0025mm, and 0.003mm. The obtained load-bearing deformation data were fitted with a power function curve using the nonlinear least squares method to obtain the load-bearing deformation relationship curve. ,like Figure 6 As shown, differentiating the equation yields the stiffness function of the YRT120 rotary table bearing. By substituting a specific load value into the load-bearing actual deformation relationship fitting equation, the actual deformation value of the YRT120 turntable bearing under that load can be obtained. Then, substituting this value into the obtained stiffness function equation yields the accurate stiffness value under the corresponding load condition. The stiffness of the YRT120 turntable bearing varies with load as follows: Figure 7 As shown.

[0033] The parts not described in detail in the above embodiments are existing technologies.

[0034] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A method for indirect measurement of bearing stiffness based on system error compensation, characterized in that: The method comprises the following steps: S1, installing a standard block on a test system, applying an axial load and measuring a first deformation of the standard block under each level of load, denoted as a system deformation; S2, installing a measured bearing on the test system, applying the same levels of axial load as in step S1 and measuring a second deformation of the measured bearing under each level of load, denoted as a total deformation; S3, calculating a real deformation of the measured bearing under each level of load according to the obtained total deformation and system deformation, the real deformation being the difference between the total deformation and the system deformation; S4, determining a load-deformation function relationship based on the correspondence between the levels of axial load and the real deformation, and obtaining the stiffness of the measured bearing.

2. The method of claim 1, wherein: In step S1, the stiffness of the standard block is greater than that of the measured bearing, and the shape and mounting coupling size of the standard block are consistent with the corresponding size of the measured bearing.

3. The method of claim 2, wherein: The material of the standard block is high-strength alloy steel.

4. The method of claim 1, wherein: In step S4, the determination of the load-deformation function relationship is specifically: Curve fitting is performed on the data set of the levels of axial load and the real deformation to obtain a fitting equation.

5. The method of claim 4, wherein: The model used for curve fitting is a nonlinear function model.

6. The method of claim 5, wherein: The nonlinear function model is a power function model.

7. The method of claim 1, wherein: The measured bearing is a rotary table bearing.

8. A bearing stiffness test system for implementing the method of any one of claims 1-7, characterized by It comprises: a rigid test platform as a bearing base of the entire test system; a standard block with a shape and size consistent with the corresponding size of the measured bearing; a loading device installed on the rigid test platform for applying different axial loads to the standard block or the measured bearing; a displacement measuring device installed on the rigid test platform for measuring the deformation of the standard block or the measured bearing under each level of load; a data processing unit for obtaining data from the displacement measuring device and calculating the stiffness value of the measured bearing.

9. The system of claim 8, wherein, The loading device comprises a loading rod and weights installed on the loading rod, the loading rod being connected to the standard block or the measured bearing through a locking member, and different weights being adjusted to apply different axial loads.

10. The system of claim 8, wherein, The displacement measuring device comprises a magnetic stand fixed on the rigid test platform and a micrometer installed on the magnetic stand.

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