Film state measurement method, film state measurement device, and program

Abstract

In a method for measuring the state of a film between a first member and a second member lubricated by a lubricant, impedance is measured by applying a predetermined voltage to the first member and the second member, and the measured impedance is fitted on the basis of equivalent circuits corresponding to each of a plurality of layers formed between the first member and the second member. Thereby, the impedance of each of the plurality of layers between the first member and the second member is derived, and the film state between the first member and the second member is measured on the basis of the derived impedance.

Description

Technical Field

[0001] The present invention relates to a film state measurement method, a film state measurement apparatus, and a program. Background Art

[0002] Conventionally, in mechanical devices such as bearing devices and sliding devices, a structure in which a lubricant (e.g., lubricating oil, grease) is used to provide a desired coating film on the contact surface between components to lubricate the operation has been widely used. In addition, a structure in which the contact area between components is protected by previously providing a coating film on the surface of the components is also used. For such mechanical devices, by periodically monitoring the film state, damage and wear are detected in advance to suppress the occurrence of failures of rotating components.

[0003] In a mechanical device using a lubricant, in order to diagnose the film state, it is required to appropriately detect the internal state. For example, in Patent Document 1, a structure is shown in which, for a device having a structure in which a rotating shaft is supported by two rolling bearings, the state of the coating film of the rolling bearing is determined in a state of being non-contact with the rotating ring and the rolling elements.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-239779 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] For example, when a rotational operation is performed in a bearing device, the film state changes according to the rotation process. More specifically, a lubricant and a coating film formed on the surface of the components are included between the components, and their states change as the rotation progresses. Between such components, a multi-layer structure formed around the lubricant can be captured as the film state. And a method for appropriately measuring the state change of multiple films by measuring them is sought. However, in the method of Patent Document 1, such a change in the film state cannot be grasped.

[0009] In view of the above problems, an object of the present invention is to provide a method capable of measuring the state change of multiple films between lubricated components.

[0010] Technical Means for Solving the Problem

[0011] In order to solve the above problems, the present invention has the following configuration. That is, a film state measurement method, characterized in that,

[0012] It is a film state measurement method between a first component and a second component lubricated by a lubricant, and has:

[0013] A measurement step of measuring impedance by applying a prescribed voltage to the first component and the second component;

[0014] A derivation step of fitting the impedance measured in the measurement step based on equivalent circuits respectively corresponding to a plurality of layers formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; and

[0015] A measurement step of measuring the film state between the first component and the second component based on the impedance derived in the derivation step.

[0016] In addition, another aspect of the present invention has the following configuration. That is, a film state measurement device, characterized in that

[0017] It is a film state measurement device between a first component and a second component lubricated by a lubricant, and has:

[0018] A measurement unit that measures impedance by applying a prescribed voltage to the first component and the second component;

[0019] A derivation unit that fits the impedance measured by the measurement unit based on equivalent circuits respectively corresponding to a plurality of layers formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; and

[0020] A measurement unit that measures the film state between the first component and the second component based on the impedance derived by the derivation unit.

[0021] In addition, another aspect of the present invention has the following configuration. That is, a program, characterized in that it causes a computer to execute the following steps:

[0022] A measurement step of measuring impedance by applying a prescribed voltage to a first component and a second component lubricated by a lubricant;

[0023] A derivation step of fitting the impedance measured in the measurement step based on equivalent circuits respectively corresponding to a plurality of layers formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; and

[0024] A measurement step of measuring the film state between the first component and the second component based on the impedance derived in the derivation step.

[0025] Advantages of the Invention

[0026] According to the present invention, it is possible to measure the state changes of multiple films between lubricated components. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the surroundings of a lubricant in a rolling bearing for explaining an embodiment of the present invention.

[0028] Figure 2A is a schematic diagram of an equivalent circuit of the surroundings of a lubricant in a rolling bearing for explaining an embodiment of the present invention.

[0029] Figure 2B is a schematic diagram of an equivalent circuit of a rolling bearing for explaining an embodiment of the present invention.

[0030] Figure 3 is a schematic diagram showing a configuration example of a measuring device according to an embodiment of the present invention.

[0031] Figure 4 is a flowchart of a film state measurement process according to an embodiment of the present invention.

[0032] Figure 5 is a graph showing an example of a measurement result according to an embodiment of the present invention.

[0033] Figure 6A is a schematic diagram for explaining the state changes of the surroundings of a lubricant in a rolling bearing according to an embodiment of the present invention.

[0034] Figure 6B is a schematic diagram for explaining the state changes of the surroundings of a lubricant in a rolling bearing according to an embodiment of the present invention.

[0035] Figure 6C is a schematic diagram for explaining the state changes of the surroundings of a lubricant in a rolling bearing according to an embodiment of the present invention.

[0036] Figure 7A is a graph showing an example of a measurement result according to an embodiment of the present invention.

[0037] Figure 7B is a graph showing an example of a measurement result according to an embodiment of the present invention.

[0038] Figure 7C is a graph showing an example of a measurement result according to an embodiment of the present invention.

[0039] Figure 7D is a graph showing an example of a measurement result according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, embodiments for implementing the present invention will be described with reference to the accompanying drawings and the like. In addition, the embodiments described below are for explaining one embodiment of the present invention and are not intended to limit the interpretation of the present invention. Moreover, all the structures described in each embodiment are not limited to the structures necessary for solving the problems of the present invention. In addition, in each drawing, the same reference numerals are used to indicate the corresponding relationship for the same components.

[0041] <First Embodiment>

[0042] Hereinafter, the first embodiment of the present invention will be described. In addition, in the present embodiment, a rolling bearing that performs a rolling motion while being lubricated with a lubricant will be taken as an example for explanation. For example, as the types of rolling bearings to which the diagnostic method of the present invention can be applied, deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings, self-aligning roller bearings, etc. can be cited. However, it is not limited thereto, and as long as it is a mechanical device that operates by lubricating the contact positions between components with a lubricant, the present embodiment can be applied.

[0043] [Lubrication State]

[0044] First, the lubrication state of the lubricant in the present embodiment will be described. As the lubricant in the present embodiment, lubricating oil, grease, etc. are included, but there is no particular limitation. In addition, in the present embodiment, an example in which a coating film is formed on the surface of the component along with the rotational motion of the rolling bearing is shown, but the coating film is not limited to the coating film caused by the main component of the lubricant. For example, it can also be applied to transfer films of thickeners, resin retainer components, oxidation coating films, boundary coating films with added oil preparations, iron phosphate coating films with added extreme pressure agents, etc.

[0045] Figure 1 FIG. is a schematic structure diagram showing the position (around the contact area between components) where lubrication is performed with a lubricant in the rolling bearing 100 as the measurement object. The rolling bearing 100 is configured to include rolling elements 101 such as balls and an outer ring and an inner ring that form rolling surfaces. Here, the outer ring 102 will be taken as an example for explanation. Lubricant 103 is filled between the rolling element 101 and the outer ring 102 to lubricate between the components. In addition, since the rolling bearing 100 rotates, a coating film 104 is formed on the surface of each component. Coating film 104a represents the film formed on the surface of the rolling element 101, and coating film 104b represents the film formed on the surface (rolling surface) of the outer ring 102.

[0046] Actually, there are irregularities (roughness) on the surface of the rolling element 101 and the surface of the outer ring 102, but here, the irregularities are collectively shown on the surface of the rolling element 101 as the combined surface roughness.

[0047] The state of the coating film 104 changes according to the operation of the rolling bearing 100. In the present embodiment, an equivalent circuit for them is defined, and the lubrication state, that is, the change in the film state formed as multiple layers between components, is measured. In addition, in the following description, the power supply used for measurement is described as an AC power supply.

[0048] FIG. 2 is a diagram showing an electrical equivalent circuit around the lubricant 103 in the rolling bearing 100. The circuit E has a structure in which a capacitor C formed by the lubricant 103 and a resistor R caused by surrounding elements are connected in parallel. Examples of the surrounding elements here include rolling elements (rollers, balls, etc.), inner rings, outer rings, etc. that make up the rolling bearing 100. In addition, the impedance of the circuit E is represented by Z. Here, the AC voltage V applied to the circuit E, the current I flowing through the circuit E, and the complex impedance Z of the entire circuit E are represented by the following equations (1) to (3).

[0049] V = |V|exp(jωt)…(1)

[0050] I = |I|exp(j(ωt - θ))…(2)

[0051] Z = V / I = |V / I|exp(jθ) = |Z|exp(jθ)…(3)

[0052] j: imaginary number

[0053] ω: angular frequency of voltage

[0054] t: time

[0055] θ: phase angle (phase shift between voltage and current)

[0056] In the present embodiment, electrochemical impedance spectroscopy (EIS) is applied for measurement. Electrochemical impedance spectroscopy is a method for separately capturing the impedance behavior of a solution and an electrode / solution interface, and it is a well-known method, so detailed description is omitted here.

[0057] As Figure 1 shown, around the contact area, the lubricant 103 and the coating film 104 (including coating films 104a and 104b) have a multi-layer structure, which can be regarded as a circuit in which the lubricant 103 and the coating film 104 are connected in series. Figure 2B represents an electrical equivalent circuit for the lubricant 103 and the coating film 104. In the present embodiment, considering the surface roughness of the rolling element and the outer ring, instead of Figure 2A the capacitor C shown, a CPE (Constant Phase Element; pseudo-capacitance) is used. Here, the resistance around the lubricant 103 is represented by R1, and the CPE is represented by CPE1. Similarly, the resistance around the coating film 104 is represented by R2, and the CPE is represented by CPE2.

[0058] A CPE is a circuit element that has elements of both a capacitor and a resistor caused by the unevenness and non-uniformity of the electrode surface. In a CPE, the time constant is not determined to be one. The impedance of a CPE is represented by the following equation (4). When p = 1 in the CPE, it becomes a capacitor based on the CPE constant T CPE and when p = 0, it becomes a resistor with a resistance value of 1 / T CPE . In addition, the R-CPE parallel circuit represents a flattened semi-circle, and the degree of flattening depends on p.

[0059] [Equation 1]

[0060]

[0061] Z CPE : Impedance

[0062] j: Imaginary number

[0063] π: Pi

[0064] f: Frequency

[0065] T CPE : CPE constant

[0066] p: CPE exponent

[0067] In the present embodiment, based on the Figure 2B equivalent circuit shown, by applying electrochemical impedance spectroscopy (EIS), the film state in the contact area of the rolling bearing 100, that is, the separation of the lubricant and the coating film, is determined.

[0068] [Device Structure]

[0069] Figure 3 is a schematic structural diagram showing an example of the overall structure of the system 1 capable of applying the film state measurement method of the present embodiment. In Figure 3 the system 1 using the film state measurement method of the present embodiment includes a measurement device 10, an LCR meter 20, and a bearing device 30 as the measurement object. In addition, Figure 3 the structure shown is an example, and different structures can be used depending on the measurement object and the like.

[0070] The bearing device 30 is configured to include two rolling bearings. In Figure 3In the example, examples of two ball bearings 31a and 31b are shown. The ball bearings 31a and 31b are arranged around the rotating shaft 40 and are configured to enable the rotation of the rotating shaft 40. Inside the ball bearings 31a and 31b, friction within each rolling bearing is reduced by a prescribed lubrication method. The lubrication method is not particularly limited. For example, grease lubrication, oil lubrication, etc. are used and supplied to the inside of each rolling bearing. The type of lubricant is also not particularly limited.

[0071] The ball bearings 31a and 31b are each configured to include an outer ring, a plurality of balls as rolling elements, and an inner ring. A case where the ball bearings 31a and 31b have the same structure will be described. In Figure 3 the example, the inner ring of each rolling bearing is used as the rotating ring and the outer ring is used as the fixed ring for description, but the opposite structure is also possible. In addition, in the present embodiment, an example where the bearing device 30 is configured to include two ball bearings is shown, but a bearing device composed of one rolling bearing can also be applied in the same way. Further, the bearing device 30 is configured to be loaded with a load (radial load, axial load) in a prescribed direction.

[0072] The motor 50 is a driving motor and supplies rotational power to the rotating shaft 40 via a rotating belt or the like. The heater 60 is used to maintain the temperature around the bearing device 30, which is the object to be measured, at a prescribed temperature. The LCR meter 20 is electrically connected to the bearing device 30 and the rotating shaft 40. At this time, the LCR meter 20 also functions as an AC power source for the bearing device 30.

[0073] The measuring device 10 operates as a measuring device capable of executing the film state measuring method of the present embodiment. When measuring, the measuring device 10 instructs the LCR meter 20 with the angular frequency ω and AC voltage V of the AC power source as inputs, and obtains the impedance |Z| (|Z| represents the absolute value of Z) and phase angle θ of the bearing device 30 from the LCR meter 20 as outputs. Then, the measuring device 10 uses these values to monitor the film state of the lubricant in the bearing device 30. Details of the film state measuring method will be described later.

[0074] The measuring device 10 can be realized, for example, by an information processing device configured to include a control device, a storage device, and an output device (not shown). The control device can be composed of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Single Processor), or a dedicated circuit, etc. The storage device is composed of volatile and non-volatile storage media such as an HDD (Hard Disk Drive), a ROM (ReadOnly Memory), and a RAM (Random Access Memory), and can input and output various information according to instructions from the control device. The output device is composed of display devices such as speakers, lights, or liquid crystal displays, etc., and outputs to the operator according to instructions from the control device. The output method of the output device is not particularly limited. For example, it can be a visual output based on screen output or an auditory output based on sound. In addition, the output device can be a network interface with a communication function, or can perform an output operation by sending data to an external device (not shown) via a network (not shown). The output content here, for example, when the film state is measured based on the measurement result, is not limited to the output when an abnormality is detected, and can also include an output indicating the normal state of the bearing device 30.

[0075] [Processing Flow]

[0076] Figure 3 It is a flowchart of the film state measurement process of the present embodiment. This process is executed by the measuring device 10. For example, it can be realized by the control device (not shown) provided in the measuring device 10 reading and executing a program for realizing the process of the present embodiment from the storage device (not shown). In addition, fitting and parameter derivation in the following processes can be configured to use the functions of general software to realize a part of them.

[0077] In S401, the measuring device 10 controls the LCR meter 20 to supply electric power of an alternating voltage V with an angular frequency ω to the bearing device 30 (that is, the ball bearings 31a, 31b) using the alternating current power supply (not shown) provided in the LCR meter 20. Thereby, an alternating voltage V with an angular frequency ω is applied to the lubricant in each rolling bearing.

[0078] In S402, the measuring device 10 obtains the impedance |Z| and the phase angle θ as the output for the input indicated in S401. That is, the LCR meter 20 outputs the impedance |Z| and the phase angle θ as the measurement results of the AC voltage V of the bearing device 30 with respect to the angular frequency ω as the input to the measuring device 10.

[0079] In S403, based on the impedance |Z| and the phase angle θ obtained in S402 and the information of the AC voltage V of the angular frequency ω indicated in S401, the measuring device 10 performs fitting (application) to the formula of the equivalent circuit shown in Figure 2B shown.

[0080] In S404, the measuring device 10 can determine each parameter in Equation (4) corresponding to the equivalent circuit shown in Figure 2B according to the fitting result of S403. The parameters determined here are R, T CPE (CPE constant), p (CPE exponent). At this time, the above parameters corresponding to the lubricant 103 and the coating film 104 that can be regarded as connected in series are derived.

[0081] In S405, the measuring device 10 uses the parameters derived in S404 to derive the frequency dependence of the impedance Z corresponding to the lubricant 103 and the coating film 104 respectively. Regarding an example of the frequency dependence of the impedance Z, Figures 7A - 7D etc. will be described later.

[0082] In S406, the measuring device 10 measures the film states of the lubricant 103 and the coating film 104 based on the result of the frequency dependence of the impedance Z derived in S405. The measurement content here is not particularly limited. For example, the presence or absence of the formation of the above coating film and its state can be determined. Furthermore, the lubricating oil film thickness h and the metal contact ratio α can also be derived by the method described in the Japanese Patent No. 6729633 of the present patent applicant. Moreover, it can also be configured to set a specified threshold for the lubricating oil film thickness h and the metal contact ratio α, and diagnose normal or abnormal by comparing with this threshold. In addition, it can also be configured to preset multiple thresholds corresponding to the emergency degree of abnormality, and diagnose the emergency degree by comparing with these thresholds. In addition, it can also be configured to preset thresholds and evaluation criteria for the states of the lubricant 103 and the coating film 104 respectively, and perform diagnosis based on the film state by comparing with them.

[0083] In S407, the measuring device 10 outputs the measurement results obtained in S406 to the user. The output method here is not particularly limited. For example, it can be a structure that displays the parameters and items determined to be abnormal on the screen or notifies by voice. Then, this processing flow ends.

[0084] [Test]

[0085] The results of the test conducted using the above-mentioned film state measurement method will be described below. The test conditions are as follows.

[0086] (Test conditions)

[0087] Bearing used: Deep groove ball bearing (Part number: 608)

[0088] Temperature (outer ring): 150 °C

[0089] Rotation speed: 6000 [min -1

[0090] Axial load: 32 [N]

[0091] Radial load: 0 [N]

[0092] Maximum contact pressure: 1.0 [GPa]

[0093] AC frequency: 20 Hz to 1000000 [Hz]

[0094] AC voltage: 0.2 V

[0095] (Lubricant used)

[0096] Base oil: Polyalphaolefin oil (PAO)

[0097] Filling amount: 1 [mg]

[0098] Kinematic viscosity: 130 [mm 2 / s] (at 40 °C)

[0099] Relative dielectric constant: 2.1

[0100] (Test results)

[0101] Figure 5 The test results obtained under the above test conditions are shown. Here, three graphs are presented corresponding to each other. In each graph, the horizontal axis represents time [minutes], indicating the time elapsed since the bearing device started rotating. The above graphs show the values of temperature (line 501) and torque (line 502) during the test. The middle graph shows the lubricating oil film thickness h around the lubricant derived from the results of the derived impedance. Additionally, the bottom graph shows the metal contact ratio α (0 ≤ α ≤ 1) representing the contact ratio between components, derived from the results of the derived impedance. It should be noted that here, the influence of the coating film is not considered, and the lubricating oil film thickness and metal contact ratio caused entirely by the oil film for the impedance Z obtained through measurement are shown.

[0102] ​In addition, the dashed line 521 indicates the moment when the impedance |Z| increases, and the dashed line 522 indicates the moment when the rotation of the bearing device stops. In addition, the dashed line 523 indicates the theoretical oil film thickness h theory . The theoretical oil film thickness h theory As an example, it represents the value calculated using the well-known Hamrock & Dowson formula.

[0103] In the present embodiment, as the state change around the lubricant, three states are described as examples. Figures 6A - 6C It is a schematic diagram showing a schematic configuration of three film states around the lubricant. Figure 6A It represents a state where no coating films are formed on the surfaces of the rolling elements 601 and the outer ring 602 in the rolling bearing 600 (hereinafter referred to as "state A"). In this state A, there is a lubricant 603 between the rolling element 601 and the outer ring 602. There are irregularities (roughness) on the surfaces of the rolling element 601 and the outer ring 602, respectively, but similar to Figure 1 Here, the irregularities are shown concentrated on the surface of the rolling element 101.

[0104] Figure 6B It represents a state where coating films 604a and 604b are formed on the surfaces of the rolling elements 601 and the outer ring 602 in the rolling bearing 600, respectively (hereinafter referred to as "state B"). Figure 6C It represents a state where coating films 604a and 604b are formed on the surfaces of the rolling elements 601 and the outer ring 602 in the rolling bearing 600, respectively, and the coating film 604a is in contact with the coating film 604b (hereinafter referred to as "state C").

[0105] The measurement results corresponding to Figure 5 the drawing 511 are shown in Figure 7A . Figure 7A It is a semi-logarithmic graph with the logarithm of the frequency [Hz] on the horizontal axis and the phase angle θ [°] on the vertical axis. The drawing 511 is before the moment when the bearing device starts to rotate and the impedance |Z| increases (the dashed line 521). In addition, the information of the drawings 701, 711, 721, and 731 shown below is determined by the operations of the processes of S401 and S402 in the flowchart shown in Figures 7A - 7D above. Figure 4 In

[0106] In Figure 7A , the drawing 701 represents the actual measurement results. The line 702 represents the estimated result obtained by fitting only to the circuit structure caused by the layer of the lubricant (i.e., the parallel circuit composed of the resistance R1 and CPE1 of Figure 2B ) based on the result obtained as the drawing 701. The line 703 represents the estimated result obtained by fitting only to the circuit structure caused by the layer of the coating film (i.e., the circuit structure composed of Figure 2BThe estimated result obtained by fitting the parallel circuit composed of the resistance R2 and CPE2. Lines 703 and 704 are obtained as the results of S404 and S405 shown in Figure 4 .

[0107] Refer to Figure 7A . The plot 701 showing the measurement result is roughly consistent with the line 702, and only one peak caused by one parallel circuit is obtained. Thus, at the moment of the plot 511 of Figure 5 , there is almost no influence of the circuit structure caused by the film layer (i.e., the parallel circuit composed of the resistance R2 and CPE2 of Figure 2B ). The state around the lubricant is presumed to be equivalent to the circuit structure caused only by the lubricant layer (i.e., the parallel circuit composed of the resistance R1 and CPE1 of Figure 2B ) in the state A shown in Figure 6A . That is, it becomes the state where the coating film 604 is not formed.

[0108] The measurement result corresponding to the plot 512 of Figure 5 is shown in Figure 7B . Figure 7B is a semi-logarithmic graph with the logarithm of the frequency [Hz] on the horizontal axis and the phase angle θ [°] on the vertical axis. The plot 512 is after the moment when the bearing device starts to rotate and the impedance |Z| increases (dashed line 521).

[0109] In Figure 7B , the plot 711 represents the actual measurement result. The line 712 represents the estimated result obtained by fitting only the circuit structure caused by the lubricant layer (i.e., the parallel circuit composed of the resistance R1 and CPE1 of Figure 2B ) based on the result obtained as the plot 711. The line 713 represents the estimated result obtained by fitting only the circuit structure caused by the film layer (i.e., the parallel circuit composed of the resistance R2 and CPE2 of Figure 2B ) based on the result obtained as the plot 711. The lines 712 and 713 are obtained as the results of S404 and S405 shown in Figure 4 .

[0110] Refer to Figure 7B . Compared with the measurement result shown in Figure 7A , the peak moves to the left, but like Figure 7A , only one peak is obtained. At the moment of the plot 512 of Figure 5 , there is almost no influence of the circuit structure caused by the film layer (i.e., the parallel circuit composed of the resistance R2 and CPE2 of Figure 2B ). That is, it is presumed that the state around the lubricant is equivalent to the circuit structure caused only by the lubricant layer (i.e., the parallel circuit composed of the resistance R1 and CPE1 of Figure 2B ).Figure 6A The state A shown. That is, similar to the drawing 511, it becomes a state where the coating film 604 is not formed.

[0111] The measurement result corresponding to Figure 5 the drawing 513 is shown in Figure 7C . Figure 7C It is a semi-logarithmic graph with the logarithm of the frequency [Hz] on the horizontal axis and the phase angle θ [°] on the vertical axis. The drawing 513 is at a time after a certain time has passed since the moment when the impedance |Z| starts to increase as the bearing device starts to rotate (the dashed line 521), and is located after the drawing 512.

[0112] In Figure 7C , the drawing 721 represents the actual measurement result. The line 722 represents the estimated result obtained by fitting only to the circuit structure caused by the lubricant layer (that is, the parallel circuit composed of Figure 2B the resistance R1 and CPE1). The line 723 represents the estimated result obtained by fitting only to the circuit structure caused by the coating film layer (that is, the parallel circuit composed of Figure 2B the resistance R2 and CPE2). The lines 722 and 723 are obtained as the results of Figure 4 shown in S404 and S405.

[0113] Referring to Figure 7C , the drawing 721 represents a curve having two peaks caused by two parallel circuits. From this, it can be seen that at the time point of the drawing 513 in Figure 5 , the circuit structure caused by the coating film layer (that is, the parallel circuit composed of Figure 2B the resistance R2 and CPE2) and the circuit structure caused by the lubricant layer (that is, the parallel circuit composed of Figure 2B the resistance R1 and CPE1) both have an impact. Therefore, it is presumed to be equivalent to Figure 6B the state B shown. That is, it becomes the state B in which the coating film 604 is formed.

[0114] The measurement result corresponding to Figure 5 the drawing 514 is shown in Figure 7D . Figure 7D It is a semi-logarithmic graph with the logarithm of the frequency [Hz] on the horizontal axis and the phase angle θ [°] on the vertical axis. The drawing 514 is after the moment when the bearing device stops rotating (the dashed line 522).

[0115] In Figure 7D , the drawing 721 represents the actual measurement result. The line 722 represents only the circuit structure caused by the lubricant layer (that is, the parallel circuit composed of Figure 2BThe estimation result obtained by fitting the parallel circuit composed of the resistance R1 and CPE1). Line 723 represents the estimation result obtained by fitting only based on the circuit structure caused by the film layer (i.e., the parallel circuit composed of Figure 2B the resistance R2 and CPE2).

[0116] Referring to Figure 7D , the plot 721 showing the measurement result coincides with line 723, and only one peak caused by one parallel circuit is obtained. Thus, at the time point of the plot 514 in Figure 5 , it is presumed to correspond to the circuit structure caused by the lubricant layer (i.e., the parallel circuit composed of Figure 2B the resistance R1 and CPE1) and the circuit structure caused by the film layer (i.e., the parallel circuit composed of Figure 2B the resistance R2 and CPE2) being in contact. Figure 6C The state C shown in. It should be noted that in state C, the rotation of the bearing device stops, so the films formed on the surfaces of the components come into contact with each other, and only the peak of the film does not exist. That is, when the metals are in contact with each other in the state without the film, the impedance |Z| is approximately 0, but when the film is formed, it also exhibits the behavior of a parallel circuit of R-CPE when the rotation stops.

[0117] As described above, according to the structure of the present embodiment, it is possible to determine the film state around the lubricant, and more specifically, it is possible to determine the presence or absence of the film. In addition, the thickness of the lubricant and the film can be estimated based on the above detection results. Regarding the thickness of the lubricant and the film, as described above, it can be derived by using the measurement parameters (ω, V, Z, θ) based on the spectroscopic impedance method and applying them to a known method.

[0118] <Other Embodiments>

[0119] In the above embodiment, a rolling bearing is cited as an example, but it is not limited thereto, and the present invention can also be applied to other devices having a layer structure formed by a lubricant.

[0120] In addition, in the above embodiment, an AC voltage is described as an example of the voltage applied to the bearing device. However, it is not limited thereto, and for example, a specified pulse or rectangular voltage can also be used.

[0121] In addition, in the present invention, it is also possible to supply a program or application program for realizing the functions of the above one or more embodiments to a system or device by using a network or a storage medium, etc., and the one or more processors in the computer of the system or device read and execute the processing of the program to realize it.

[0122] Alternatively, it can also be implemented by a circuit that implements more than one function (e.g., ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array)).

[0123] Thus, the present invention is not limited to the above-described embodiments. Combinations of the structures of the embodiments and changes and applications made by those skilled in the art based on the description in the specification and well-known technologies are also intended by the present invention and are included within the scope of the claims.

[0124] As described above, the following matters are disclosed in this specification.

[0125] (1) A method for measuring a film state, which is a method for measuring the film state between a first component (e.g., 101) lubricated by a lubricant (e.g., 103) and a second component (e.g., 102), characterized in that:

[0126] It has: a measurement step (e.g., S401, S402), where the impedance is measured by applying a specified voltage to the first component and the second component;

[0127] A derivation step (e.g., S403, S404, S405), where the impedance of each of the multiple layers (e.g., 103, 104) formed between the first component and the second component is derived by fitting the impedance measured in the measurement step based on equivalent circuits (e.g., Figure 2B ) corresponding to the multiple layers respectively; and

[0128] A measurement step (e.g., S406), where the film state between the first component and the second component is measured based on the impedance derived in the derivation step.

[0129] According to this structure, it is possible to measure the state changes of multiple films between lubricated components.

[0130] (2) The method for measuring a film state according to (1), characterized in that:

[0131] The equivalent circuit is composed of quasi-capacitors (e.g., CPE1, CPE2) corresponding to the lubricant between the first component and the second component and the coating film formed on at least one of the first component and the second component respectively.

[0132] According to this structure, it is possible to measure the film state with respect to the lubricant between components and the coating film on the component surface, taking into account the surface roughness of the component surface.

[0133] (3) The film state measurement method according to (1), characterized in that

[0134] The equivalent circuit is a circuit formed by connecting two parallel circuits of a resistance circuit and a CPE circuit in series (for example, Figure 2B ).

[0135] One of the two parallel circuits corresponds to the lubricant (for example, 103) between the first component and the second component, and the other corresponds to a coating film (for example, 104a, 104b) formed on at least one of the first component and the second component as the first component and the second component operate.

[0136] According to this structure, it is possible to measure the film state with respect to the lubricant between components and the coating film formed as the components operate.

[0137] (4) The film state measurement method according to (3), characterized in that

[0138] In the measurement process, it is diagnosed whether there is a coating film formed on the surface of at least one of the first component and the second component as the film state.

[0139] According to this structure, it is possible to measure whether there is a coating film formed as the components operate between components as the film state.

[0140] (5) The film state measurement method according to (1), characterized in that

[0141] The first component and the second component are provided in a bearing device (for example, 30), and the first component is a rolling element,

[0142] The second component is an inner ring or an outer ring.

[0143] According to this structure, it is possible to measure the film state between the rolling element and the inner and outer rings inside a rolling device.

[0144] (6) A film state measurement device is a film state measurement device (for example, 10) between a first component (for example, 101) and a second component (for example, 102) lubricated by a lubricant (for example, 103), characterized by comprising:

[0145] A measurement unit (for example, 20) that measures impedance by applying a prescribed voltage to the first component and the second component;

[0146] An output unit (e.g., 10) that fits the impedance measured by the measurement unit based on equivalent circuits respectively corresponding to a plurality of layers (e.g., 103, 104) formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; and

[0147] A measurement unit (e.g., 10) that measures the film state between the first component and the second component based on the impedance derived by the output unit.

[0148] With this structure, it is possible to measure changes in the state of a plurality of films between lubricated components.

[0149] (7) A program for causing a computer (e.g., 10) to execute the following steps:

[0150] A measurement step (e.g., S401, S402) of measuring impedance by applying a prescribed voltage to a first component (e.g., 101) and a second component (e.g., 102) lubricated by a lubricant (e.g., 103);

[0151] An output step (e.g., S403, S404, S405) of deriving the impedance of each of the plurality of layers between the first component and the second component by fitting the impedance measured in the measurement step based on equivalent circuits respectively corresponding to a plurality of layers (e.g., 103, 104) formed between the first component and the second component; and

[0152] A measurement step (e.g., S406) of measuring the film state between the first component and the second component based on the impedance derived in the output step.

[0153] With this structure, it is possible to measure changes in the state of a plurality of films between lubricated components.

[0154] As described above, various embodiments have been described with reference to the drawings, but the present invention is of course not limited to this example. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and these modification examples or correction examples also of course belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above-described embodiments can be arbitrarily combined.

[0155] As described above, various embodiments have been explained, but the present invention is of course not limited to this example. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and these modification examples or correction examples also of course belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above-described embodiments can be arbitrarily combined.

[0156] In addition, this application is based on a Japanese patent application (Japanese Patent Application No. 2022-178452) filed on November 7, 2022, the content of which is incorporated herein by reference.

[0157] Explanation of Reference Numerals

[0158] 1 System

[0159] 10 Measuring Device

[0160] 20 LCR Meter

[0161] 30 Bearing Device

[0162] 40 Rotating Shaft

[0163] 50 Motor

[0164] 60 Heater

Claims

1. A method for measuring the state of a membrane, characterized in that, A method for measuring the film state between a first component and a second component lubricated by a lubricant, comprising: A measuring step of measuring impedance by applying a prescribed voltage to the first component and the second component; A deriving step of fitting the impedance measured in the measuring step based on equivalent circuits respectively corresponding to a plurality of layers formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; And A measuring step of measuring the film state between the first component and the second component based on the impedance derived in the deriving step.

2. The method for measuring the state of a membrane according to claim 1, characterized in that, The equivalent circuit is composed of quasi-capacitances respectively corresponding to the lubricant between the first component and the second component and a coating film formed on at least one of the first component and the second component.

3. The method for measuring the state of a membrane according to claim 1, characterized in that, The equivalent circuit is a circuit formed by connecting two parallel circuits of a resistance circuit and a CPE circuit in series. One of the two parallel circuits corresponds to the lubricant between the first component and the second component, and the other of the two parallel circuits corresponds to a coating film formed on at least one of the first component and the second component as the first component and the second component operate.

4. The method for measuring the state of a membrane according to claim 3, characterized in that, In the measuring step, it is diagnosed whether there is a coating film formed on the surface of at least one of the first component and the second component as the film state.

5. The method for measuring the state of a membrane according to claim 1, characterized in that, The first component and the second component are provided in a bearing device. The first component is a rolling element. The second component is an inner ring or an outer ring.

6. A device for measuring the state of a membrane, characterized in that, A device for measuring the film state between a first component and a second component lubricated by a lubricant, comprising: A measuring unit that measures impedance by applying a prescribed voltage to the first component and the second component; A deriving unit that fits the impedance measured by the measuring unit based on equivalent circuits respectively corresponding to a plurality of layers formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; And A measuring unit that measures the film state between the first component and the second component based on the impedance derived by the deriving unit.

7. A program, characterized in that, For causing a computer to execute the following steps: A measuring step of measuring impedance by applying a prescribed voltage to a first component and a second component lubricated by a lubricant; A deriving step of fitting the impedance measured in the measuring step based on equivalent circuits respectively corresponding to a plurality of layers formed between the first component and the second component, thereby deriving the impedance of each of the plurality of layers between the first component and the second component; And A measuring step of measuring the film state between the first component and the second component based on the impedance derived in the deriving step.

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