Water intrusion detection method for device using lubricant, water intrusion detection device, and program

Abstract

A water intrusion detection method for detecting intrusion of water into a device configured so as to lubricate a plurality of sites with a lubricant, the water intrusion detection method comprising: measuring the impedance of a circuit configured from the plurality of sites by applying an AC voltage while scanning a frequency to the circuit; and detecting the intrusion of water into the lubricant by comparing the characteristics represented by the real part and imaginary part of the impedance measured in a state in which no water is mixed into the lubricant with the characteristics represented by the measured real part and imaginary part of the impedance.

Description

Technical Field

[0001] The present invention relates to a water intrusion detection method, a water intrusion detection device, and a program for a device using a lubricant. Background Art

[0002] In the past, in bearing devices, the structure of using lubricants (e.g., lubricating oil, grease) to lubricate the rotation is widely used. On the other hand, for rotating parts such as bearing devices, by regularly performing status diagnosis, abnormalities and status changes of the bearing devices can be detected in advance, and the occurrence of failures of the rotating parts can be suppressed.

[0003] In a bearing device using a lubricant, in order to ensure that the rotational motion continues to operate stably or to detect damage to the device in advance, it is required to properly monitor the state of the oil film. For example, as an example of a method for visualizing the oil film, as a method using light, known methods include optical interference, fluorescence, infrared spectroscopy, etc. In the above-mentioned methods, on the other hand, a translucent material is required, otherwise it is difficult to visualize the state of the oil film of the bearing device, especially the lubricant on the friction surface around the rolling element. In contrast, in order to evaluate the state of the oil film of the bearing device, the application of electrical methods can be cited. For example, in Patent Document 1, a method for detecting the thickness of the lubricating oil film and the contact ratio of the metal in a rolling device is disclosed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-211317 Summary of the invention

[0007] Technical problem that the invention aims to solve

[0008] Depending on the operating environment of the bearing device, various substances may be mixed into the oil film from the outside. Since the mixing of various substances may affect the state of the lubricating oil and the state of the bearing device, it is necessary to detect the mixing at an appropriate time. For example, water can be cited as an example of a substance mixed into the oil film. Since water intrudes into the rolling device and then mixes into the lubricant, it may affect the functions required of the lubricant. Therefore, it is required to properly detect the intrusion of water into the rolling device.

[0009] In view of the above problems, an object of the present invention is to provide a method for detecting the intrusion of water into the lubricant of a bearing device by an electrical method.

[0010] Technical solutions to the problem

[0011] In order to solve the above-mentioned problem, the present invention has the following structure. That is, a water intrusion detection method for detecting the intrusion of water into a lubricant in a device configured to lubricate a plurality of parts with a lubricant,

[0012] The water intrusion detection method has the following features:

[0013] a measuring step of measuring the impedance of the circuit by applying an AC voltage while sweeping a frequency to the circuit composed of the plurality of the portions; and

[0014] The detection step detects the intrusion of water into the lubricant by comparing the characteristics represented by the real and imaginary parts of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real and imaginary parts of the impedance measured in the measurement step.

[0015] Another aspect of the present invention has the following structure. That is, a water intrusion detection device for detecting the intrusion of water into a lubricant in a device configured to lubricate a plurality of locations with a lubricant,

[0016] The water intrusion detection device comprises:

[0017] a measuring unit that measures the impedance of the circuit by applying an AC voltage while sweeping a frequency to the circuit composed of the plurality of the portions; and

[0018] The detection unit detects the intrusion of water into the lubricant by comparing the characteristics represented by the real and imaginary parts of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real and imaginary parts of the impedance measured by the measurement unit.

[0019] In addition, another embodiment of the present invention has the following structure. That is,

[0020] A procedure,

[0021] Used to enable the computer to perform the following processes:

[0022] a measuring step of measuring the impedance of a circuit formed by a device configured to lubricate a plurality of parts with a lubricant by applying an AC voltage while sweeping a frequency to the circuit formed by the plurality of parts; and

[0023] The detection step detects the intrusion of water into the lubricant by comparing the characteristics represented by the real part and the imaginary part of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real part and the imaginary part of the impedance measured in the measurement step.

[0024] Effects of the Invention

[0025] According to the present invention, it is possible to provide a method for electrically detecting the intrusion of water into the lubricant of a bearing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram showing an example of the device configuration during diagnosis according to the present invention.

[0027] Figure 2 It is a graph showing the physical model of the bearing device of the present invention.

[0028] Figure 3 It is a graph showing the geometric model of the present invention.

[0029] Figure 4 This is a circuit diagram for explaining an equivalent circuit of the bearing device of the present invention.

[0030] Figure 5 This is a conceptual diagram for explaining the intrusion of water into the bearing device of the present invention.

[0031] Figure 6 This is a conceptual diagram for explaining the intrusion of water into the bearing device of the present invention.

[0032] Figure 7 It is a diagram for explaining the equivalent circuit of the present invention and changes during frequency sweeping.

[0033] Figure 8 This is a flowchart of a water intrusion detection process according to one embodiment of the present invention.

[0034] Fig. 9 It is a graph showing an example of the detection result according to one embodiment of the present invention.

[0035] Fig.10 It is a graph showing an example of the detection result according to one embodiment of the present invention.

[0036] Fig.11 It is a graph showing an example of the detection result according to one embodiment of the present invention.

[0037] Fig.12 It is a graph showing an example of the detection result according to one embodiment of the present invention. DETAILED DESCRIPTION

[0038] Hereinafter, the mode for implementing the present invention will be described with reference to the accompanying drawings and the like. In addition, the embodiment described below is used to illustrate one embodiment of the present invention and is not intended to limit the interpretation of the present invention. In addition, all structures described in each embodiment are not limited to structures necessary to solve the problems of the present invention. In addition, in each of the drawings, the same constituent elements are indicated by marking the same reference numerals to indicate the corresponding relationship.

[0039] <First Embodiment>

[0040] The first embodiment of the present invention is described below. In addition, in the following description, a ball bearing is cited as an example of a rolling bearing provided by a bearing device, but it is not limited to this. The present invention can also be applied to rolling bearings of other structures that can utilize lubricants and assume that water will invade from the outside. For example, as types of rolling bearings to which the present invention can be applied, there can be cited: deep groove ball bearings, angular contact ball bearings, tapered roller bearings, cylindrical roller bearings, self-aligning roller bearings, etc. Moreover, the present invention can also be applied to other rolling devices, such as axle bearings, drive oil gear devices, cylinder blocks, main shafts, etc.

[0041] In addition, in this specification, the term "water" includes all liquids that affect the lubricant described later. Therefore, even if it is simply described as "water", it can be understood to include substances such as fresh water, salt water, muddy water, snow melting agent, coolant, grinding agent, and liquid obtained by dissolving electrolytes.

[0042] [Device structure]

[0043] Figure 1 1 is a schematic configuration diagram showing an example of the overall configuration when the diagnosis device 1 according to the present embodiment performs a diagnosis. Figure 1 A bearing device 2 to which the water intrusion detection method of the present embodiment is applied and a diagnostic device 1 for performing water intrusion detection and diagnosis are provided. It should be noted that: Figure 1 The structure shown is an example, and a different structure may be used depending on the structure of the bearing device 2, etc. Figure 1 In FIG. 1 , the bearing device 2 is shown to include one rolling bearing, but the present invention is not limited thereto, and one bearing device 2 may include a plurality of rolling bearings.

[0044] In the bearing device 2, the rolling bearing supports the rotating shaft 7 so that it can rotate freely. The rotating shaft 7 is supported by a housing (not shown) covering the outer side of the rotating shaft 7 via the rolling bearing as a rotating member. The rolling bearing includes: an outer ring (outer member) 3 as a fixed ring embedded in the housing, an inner ring (inner member) 4 as a rotating ring embedded outside the rotating shaft 7, a plurality of balls (rollers) as rolling elements 5 arranged between the inner ring 4 and the outer ring 3, and a retainer (not shown) for retaining the rolling elements 5 so that they can roll freely. Here, the structure in which the outer ring 3 is fixed is set, but it can also be a structure in which the inner ring 4 is fixed and the outer ring 3 rotates. In addition, a seal 6 is provided, which is a peripheral member for preventing garbage from intruding around the rolling element 5 and preventing lubricating oil from leaking. In addition, here, a structure in which the seal 6 is provided is shown, but as a possibility, it is assumed that a structure in which water can intrude. Inside the rolling bearing, the friction between the inner ring 4 and the rolling element 5 and between the outer ring 3 and the rolling element 5 is reduced by a predetermined lubrication method. The lubrication method is not particularly limited, and for example, grease lubrication, oil lubrication, etc. are used to supply lubricant to the inside of the rolling bearing. The type of lubricant is also not particularly limited.

[0045] The motor 10 is a driving motor that supplies rotational power to the rotating shaft 7. The rotating shaft 7 is connected to the LCR meter 8 via a rotating connector 9. The rotating connector 9 can be formed using, for example, a carbon brush, but is not limited thereto. In addition, the bearing device 2 is also electrically connected to the LCR meter 8, and at this time, the LCR meter 8 also functions as an AC power supply for the bearing device 2.

[0046] The diagnostic device 1 operates as a water intrusion detection device capable of executing the detection method of the present embodiment. During diagnosis, the diagnostic device 1 uses the angular frequency ω and the AC voltage V of the AC power source as inputs to indicate the LCR meter 8, and obtains the impedance Z of the bearing device 2 from the LCR meter 8 as the corresponding output. Then, the diagnostic device 1 uses these values ​​to detect information related to the state of the lubricant in the bearing device 2. The details of the detection method will be described later.

[0047] The diagnostic device 1 can be realized, for example, by an information processing device that is constituted as a control device, a storage device, and an output device that are not shown in the figure. 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. The storage device is composed of volatile and non-volatile storage media such as HDD (Hard Disk Drive), ROM (Read Only Memory), and RAM (Random Access Memory), and can input and output various information according to instructions from the control device. The output device is composed of a display device such as a speaker, a lamp, or a liquid crystal display, and reports to the operator according to instructions from the control device. The notification method of the output device is not particularly limited, for example, it can be an auditory notification based on sound, or it can be a visual notification based on screen output. In addition, the output device can also be a network interface with a communication function, and the notification action can be performed by sending data to an external device (not shown) via a network (not shown). The content of the notification here is not limited to the notification when water intrusion is detected, for example, when water intrusion diagnosis is performed based on the detection result, and may include a notification indicating that the bearing device 2 is normal.

[0048] [Physical Model]

[0049] First, use Figure 2 The contact state between the rolling element 5 and the outer ring 3 (or the inner ring 4 ) in the bearing device 2 will be described. Figure 2 This is a diagram showing the physical model when the ball plate and the disc plate are in contact. The ball plate corresponds to the rolling element, and the disc plate corresponds to the outer ring 3 (or inner ring 4). The h-axis represents the direction of the oil film thickness, and the y-axis represents the direction orthogonal to the oil film thickness direction. In addition, Figure 2 The variables shown are as follows.

[0050] S1: Hertzian contact region

[0051] c: Hertzian contact circle radius (= S1 / 2)

[0052] α: Oil film rupture rate (metal contact ratio) (0≤α<1)

[0053] r b : The radius of the ball bearing

[0054] αS1: Actual contact area (rupture area of ​​oil film)

[0055] h: Oil film thickness

[0056] h1: Oil film thickness in the Hertzian contact region

[0057] In the Hertzian contact region, the ratio of the metal contact range to the non-contact range is α:(1-α). In addition, in the ideal state where the ball plate and the disc plate are not in contact, α=0, and when y=0, h>0.

[0058] Figure 2 The oil film thickness h shown is expressed by the following formula.

[0059] h=0(-αS1 / 2≤y≤αS1 / 2)

[0060] h=h1(-c≤y<-αS1 / 2, or αS1 / 2 <y≤c)

[0061] h=h1+√(r b 2 -c 2 )-√(r b 2 -y 2 ) (-r b ≤y<-c or c <y≤r b ) (1)

[0062] It should be noted that in an actual rolling bearing, the rolling element 5 undergoes elastic deformation when subjected to a load, and is therefore not strictly a sphere, but in this embodiment, the rolling element 5 is regarded as a sphere and the above formula (1) is used. Therefore, the formula used when calculating the oil film thickness is not limited to formula (1), and other calculation formulas may also be used.

[0063] Figure 3 1 is a diagram showing a geometrical model of a rolling bearing. The x-axis represents an axial direction perpendicular to the y-axis and the h-axis. Figure 3 The variables shown are as follows. Figure 2 The same symbols correspond.

[0064] R x : Effective radius (x-axis)

[0065] R y : Effective radius (y axis)

[0066] h1: Oil film thickness in the Hertzian contact region

[0067] r b : The radius of the ball bearing

[0068] like Figure 3As shown in FIG. 1 , a case where the rolling element 5 rotates about the y-axis and a load (axial load) is applied in the y-axis direction will be described.

[0069] [Equivalent circuit]

[0070] Figure 4 It is expressed as an electrically equivalent circuit (equivalent circuit) Figure 2 The physical model shown in FIG. The equivalent circuit E1 includes a resistor R1, a resistor R2, a capacitor C1, and a capacitor C2. The resistor R1 corresponds to the resistor in the rupture region (=αS1). The resistor R2 corresponds to the resistor around the rupture region. The capacitor C1 corresponds to the capacitor formed by the oil film in the Hertzian contact region, and is set to the electrostatic capacitance C1. The capacitor C2 corresponds to the capacitor formed by the surrounding of the Hertzian contact region ( Figure 2 -r b ≤y<-c and c<y≤r b ) is formed by the oil film, and is defined as the electrostatic capacitance C2. The Hertzian contact region (= S1) forms a parallel circuit of the resistor R1 and the capacitor C1 in the equivalent circuit E1. In addition, the Hertzian contact region forms a parallel circuit of the resistor R2 and the capacitor C2 in the equivalent circuit E1. Furthermore, by connecting these parallel circuits in parallel, the equivalent circuit E1 is formed. At this time, in the vicinity of the Hertzian contact region ( Figure 2 -r b ≤y<-c and c<y≤r b ) is filled with lubricant.

[0071] The impedance of the equivalent circuit E1 is represented by Z. Here, the AC voltage V applied to the equivalent circuit E1, the current I flowing through the equivalent circuit E1, and the complex impedance Z of the entire equivalent circuit E1 are represented by the following equations (2) to (4).

[0072] V=|V|exp(jωt) (2)

[0073] I=|I|exp(jωt-jθ) (3)

[0074] Z=V / I=|V / I|exp(jθ)=|Z|exp(jθ) (4)

[0075] j: imaginary number

[0076] ω: angular frequency of AC voltage

[0077] t: time

[0078] θ: Phase angle (phase shift between voltage and current)

[0079] Furthermore, if we focus on one rolling element 5, an equivalent circuit E2 is formed between the outer ring 3 and the rolling element 5, and between the inner ring 4 and the rolling element 5. Here, the upper side is described as a circuit formed by the outer ring 3 and the rolling element 5, and the lower side is described as a circuit formed by the inner ring 4 and the rolling element 5, but the opposite is also possible. Around one rolling element 5, these circuits are connected in series to form an equivalent circuit E2. Furthermore, since a plurality of rolling elements 5 are provided, the equivalent circuit E2 is connected in parallel to form a Figure 4 The equivalent circuit of the rolling bearing as a whole is shown.

[0080] [Water intrusion]

[0081] use Figure 5 and Figure 6 , the intrusion of water into the bearing device 2 of this embodiment is described. Figure 5 This is a conceptual diagram showing a state where water has not penetrated into the lubricant. Figure 5 In (a), the lubricant 500 is filled between the outer ring 4 and the rolling element 5. At this time, as described above, when an AC voltage is applied to the bearing device 2 by the AC power source 501, the lubricant 500 functions as a capacitor.

[0082] on the other hand, Figure 6 This is a conceptual diagram showing the state of water intrusion into the lubricant. Figure 6 In (a), lubricant 600 is filled between the outer ring 4 and the rolling element 5, and water 601 intrudes into a portion of the lubricant 600. In this state, when an AC voltage is applied to the bearing device 2 via an AC power supply 602, the lubricant 600 functions as a capacitor, but due to the influence of the intruding water 601, the lubricant 600 is not as good as the bearing device 2. Figure 5 This assumes that the current tends to flow more easily due to the influence of water 601 invading the lubricant 600. In other words, when water does not invade the lubricant Figure 5 In the state (b), it becomes Figure 6 The state (b) is a state in which it is difficult for current to flow compared to the state in which current is difficult to flow.

[0083] [Sweep of AC power frequency]

[0084] Figure 7 This is a diagram for explaining a detection example obtained when the frequency of the AC power supply is swept for the bearing device 2 according to the present embodiment. Figure 7 (a) means focusing on Figure 4 The illustrated embodiment shows a parallel circuit of a resistor R and a capacitor C, which is a part of the equivalent circuit of the bearing device 2 . Figure 7 (b) The Nyquist plot is used to represent Figure 7 The equivalent circuit shown in (a) shows the impedance obtained when the AC power source is applied while sweeping the frequency. Figure 7 In (b), the horizontal axis represents the real part of the complex impedance Z (Z real part), and the vertical axis represents the imaginary part of the complex impedance Z (-Z imaginary part).

[0085] like Figure 7 As shown by the arrow in (b), in the equivalent circuit around the lubricant, a semicircular change is shown when the frequency of the AC power supply is swept from low frequency to high frequency. The applicant has determined that such a characteristic changes when water intrudes into the lubricant. An example of a specific change will be described later as a test result.

[0086] [Processing Flow]

[0087] Figure 8 This process is executed by the diagnostic device 1 , and can be realized by, for example, a control device (not shown) included in the diagnostic device 1 reading and executing a program for realizing the process of this embodiment from a storage device (not shown).

[0088] In S801, the diagnostic device 1 starts the rotation of the rotating shaft 7 through the motor 10. As a result, the inner ring 4 connected to the rotating shaft 7 starts to rotate. In addition, the control of the motor 10 can also be performed by a device different from the diagnostic device 1. At this time, it can also be controlled to apply a constant load (for example, an axial load). In addition, the control of applying the load can also be performed by a device different from the diagnostic device 1.

[0089] In S802 , diagnostic device 1 controls LCR meter 8 to supply AC voltage V of angular frequency ω to bearing device 2 while sweeping the frequency using an AC power source (not shown) provided in LCR meter 8 . Thus, AC voltage V of angular frequency ω is applied to bearing device 2 .

[0090] In S803, the diagnostic device 1 obtains impedance Z as an output for the input of S802 from the LCR meter 8. That is, the LCR meter 8 outputs impedance Z (real part, imaginary part) to the diagnostic device 1 as a detection result of the bearing device 2 for the input AC voltage V and the angular frequency ω of the AC voltage.

[0091] In S804, the diagnostic device 1 estimates the change in the equivalent circuit based on the impedance parameter obtained in S803. Figure 3 , Figure 7The output result of the equivalent circuit shown in the figure can be predetermined. On the other hand, in the case where water intrudes into the lubricant, an output result that deviates from the output result corresponding to the equivalent circuit can be determined. In this process, the change of the equivalent circuit is estimated by comparing with the parameters predetermined as the state where water does not intrude into the lubricant. The parameters for the state where water does not intrude can be determined and defined in advance according to the structure of the bearing device 2 and maintained in a storage unit, etc. In addition, since the output result obtained changes according to the degree of water intrusion, the degree of intrusion can be estimated at the same time. An example of a detailed change in the output result will be described later.

[0092] In S805, the diagnostic device 1 detects water intrusion based on the estimated result of S804 and performs a state diagnosis. The diagnostic content here is not particularly limited. For example, it can be configured to set a threshold value for each parameter and diagnose normality or abnormality by comparing with the threshold value. In addition, it can also be configured to pre-set multiple threshold values ​​corresponding to the urgency of the abnormality and diagnose the urgency by comparing with these threshold values.

[0093] In S806, the diagnostic device 1 notifies the user of the diagnostic result obtained in S805. The notification method here is not particularly limited, and may be, for example, a structure in which the presence or absence of water intrusion and its degree are displayed on a screen, or a notification is made by sound. Then, this processing flow ends.

[0094] [Example of water intrusion detection]

[0095] Below, use Fig. 9 , Fig.10 An example of water intrusion detection according to the present embodiment will be described.

[0096] Fig. 9 This is an example of a Nyquist plot showing the detection results obtained by sweeping the frequency (20 Hz to 1 MHz) while the voltage (1 V) of an AC power source is swept. Fig. 9 In FIG. 1 , the horizontal axis represents the real part of the impedance Z (Z real part), and the vertical axis represents the imaginary part of the impedance Z (−Z imaginary part).

[0097] The black circle indicates the detection result when water has not intruded into the lubricant. On the other hand, the white circle indicates the detection result when water has intruded into the lubricant. In this way, a clear difference in output can be identified and determined according to whether water has intruded.

[0098] Fig.10 It focuses on Fig. 9 The lower left part of the Nyquist plot is shown with different scales. Therefore, the experimental conditions are similar to Fig. 9 Same. Fig.10 The difference in the impedance output results obtained depending on whether water enters the lubricant is also obvious.

[0099] Next, Figure 3 The differences in the metal contact and water intrusion that may occur in the structures of the bearing devices shown are explained. Fig.11 The white circle shows the detection result when water intrusion into the lubricant occurs. Fig.10 On the other hand, Fig.11 The black circle in the figure shows an example of the detection result when metal contact between the rolling element and the outer ring (or inner ring) occurs. In this way, it is possible to identify and determine a clear difference in output between the case of water intrusion and the case of metal contact.

[0100] Next, a description will be given of changes in output according to the degree of water intrusion into the lubricant. Fig.12 This is a Nyquist diagram showing the state in which the output changes according to the degree of water intrusion into the lubricant. Here, three examples (intrusion ratios) are shown as water intrusion states, and the intrusion ratio is W0 (=0%) < W1 < W2. In addition, in W2, the lubricant and water are separated.

[0101] like Fig.12 As shown in FIG. 1 , the greater the degree of water intrusion into the lubricant, the more it deviates from the situation where no water intrusion occurs. Therefore, by prescribing the tendency of the output change when the frequency is swept and comparing it with the detection result, the ratio of the intruded water to the lubricant can be estimated. In other words, the characteristics obtained when the frequency is swept will also change according to the water intrusion ratio.

[0102] As described above, according to this embodiment, a method for detecting water intrusion into the lubricant in the bearing device by an electrical method can be provided. In addition, the degree of water intrusion into the lubricant can also be estimated by the method of this embodiment. Moreover, based on these, state diagnosis can be easily performed.

[0103] <Other Implementation Methods>

[0104] In addition, in the present invention, a program or application for implementing the functions of one or more of the above-mentioned embodiments can be supplied to a system or device using a network or storage medium, and one or more processors in a computer of the system or device read and execute the processing of the program to implement the functions.

[0105] Alternatively, the present invention may be implemented by a circuit that implements one or more functions (for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array)).

[0106] Thus, the present invention is not limited to the above-mentioned embodiments, and combining the structures of the embodiments with each other, and changing and applying them by those skilled in the art based on the description in the specification and known technologies are also the intended contents of the present invention and are included in the scope of the protection required.

[0107] As described above, the following matters are disclosed in this specification. (1)

[0109] A water intrusion detection method, characterized in that:

[0110] for detecting the intrusion of water into a lubricant in a device configured to lubricate a plurality of locations with the lubricant,

[0111] The water intrusion detection method has the following features:

[0112] a measuring step of measuring the impedance of the circuit by applying an AC voltage while sweeping a frequency to the circuit composed of the plurality of the portions; and

[0113] The detection step detects the intrusion of water into the lubricant by comparing the characteristics represented by the real and imaginary parts of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real and imaginary parts of the impedance measured in the measurement step.

[0114] According to this structure, a method for detecting water intrusion into the lubricant in the bearing device by an electrical method can be provided. In addition, the degree of water intrusion into the lubricant can also be estimated. Furthermore, based on these, the state diagnosis can be easily performed.

[0115] (2) The water intrusion detection method according to (1), wherein:

[0116] In the detection process, the shape on the Nyquist diagram is used as the characteristic represented by the real part and the imaginary part of the impedance.

[0117] According to this configuration, the intrusion of water into the lubricant can be detected in accordance with the shape on the Nyquist diagram represented by the real part and the imaginary part of the impedance.

[0118] (3) The water intrusion detection method according to (1) or (2), wherein:

[0119] The detection step further detects contact of the plurality of locations by comparing a characteristic represented by a real part and an imaginary part of impedance measured in a state where no water is mixed in the lubricant with a characteristic represented by a real part and an imaginary part of impedance measured in the measurement step.

[0120] According to this configuration, in addition to the presence or absence of water intrusion into the lubricant, contact between components can also be identified and detected.

[0121] (4) The water intrusion detection method according to any one of (1) to (3), wherein:

[0122] The method further includes a diagnosis step of diagnosing a state of the device using the detection result of the detection step.

[0123] According to this configuration, it is possible to diagnose an abnormal state of the device based on the detection result of the intrusion of water into the lubricant.

[0124] (5) The water intrusion detection method according to any one of (1) to (4), wherein:

[0125] The device is a rolling device.

[0126] According to this configuration, it is possible to detect the intrusion of water into the lubricant in the rolling device.

[0127] (6) The water intrusion detection method according to any one of (1) to (4), wherein:

[0128] The device is a bearing device,

[0129] The plurality of parts include an outer member, an inner member and a rolling element.

[0130] According to this configuration, it is possible to detect the intrusion of water into the lubricant in the bearing device. (7)

[0132] A water intrusion detection device, characterized in that:

[0133] for detecting the intrusion of water into a lubricant in a device configured to lubricate a plurality of locations with the lubricant,

[0134] The water intrusion detection device comprises:

[0135] a measuring unit that measures the impedance of the circuit by applying an AC voltage while sweeping a frequency to the circuit composed of the plurality of the portions; and

[0136] The detection unit detects the intrusion of water into the lubricant by comparing the characteristics represented by the real and imaginary parts of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real and imaginary parts of the impedance measured by the measurement unit.

[0137] According to this structure, a method for detecting water intrusion into the lubricant in the bearing device by an electrical method can be provided. In addition, the degree of water intrusion into the lubricant can also be estimated. Furthermore, based on these, the state diagnosis can be easily performed.

[0138] (8) A program, wherein:

[0139] Used to enable the computer to perform the following processes:

[0140] a measuring step of measuring the impedance of a circuit formed by a device configured to lubricate a plurality of parts with a lubricant by applying an AC voltage while sweeping a frequency to the circuit formed by the plurality of parts; and

[0141] The detection step detects the intrusion of water into the lubricant by comparing the characteristics represented by the real part and the imaginary part of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real part and the imaginary part of the impedance measured in the measurement step.

[0142] According to this structure, a method for detecting water intrusion into the lubricant of a bearing device by an electrical method can be provided. In addition, the degree of water intrusion into the lubricant can also be estimated. Furthermore, based on these, the state diagnosis can be easily performed.

[0143] Various embodiments have been described above, but the present invention is certainly not limited to these examples. As long as one skilled in the art can think of various variations or modifications within the scope described in the claims, it is obvious that these variations or modifications also belong to the technical scope of the present invention. In addition, within the scope of not departing from the gist of the invention, the various constituent elements in the above-mentioned embodiments may also be arbitrarily combined.

[0144] In addition, this application is based on the Japanese patent application (Japanese Patent Application No. 2022-114947) filed on July 19, 2022, and the contents are incorporated herein by reference.

[0145] Description of Reference Numerals

[0146] 1 Diagnostic device

[0147] 2 Bearing assembly

[0148] 3 Outer ring (outer part)

[0149] 4 Inner ring (inner part)

[0150] 5 Rolling elements

[0151] 6 Seals

[0152] 7 Rotation axis

[0153] 8 LCR Meter

[0154] 9 Rotary connector

[0155] 10 Motor

Claims

1. A water intrusion detection method, characterized in that: for detecting the intrusion of water into a lubricant in a device configured to lubricate a plurality of locations with the lubricant, The water intrusion detection method has the following features: a measuring step of measuring the impedance of the circuit by applying an AC voltage while sweeping a frequency to the circuit composed of the plurality of the portions; as well as The detection step detects the intrusion of water into the lubricant by comparing the characteristics represented by the real and imaginary parts of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real and imaginary parts of the impedance measured in the measurement step.

2. The water intrusion detection method according to claim 1, characterized in that: In the detection process, the shape on the Nyquist diagram is used as the characteristic represented by the real part and the imaginary part of the impedance.

3. The water intrusion detection method according to claim 1, characterized in that: The detection step further detects contact of the plurality of locations by comparing a characteristic represented by a real part and an imaginary part of impedance measured in a state where no water is mixed in the lubricant with a characteristic represented by a real part and an imaginary part of impedance measured in the measurement step.

4. The water intrusion detection method according to claim 1, characterized in that: The method further includes a diagnosis step of diagnosing a state of the device using the detection result of the detection step.

5. The water intrusion detection method according to any one of claims 1 to 4, characterized in that: The device is a rolling device.

6. The water intrusion detection method according to any one of claims 1 to 4, characterized in that: The device is a bearing device, The plurality of parts include an outer member, an inner member and a rolling element.

7. A water intrusion detection device, characterized in that: for detecting the intrusion of water into a lubricant in a device configured to lubricate a plurality of locations with the lubricant, The water intrusion detection device comprises: a measuring unit that measures the impedance of the circuit by applying an AC voltage while sweeping a frequency to the circuit composed of the plurality of the portions; as well as The detection unit detects the intrusion of water into the lubricant by comparing the characteristics represented by the real and imaginary parts of the impedance measured in a state where no water is mixed into the lubricant with the characteristics represented by the real and imaginary parts of the impedance measured by the measurement unit.

8. A program, characterized in that Used to enable the computer to perform the following processes: A measuring step of measuring the impedance of a circuit formed by a device configured to lubricate a plurality of parts with a lubricant by applying an AC voltage while sweeping a frequency to the circuit formed by the plurality of parts; as well as The detection step detects the intrusion of water into the lubricant by comparing the characteristics represented by the real part and the imaginary part of the impedance measured in a state where the lubricant is not mixed with water with the characteristics represented by the real part and the imaginary part of the impedance measured in the measurement step.

Images