JP5853265B2 - Lubrication target part diagnosis method - Google Patents

Description

  The present invention relates to a lubrication target part diagnosis method, and more particularly to a lubrication target part diagnosis method capable of diagnosing a lubrication target part including a resin sliding material with high accuracy.

  Conventionally, in sliding bearings used in water turbine generators, etc., the oil film formed on the sliding surface tends to be thin at low speeds when starting and stopping, and mixed lubrication and partly mixed fluid lubrication and solid contact In this case, boundary lubrication or the like where metal contact occurs may cause the bearing surface to become coarse and cause damage such as seizure or burnout. Therefore, introduction of resin-made sliding bearings, which are superior in wear resistance and slidability as compared with metallic sliding bearings such as white metal, has been promoted.

  Here, as a conventional method for diagnosing a metal sliding bearing, there is known a method for diagnosing a lubrication state by inspecting metal wear particles and the like generated by friction and wear (see, for example, Patent Documents 1 and 2). . Patent Document 1 discloses a method for diagnosing a lubrication state by ferrography. Patent Document 2 discloses a method for diagnosing a lubrication state by analyzing the concentration of metal elements in oil. According to these techniques of Patent Documents 1 and 2, it is possible to optimize the periodic inspection cycle and overhaul execution cycle of the slide bearing. However, since the technique of these patent documents 1 and 2 makes the inspection object a metal particle, it cannot apply to the above-mentioned resin sliding bearing.

JP 2004-20444 A JP 2003-344293 A

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a lubrication target portion diagnosis method capable of diagnosing a lubrication target portion including a resin sliding material with high accuracy.

The present inventors have found that there is a specific correlation between the size and type of wear particles and the lubrication state of the lubrication target portion provided with the resin sliding material, and have completed the present invention. It was.
In order to solve the above-mentioned problem, the invention according to claim 1 is a method for diagnosing a lubrication target part including a resin sliding material including a reinforcing fiber, and the size and type of wear particles contained in the lubricating fluid. A first diagnostic processing step of diagnosing the lubrication target portion based on the first diagnostic processing step, wherein the lubricating fluid contains rod-like fiber wear particles made of the reinforcing fibers and has a maximum length. When the final resin wear particles exceeding the upper limit of the predetermined numerical range are included, it is determined that the lubrication state of the lubrication target portion is abnormal, and the fiber wear particles and the final wear particles are contained in the lubricating fluid. When the resin wear particles are not included, and the medium length resin wear particles whose maximum length is within the predetermined numerical range are included, the lubrication state of the lubrication target portion is a caution. Determining, in the lubricating fluid, said fiber wear particles, When the final resin wear particles and the medium-term resin wear particles are not included, and the initial resin wear particles whose maximum length is less than the lower limit of the predetermined numerical range are included, The gist is to determine that the lubrication state of the lubrication target portion is normal.
The invention according to claim 2 includes a second diagnosis processing step of diagnosing the lubrication target portion based on the wear depth and wear speed of the resin sliding material according to claim 1, and the second diagnosis processing. The process is based on the resin component concentration in the lubricating fluid analyzed by pyrolysis chromatography, and the wear depth (Dp) of the resin sliding material and the wear rate indicating the rate of change of the wear depth over time. (Wsp) is calculated, and when the wear depth (Dp) exceeds a predetermined first reference value (C1), it is determined that the lubrication state of the lubrication target portion is abnormal, and the wear is performed. When the speed (Wsp) exceeds a predetermined second reference value (C2) and the wear depth (Dp) is equal to or less than a predetermined third reference value (C3) smaller than the predetermined first reference value. , It is determined that the lubrication state of the lubrication target part needs attention, When the wear depth (Dp) is not more than the predetermined first reference value (C1) or the wear speed (Wsp) is not more than the predetermined second reference value (C2), the lubrication target The gist is to determine that the lubrication state of the part is normal.
According to a third aspect of the present invention, in the second aspect, the wear rate (Wsp) exceeds the predetermined second reference value (C2), and the wear depth (Dp) is the predetermined third value. The gist is that when the reference value (C3) is exceeded, it is determined that the resin sliding material exceeds the use limit.

According to the lubrication target part diagnosis method of the present invention, when the lubricating fluid contains fiber wear particles and final resin wear particles, it is determined that the lubrication state of the lubrication target part is abnormal, and the lubricating fluid contains When the fiber wear particles and the final resin wear particles are not included, and the medium-term resin wear particles are included, it is determined that the lubrication state of the lubrication target portion needs attention, and in the lubricating fluid If the fiber wear particles, the final resin wear particles and the medium resin wear particles are not included, and the initial resin wear particles are included, the lubrication state of the lubrication target part is normal. Determined. As described above, since the lubrication target portion is diagnosed based on the size and type of the wear particles, the lubrication target portion including the resin sliding material can be diagnosed with high accuracy.
Further, based on the resin component concentration in the lubricating fluid analyzed by pyrolysis chromatography, the wear depth (Dp) of the resin sliding material and the wear rate indicating the rate of change of the wear depth over time ( Wsp), and when the wear depth (Dp) exceeds a predetermined first reference value (C1), it is determined that the lubrication state of the lubrication target portion is abnormal, and the wear rate (Wsp) exceeds a predetermined second reference value (C2) and the wear depth (Dp) is equal to or smaller than a predetermined third reference value (C3) smaller than the predetermined first reference value. It is determined that the lubrication state of the lubrication target part needs attention, and the wear depth (Dp) is equal to or less than the predetermined first reference value (C1), or the wear rate (Wsp) is the predetermined value. When the second reference value (C2) or less, When determining that the state is normal, the lubrication target part is diagnosed based on the wear depth (Dp) and wear speed (Wsp) of the resin sliding material in addition to the size and type of the wear particles. The lubrication target part can be diagnosed with higher accuracy.
Further, when the wear rate (Wsp) exceeds the predetermined second reference value (C2) and the wear depth (Dp) exceeds the predetermined third reference value (C3), the resin When it is determined that the sliding material exceeds the use limit, the lubrication target portion can be diagnosed with higher accuracy.

The present invention will be further described in the following detailed description with reference to the drawings referred to, with reference to non-limiting examples of exemplary embodiments according to the present invention. Similar parts are shown throughout the several figures.
It is a flowchart figure which shows the 1st diagnostic process of the sliding bearing part which concerns on an Example. It is a flowchart figure which shows the 2nd diagnostic process of the sliding bearing part which concerns on an Example. It is an image processing figure of the result of having observed the wear particle | grains of the slide bearing (PEEK material) which concerns on an Example with a micro infrared spectroscopy apparatus (micro FT-IR). It is an image processing figure of the result of having observed the abrasion particle of the slide bearing (PTFE material) which concerns on an Example with a micro infrared spectroscopy apparatus (micro FT-IR). It is an image processing figure of the result of having observed the wear particle of the slide bearing (PEEK material) which concerns on an Example with a scanning electron microscope (SEM), (a) shows initial wear particle, (b) (c) Shows medium-term wear particles. It is an image processing figure of the result of having observed the wear particle of the plain bearing (PEEK material) which concerns on an Example with a scanning electron microscope (SEM), (a)-(c) shows a terminal wear particle. It is an image processing figure of the result of having observed the wear particle of the slide bearing (PTFE material) which concerns on an Example with a scanning electron microscope (SEM), (a) shows an initial wear particle, (b) (c). Shows medium-term wear particles. It is an image processing figure of the result of having observed the wear particle of the slide bearing (PTFE material) which concerns on an Example with a scanning electron microscope (SEM), (a)-(c) shows a terminal wear particle.

  The items shown here are exemplary and illustrative of the embodiments of the present invention, and are the most effective and easy-to-understand explanations of the principles and conceptual features of the present invention. It is stated for the purpose of providing what seems to be. In this respect, it is not intended to illustrate the structural details of the present invention beyond what is necessary for a fundamental understanding of the present invention. It will be clear to those skilled in the art how it is actually implemented.

1. Lubrication target part diagnosis method Embodiment 1 The lubrication target part diagnosis method according to the present invention is a lubrication target part diagnosis method comprising a resin sliding material including reinforcing fibers, and the lubricating fluid contains rod-like fiber wear particles made of reinforcing fibers and has a maximum length. When the final resin wear particles exceeding the upper limit of the predetermined numerical range are included, it is determined that the lubrication state of the lubrication target part is abnormal, and the fiber wear particles and the final resin are contained in the lubricating fluid. When the wear particles are not included, and the medium length resin wear particles whose maximum length is within a predetermined numerical range are included, it is determined that the lubrication state of the lubrication target portion needs attention, Lubricating fluid does not contain fiber wear particles, final resin wear particles, and medium-term resin wear particles, and includes initial resin wear particles whose maximum length is less than the lower limit of the predetermined numerical range. The lubrication condition of the lubrication target part is normal. Determining characterized by (for example, see 2, etc. Figure). The term “not included” means that the target wear particles are less than 3% (particularly 1%) of the total number of wear particles, in addition to the state where the target wear particles are not included at all. Some states are also included.

  Examples of the resin sliding material include substrates such as PEEK (polyetheretherketone), PTFE (polytetrafluoroethylene), POM (polyacetal), PF (phenol), PI (polyimide), PAI (polyamideimide), and the like. And those containing reinforcing fibers. In particular, as a resin sliding material used for a bearing of a large rotating machine, PEEK or PTFE contains a reinforcing fiber (for example, carbon fiber, glass fiber, etc.), and has mechanical strength, sliding characteristics and resistance. It is preferable to improve the wear and the like.

  For example, the predetermined numerical range may have a lower limit of 5 to 50 μm (particularly 7 to 30 μm) and an upper limit of 20 to 100 μm (particularly 30 to 80 μm). In particular, when the resin sliding material is made of PEEK resin, the predetermined numerical range is, for example, a lower limit of 10 to 30 μm (particularly 15 to 25 μm) and an upper limit of 40 to 80 μm (particularly 50 to 50 μm). 70 μm). When the resin sliding material is made of PTFE resin, the predetermined numerical range is, for example, a lower limit of 5 to 20 μm (especially 7 to 15 μm) and an upper limit of 20 to 60 μm (particularly 30 to 30 μm). 50 μm). Moreover, the maximum length of the said fiber abrasion particle can be 10-60 micrometers (further 15-55 micrometers, especially 20-50 micrometers), for example. For example, when the resin sliding material is made of PEEK resin containing carbon fibers as reinforcing fibers, the maximum length of the fiber wear particles (carbon fibers) is 10 to 30 μm (further 15 to 25 μm, particularly 17 to 23 μm). Can be. For example, when the resin sliding material is made of PTFE resin containing glass fibers as reinforcing fibers, the maximum length of the fiber wear particles (glass fibers) is 10 to 60 μm (further 15 to 55 μm, particularly 20 to 50 μm). ).

  Embodiment 1 As a method for diagnosing the lubrication target part, for example, based on the resin component concentration in the lubricating fluid analyzed by pyrolysis chromatography, the wear depth (Dp) of the resin sliding material and the time course of the wear depth are determined. A step (steps 1 to 3) for calculating a wear rate (Wsp) indicating a rate of change accompanying the lubrication, and when the wear depth (Dp) exceeds a predetermined first reference value (C1), It is determined that the state is abnormal, the wear rate (Wsp) exceeds a predetermined second reference value (C2), and the wear depth (Dp) is a predetermined third reference value smaller than the predetermined first reference value. (C3) If it is less than or equal to, it is determined that the lubrication state of the lubrication target portion needs attention, and the wear depth (Dp) is less than or equal to a predetermined first reference value (C1) or the wear rate (Wsp ) Is less than or equal to a predetermined second reference value (C2), Embodiment determined slip condition is normal (e.g., see FIG. 1 and the like) can be mentioned.

  In the above-described embodiment, for example, when the wear rate (Wsp) exceeds a predetermined second reference value (C2) and the wear depth (Dp) exceeds a predetermined third reference value (C3), It can be determined that the resin sliding material exceeds the use limit (see, for example, FIG. 1).

  Embodiment 1 As a method for diagnosing a lubrication target portion according to the present invention, for example, a component of wear particles is identified using a micro infrared spectrometer (micro FT-IR) and the wear particles are observed (step S11), and a scanning electron microscope is used. Or the form (for example, refer FIG. 2 etc.) provided with the process (step S14) of observing an abrasion particle using a transmission electron microscope can be mentioned. As a result, the wear particles can be observed accurately, and the diagnostic accuracy of the lubrication target portion is further enhanced.

  Hereinafter, the present invention will be specifically described with reference to the drawings. In the present embodiment, a plain bearing portion is illustrated as the “lubrication target portion” according to the present invention.

(1) Sliding bearing portion diagnosis method The sliding bearing portion diagnosis method in this embodiment is a PEEK sliding bearing (exemplified as a “resin sliding material” according to the present invention) or a PTFE sliding bearing (according to the present invention). This is a method for diagnosing a sliding bearing portion provided as an example of “resin sliding material”. This diagnosis method includes a first diagnosis process (see FIG. 1) based on the wear depth and wear speed described below (see FIG. 1) and a second diagnosis process (see FIG. 2) based on the size and type of wear particles.

  As shown in FIG. 1, the first diagnostic process includes a step (step S1) of analyzing a resin component concentration in lubricating oil (exemplified as “lubricating fluid” according to the present invention) by pyrolysis chromatography, and analysis. A step of calculating the wear depth Dp of the plain bearing based on the resin component concentration (step S2), and a step of calculating the wear speed Wsp based on the wear depth Dp (step S3). . The wear depth Dp is calculated by the following formula (1), and the wear speed Wsp is calculated by the following formula (2).

  In the above-mentioned plain bearing (PEEK), PEEK wear particles in 100 ml of sample oil are separated and extracted by a 0.8 μm silver filter, and the wear particles trapped on the filter are put together with the filter into a thermal decomposition apparatus. Measure the phenol concentration. Moreover, in the above-mentioned slide bearing (PTFE), PTFE wear particles in 100 ml of sample oil are separated and extracted by a 0.8 μm membrane filter, and the wear particles trapped on the filter are put into a thermal decomposition apparatus together with the filter. Measure the fluorine concentration.

  In the first diagnosis process, the first comparison step (step S4) for comparing the wear depth Dp with a predetermined first reference value C1, and the wear speed Wsp with a predetermined second reference value C2. The wear depth Dp and a predetermined third reference value C3 (third reference value C3 <first reference value C1) are compared with the second comparison step (step S7) and the comparison result of the second comparison step. A third comparison step (step S8). The first reference value C1 is an appropriate value indicating the wear depth that reaches the limit of use of the slide bearing. Further, the second reference value C2 is an appropriate value indicating how much the remaining remaining operating time of the sliding bearing portion is used. Further, the third reference value C3 is an appropriate value indicating the wear depth in the region where the wear of the sliding bearing portion is proceeding.

  In the first comparison step, when the wear depth Dp is less than the predetermined first reference value C1 (No determination in step S4), it is determined that the lubrication state of the sliding bearing portion is healthy (that is, normal). (Step S5). On the other hand, when the wear depth Dp exceeds the predetermined first reference value C1 in the first comparison step (Yes in step S4), the lubrication state of the slide bearing portion is abnormal (that is, the slide bearing portion It is determined that inspection is necessary) (step S6).

  Further, when the wear speed Wsp is less than the predetermined second reference value C2 in the second comparison step (No determination in step S7), it is determined that the lubrication state of the sliding bearing portion is healthy (that is, normal) ( Step S5). On the other hand, when the wear speed Wsp exceeds the predetermined second reference value C2 in the second comparison process (Yes in step S7) and the wear depth Dp is less than the predetermined third reference value C3 in the third comparison process (step If the lubrication state of the sliding bearing portion needs attention (that is, it is necessary to shorten the diagnostic cycle of the sliding bearing portion) (No in S8) (step S9). Furthermore, when the wear speed Wsp exceeds the predetermined second reference value C2 in the second comparison step (Yes in step S7) and the wear depth Dp exceeds the predetermined third reference value C3 in the third comparison step ( In step S8 (Yes determination), it is determined that the sliding bearing portion exceeds the use limit (step S10).

  As shown in FIG. 2, the second diagnostic process includes a first observation step of identifying the components of the wear particles in the lubricating oil and observing the wear particles using a micro infrared spectrometer (micro FT-IR) ( Step S11), a step of determining the presence or absence of medium-term wear particles based on the observation results (Step S12), and a second observation step of observing the wear particles in the lubricating oil using a scanning electron microscope (SEM) (Step S14) and a step of determining the presence or absence of final wear particles based on the observation result (step S15).

  In the first observation step, wear particles in the sample oil are separated and extracted by a filter, the filter is set as it is in a micro infrared spectrometer, and the wear particles on the filter are analyzed one by one. Here, in the sliding bearing (PEEK), in the first observation step, as shown in FIG. 3, the resin component is identified and the wear particles are observed. On the other hand, in the slide bearing (PTFE), in the first observation step, as shown in FIG. 4, the resin component is identified and the wear particles are observed.

  In the slide bearing (PEEK), as shown in FIG. 5A, initial wear particles are flakes having a maximum length of less than 20 μm, and very thin resin wear particles are observed. Further, as medium-term wear particles, flaky resin wear particles having a maximum length of 20 to 60 μm are observed as shown in FIGS. Furthermore, as shown in FIGS. 6A and 6B, rod-like fiber wear particles made of carbon fibers (reinforcing fibers) having a maximum length of about 20 μm included in the slide bearing are observed as final wear particles. As shown in FIG. 6C, large-sized resin wear particles having a maximum length exceeding 60 μm are observed.

  On the other hand, in the slide bearing (PTFE), flaky resin wear particles having a maximum length of less than 10 μm are observed as initial wear particles as shown in FIG. Further, as the medium-term wear particles, as shown in FIGS. 7B and 7C, resin wear particles having a maximum thickness of 10 to 40 μm and a slight thickness are observed. Further, as the final wear particles, rod-like fiber wear particles made of glass fibers (reinforcing fibers) having a maximum length of about 20 to 40 μm included in the slide bearing are observed as shown in FIGS. 8 (a) and 8 (b). Or, as shown in FIG. 8C, large-sized resin wear particles having a maximum length exceeding 40 μm are observed.

  Then, in the second diagnosis process, as shown in FIG. 2, when the presence of medium-term wear particles is not confirmed (No determination in step S12), that is, when the existence of only the initial wear particles is confirmed, slipping occurs. It determines with the lubrication state of a bearing part being healthy (namely, normal) (step S13). On the other hand, if the presence of medium-term wear particles is confirmed (Yes in step S12) and the presence of final wear particles is not confirmed (No determination in step S15), the lubrication state of the sliding bearing portion is a concern. (In other words, it is necessary to shorten the diagnostic cycle of the sliding bearing portion) (step S16). Furthermore, when the presence of medium-term wear particles is confirmed (Yes in step S12) and the presence of final wear particles is confirmed (Yes in step S15), the lubrication state of the sliding bearing portion is abnormal. (In other words, it is necessary to check the sliding bearing portion) (step S17).

  When different diagnosis results are obtained in the first and second diagnosis processes, one diagnosis result (for example, the worse diagnosis result) may be selected, or a new one may be selected based on both diagnosis results. You may make it give a diagnostic result.

(2) Effect of Example As described above, according to the slide bearing part diagnosis method of this example, when the lubricating oil contains fiber wear particles and final resin wear particles, the lubrication state of the slide bearing part is When the lubricating oil does not contain fiber wear particles and final resin wear particles and does not contain medium-term resin wear particles, the lubrication state of the sliding bearing portion is determined to be abnormal. When it is determined that it is important to note that the lubricant fluid does not contain fiber wear particles, final resin wear particles, and medium resin wear particles, and initial resin wear particles. It is determined that the lubrication state of the sliding bearing portion is normal. Thus, since the slide bearing portion is diagnosed based on the size and type of the wear particles, the slide bearing portion including the resin sliding material made of PEEK or PTFE can be diagnosed with high accuracy.

  Further, in this example, the wear rate indicating the wear depth Dp of the resin sliding material and the rate of change with time of the wear depth based on the resin component concentration in the lubricating oil analyzed by pyrolysis chromatography. Since the step of calculating Wsp is provided, when the wear depth Dp exceeds the predetermined first reference value C1, it is determined that the lubrication state of the sliding bearing portion is abnormal, and the wear speed Wsp is determined to be the predetermined second reference. When the value C2 is exceeded and the wear depth Dp is equal to or less than a predetermined third reference value C3, it is determined that the lubrication state of the slide bearing portion is a caution, and the wear depth Dp is a predetermined first reference. When the value is equal to or less than the value C1 or the wear rate Wsp is equal to or less than the predetermined second reference value C2, it is determined that the lubrication state of the plain bearing portion is normal. Thereby, since the slide bearing portion is diagnosed based on the wear depth and wear speed of the resin sliding material in addition to the size and type of the wear particles, the slide bearing portion can be diagnosed with higher accuracy.

  Furthermore, in this embodiment, when the wear speed Wsp exceeds the predetermined second reference value C2 and the wear depth Dp exceeds the predetermined third reference value C3, the resin sliding material exceeds the use limit. Therefore, the slide bearing can be diagnosed with higher accuracy.

  In the present invention, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention depending on the purpose and application. That is, in the above-described embodiment, the sliding bearing portion is exemplified as the lubrication target portion. However, the present invention is not limited to this, and may be, for example, a rolling bearing portion, a gear portion, or a sliding portion of a contact switching mechanism in a transformer. Moreover, in the said Example, although the sliding material made from PEEK or PTFE was illustrated as a resin sliding material, it is not limited to this, For example, it is good also as a sliding material which consists of resin excellent in other slidability. . Furthermore, in the said Example, although lubricating oil was illustrated as a lubricating fluid, it is not limited to this, For example, it is good also as grease, air, etc.

  The foregoing examples are for illustrative purposes only and are not to be construed as limiting the invention. Although the invention has been described with reference to exemplary embodiments, it is to be understood that the language used in the description and illustration of the invention is illustrative and exemplary rather than limiting. As detailed herein, changes may be made in its form within the scope of the appended claims without departing from the scope or spirit of the invention. Although specific structures, materials and examples have been referred to in the detailed description of the invention herein, it is not intended to limit the invention to the disclosure herein, but rather, the invention is claimed. It covers all functionally equivalent structures, methods and uses within the scope.

  The present invention is not limited to the embodiments described in detail above, and various modifications or changes can be made within the scope of the claims of the present invention.

  It is widely used as a technique for diagnosing a lubrication target portion provided with a resin sliding material.

  S1; resin component concentration analysis step, S2; wear depth calculation step, S3; wear rate calculation step, S4; first comparison step, S7; second comparison step, S8; third comparison step, S11, S14 An observation process of wear particles.

Claims (3)

A lubrication target part diagnosis method comprising a resin sliding material containing reinforcing fibers,
A first diagnostic processing step of diagnosing the lubrication target portion based on the size and type of wear particles contained in the lubricating fluid;
The first diagnostic processing step includes
When the lubricating fluid contains rod-like fiber wear particles composed of the reinforcing fibers and the final resin wear particles whose maximum length exceeds the upper limit of a predetermined numerical range, the lubrication target It is determined that the lubrication state of the part is abnormal,
When the fiber wear particles and the final resin wear particles are not included in the lubricating fluid, and the medium length resin wear particles having a maximum length within the predetermined numerical range are included, It is determined that the lubrication state of the lubrication target portion needs attention,
An initial resin that does not contain the fiber wear particles, the final resin wear particles, and the medium-term resin wear particles in a lubricating fluid, and has a maximum length that is less than the lower limit of the predetermined numerical range. A method for diagnosing a lubrication target part, comprising determining that the lubrication state of the lubrication target part is normal when wear particles are included. A second diagnostic processing step of diagnosing the lubrication target portion based on the wear depth and wear speed of the resin sliding material;
The second diagnostic processing step includes
Based on the concentration of the resin component in the lubricating fluid analyzed by pyrolysis chromatography, the wear depth (Dp) of the resin sliding material and the wear rate (Wsp) indicating the rate of change of the wear depth over time Comprising the step of calculating
When the wear depth (Dp) exceeds a predetermined first reference value (C1), it is determined that the lubrication state of the lubrication target portion is abnormal,
The wear rate (Wsp) exceeds a predetermined second reference value (C2), and the wear depth (Dp) is equal to or less than a predetermined third reference value (C3) smaller than the predetermined first reference value. In this case, it is determined that the lubrication state of the lubrication target portion is a caution,
When the wear depth (Dp) is less than or equal to the predetermined first reference value (C1) or the wear rate (Wsp) is less than or equal to the predetermined second reference value (C2), the lubrication target The lubrication target part diagnosis method according to claim 1, wherein the lubrication state of the part is determined to be normal.   When the wear rate (Wsp) exceeds the predetermined second reference value (C2) and the wear depth (Dp) exceeds the predetermined third reference value (C3), the resin sliding The lubrication target part diagnosis method according to claim 2, wherein the material is determined to exceed a use limit.