Working machinery

Abstract

To accurately determine the degradation of environmentally friendly lubricants. [Solution] In a work machine comprising a hydraulic oil tank (1), a hydraulic actuator (4), a hydraulic pump (3), a return pipe (12), and a first oil filter (6) provided in the return pipe, the return pipe is provided with an oil sensor (7) for measuring the temperature and properties of the hydraulic oil, a spectrometer (8) for measuring the absorption spectrum of the hydraulic oil, and a bypass oil passage (13) branched from the return pipe. The work machine has a storage device (202) for storing measurement data measured and output by the oil sensor and spectrometer, a database (203) in which the type of hydraulic oil and threshold values ​​for determining the corresponding degree of deterioration are stored in advance, and a calculation device (204) for determining the degree of deterioration of the hydraulic oil. The bypass oil passage (13) is provided with a switching valve (9) and a second oil filter (11) for returning the hydraulic oil.

Description

[Technical Field]

[0001] This invention relates to a work machine. [Background technology]

[0002] In recent years, the use of environmentally friendly lubricants in industrial machinery has been increasing globally, from the perspective of reducing the risk of oil leaks. Industrial machinery requires not only biodegradability but also high sliding performance and oil life in high-load environments, so synthetic ester-based lubricants, which have superior load-bearing capacity and thermal stability compared to naturally derived lubricants, are used. This type of lubricant is more susceptible to oxidation and hydrolysis in high-pressure and high-temperature environments than conventionally used mineral oil-based hydraulic oils, and in some working environments, oxidation can progress extremely quickly, leading to the end of its service life.

[0003] In this case, the risk of accidents caused by insufficient lubrication increases as oil performance deteriorates, so oil changes are recommended. However, synthetic ester-based lubricants are generally more expensive than mineral oil-based hydraulic fluids, resulting in higher costs for oil changes. Using environmentally friendly lubricants is not practical in work environments where oxidation progresses extremely quickly and leads to the limit of use.

[0004] Furthermore, because environmentally friendly lubricants have lower base oil performance than mineral oils, additives are generally used to compensate for the lack of performance. Additives gradually wear down as they perform their function, but there are cases where additives undergo direct hydrolysis under high temperature and pressure, or where contamination with other oils has a fatal impact on the function of the additives. In environmentally friendly lubricants, the risk of malfunction when additives lose their function is higher than in mineral oil-based lubricants, and particular attention must be paid to sudden abnormalities in additives.

[0005] Furthermore, environmentally friendly lubricants include products with adjusted additives to comply with local environmental regulations, and minor modifications to reduce manufacturing costs and lower prices. These are often confused and used interchangeably in the field. However, these products differ in performance and lifespan, and not knowing the exact brand of lubricant being used can lead to unexpected malfunctions.

[0006] Therefore, Patent Document 1 discloses a system comprising a contamination measuring device that monitors the permeability, number of particles, and density of lubricating oil, a bypass oil passage with adjustable flow rate, and a second filter led by the bypass oil passage. This system optimizes the timing of lubricating oil replacement by appropriately adjusting the efficiency of capturing contaminating particles by increasing the bypass flow rate in accordance with the progression of contamination and deterioration.

[0007] Furthermore, Patent Document 2 describes a configuration in which a Raman spectrum of lubricating oil is obtained within a machine, and the degree of deterioration of the lubricating oil is diagnosed based on the correlation between the Raman spectrum and the total acid number of the lubricating oil. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2000-303504 [Patent Document 2] International Publication No. 2021 / 149762 [Overview of the project] [Problems that the invention aims to solve]

[0009] The contamination measuring device described in Patent Document 1 can diagnose the deterioration status using simple sensors such as color sensors and particle counters, but it has the drawback of making it difficult to accurately determine the degree of deterioration. In particular, with environmentally friendly lubricants, there are types of oil that turn black quickly after use even when almost new, and there are also many cases where oxidative deterioration progresses without the presence of contaminating particles.

[0010] Furthermore, since Patent Document 1 only removes contaminating particles and moisture using an oil filter, it is difficult to suppress the oxidative degradation of the lubricating oil. In particular, if the system described in Patent Document 1 is applied to a lubricating oil that is extremely susceptible to oxidative degradation, such as an environmentally friendly lubricating oil, the acid value is likely to rise rapidly, and it is highly probable that it will reach its usage limit.

[0011] Furthermore, since lubricating oils generally deteriorate with an increase in their total acid number, the diagnostic system described in Patent Document 2 is effective for diagnosing the normal deterioration of lubricating oils.

[0012] However, identifying and quantifying additive elements contained in lubricating oil is difficult using Raman spectroscopy as described in Patent Document 2. In actual use of lubricating oil, the consumption or deterioration of additives may not be accompanied by an increase in the total acid number, and in particular, environmentally friendly lubricating oils have lower base oil performance, so the performance degradation when additives are consumed is significant.

[0013] Furthermore, in terms of identifying lubricating oils, the identification and quantification of additive elements is effective. For example, to distinguish a minorly modified environmentally friendly lubricating oil product, in which only the additives have been adjusted, from a conventional product, infrared and near-infrared spectroscopy is more appropriate than Raman spectroscopy as described in Patent Document 2.

[0014] This invention has been made in view of the above circumstances, and its purpose is to provide a work machine that can accurately determine the deterioration of environmentally friendly lubricants and use the lubricants for as long as possible. [Means for solving the problem]

[0015] In order to achieve the above object, one aspect of the present invention provides a working machine comprising: a hydraulic oil tank; a hydraulic actuator; a hydraulic pump that supplies hydraulic oil in the hydraulic oil tank to the hydraulic actuator; a return pipe for returning the hydraulic oil supplied to the hydraulic actuator back to the hydraulic oil tank; and a first oil filter provided in the return pipe for filtering impurities contained in the hydraulic oil, wherein the return pipe is provided with: an oil sensor that measures the temperature and properties of the hydraulic oil; a spectrometer that measures the infrared or near-infrared absorption spectrum of the hydraulic oil; and a bypass oil passage branched from the return pipe and connected to the hydraulic oil tank, the working machine comprises: a storage device that stores measurement data measured and output by the oil sensor and the spectrometer; a database in which types of hydraulic oil and threshold values for determining the degree of deterioration corresponding to the types of hydraulic oil are stored in advance; an arithmetic device that determines the degree of deterioration of the hydraulic oil based on the measurement data and the threshold values; a switching valve provided in the bypass oil passage that opens and closes based on a determination result of the arithmetic device; and a second oil filter that purifies the hydraulic oil flowing through the bypass oil passage, the second oil filter being provided downstream of the switching valve in the bypass oil passage. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a working machine that can accurately determine the deterioration of environmentally friendly lubricating oil and allow the lubricating oil to be used for as long a time as possible. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments. [Brief Description of the Drawings]

[0017] [Figure 1] It is a schematic perspective view of the hydraulic excavator according to the present embodiment. [Figure 2] It is a schematic configuration diagram of a hydraulic circuit of the hydraulic excavator. [Figure 3] It is a block diagram showing a schematic configuration of a management system for a hydraulic excavator. [Figure 4] It is a flowchart showing a flow of processing until specifying an oil type and outputting a threshold value by an arithmetic device. [Figure 5] It is a diagram illustrating the concept of identifying the brand of hydraulic oil from measured density values and outputting a deterioration threshold related to density. [Figure 6] It is a table showing characteristics of absorption spectra of hydraulic oils A, B, and C. [Figure 7] It is a diagram showing absorption spectra obtained from hydraulic oils A and B. [Figure 8] It is a diagram showing absorption spectra of hydraulic oil A having different total acid values. [Figure 9] It is an enlarged diagram of the wavenumber range of 3700~3300cm-1 in FIG. 8. [Figure 10] It is a diagram showing absorption spectra of hydraulic oil B having different additive element concentrations. [Figure 11A] It is a flowchart showing the procedure of processing for opening and closing a switching valve communicating with a reduction filter. [Figure 11B] It is a flowchart showing the procedure of processing for opening and closing a switching valve communicating with a reduction filter. MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, as an embodiment of a working machine according to the present invention, a hydraulic excavator 100 will be described as an example with reference to the drawings.

[0019] FIG. 1 is a schematic perspective view of the hydraulic excavator 100 according to the present embodiment. The hydraulic excavator 100 shown in FIG. 1 includes a crawler-type lower traveling body 103 and an upper revolving structure 102 provided rotatably with respect to the lower traveling body 103. The lower traveling body 103 and the upper revolving structure 102 constitute the vehicle body of the hydraulic excavator 100. Note that the moving mechanism of the lower traveling body 103 is not limited to the crawler type. Furthermore, the hydraulic excavator 100 includes a front working implement 115. The front working implement 115 includes a boom 107, an arm 108, a bucket 109, and hydraulic cylinders 4a, 4b, 4c as hydraulic actuators 4 that drive these components.

[0020] Furthermore, a driver's cab 105, which encloses the driver's seat 104, is provided on the upper rotating body 102. In front of the driver's seat 104 inside the driver's cab 105, a monitor 106 is provided that displays operating information of the hydraulic excavator 100 and recommendations for oil analysis and replacement (described later).

[0021] Operating levers 110L and 110R are provided on either side of the driver's seat 104 inside the driver's cab 105. The operator can operate the front work implement 115 and rotate the upper slewing body 102 by tilting the operating levers 110L and 110R in any direction. The upper slewing body 102 is equipped with a hydraulic circuit HC, which will be described below, for driving the front work implement 115 and the upper slewing body 102.

[0022] Figure 2 is a schematic diagram of the hydraulic circuit HC of the hydraulic excavator 100. As shown in Figure 2, the hydraulic circuit HC includes a hydraulic oil tank 1, a suction filter 2, a hydraulic pump 3, a hydraulic actuator 4, an oil cooler 5, a full-flow filter 6 (first oil filter), an oil sensor 7, a spectrometer 8, a switching valve 9, a flow control valve 10, and a reduction filter 11 (second oil filter). The oil sensor 7 and the spectrometer 8 are electrically connected to a storage device 202.

[0023] The hydraulic fluid in the hydraulic fluid tank 1 is pumped up by the hydraulic pump 3 and supplied to the hydraulic actuator 4. Afterward, the hydraulic fluid that flows out of the hydraulic actuator 4 is cooled by the oil cooler 5 as it flows through the return pipe 12, and then passes through the full-flow filter 6. During this process, impurities in the hydraulic fluid are filtered out by the full-flow filter 6. Finally, the hydraulic fluid is returned to the hydraulic fluid tank 1.

[0024] In the hydraulic circuit HC described above, an oil sensor 7 and a spectrometer 8 for measuring the absorption spectrum of the hydraulic fluid are installed between the full-flow filter 6 of the return pipe 12 and the hydraulic fluid tank 1. The oil sensor 7 measures the viscosity, density, dielectric constant, and other oil properties of the hydraulic fluid passing through the oil passage, as well as its temperature, and the spectrometer 8 measures the absorption spectrum of the hydraulic fluid. This measurement data is stored in the storage device 202.

[0025] Furthermore, in the hydraulic circuit HC described above, a bypass oil passage 13 is provided between the full-flow filter 6 and the hydraulic oil tank 1, downstream of the oil sensor 7, which branches off from the return pipe 12 and is connected to the hydraulic oil tank 1. This bypass oil passage 13 is normally closed by a switching valve 9.

[0026] The switching valve 9 is a solenoid valve and opens and closes according to a command signal output from the hydraulic excavator controller 205 (see Figure 3) based on the results of calculations described later. When the switching valve 9 is open, 1 to 5% of the hydraulic fluid returning to the hydraulic fluid tank 1 is directed to the reduction filter 11 by the flow control valve 10. Note that the switching valve 9 and the flow control valve 10 can also be configured as a single valve.

[0027] The reduction filter 11 is an oil filter that adsorbs oxides contained in the oil, and has the effect of lowering the total acid value of the hydraulic fluid by adsorbing oxidation products. For example, the reduction filter 11 can adopt the configuration described in Japanese Patent Application Publication No. 2011-162655.

[0028] Figure 3 is a block diagram showing the schematic configuration of the management system 200 for the hydraulic excavator 100.

[0029] As shown in Figure 3, the management system 200 according to this embodiment includes a hydraulic excavator 100, a service computer 206, and a business office server 207. The hydraulic excavator 100, the service computer 206, and the business office server 207 are connected to each other via a communication line (wired or wireless).

[0030] The hydraulic excavator 100 includes an oil sensor 7 and a small spectrometer 8 (hereinafter, both may be collectively referred to as the oil sensor and spectrometer 201) incorporated within the hydraulic circuit HC, a storage device 202, a database 203, a computing device 204, and a hydraulic excavator controller 205 (hereinafter abbreviated as controller 205) incorporated within the hydraulic excavator 100.

[0031] The service computer 206 (hereinafter abbreviated as computer 206) is, for example, a portable terminal owned by a service representative or service office. The office server 207 (hereinafter abbreviated as server 207) is, for example, a server owned by the manufacturer of the hydraulic excavator 100.

[0032] The measurement data obtained by the oil sensor and spectrometer 201 is stored in the storage device 202. The calculation unit 204 refers to the measurement data and the database 203 to identify the type of hydraulic fluid, output a threshold for determining hydraulic fluid degradation, and determine the degradation of the hydraulic fluid. The calculation unit 204 then sends an ON / OFF command to the controller 205 for the switching valve.

[0033] Furthermore, the service personnel record maintenance information (type of oil filled, oil change history) in the computer 206, and this information is transmitted to the storage device 202 of the hydraulic excavator 100 and used for calculation processing of the hydraulic excavator 100.

[0034] Furthermore, the manufacturer's administrator can view the measurement data from the storage device 202 and the output data from the computing device 204 via the server 207, and remotely acquire actual operating data of the hydraulic fluid.

[0035] Figure 4 is a flowchart showing the processing flow from the identification of the oil type by the arithmetic unit 204 to the output of the threshold value.

[0036] First, the calculation unit 204 sets initial values ​​for each parameter (S100, 101) from the density, viscosity, dielectric constant, and spectral data (hereinafter referred to as "property data") measured by the oil sensor and spectrometer 201 and stored in the memory device 202. The calculation unit 204 compares these initial values ​​with the property data for each brand and grade stored in the database 203, automatically outputs the brand and grade if a corresponding hydraulic oil exists, and outputs the pre-set degradation judgment thresholds for each hydraulic oil brand from the database 203 (S102-105). The reason for using the data from the first 10 measurements is to prevent data variability. Therefore, if variability can be prevented, this number is not limited to 10.

[0037] If the database 203 and initial values ​​are not found to match the brand name and number, the arithmetic unit 204 refers to the storage device 202 and obtains the brand name and number from the maintenance information entered by the service worker (S106). If the obtained brand name and number are already registered in the database 203, the arithmetic unit 204 obtains the corresponding hydraulic fluid threshold from the database 203 (S107), notifies the server 207 of the mismatch between the measurement data and the input brand name (S108), and obtains and outputs the threshold for the relevant brand name from the database 203 (S109).

[0038] In S108, if the entered brand and viscosity code of the hydraulic fluid are already registered in database 203, but the measured initial value does not match the trend of the corresponding brand in database 203, it is possible that a different type of oil has been mixed in, or that a minor change product of a registered brand is being used. In this case, the hydraulic excavator manufacturer can analyze the data in the storage device 202, conduct interviews with local service personnel and hydraulic fluid manufacturers, and take measures such as adjusting the hydraulic fluid management method.

[0039] In S107, the calculation unit 204 refers to the maintenance information entered by the service worker and determines that an unknown hydraulic fluid is being used if the brand of the hydraulic fluid is not registered in the database 203. The calculation unit 204 then notifies the server 207 of this (S110). Subsequently, the calculation unit 204 outputs a provisional threshold that is applied when the brand and type are unknown (S111).

[0040] The provisional threshold set in S111 monitors the rate of change from the initial values ​​of density and dielectric constant. For example, the rate of change of density and dielectric constant is set to a threshold equivalent to the management standard value of environmentally friendly lubricants distributed in the area of ​​use.

[0041] In the above case, while maintaining the functionality of the oil purification system by a provisional threshold, the hydraulic excavator manufacturer can analyze the data in the memory device 202 and take measures such as adjusting the hydraulic fluid management method by interviewing local service personnel and hydraulic fluid manufacturers.

[0042] Here, the processing of the calculation unit 204, which determines the brand and viscosity from the hydraulic fluid measurement data and sets the corresponding threshold, will be explained using Figures 5 to 10.

[0043] Figure 5 shows a concept that identifies the brand of hydraulic fluid from density measurements and outputs a degradation threshold related to density.

[0044] When the oil sensor 7 records the first 10 measurement values ​​in the storage device 202, the arithmetic unit 204 refers to the temperature-density function for each brand and grade that has been pre-stored in the database 203 and performs a process to narrow down the oil type. For example, since the 10 measurement values ​​shown in Figure 5 match the trend of the temperature-density function of hydraulic oil A, the arithmetic unit 204 determines that the measured hydraulic oil is hydraulic oil A.

[0045] Here, the database 203 has a temperature-threshold formula pre-stored for the density of the hydraulic fluid A, and in S105 and S109 (see Figure 4), the calculation unit 204 outputs the above threshold formula.

[0046] Furthermore, the dielectric constant is processed in the same way as the density, and in S105 and S109, the calculation unit 204 outputs the above threshold formula.

[0047] Furthermore, if the hydraulic fluid cannot be narrowed down to a single type by the density and dielectric constant criteria described above, the calculation unit 204 identifies the type of oil using the absorption spectrum, which will be described later.

[0048] Figure 6 is a table showing the characteristics of the absorption spectra of hydraulic fluids A, B, and C, obtained by FTIR (Fourier Transform Infrared Spectroscopy), which were pre-recorded in database 203.

[0049] Figure 7 also shows an example of FTIR absorbance spectrum data obtained from hydraulic fluid A and hydraulic fluid B.

[0050] Hydraulic fluids have different molecular structures depending on the brand, due to differences in base oils and additives. For example, hydraulic fluid A shown in Figures 6 and 7 is a biodegradable hydraulic fluid with a synthetic ester base oil, containing sulfur-based and phosphorus-based additives, and exhibits a broad peak (wavenumber 745 cm) derived from the P compound. -1 , wave number 970cm -1 ) and a sharp peak (1070 cm) originating from the S compound. -1 ) has.

[0051] On the other hand, hydraulic fluid B shown in Figure 6, like hydraulic fluid A, is a biodegradable hydraulic fluid with a synthetic ester base oil and contains sulfur-based and phosphorus-based additives, but as shown in Figure 7, it has a sharp peak (wavenumber 720 cm) originating from the P compound. -1 , wave number 1000cm -1 ) and small, staccato peaks (1150-1070 cm) originating from S compounds. -1 ) has.

[0052] The database 203 stores, for each brand of hydraulic fluid, characteristics of an absorption spectrum consisting of combinations of the aforementioned peak positions and absorption intensities, and by collating the obtained absorption spectrum with measurement data from the spectroscope 8, the arithmetic unit 204 identifies the brand of the hydraulic fluid.

[0053] Figure 8 is a diagram showing absorption spectra of hydraulic fluid A recovered from an actual machine and having different total acid numbers. Figure 9 is a diagram of 3700~3300cm -1 showing an enlarged view of the range.

[0054] It is known that the absorption spectrum of hydraulic fluid changes as the total acid number (TAN) increases. For example, in hydraulic fluid A using synthetic ester as a base oil shown in Figures 8 and 9, the peak of O-H stretching vibration (at a wave number of 3523cm -1 ) increases as the total acid number rises. In the database 203, as a management reference value for monitoring the total acid number of hydraulic fluid A, a threshold for absorbance change at a wave number of 3523cm -1 is set, and the arithmetic unit 204 uses this threshold to determine oxidative deterioration. For other hydraulic fluids, the wave number of the absorption spectrum to be referenced and the threshold for absorbance change are also set for each respective brand.

[0055] Figure 10 is a diagram showing absorption spectra of hydraulic fluid B having different additive element concentrations.

[0056] Both of the two absorption spectra shown in Figure 10 were measured from hydraulic fluid B; one is from new oil, while the other is a measurement value from oil recovered from an actual machine in which the amount of additive elements has decreased. When these absorption spectra are overlaid, the peak derived from S compounds (1150~930cm -1 ) and the peak derived from P compounds (1020~930cm -1 ) are decreased in deteriorated oil. By measuring the amount of decrease in absorbance in the aforementioned wavelength range relative to new oil, a decrease in the amount of additive elements can be detected.

[0057] With the above configuration, it is possible to detect an increase in the total acid number of the hydraulic fluid and a decrease in additive elements from the measured absorbance spectrum. By combining this with a method for identifying the brand and determining the degree of deterioration by referring to density and dielectric constant, the deterioration of the hydraulic fluid can be accurately captured.

[0058] In the above example, a method was described for detecting an increase in the total acid number and a decrease in additive elements using the absorption spectrum obtained by FTIR. However, a similar configuration can be achieved not only with FTIR, but also with a spectrometer that measures NIR (near-infrared).

[0059] Next, a system that performs oil purification according to the threshold set by the above means will be explained using Figures 11A and 11B.

[0060] Figures 11A and 11B are flowcharts showing the procedure for opening and closing the switching valve 9 leading to the reduction filter 11 using the temperature-threshold formula and the absorbance change threshold set in steps S100 to S111 (see Figure 4).

[0061] Here, the reduction filter 11 incorporated into the bypass oil passage 13 primarily functions to adsorb oxidation products in the hydraulic fluid using ion exchange resin. Since this ion exchange resin undergoes irreversible degradation at high temperatures, proper temperature control is necessary when the reduction filter 11 is permanently installed in the hydraulic circuit. On the other hand, it is known that the efficiency of oil purification decreases at low oil temperatures due to low-temperature viscosity.

[0062] Therefore, the oil sensor and spectrometer 201 measure the temperature, density, dielectric constant, and absorbance (S200), and when the measured temperature is within a predetermined range, the calculation unit 204 continues the process of opening the switching valve 9 (S201). For the reasons mentioned above, it is desirable to set the predetermined temperature range to 50 to 60°C.

[0063] In S202, the computing unit 204 compares the change in absorbance at a specific wavefrequency due to the additive with the threshold set in S105 and 109. If the change in absorbance is above the threshold, there is a risk of a decrease in hydraulic fluid performance due to additive consumption, and since performance recovery by oil purification is difficult, a recommendation for oil analysis and replacement is displayed on the monitor 106 (S203). However, performance degradation due to additive consumption and the countermeasures taken should be avoided as much as possible because it increases the operating cost of the hydraulic fluid. When this recommendation occurs, it is desirable for the computing unit 204 to notify the server 207, analyze the operating information of the storage device 202, and adjust the threshold in the database 203 and the hydraulic fluid operation method.

[0064] In S204, the calculation unit 204 compares the measured density, dielectric constant, and absorbance changes with the thresholds set in S105 and 109. If all items are within the thresholds, the calculation unit 204 determines that the hydraulic fluid is normal and returns to S200. If any of the measured values ​​are outside the thresholds, the calculation unit 204 determines that the hydraulic fluid is deteriorated, and the controller 205 opens the switching valve 9. Then, some of the hydraulic fluid passing through the return pipe 12 is guided to the reduction filter 11 via the bypass oil passage 13, and the oil purification process begins (S205).

[0065] The oil sensor and spectrometer 201 continue to measure temperature, density, dielectric constant, and absorbance even after the switching valve 9 is opened (S206). In S207, if the measured temperature is outside the predetermined range, the controller 205 closes the switching valve 9 to protect the reduction filter 11 and interrupts the oil purification process (S209).

[0066] If the measured temperature is within a predetermined range, the calculation unit 204 determines whether the hydraulic fluid has deteriorated by comparing the measured density, dielectric constant, and absorbance changes with thresholds (S208). If the density, dielectric constant, and absorbance changes are all within the thresholds (S208 / Yes), the calculation unit 204 determines that the oil purification is complete, and the controller 205 closes the switching valve 9 (S209). If any of the items exceeds the threshold (S208 / NO), the calculation unit 204 determines that the hydraulic fluid has deteriorated, continues the oil purification process, and returns to the measurement in S206 (via S210).

[0067] Furthermore, if, despite performing oil purification treatment for a sufficient amount of time in S208, it is determined that the hydraulic fluid has deteriorated after n repetitions, the calculation unit 204 determines that either the reduction filter 11 or the hydraulic fluid has reached its usage limit (S210 / Yes). Next, the calculation unit 204 determines whether the reduction filter 11 has reached its usage limit by referring to the cumulative opening time of the switching valve 9 (S211).

[0068] If the switching valve 9 has been open for more than the specified (X) hours (S211 / Yes), the calculation unit 204 determines that the reduction filter 11 has reached its usage limit. The controller 205 then displays a recommendation on the monitor 106 to replace the reduction filter 11 (S212). Otherwise (S211 / Yes), the calculation unit 204 determines that the reduction filter 11 is still functional and that the hydraulic fluid has reached its usage limit. The controller 205 then displays a recommendation on the monitor 106 to analyze and replace the hydraulic fluid (S213).

[0069] As described above, this embodiment allows for accurate determination of the degradation of environmentally friendly lubricants with low oxidation stability, and as a result, these environmentally friendly lubricants can be used for as long as possible with fewer replacements. Therefore, operating costs can be reduced.

[0070] More specifically, the hydraulic excavator 100 according to this embodiment is equipped with an oil sensor 7 for measuring the temperature and properties of the hydraulic fluid, and a spectrometer 8 for measuring the infrared or near-infrared absorption spectrum of the hydraulic fluid, so that the deterioration state of the hydraulic fluid can be measured with high accuracy.

[0071] The calculation unit 204 can then accurately determine the deterioration of the hydraulic fluid by referring to the measured hydraulic fluid data and the type and threshold of the hydraulic fluid stored in the database 203. As a result, the switching valve 9 can be opened at an appropriate timing, allowing the hydraulic fluid to flow to the reduction filter 11 for purification. Therefore, environmentally friendly lubricating oil can be used for extended periods.

[0072] Furthermore, since the measurement data stored in the storage device 202 and the judgment results of the arithmetic unit 204 can be viewed via the server 207, lubricant management can be easily performed remotely. In addition, since the types of hydraulic fluids and their corresponding thresholds stored in the database 203 can be updated via the server 207, lubricant degradation can be judged more accurately.

[0073] Furthermore, since the type of hydraulic fluid and the history of fluid changes can be manually entered from the computer 206 to the storage device 202, the arithmetic unit 204 can more accurately determine the deterioration of the hydraulic fluid.

[0074] Furthermore, various information and warnings regarding the deterioration of the hydraulic fluid are displayed on monitor 106 and also sent to server 207, allowing operators and administrators to easily understand the timing for managing and replacing the hydraulic fluid.

[0075] Furthermore, it is possible to distinguish between minorly modified versions of environmentally friendly lubricants circulating locally based on sensor information, and by analyzing the data in the storage device 202, it is possible to easily adjust management standards and management methods.

[0076] The present invention is not limited to the embodiments described above, and includes various modifications that do not depart from the spirit of the invention. For example, the present invention is not limited to having all the configurations described in the embodiments described above, but also includes configurations in which some of the configurations are omitted. Furthermore, it is possible to add or replace a part of the configuration of one embodiment with a configuration of another embodiment. Other embodiments that can be conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0077] In the above embodiment, an example of applying the present invention to a hydraulic excavator 100 was described, but the present invention can be applied to any work machine other than a hydraulic excavator, such as a wheel loader or a forklift. [Explanation of symbols]

[0078] 1: Hydraulic oil tank 2: Suction filter 3: Hydraulic pump 4(4a, 4b, 4c): Hydraulic cylinder (hydraulic actuator) 5: Oil cooler 6: Full-flow filter (first oil filter) 7. 201: Oil sensor 8, 201: Spectrometer 9: Switching valve 10: Flow control valve 11: Reduction filter (second oil filter) 12: Return piping 13: Bypass oil channel 100: Hydraulic excavator (working machine) 200: Management System 202: Storage device 203: Database 204: Arithmetic device 205: Controller for hydraulic excavators 206: Service Computer 207: Office Server (External Server)

Claims

1. A work machine comprising a hydraulic oil tank, a hydraulic actuator, a hydraulic pump for supplying hydraulic oil from the hydraulic oil tank to the hydraulic actuator, a return pipe for returning the hydraulic oil supplied to the hydraulic actuator to the hydraulic oil tank, and a first oil filter provided in the return pipe for filtering out impurities contained in the hydraulic oil, The aforementioned return piping includes: An oil sensor that measures the temperature and properties of the hydraulic fluid, A spectrometer for measuring the infrared or near-infrared absorption spectrum of hydraulic fluid, A bypass oil passage is provided, branching off from the aforementioned return pipe and connected to the aforementioned hydraulic oil tank. The aforementioned work machine is A storage device that stores the measurement data measured and output by the oil sensor and the spectrometer, A database in which the type of hydraulic fluid and threshold values ​​for determining the degree of deterioration corresponding to the type of hydraulic fluid are pre-stored, The system includes a calculation device that determines the degree of deterioration of the hydraulic fluid based on the measurement data and the threshold value, A switching valve is provided in the bypass oil passage and opens and closes based on the determination result of the calculation device, A work machine characterized in that a second oil filter is provided downstream of the switching valve in the bypass oil passage for returning the hydraulic fluid flowing through the bypass oil passage.

2. In the work machine described in claim 1, The system includes a controller that controls the aforementioned switching valve, The aforementioned controller, A working machine characterized in that, when the calculation device determines that the hydraulic fluid has deteriorated and the hydraulic fluid is within a predetermined temperature range, the switching valve is opened so that the hydraulic fluid flows through the bypass oil passage and is returned by the second oil filter.

3. In the work machine described in claim 1, A work machine characterized by transmitting the measurement data stored in the storage device and the determination results of the calculation device so that they can be viewed on an external server.

4. In the work machine described in claim 1, A work machine characterized in that the types of hydraulic fluids and the corresponding threshold values ​​stored in the database can be updated by an external server.

5. In the work machine described in claim 1, The aforementioned database pre-stores, for each brand and viscosity of hydraulic fluid, the correlation formula between temperature, dielectric constant, and density, as well as the absorbance of the absorption spectrum at a specified frequency. The aforementioned computing device is characterized by automatically detecting the brand and viscosity of the hydraulic fluid by comparing the measurement data output to the storage device with the database.

6. In the work machine described in claim 5, The aforementioned database pre-stores threshold values ​​for changes in dielectric constant and absorbance, which serve as criteria for determining deterioration, for each brand and viscosity of hydraulic fluid. The work machine is characterized in that the database outputs the threshold values ​​corresponding to the automatically detected hydraulic fluid brand and grade to the calculation device.

7. In the work machine described in claim 5, If the brand and viscosity of the hydraulic fluid that matches the measurement data output to the storage device does not exist in the database, The work machine is characterized in that the calculation device refers to the brand and type of hydraulic fluid manually entered into the storage device, and if the corresponding brand and type of hydraulic fluid exists in the database, the database provisionally outputs a threshold value for the hydraulic fluid to the calculation device, and the calculation device notifies an external server of the mismatch between the measurement data and the input brand.

8. In the work machine described in claim 5, A work machine characterized in that, when the brand and viscosity of hydraulic fluid that matches the measurement data output to the storage device does not exist in the database, and there is no threshold corresponding to the manually entered brand and viscosity of hydraulic fluid, the database provisionally outputs a threshold for unknown brands to the calculation device, and the calculation device notifies an external server of the use of unknown hydraulic fluid.

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