Turbidity determination device

Abstract

A turbidity determination device (10) for determining turbidity of hydraulic oil comprises a member (40) to be imaged, an imaging unit (35), and a determination unit (25). The member (40) forms a bright part and a dark part. The imaging unit (35) is positioned at a distance from the member (40) such that hydraulic oil is present between the imaging unit (35) and the member (40). The imaging unit (35) acquires an image of the member (40) as an image for determination. The determination unit (25) determines the degree of turbidity of the hydraulic oil on the basis of a gradation difference between the bright part and the dark part in said image.

Description

Turbidity detection device

[0001] The present disclosure relates to a turbidity determination device and a turbidity determination system for determining the degree of turbidity of hydraulic oil.

[0002] For example, hydraulic oil is used to operate hydraulic equipment such as hydraulic cylinders installed in machine tools. Hydraulic oil gradually deteriorates due to contamination with foreign matter, oxidation, etc. Devices for determining the condition of hydraulic oil have been known. Patent Document 1 discloses a device for determining deterioration of hydraulic oil.

[0003] International Publication No. 2015 / 060457

[0004] Conventional devices for determining the condition of hydraulic oil often require the operator to take a hydraulic oil test sample from the hydraulic equipment and then insert it into the device, making it difficult to use.

[0005] An object of the present disclosure is to provide an easy-to-use turbidity determination device for determining the turbidity of hydraulic oil.

[0006] A first aspect of the present disclosure is a turbidity determination device (10) for determining the turbidity of hydraulic oil of a hydraulic device, comprising: an imaged member (40) that forms a light portion (51) and a dark portion (52); an imaging unit (35) that is provided at a position away from the imaged member (40) so that the hydraulic oil is present between the imaged member (40) and the imaged member (40) and that acquires an image of the imaged member (40) as an image for determination (50); and a determination unit (25) that performs a turbidity determination operation to determine the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portion (51) and the dark portion (52) in the image for determination (50) acquired by the imaging unit (35).

[0007] In the first aspect, the imaging unit (35) acquires an image of the photographed member (40) as a determination image (50). Between the imaging unit (35) and the photographed member (40) is present hydraulic oil whose turbidity is to be determined. The difference in gradation between the light portion (51) and the dark portion (52) in the determination image (50) varies depending on the degree of turbidity of the hydraulic oil present between the imaging unit (35) and the photographed member (40). Therefore, the determination unit (25) determines the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portion (51) and the dark portion (52) in the determination image (50).

[0008] The turbidity determining device (10) of the first aspect can determine the degree of turbidity of hydraulic oil if the hydraulic oil to be determined for turbidity is present between the imaging unit (35) and the photographed member (40). Therefore, by using this turbidity determining device (10), the degree of turbidity of hydraulic oil can be determined without collecting a test sample of the hydraulic oil from the hydraulic equipment.

[0009] A second aspect of the present disclosure is the first aspect, wherein in the turbidity determination operation, the determination unit (25) determines that the smaller the difference in gradation between the light portion (51) and the dark portion (52) in the determination image (50), the higher the degree of turbidity of the hydraulic oil.

[0010] As the degree of turbidity of the hydraulic oil increases, the difference in gradation between the light portion 51 and the dark portion 52 in the determination image 50 decreases. By utilizing this, the determination unit 25 of the second aspect determines the degree of turbidity of the hydraulic oil.

[0011] A third aspect of the present disclosure is the first or second aspect, wherein the turbidity determination operation is an operation in which the determination unit (25) determines the degree of turbidity of the hydraulic oil by comparing the gradation difference between the light portion (51) and the dark portion (52) in the determination image (50) with a reference gradation difference.

[0012] In the third aspect, the determination unit (25) determines the degree of turbidity of the hydraulic oil by comparing the difference in gradation between the light portion (51) and the dark portion (52) in the determination image (50) with a reference difference in gradation.

[0013] A fourth aspect of the present disclosure is the third aspect, wherein the reference gradation difference is the gradation difference between the bright area (51) and the dark area (52) in the determination image (50) acquired by the imaging unit (35) when the hydraulic oil in a clear state is present between the photographed member (40) and the imaging unit (35).

[0014] In the fourth aspect, the determination unit (25) uses, as a reference gradation difference, the difference in gradation between the light portion (51) and the dark portion (52) when the hydraulic oil present between the photographed member (40) and the imaging unit (35) is in a clear state.

[0015] A fifth aspect of the present disclosure is the third or fourth aspect, wherein the judgment unit (25) performs a color judgment operation to judge the color of the hydraulic oil based on the judgment image (50), and in the turbidity judgment operation, compares the reference gradation difference corresponding to the color of the hydraulic oil judged in the color judgment operation with the gradation difference between the light portion (51) and the dark portion (52) in the judgment image (50).

[0016] The determination unit (25) of the fifth aspect determines the color of hydraulic oil in a color determination operation. In the turbidity determination operation, the determination unit (25) compares a reference gradation difference corresponding to the color of the hydraulic oil with the gradation difference between the light area (51) and the dark area (52) in the determination image (50) acquired by the imaging unit (35). Therefore, even if the color of the hydraulic oil changes during use, the determination unit (25) can appropriately determine the degree of turbidity of the hydraulic oil.

[0017] A sixth aspect of the present disclosure is that in the fifth aspect, the portion of the determination image (50) that includes only the bright portion (51) is a first region (56), and the color determination operation is an operation in which the determination unit (25) determines the color of the hydraulic oil based on the first region (56) of the determination image (50).

[0018] In the sixth aspect, the determination section (25) determines the color of the hydraulic oil based on a first region (56) that is a part of the determination image (50) and includes only the bright portion (51).

[0019] A seventh aspect of the present disclosure is any one of the first to sixth aspects, wherein the photographed member (40) forms a plurality of the bright portions (51) and the dark portions (52), and the region of the determination image (50) that includes a plurality of the bright portions (51) and the dark portions (52) is a second region (57), and in the turbidity determination operation, the determination unit (25) determines the degree of turbidity of the hydraulic oil based on the difference between the maximum gradation value of the bright portions (51) and the minimum gradation value of the dark portions (52) in the second region (57).

[0020] In the seventh aspect, the second region (57) of the determination image (50) includes a plurality of light portions (51) and a plurality of dark portions (52). The determination unit (25) determines the degree of turbidity of the hydraulic oil based on the difference between the “maximum value of the gradation value of the light portions (51)” and the “minimum value of the gradation value of the dark portions (52)” in the second region (57).

[0021] An eighth aspect of the present disclosure is any one of the first to sixth aspects, wherein the determination section (25) performs a cause determination operation for determining the cause of turbidity of the hydraulic oil.

[0022] In the eighth aspect, the determining section (25) determines the cause of turbidity of the hydraulic oil.

[0023] A ninth aspect of the present disclosure is the eighth aspect, wherein a region of the determination image (50) that includes both the bright portion (51) and the dark portion (52) is a second region (57), and the cause determination operation is an operation in which the determination unit (25) determines the cause of turbidity of the hydraulic oil based on the average value of the gradation values ​​in the second region (57) of the determination image (50).

[0024] In the ninth aspect, the second region (57) of the determination image (50) includes both the bright region (51) and the dark region (52). In the cause determination operation, the determination unit (25) determines the cause of the turbidity of the hydraulic oil based on the average value of the gradation values ​​in the second region (57).

[0025] A tenth aspect of the present disclosure is the ninth aspect, wherein the photographed member (40) forms a plurality of bright areas (51) and a plurality of dark areas (52), and the second region (57) is a region of the determination image (50) that includes a plurality of bright areas (51) and a plurality of dark areas (52).

[0026] In the tenth aspect, the second region (57) of the determination image (50) includes a plurality of bright areas (51) and a plurality of dark areas (52).

[0027] An eleventh aspect of the present disclosure is the ninth or tenth aspect, wherein the cause determination operation is an operation in which the determination unit (25) determines the cause of turbidity of the hydraulic oil by comparing the average gradation value in the second region (57) of the determination image (50) with a reference gradation value.

[0028] In the cause determination operation, the determination section (25) of the eleventh aspect determines the cause of turbidity of the hydraulic oil by comparing the average value of the gradation values ​​in the second region (57) of the determination image (50) with the reference gradation value.

[0029] A twelfth aspect of the present disclosure is the eleventh aspect, wherein the reference gradation value is the gradation value of the bright portion (51) in the determination image (50) acquired by the imaging unit (35) in a state where the hydraulic oil in a clear state is present between the photographed member (40) and the imaging unit (35).

[0030] In the twelfth aspect, the determination unit (25) uses, as the reference gradation value, the gradation value of the bright portion (51) when the hydraulic oil present between the photographed member (40) and the imaging unit (35) is in a clear state.

[0031] A thirteenth aspect of the present disclosure is the eleventh or twelfth aspect, wherein in the cause determination operation, the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is the mixing of water into the hydraulic oil when the average value of the gradation values ​​in the second region (57) of the determination image (50) is higher than the reference gradation value.

[0032] In the cause determination operation, the determination unit (25) of the thirteenth aspect determines that the cause of the turbidity of the hydraulic oil is the mixing of water into the hydraulic oil when the average value of the gradation values ​​in the second region (57) of the determination image (50) is closer to the “white” gradation value than the reference gradation value.

[0033] A fourteenth aspect of the present disclosure is any one of the eleventh to thirteenth aspects, wherein, in the cause determination operation, the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is the inclusion of solid matter in the hydraulic oil when the average value of the gradation values ​​in the second region of the determination image (50) is lower than the reference gradation value.

[0034] In the cause determination operation, the determination unit (25) of the fourteenth aspect determines that the cause of the turbidity of the hydraulic oil is the inclusion of solid matter (e.g., particles such as sludge) in the hydraulic oil when the average value of the gradation values ​​in the second region (57) of the determination image (50) is closer to the “black” gradation value than the reference gradation value.

[0035] A fifteenth aspect of the present disclosure is any one of the first to fourteenth aspects, wherein the photographed member (40) has a through hole (43) that opens on a surface facing the imaging unit (35), and the portion of the photographed member (40) other than the through hole (43) forms the bright portion (51), and the through hole (43) forms the dark portion (52).

[0036] In the fifteenth aspect, a through hole 43 is formed in the photographed member 40. The portion of the photographed member 40 other than the through hole 43 reflects light and forms a bright portion 51. The through hole 43 of the photographed member 40 does not reflect light and forms a dark portion 52.

[0037] A sixteenth aspect of the present disclosure is the fifteenth aspect, wherein the photographed member (40) has a plurality of through holes (43).

[0038] The photographed member (40) of the sixteenth aspect has a plurality of through holes (43) formed therein, so that the photographed member (40) has a plurality of bright portions (51) and a plurality of dark portions (52).

[0039] A seventeenth aspect of the present disclosure is the fifteenth or sixteenth aspect, wherein the photographed member (40) is white.

[0040] In the seventeenth embodiment, the white photographed member (40) forms the bright portion (51).

[0041] An eighteenth aspect of the present disclosure is any one of the first to eighteenth aspects, wherein the photographed member (40) is fixed to the imaging unit (35).

[0042] In the eighteenth aspect, the distance between the photographed member (40) and the imaging unit (35) is kept constant.

[0043] A nineteenth aspect of the present disclosure is the eighteenth aspect, further comprising a mesh-like partition member (31) surrounding a space (32) between the photographed member (40) and the imaging unit (35).

[0044] In the nineteenth aspect, the space (32) between the photographed member (40) and the imaging unit (35) is enclosed by a partition member (31). The partition member (31) is mesh-shaped. Therefore, the partition member (31) can prevent foreign matter from entering the space (32) between the photographed member (40) and the imaging unit (35) while allowing hydraulic oil to flow into the space (32) between the photographed member (40) and the imaging unit (35).

[0045] A twentieth aspect of the present disclosure is the first to fourteenth aspects, further comprising an intermediate member (73) arranged between the photographed member (40) and the imaging unit (35), made of a transparent material, and having an oil passage (74) formed therein for flowing hydraulic oil.

[0046] In the twentieth aspect, an intermediate member (73) is provided between the photographed member (40) and the imaging unit (35). When hydraulic oil flows through the oil passage (74) of the intermediate member (73), hydraulic oil to be subjected to turbidity determination is present between the imaging unit (35) and the photographed member (40). In this state, the imaging unit (35) acquires an image of the photographed member (40) as a determination image (50).

[0047] In the twentieth aspect, the hydraulic oil to be subjected to the turbidity determination flows through an oil passage (74) formed inside the intermediate member (73). In this aspect, the hydraulic oil does not come into contact with the photographed member (40) and the imaging unit (35). Therefore, foreign matter contained in the hydraulic oil does not adhere to the photographed member (40) and the imaging unit (35).

[0048] A 21st aspect of the present disclosure is the 20th aspect, wherein the intermediate member (73) has a first side surface (73a) and a second side surface (73b), each of the first side surface (73a) and the second side surface (73b) being flat and parallel to each other, the oil passage (74) is arranged in the intermediate member (73) between the first side surface (73a) and the second side surface (73b), the photographed member (40) is provided in contact with the first side surface (73a) of the intermediate member (73), and the imaging unit (35) is provided at a position facing the second side surface (73b) of the intermediate member (73).

[0049] In the twenty-first aspect, the first side surface (73a) of the intermediate member (73) that contacts the photographed member (40) is flat. The imaging unit (35) faces the second side surface (73b) of the intermediate member (73) and captures an image of the photographed member (40) located on the other side of the intermediate member (73) as the determination image (50). The second side surface (73b) of the intermediate member (73) is a flat surface parallel to the first side surface (73a). Therefore, the imaging unit (35) can capture an image of the photographed member (40) with relatively little distortion as the determination image (50).

[0050] A 22nd aspect of the present disclosure is the 20th or 21st aspect, further comprising a first coupling member (75a) that communicates with one end of the oil passage (74) and is connected to an oil pipe (63) through which the hydraulic oil flows, and a second coupling member (75b) that communicates with the other end of the oil passage (74) and is connected to the oil pipe (63).

[0051] In the twenty-second aspect, the oil passage (74) formed in the intermediate member (73) communicates with the oil pipe (63) through the first joint member (75a) and the second joint member (75b). Therefore, the hydraulic oil flowing through the oil pipe (63) passes through the oil passage (74) of the intermediate member (73).

[0052] A 23rd aspect of the present disclosure is any one of the 20th to 22nd aspects, and includes a case (71) that houses the photographed member (40), the imaging unit (35), and the intermediate member (73).

[0053] In the twenty-third aspect, the photographed member (40), the imaging unit (35), and the intermediate member (73) are arranged in a case (71).

[0054] A twenty-fourth aspect of the present disclosure is the twenty-third aspect, further comprising a light source (36) that is housed in the case (71) and emits light, and the case (71) is made of a material that does not transmit light.

[0055] In the twenty-fourth aspect, the photographed member (40), the imaging unit (35), the intermediate member (73), and the light source (36) are disposed inside a case (71). The case (71) is opaque to light. Inside the case (71), the imaging unit (35) captures an image of the photographed member (40) that receives only the light emitted by the light source (36), as the evaluation image (50). Therefore, the imaging unit (35) can capture an image of the photographed member (40) without being affected by light outside the case (71).

[0056] A 25th aspect of the present disclosure is the 24th aspect, wherein the oil passage (74) of the intermediate member (73) is a linear passage, the light source (36) includes a first light source (36a) and a second light source (36b), and the first light source (36a), the imaging unit (35), and the second light source (36b) are arranged in a row in order along the extension direction of the oil passage (74).

[0057] In a twenty-fifth aspect, the imaging unit (35) captures an image of the photographed member (40) receiving light emitted from the first light source (36a) and the second light source (36b). In this aspect, the first light source (36a), the imaging unit (35), and the second light source (36b) are aligned along the linear oil passage (74). This allows the imaging unit (35) to capture an image of the photographed member (40) receiving light with a relatively uniform intensity.

[0058] A 26th aspect of the present disclosure is a turbidity determination system (15) for determining the turbidity of hydraulic oil of hydraulic equipment, comprising: an imaged member (40) forming a light portion (51) and a dark portion (52); an imaging unit (35) that is provided at a position away from the imaged member (40) so that the hydraulic oil is present between the imaged member (40) and the imaged member (40) and that acquires an image of the imaged member (40) as an image for determination (50); and a determination unit (25) that performs a turbidity determination operation to determine the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portion (51) and the dark portion (52) in the image for determination (50) acquired by the imaging unit (35).

[0059] In a twenty-sixth aspect, the imaging unit (35) acquires an image of the photographed member (40) as a determination image (50). Between the imaging unit (35) and the photographed member (40) is present hydraulic oil whose turbidity is to be determined. The difference in gradation between the light portion (51) and the dark portion (52) in the determination image (50) varies depending on the degree of turbidity of the hydraulic oil present between the imaging unit (35) and the photographed member (40). Therefore, the determination unit (25) determines the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portion (51) and the dark portion (52) in the determination image (50).

[0060] The turbidity determination system (15) of the twenty-sixth aspect can determine the degree of turbidity of hydraulic oil if the hydraulic oil to be determined for turbidity is between the imaging unit (35) and the photographed member (40). Therefore, by using this turbidity determination device (10), the degree of turbidity of hydraulic oil can be determined without collecting a test sample of the hydraulic oil from the hydraulic equipment.

[0061] FIG. 1 is a schematic cross-sectional view of a hydraulic oil tank showing the installation state of the turbidity determination device of the first embodiment. FIG. 2 is a schematic front view of the turbidity determination device of the first embodiment. FIG. 3 is a schematic cross-sectional view of the main parts of the turbidity determination device of the first embodiment. FIG. 4 is a plan view of a member to be photographed by the turbidity determination device of the first embodiment. FIG. 5 is a perspective view of the member to be photographed by the turbidity determination device of the first embodiment. FIG. 6 is a block diagram showing the configuration of the determination unit of the turbidity determination device of the first embodiment. FIG. 7 is an example of a determination image acquired by a camera of the turbidity determination device of the first embodiment. FIG. 8 is an example of a determination image showing a first region. FIG. 9 is an example of a determination image showing a second region. FIG. 10 is a graph showing the gradation values ​​of the second region of the determination image when there is no turbidity in the hydraulic oil. FIG. 11 is a diagram showing the level divisions of the reference gradation difference ΔVC_r. FIG. 12 is a flow chart showing the operation of the determination unit of the turbidity determination device of the first embodiment. FIG. 13 is a perspective view of a member to be photographed in a second modified example of the first embodiment. FIG. 14 is a perspective view of a photographed member in a third modified example of the first embodiment. FIG. 15 is a perspective view of a photographed member in a fourth modified example of the first embodiment. FIG. 16 is a schematic cross-sectional view of a hydraulic oil tank showing the installation state of a turbidity determination device in a second modified example. FIG. 17 is a cross-sectional view of an imaging unit in a second modified example, showing the XVII-XVII section in FIG. 18. FIG. 18 is a cross-sectional view of an imaging unit in a second modified example, showing the XVIII-XVIII section in FIG. 17. FIG. 19 is a cross-sectional view of an imaging unit in a second modified example, showing the XIX-XIX section in FIG. 18. FIG. 20 is a cross-sectional view of an imaging unit in a second modified example, showing the XX-XX section in FIG. 18. FIG. 21 is a plan view of a photographed member in the turbidity determination device in a second modified example. FIG. 22 is a determination image in the turbidity determination device in a second modified example. FIG. 23 is a determination image in the turbidity determination device in a second modified example. FIG. 24 is a cross-sectional view of an imaging unit in a first modified example of the second embodiment, showing a cross section corresponding to FIG. 18. Fig. 25 is a plan view of an imaged member of a second modified example of embodiment 2. Fig. 26 is a plan view of an imaged member of a second modified example of embodiment 2. Fig. 27 is a schematic plan view of an imaging unit showing the configuration of a turbidity determination device of a third modified example of embodiment 2. Fig. 28 is a diagram showing the configuration of a turbidity determination device of a first modified example of another embodiment.

[0062] First Embodiment A first embodiment will be described. This embodiment is a turbidity determination device (10) that determines the degree of turbidity of hydraulic oil. The turbidity determination device (10) of this embodiment also functions as a turbidity determination system (15). The turbidity determination device (10) of this embodiment is provided in a hydraulic oil tank (60) that constitutes a hydraulic circuit.

[0063] -Hydraulic Oil Tank- The hydraulic oil tank (60) in which the turbidity determining device (10) of this embodiment is provided will be described with reference to FIG.

[0064] The hydraulic oil tank (60) includes a tank body (61), a delivery pipe (62), a return pipe (63), and a filter (64). The hydraulic oil tank (60) stores hydraulic oil. The hydraulic oil stored in the hydraulic oil tank (60) is used to drive hydraulic equipment such as hydraulic cylinders.

[0065] The tank body (61) is a rectangular parallelepiped container. The delivery pipe (62) is a pipe that connects the tank body (61) to the hydraulic pump. The inlet end of the delivery pipe (62) communicates with the internal space of the tank body (61). The filter (64) is connected to the inlet end of the delivery pipe (62). The filter (64) collects solid matter such as sludge contained in the hydraulic oil flowing into the delivery pipe (62). The return pipe (63) is a pipe that introduces hydraulic oil discharged from hydraulic equipment into the tank body (61). The outlet end of the return pipe (63) communicates with the internal space of the tank body (61).

[0066] -Configuration of the turbidity determination device- As shown in Figure 2, the turbidity determination device (10) includes a main unit (20), a sleeve pipe (30), a camera (35), a partition member (31), a photographed member (40), and a determination section (25).

[0067] <Main Unit> The main unit (20) is a rectangular box-shaped member. The main unit (20) houses a determination unit (25) inside. A display unit (21) is provided on the top surface of the main unit (20). The display unit (21) is one or more LED (Light Emitting Diode) lamps.

[0068] <Sheath Pipe> The sheath pipe (30) is a circular pipe made of metal or resin, and the base end of the sheath pipe (30) is connected to the lower surface of the main unit (20).

[0069] <Camera> As shown in Fig. 3, the camera (35) is formed in a small cylindrical shape. The camera (35) is provided inside the sleeve pipe (30). The tip of the camera (35) is exposed to the outside from the tip of the sleeve pipe (30). The camera (35) acquires color images. The camera (35) is an imaging unit that acquires an image of the photographed member (40).

[0070] The camera (35) is equipped with a light source (36). The light source (36) is a white LED lamp. The light source (36) is disposed near the tip of the camera (35) and emits light forward from the tip of the camera (35). A connection cable (37) of the camera (35) is electrically connected to the determination unit (25) in the main unit (20). The camera (35) sends an image signal to the determination unit (25) via the connection cable (37).

[0071] <Partition Member> The partition member (31) is a cylindrical wire mesh. The base end of the partition member (31) is attached to the tip of the sleeve pipe (30). The partition member (31) extends forward (downward in FIG. 2 ) from the tip of the sleeve pipe (30). The diameter of the partition member (31) is equal to or greater than the diameter of the sleeve pipe (30).

[0072] The space inside the partition member (31) is a determination space (32). The determination space (32) is surrounded by the partition member (31) which is a cylindrical wire mesh.

[0073] The photographed member (40) is a member formed in the shape of a thick disk as a whole. The diameter of the photographed member (40) is, for example, about 13 mm. The material of the photographed member (40) is white resin.

[0074] As shown in Figure 3, the photographed member (40) is provided so as to close the tip of the partition member (31). The photographed member (40) is fixed to the camera (35) via the partition member (31) and the sleeve pipe (30). The photographed member (40) is immovable relative to the camera (35). Therefore, the distance L from the camera (35) to the photographed member (40) is maintained constant.

[0075] As shown in Figures 4 and 5, the photographed member (40) has one ring portion (41) and two bridge portions (42). The ring portion (41) is a ring-shaped portion that follows the outer edge of the photographed member (40). Each bridge portion (42) is a straight rod-shaped portion that crosses the space inside the ring portion (41). The ring portion (41) and each bridge portion (42) are integrally formed.

[0076] In the photographed member 40, the two bridge portions 42 are arranged substantially parallel to each other with a gap between them. The space inside the ring portion 41 is divided into three parts by the two bridge portions 42. Each of the three spaces divided by the two bridge portions 42 is a through hole 43 that penetrates the photographed member 40 in the thickness direction.

[0077] 6, the determination unit (25) includes a CPU (26) mounted on a board and a memory device (27) that stores a program for operating the CPU (26). The memory device (27) is a semiconductor memory.

[0078] The CPU (26) executes a program stored in the memory device (27) to perform a color determination operation, a turbidity determination operation, and a cause determination operation. The color determination operation, the turbidity determination operation, and the cause determination operation will be described in detail below.

[0079] 1, the turbidity determining device (10) is provided in a hydraulic oil tank (60). The turbidity determining device (10) is attached to the tank body (61) of the hydraulic oil tank (60) in an orientation in which the sheath pipe (30) extends downward from the main unit (20).

[0080] The main unit (20) of the turbidity determining device (10) is located outside the tank body (61). The sleeve pipe (30) of the turbidity determining device (10) penetrates the top plate of the tank body (61) and is inserted into the internal space of the tank body (61). The sleeve pipe (30) of the turbidity determining device (10) is inserted, for example, into an auxiliary port of the hydraulic oil tank (60). The auxiliary port is a member for attaching an additional return pipe (63) to the hydraulic oil tank (60).

[0081] When the turbidity determination device (10) is installed in the hydraulic oil tank (60), the tip of the sleeve pipe (30) incorporating the camera (35), the partition member (31) fixed to the tip of the sleeve pipe (30), and the photographed member (40) are located below the oil level (65) in the tank body (61). In other words, the tip of the sleeve pipe (30), the partition member (31), and the photographed member (40) are immersed in the hydraulic oil stored in the hydraulic oil tank (60).

[0082] The hydraulic oil in the tank body (61) flows through the wire mesh partition member (31) into the determination space (32) formed between the camera (35) and the photographed member (40), so that the determination space (32) is filled with the hydraulic oil stored in the hydraulic oil tank (60).

[0083] - Operation of the Turbidity Determining Device - The operation of the turbidity determining device (10) will be described.

[0084] In the turbidity determination device (10), a camera (35) serving as an imaging unit captures an image of the photographed member (40) as a determination image (50). In the turbidity determination device (10), the determination unit (25) performs a color determination operation, a turbidity determination operation, and a cause determination operation based on the determination image (50). The determination unit (25) performs the color determination operation and the turbidity determination operation in that order. In addition, when the determination unit (25) determines in the turbidity determination operation that the hydraulic oil is highly turbid (in other words, that the state of the hydraulic oil is poor), it performs the cause determination operation.

[0085] <Image for Determination> As described above, the camera (35) acquires an image of the photographed member (40) as the image for determination (50). The camera (35) transmits the acquired image for determination (50) to the determination unit (25). The determination unit (25) stores the image for determination (50) received from the camera (35) in the memory device (27) as a color image with 256 gradations for each of R (red), G (green), and B (blue). Note that the RGB gradations shown here are merely an example.

[0086] An example of the image for determination (50) is shown in Fig. 7. The image for determination (50) is an image of the plane of the photographed member (40).

[0087] Light emitted by the light source (36) of the camera (35) is reflected by the ring portion (41) and the bridge portion (42) of the photographed member (40). As a result, in the evaluation image (50), the portions corresponding to the ring portion (41) and the bridge portion (42) of the photographed member (40) become bright portions (51) with relatively high brightness.

[0088] On the other hand, light emitted by the light source (36) of the camera (35) passes through the through-hole (43) of the photographed member (40). Because there is a certain distance between the photographed member (40) and the bottom of the hydraulic oil tank (60), the light that passes through the through-hole (43) of the photographed member (40) hardly reaches the bottom of the hydraulic oil tank (60). Therefore, in the determination image (50), the portion corresponding to the through-hole (43) of the photographed member (40) becomes a dark portion (52) with a relatively low brightness.

[0089] In addition, the partition member (31) made of a wire mesh is reflected in the area of ​​the determination image (50) outside the ring portion (41) of the photographed member (40).

[0090] <Color Determination Operation> The color determination operation will be described. The color determination operation is "an operation in which the determination unit (25) determines the color of the hydraulic oil based on the determination image (50)."

[0091] As shown in FIG. 8 , the determination unit (25) sets four first regions (56) in the determination image (50), which is a color image. The first regions (56) are portions of the determination image (50) and include only the bright portions (51). Note that the number of first regions (56) is merely an example, and there may be only one. The determination unit (25) sets the first regions (56) in portions of the determination image (50) that correspond to the ring portions (41) of the photographed member (40). However, the determination unit (25) may also set the first regions (56) in portions of the determination image (50) that correspond to the bridge portions (42) of the photographed member (40).

[0092] The determination unit (25) determines the color of the hydraulic oil based on the ASTM color. The ASTM color is a classification of petroleum product colors into 16 levels based on the ASTM D1500 standard. The determination unit (25) of this embodiment classifies the color of the hydraulic oil into four categories: "clear," "yellow," "bright yellow," and "black." Each of "clear," "yellow," "bright yellow," and "black" corresponds to one or more ASTM color levels. Note that the number of hydraulic oil color categories is merely an example.

[0093] The memory device (27) of the judgment unit (25) pre-stores the ranges of RGB gradation values ​​for each of "transparent," "yellow," "bright yellow," and "black" as reference ranges for color judgment. The gradation values ​​are numerical values ​​indicating the number of steps out of 256 gradations.

[0094] The ring portion (41) and bridge portion (42) of the photographed member (40) are white. Furthermore, at the time when the camera (35) captures the determination image (50), the determination space (32) between the camera (35) and the photographed member (40) is filled with hydraulic oil in the hydraulic oil tank (60). Therefore, the color of the portions of the determination image (50) corresponding to the ring portion (41) and bridge portion (42) is generally the same as the color of the hydraulic oil filling the determination space (32).

[0095] Therefore, the determination unit (25) calculates the average value of each RGB gradation value for all first regions (56).The determination unit (25) then compares the calculated average value of each RGB gradation value for the first regions (56) with the color determination reference range read from the memory device (27), thereby determining whether the color of the hydraulic oil corresponds to "transparent (n=1)," "yellow (n=2)," "bright yellow (n=3)," or "black (n=4)."

[0096] <Reference Gradation Difference> In the turbidity determination operation, the determination section (25) determines the degree of turbidity of the hydraulic oil using the reference gradation difference, which will be described in detail later. Here, the reference gradation difference will be described.

[0097] The reference gradation difference is determined based on the determination image (50) captured by the camera (35) when the determination space (32) is filled with unclouded hydraulic oil. The reference gradation difference ΔVC_r is the difference between the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) in a second region (57) of the determination image (50) (ΔVC_r = VC_max(n) - VC_min(n)). The second region (57) will be described later. The maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) used to calculate the reference gradation difference are determined during the design process of the turbidity determination device (10) and are recorded in advance in the memory device (27) of the determination unit (25).

[0098] As shown in Figure 9, the second region 57 is a part of the image for evaluation 50. The second region 57 is a linear region that is substantially perpendicular to the bridge portion 42 of the photographed member 40. The second region 57 passes through the center of the ring portion 41 of the photographed member 40.

[0099] The second region (57) crosses the ring portion (41), each bridge portion (42), and all the through holes (43). The second region (57) includes two light portions (51) formed by the ring portion (41), one light portion (51) formed by each bridge portion (42), and one dark portion (52) formed by each through hole (43). Thus, the second region (57) includes four light portions (51) and three dark portions (52). In addition, the light portions (51) and dark portions (52) are alternately arranged in the second region (57) from one end to the other.

[0100] 10 shows the gradation values ​​of the second region (57) in the determination image (50) converted into a 256-level grayscale image. This determination image (50) was acquired by the camera (35) to determine a reference gradation difference in the process of designing the turbidity determination device (10). This determination image (50) was acquired by the camera (35) when the determination space (32) was filled with unturbided hydraulic oil.

[0101] The above-described grayscale gradations are merely an example. In a 256-level grayscale, the lowest grayscale value "0" corresponds to "black," and the highest grayscale value "255" corresponds to "white." The grayscale value indicates the level of gray from "0 (black)" to "255 (white)." In the grayscale, the lower the grayscale value, the closer to black the gray is, and the higher the grayscale value, the closer to white the gray is.

[0102] 10 , in the second region (57), the gradation values ​​of the light portions (51) are relatively high and the gradation values ​​of the dark portions (52) are relatively low. The memory device (27) of the determination unit (25) stores the maximum gradation value of the light portions (51) in the second region (57) as the maximum reference gradation value VC_max(n) of the second region (57). The memory device (27) of the determination unit (25) also stores the minimum gradation value of the dark portions (52) in the second region (57) as the minimum reference gradation value VC_min(n) of the second region (57).

[0103] Here, the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) of the second region (57) change depending on the color of the hydraulic oil. As the color of the hydraulic oil becomes darker (in other words, as the color approaches black from transparent), the difference between the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) in the second region (57) gradually decreases. In FIG. 10 , VC_max(1) and VC_min(1) are the maximum and minimum reference gradation values ​​when the color of the hydraulic oil is "transparent (n=1)." Also, VC_max(3) and VC_min(3) are the maximum and minimum reference gradation values ​​when the color of the hydraulic oil is "bright yellow (n=3)."

[0104] Therefore, the memory device (27) of the determination unit (25) stores the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) individually for each of the cases where the color of the hydraulic oil in a clear state is "transparent (n=1)," "yellow (n=2)," "bright yellow (n=3)," and "black (n=4)." The number of "pairs of reference gradation value VC_max(n) and minimum reference gradation value VC_min(n)" stored in the memory device (27) of the determination unit (25) is the same as the number of color categories of the hydraulic oil in the color determination operation.

[0105] <Turbidity Determining Operation> The turbidity determining operation will be described. The turbidity determining operation is "an operation in which the determining unit (25) determines the degree of turbidity of the hydraulic oil based on the determination image (50)."

[0106] In the turbidity determination operation, the determination unit (25) reads from the memory device (27) a maximum reference gradation value VC_max(n) and a minimum reference gradation value VC_min(n) corresponding to the color of the hydraulic oil determined in the color determination operation. For example, if the color of the hydraulic oil is determined to be "yellow (n=2)" in the color determination operation, the determination unit (25) reads from the memory device (27) a maximum reference gradation value VC_max(n) and a minimum reference gradation value VC_min(n) corresponding to "yellow." The determination unit (25) determines the difference between the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) read from the memory device (27) as a reference gradation difference ΔVC_r (ΔVC_r=VC_max(n)-VC_min(n)).

[0107] As shown in FIG. 11 , the determination unit (25) divides the reference grayscale difference ΔVC_r into a plurality of levels. Specifically, the determination unit (25) divides the reference grayscale difference ΔVC_r into h equal levels, where "h" is an integer equal to or greater than 2. The determination unit (25) of this embodiment divides the reference grayscale difference ΔVC_r into 10 equal levels (h=10). The determination unit (25) calculates a threshold value ΔVC_s(m) for the grayscale difference using the following equation 1. "m" in equation 1 is an integer between 0 (zero) and h. ΔVC_s(m) = m × (ΔVC_r / h) (Equation 1)

[0108] Then, the determination section (25) sets h levels (LEVEL(m)), each of which is in a numerical range shown in the following formula 2: ΔVC_s(m−1)<LEVEL(m)≦ΔVC_s(m) (Formula 2)

[0109] In the turbidity determination operation, the determination unit 25 converts the determination image 50 from a color image to a grayscale image. In this embodiment, the determination unit 25 converts the determination image 50 into a grayscale image with 256 gradations.

[0110] The above-described grayscale gradations are merely an example. In a 256-level grayscale, the lowest grayscale value "0" corresponds to "black," and the highest grayscale value "255" corresponds to "white." The grayscale value indicates the level of gray from "0 (black)" to "255 (white)." In the grayscale, the lower the grayscale value, the closer to black the gray is, and the higher the grayscale value, the closer to white the gray is.

[0111] The determination unit (25) identifies the maximum gradation value VC1 and the minimum gradation value VC2 of the second region (57) in the determination image (50) converted into a grayscale image. The maximum gradation value VC1 of the second region (57) is the maximum value of the gradation value of the light portion (51) in the second region (57). The minimum gradation value VC2 of the second region (57) is the minimum value of the gradation value of the dark portion (52) in the second region (57). The determination unit (25) calculates the difference between the maximum gradation value VC1 and the minimum gradation value VC2 of the second region (57) and sets this value as the gradation difference ΔVC (= VC1 - VC2) between the light portion (51) and the dark portion (52) in the second region (57).

[0112] As described above, when the turbidity determination device (10) is in use, the determination space (32) between the camera (35) and the photographed member (40) is filled with hydraulic oil stored in the hydraulic oil tank (60). The higher the degree of turbidity of the hydraulic oil filling the determination space (32), the smaller the gradation difference ΔVC (=VC1−VC2) between the bright portion (51) and the dark portion (52) in the second region (57) of the determination image (50).

[0113] Therefore, the determination unit (25) determines to which of the levels shown in Fig. 11 the calculated gradation difference ΔVC (=VC1-VC2) between the light portion (51) and the dark portion (52) belongs. Then, the determination unit (25) determines whether the degree of turbidity of the hydraulic oil is "substantially none," "low," or "high," depending on the level to which the gradation difference ΔVC belongs.

[0114] An example of the correspondence between these three stages and the levels to which the gradation difference ΔVC belongs is shown below. When the gradation difference ΔVC belongs to LEVEL(8) to LEVEL(10), the determination unit (25) determines that "the hydraulic oil is substantially free of turbidity and is in a good state." When the gradation difference ΔVC belongs to LEVEL(3) to LEVEL(7), the determination unit (25) determines that "the hydraulic oil is not very turbid and is in a usable state." When the gradation difference ΔVC belongs to LEVEL(1) to LEVEL(2), the determination unit (25) determines that "the hydraulic oil is very turbid and is in a state where it is not suitable for use."

[0115] <Cause Determining Operation> The determining unit (25) performs a cause determining operation when it determines that “the hydraulic oil is highly turbid and is in a state where the hydraulic oil is unsuitable for use.” The cause determining operation is “an operation in which the determining unit (25) determines the cause of the turbidity of the hydraulic oil based on the determination image (50).”

[0116] In the cause determination operation, the determination unit (25) calculates the average value VC_ave of the gradation values ​​in the second region (57) of the determination image (50). The determination unit (25) also sets the maximum reference gradation value VC_max(n) read from the memory device (27) as the reference gradation value for the cause determination operation. The determination unit (25) then compares the calculated average value VC_ave of the gradation values ​​in the second region (57) with the reference gradation value to determine the cause of the turbidity of the hydraulic oil.

[0117] When hydraulic oil is cloudy due to the inclusion of water, the gradation of the determination image (50) approaches "white" overall as the degree of turbidity of the hydraulic oil increases. Therefore, the gradation of the second region (57) of the determination image (50) becomes higher overall. Therefore, when the calculated average value VC_ave of the gradation values ​​of the second region (57) is higher than the reference gradation value (VC_max(n)<VC_ave), the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is "water contamination."

[0118] On the other hand, if the hydraulic oil is cloudy due to the inclusion of particulate solid matter such as sludge, the gradation of the determination image (50) generally approaches "black" as the degree of turbidity of the hydraulic oil increases. Therefore, the gradation of the second region (57) of the determination image (50) generally becomes lower. Therefore, if the calculated average value VC_ave of the gradation values ​​of the second region (57) is equal to or less than the reference gradation value (VC_ave≦VC_max(n)), the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is "the inclusion of solid matter such as sludge."

[0119] -Overall Flow of Operation of Turbidity Determining Device- The overall flow of operation of the turbidity determining device (10) will be described with reference to the flow chart of FIG.

[0120] The determination unit (25) of the turbidity determination device (10) performs a series of processes shown in the flowchart of Fig. 12 by having the CPU (26) execute a program recorded in the memory device (27). In the flowchart of Fig. 12, the process of step ST2 is a color determination operation performed by the determination unit (25), the processes of steps ST3 to ST9 are a turbidity determination operation performed by the determination unit (25), and the processes of steps ST10 to ST11 are a cause determination operation performed by the determination unit (25).

[0121] <Step ST1> In the processing of step ST1, the camera (35) acquires a determination image (50). Specifically, with the determination space (32) filled with hydraulic oil from the hydraulic oil tank (60), the light source (36) of the camera (35) irradiates the photographed member (40) with light, and the camera (35) photographs the photographed member (40). The camera (35) transmits the acquired determination image (50) to the determination unit (25). The determination unit (25) stores the determination image (50) sent from the camera (35) in the memory device (27) as a color image with 256 gradations for each of R (red), G (green), and B (blue). After completing the processing of step ST1, the determination unit (25) performs the processing of step ST2.

[0122] <Step ST2> The process of step ST2 is a color determination operation performed by the determination unit (25). The details of the color determination operation are as described above. In the process of step ST2, the determination unit (25) determines whether the color of the hydraulic oil filling the determination space (32) is “transparent (n=1),” “yellow (n=2),” “bright yellow (n=3),” or “black (n=4),” based on the four first regions (56) set in the determination image (50), which is a color image.

[0123] The color of the hydraulic oil filling the determination space (32) is the same as the color of the hydraulic oil in the hydraulic oil tank (60). Therefore, in the process of step ST2, the determination section (25) determines the color of the hydraulic oil in the hydraulic oil tank (60). After completing the process of step ST2, the determination section (25) performs the process of step ST3.

[0124] <Step ST3> In the process of step ST3, the determination section (25) starts the turbidity determination operation.

[0125] In the process of step ST3, the determination unit (25) sets a reference gradation difference ΔVC_r. Specifically, the determination unit (25) reads out from the memory device (27) the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) corresponding to the color of the hydraulic oil determined in the process of step ST2. Then, the determination unit (25) sets the difference between the maximum reference gradation value VC_max(n) and the minimum reference gradation value VC_min(n) read out from the memory device (27) as the reference gradation difference ΔVC_r (ΔVC_r=VC_max(n)−VC_min(n)). After completing the process of step ST3, the determination unit (25) performs the process of step ST4.

[0126] <Step ST4> In the process of step ST4, the determination unit (25) uses the reference gray level difference ΔVC_r set in the process of step ST3 to set a plurality of levels (LEVEL(m)) (in this embodiment, 10 levels) by performing the calculation process shown in Equation 1. After completing the process of step ST4, the determination unit (25) performs the process of step ST5.

[0127] <Step ST5> In the process of step ST5, the determination unit 25 converts the determination image 50, which is a color image acquired by the camera 35 in the process of step ST1, into a grayscale image with 256 gradations. After completing the process of step ST5, the determination unit 25 performs the process of step ST6.

[0128] <Step ST6> In the processing of step ST6, the determination unit (25) identifies the maximum gradation value VC1 and the minimum gradation value VC2 of the second region (57) in the determination image (50) based on the determination image (50) converted into a grayscale image in the processing of step ST5. Then, the determination unit (25) calculates the difference between the maximum gradation value VC1 and the minimum gradation value VC2 of the second region (57) and sets this value as the gradation difference ΔVC (= VC1 - VC2) between the light portion (51) and the dark portion (52) in the second region (57). After completing the processing of step ST6, the determination unit (25) performs the processing of step ST7.

[0129] <Step ST7> In the process of step ST7, the determination unit (25) determines whether the condition "ΔVC_s(10)<ΔVC" is met. If this condition is met, the gradation difference ΔVC between the light portion (51) and the dark portion (52) in the second region (57) exceeds LEVEL(10). If the determination image (50) acquired by the camera (35) in the process of step ST1 is normal, the gradation difference ΔVC does not exceed LEVEL(10). Therefore, if the gradation difference ΔVC exceeds LEVEL(10), for example, a defect such as the adhesion of air bubbles to the photographed member (40) has occurred, and it is highly likely that the state of the hydraulic oil cannot be appropriately determined based on the determination image (50) acquired by the camera (35) in the process of step ST1.

[0130] Therefore, if the condition "ΔVC_s(10)<ΔVC" is satisfied, the determination unit (25) performs the processes from step ST1 to step ST6 again. That is, in this case, the determination unit (25) performs a color determination operation using the determination image (50) acquired again by the camera (35), and calculates the gradation difference ΔVC between the light portion (51) and the dark portion (52) in the second region (57) of the determination image (50). On the other hand, if this condition is not satisfied, the determination unit (25) performs the process of step ST8.

[0131] <Step ST8> In the process of step ST8, the determination unit (25) determines whether the condition "ΔVC_s(7)<ΔVC" is met. If this condition is met, the gradation difference ΔVC between the light portion (51) and the dark portion (52) in the second region (57) falls within the range of LEVEL(8) to LEVEL(10). If the gradation difference ΔVC falls within the range of LEVEL(8) to LEVEL(10), the degree of turbidity of the hydraulic oil corresponds to "substantially no turbidity." Therefore, if this condition is met, the determination unit (25) performs the process of step ST12. On the other hand, if this condition is not met, the determination unit (25) performs the process of step ST9.

[0132] <Step ST9> In the process of step ST9, the determination unit (25) determines whether the condition "ΔVC_s(2)<ΔVC" is met. If this condition is met, the gradation difference ΔVC between the light portion (51) and the dark portion (52) in the second region (57) falls within the range of LEVEL(3) to LEVEL(7). If the gradation difference ΔVC falls within the range of LEVEL(3) to LEVEL(7), the degree of turbidity of the hydraulic oil is "low." Therefore, if this condition is met, the determination unit (25) performs the process of step ST13. On the other hand, if this condition is not met, the determination unit (25) performs the process of step ST10.

[0133] <Step ST10> If the condition "ΔVC_s(2)<ΔVC" is not satisfied in the processing of step ST9, the gradation difference ΔVC between the light portion (51) and the dark portion (52) in the second region (57) falls within the range from LEVEL(1) to LEVEL(2). If the gradation difference ΔVC falls within the range from LEVEL(1) to LEVEL(2), the degree of turbidity of the hydraulic oil corresponds to "high." If the degree of turbidity of the hydraulic oil corresponds to "high," the determination unit (25) determines that "the degree of turbidity of the hydraulic oil is high and the hydraulic oil is in a state unsuitable for use." Then, the determination unit (25) starts a cause determination operation in the processing of step ST10.

[0134] In the process of step ST10, the determination unit 25 calculates the average value VC_ave of the gradation values ​​in the second region 57 of the determination image 50 converted into a grayscale image in the process of step ST5. After completing the process of step ST10, the determination unit 25 performs the process of step ST11.

[0135] <Step ST11> In the process of step ST11, the determination unit (25) sets the maximum reference gradation value VC_max(n) read from the memory device (27) in the process of step ST3 as the reference gradation value for the cause determination operation. Then, the determination unit (25) determines whether the condition "VC_max(n)<VC_ave" is met.

[0136] If the condition "VC_max(n)<VC_ave" is satisfied, the gradation of the second region (57) of the determination image (50) is generally close to "white." Therefore, the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is "water contamination," and performs the process of step ST14.

[0137] On the other hand, if the condition "VC_max(n)<VC_ave" is not satisfied, the gradation of the second region (57) of the determination image (50) approaches "black" overall. Therefore, the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is "the inclusion of solid matter such as sludge," and performs the process of step ST15.

[0138] <Step ST12> The process of step ST12 is performed when it is determined in the process of step ST8 that the degree of turbidity of the hydraulic oil corresponds to "substantially no turbidity."

[0139] In the process of step ST12, the determination unit (25) performs a first display operation. The first display operation is an operation for displaying information that "the hydraulic oil is substantially free of turbidity and is in good condition" on the display unit (21) of the main unit (20). As the first display operation, the determination unit (25) performs an operation for "turning on the LED lamp of the display unit (21) in green." Note that the color of the light emitted by the display unit (21) is merely an example.

[0140] <Step ST13> The process of step ST13 is performed when it is determined in the process of step ST9 that the degree of turbidity of the hydraulic oil corresponds to "low".

[0141] In the process of step ST13, the determination unit (25) performs a second display operation. The second display operation is an operation for displaying information that "the degree of turbidity of the hydraulic oil is low and the hydraulic oil is usable" on the display unit (21) of the main unit (20). As this second display operation, the determination unit (25) performs, for example, "an operation for lighting up the LED lamp of the display unit (21) in orange." Note that the color of the light emitted by the display unit (21) is merely an example.

[0142] <Step ST14> The process of step ST14 is performed when it is determined in the process of step ST11 that the cause of the turbidity of the hydraulic oil is "water contamination."

[0143] In the process of step ST14, the determination unit (25) performs a third display operation. The third display operation is an operation for displaying information indicating that the cause of the turbidity of the hydraulic oil is “water contamination” on the display unit (21) of the main unit (20). As this third display operation, the determination unit (25) performs, for example, “an operation for lighting the LED lamp of the display unit (21) alternately in red and blue.” Note that the color of the light emitted by the display unit (21) is merely an example.

[0144] <Step ST15> The process of step ST15 is performed when it is determined in the process of step ST11 that the cause of the turbidity of the hydraulic oil is "mixing in of solid matter."

[0145] In the process of step ST15, the determination unit (25) performs a fourth display operation. The fourth display operation is an operation for displaying information indicating that the cause of the turbidity of the hydraulic oil is "the inclusion of solid matter such as sludge" on the display unit (21) of the main unit (20). As this fourth display operation, the determination unit (25) performs, for example, "an operation for lighting up an LED lamp serving as the display unit (21) in red." Note that the color of the light emitted by the display unit (21) is merely an example.

[0146] Feature (1) of First Embodiment In the turbidity determination device (10) of this embodiment, the camera (35) acquires an image of the photographed member (40) as a determination image (50). The hydraulic oil to be subjected to the turbidity determination is interposed between the camera (35) and the photographed member (40). The difference in gradation between the light portions (51) and the dark portions (52) in the determination image (50) varies depending on the degree of turbidity of the hydraulic oil present between the imaging unit (35) and the photographed member (40). Therefore, the determination unit (25) determines the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portions (51) and the dark portions (52) in the determination image (50).

[0147] In the description of this embodiment, the term "tone difference" is an index indicating the "difference in color density." The meaning of "tone difference" in a grayscale image is substantially the same as the meaning of "contrast."

[0148] The turbidity determining device (10) of the present embodiment can determine the degree of turbidity of hydraulic oil as long as the hydraulic oil to be determined for turbidity is present between the imaging unit (35) and the photographed member (40). Therefore, by using this turbidity determining device (10), the degree of turbidity of hydraulic oil can be determined without collecting a test sample of the hydraulic oil from the hydraulic equipment.

[0149] In particular, the turbidity determining device (10) of this embodiment determines the degree of turbidity of hydraulic oil while installed in the hydraulic oil tank (60). Therefore, it is possible to continuously determine the condition of the hydraulic oil actually being used and to promptly notify users or managers of hydraulic equipment when the condition of the hydraulic oil deteriorates. Therefore, the turbidity determining device (10) of this embodiment can provide users or managers of hydraulic equipment with information that is useful for preventing problems in hydraulic equipment caused by the continued use of degraded hydraulic oil.

[0150] Feature (2) of First Embodiment In the turbidity determination device (10) of this embodiment, the determination unit (25) determines the color of the hydraulic oil by performing a color determination operation. The determination unit (25) then determines the degree of turbidity of the hydraulic oil by comparing the reference gradation difference ΔVC_r corresponding to the color of the hydraulic oil with the gradation difference ΔVC between the light areas (51) and the dark areas (52) in the determination image (50) acquired by the imaging unit (35). Therefore, the turbidity determination device (10) of this embodiment can appropriately determine the degree of turbidity of the hydraulic oil even if the color of the hydraulic oil changes during use.

[0151] In particular, the determination unit (25) of this embodiment performs a color determination operation based on a first region (56) including only the bright portion (51) of the determination image (50). Furthermore, in this embodiment, the ring portion (41) of the photographed member (40) that forms the bright portion (51) of the determination image (50) is white. Therefore, the color of the first region (56) of the determination image (50) is generally the same as the color of the hydraulic oil filling the determination space (32). Therefore, in the turbidity determination device (10) of this embodiment, the color determination operation of the determination unit (25) allows the color of the hydraulic oil stored in the hydraulic oil tank (60) to be accurately determined.

[0152] -Feature (3) of Embodiment 1- In the turbidity determination operation, the determination unit (25) of the turbidity determination device (10) of this embodiment determines the degree of turbidity of the hydraulic oil based on the gradation difference ΔVC between the light portion (51) and the dark portion (52) in the second region (57) of the determination image (50).

[0153] The second region (57) of the determination image (50) used in the turbidity determination operation includes a plurality of bright portions (51) and a plurality of dark portions (52). The determination unit (25) of this embodiment determines the difference between a maximum gradation value VC1, which is the maximum value of the gradation values ​​of the bright portions (51) in the second region (57), and a minimum gradation value VC2, which is the minimum value of the gradation values ​​of the dark portions (52) in the second region (57), as the gradation difference ΔVC (= VC1 - VC2) between the bright portions (51) and the dark portions (52) in the second region (57). Therefore, according to this embodiment, it is possible to accurately calculate the gradation difference ΔVC between the bright portions (51) and the dark portions (52) in the second region (57), and as a result, it is possible to accurately determine the degree of turbidity of the hydraulic oil.

[0154] Feature (4) of First Embodiment In the turbidity determination device (10) of this embodiment, the determination unit (25) performs a cause determination operation when the level of turbidity of the hydraulic oil is high. In the cause determination operation, the determination unit (25) determines whether the cause of the turbidity of the hydraulic oil is “inclusion of water” or “inclusion of solid matter.”

[0155] The measures to be taken differ depending on whether the cause of turbidity in the hydraulic oil is "water contamination" or "solid matter contamination." Therefore, the turbidity determining device (10) of the present embodiment determines the cause of turbidity in the hydraulic oil, thereby providing users and managers of hydraulic equipment with information for determining the measures to be taken.

[0156] -Feature (5) of Embodiment 1- Here, if the distance from the camera (35) to the photographed member (40) changes, the correlation between the "degree of turbidity of the hydraulic oil" and the "difference in gradation ΔVC between the bright and dark areas (51) in the determination image (50)" changes. On the other hand, in the turbidity determination device (10) of this embodiment, the photographed member (40) is fixed to the sleeve pipe (30) via the partition member (31), and the distance L from the camera (35) to the photographed member (40) is kept constant. Therefore, in the turbidity determination device (10) of this embodiment, the correlation between the "degree of turbidity of the hydraulic oil" and the "difference in gradation ΔVC between the bright and dark areas (51) in the determination image (50)" can be kept constant, and the degree of turbidity of the hydraulic oil can be accurately determined.

[0157] Feature (6) of First Embodiment In the turbidity determination device (10), the photographed member (40) may be formed in a flat plate shape without a through-hole (43), and white and black regions may be formed on the upper surface of the photographed member (40), with the black regions forming the dark portions (52) of the determination image (50). However, in this case, if a whitish foreign object is placed on the black region of the photographed member (40), the determination unit (25) may erroneously determine the gradation value of the dark portions (52) of the determination image (50) to be higher than the actual value, which may result in an erroneous determination of the degree of turbidity of the hydraulic oil.

[0158] In contrast, in the turbidity determination device (10) of the present embodiment, the through-holes (43) of the photographed member (40) form the dark portions (52) of the determination image (50). No foreign matter remains in the through-holes (43) of the photographed member (40). Therefore, the determination unit (25) can accurately determine the gradation values ​​of the dark portions (52) of the determination image (50), and as a result, can accurately determine the degree of turbidity of the hydraulic oil.

[0159] Feature (7) of First Embodiment If a foreign object enters the determination space (32) between the camera (35) and the photographed member (40), the foreign object may be reflected in the determination image (50). If something other than the photographed member (40) is reflected in the determination image (50), the determination result of the color of the hydraulic oil in the color determination operation, the determination result of the degree of hydraulic oil turbidity in the turbidity determination operation, and the determination result of the cause of hydraulic oil turbidity in the cause determination operation may be inaccurate.

[0160] On the other hand, in the turbidity determination device (10) of this embodiment, the determination space (32) between the camera (35) and the photographed member (40) is enclosed by a wire mesh partition member (31). This allows hydraulic oil to flow in and out of the determination space (32) while preventing relatively large foreign objects from entering the determination space (32). Therefore, the turbidity determination device (10) of this embodiment can reduce the possibility of erroneous determination due to foreign objects entering the determination space (32). As a result, it becomes possible to accurately determine the color of the hydraulic oil in the color determination operation, the degree of turbidity of the hydraulic oil in the turbidity determination operation, and the cause of turbidity of the hydraulic oil in the cause determination operation.

[0161] -Modifications of Embodiment 1- The following modifications may be applied to the turbidity determining device (10) of Embodiment 1. Note that the following modifications may be combined or substituted as appropriate, as long as the functionality of the turbidity determining device (10) is not impaired.

[0162] First Modification The color of the photographed member (40) is not limited to white, but it is preferable that the color of the portion of the photographed member (40) that forms the bright portion (51) be a bright color.

[0163] <Second Modification> The shape of the bridge portion (42) of the photographed member (40) is not limited to a straight rod shape. For example, as shown in Fig. 13, the bridge portion (42) may be formed in an X-shape. In the photographed member (40) shown in Fig. 13, four through holes (43) separated by the X-shaped bridge portions (42) are formed inside the ring portion (41).

[0164] <Third Modification> The photographed member (40) may be a flat plate-like member without a through-hole (43).

[0165] 14 and 15 , in the photographed member (40) of this modification, a white region (44) and a black region (45) are formed on the surface facing the imaging unit (35). The white region (44) forms a light region (51) of the determination image (50). The black region (45) forms a dark region (52) of the determination image (50).

[0166] In the photographed member (40) shown in Figure 14, the surface facing the camera (35) is divided into two equal parts: a white region (44) and a black region (45). In the photographed member (40) shown in Figure 15, the surface facing the camera (35) has circular white regions (44) and black regions (45) alternately arranged in a concentric pattern.

[0167] <Fourth Modification> The turbidity determining device (10) of this embodiment may be configured to display the determination results obtained in the turbidity determining operation and the cause determining operation of the determining unit (25) on an external device such as a smartphone. In this case, the turbidity determining device (10) is configured to be able to wirelessly communicate with the external device such as a smartphone.

[0168] Second Embodiment A turbidity determining device (10) of a second embodiment will be described. Similar to the turbidity determining device (10) of the first embodiment, the turbidity determining device (10) of this embodiment also functions as a turbidity determining system (15).

[0169] As shown in Fig. 16, the turbidity determination device (10) of this embodiment includes an imaging unit (70) and a determination unit (80). The imaging unit (70) and the determination unit (80) are electrically connected via a connection cable (85). The imaging unit (70) and the determination unit (80) communicate with each other via the connection cable (85). The imaging unit (70) is provided midway in a return pipe (63) connected to a hydraulic oil tank (60). The return pipe (63) is an oil pipe through which hydraulic oil flows.

[0170] -Imaging unit- The imaging unit (70) will be described with reference to Figures 17 to 21. In the following description, "upper," "lower," "right," "left," "front," and "rear" refer to the directions shown in Figures 17 and 18.

[0171] 17 and 18 , the imaging unit (70) includes a case (71). The case (71) accommodates the camera (35), the first light source (36a), the second light source (36b), the passage block (73), the photographed member (40), and the base plate (72). A first joint member (75a) and a second joint member (75b) are connected to the passage block (73).

[0172] <Case> The case (71) is a box-shaped member having a rectangular parallelepiped shape. As shown in FIG. 18 , the case (71) includes a case body (71a) and a case lid (71b). The case lid (71b) is disposed in front of the case body (71a) and covers the opening of the case body (71a). As shown in FIG. 17 , a coupler (77) for connecting a connection cable (85) is provided on a side of the case (71) (the right side in this embodiment).

[0173] The case body (71a) and the case lid (71b) constituting the case (71) are made of a synthetic resin that is opaque to light, although one or both of the case body (71a) and the case lid (71b) may be made of a metal.

[0174] <Base Plate> The base plate (72) is a thick rectangular plate-like member and is made of a transparent synthetic resin (for example, an acrylic resin).

[0175] 17 and 18, the base plate (72) is housed in the case body (71a). The base plate (72) is fixed to the bottom of the case body (71a) in an orientation generally parallel to the bottom of the case body (71a). The base plate (72) is disposed in the center in the left-right direction of the case body (71a) with its long sides aligned in the vertical direction.

[0176] 21, the photographed member (40) of this embodiment is a rectangular sheet-like member, and is made of a white synthetic resin that does not transmit light.

[0177] A determination graphic 46 is drawn on the surface of the photographed member 40. In this embodiment, the determination graphic 46 is a black grid-like graphic. The determination graphic 46 is composed of a plurality of slightly thick black vertical lines spaced at regular intervals and a plurality of slightly thick black horizontal lines spaced at regular intervals.

[0178] In the photographed member (40) of this embodiment, the black determination figure (46) forms the dark portion (52) of the determination image (50), and the white portion other than the determination figure (46) forms the light portion (51) of the determination image (50).

[0179] 18 and 20, the sheet-like photographed member 40 is attached to the front surface of the base plate 72 with the surface on which the determination figure 46 is drawn facing forward. The photographed member 40 is positioned in the vertical and horizontal center of the base plate 72.

[0180] <Passage Block> The passage block (73) is an intermediate member disposed between the photographed member (40) and the camera (35).

[0181] The passage block (73) is a block-shaped member having a rectangular parallelepiped shape. The passage block (73) is a hexahedron having six side faces. Each side face of the passage block (73) is substantially flat. In the passage block (73), a pair of opposing side faces are substantially parallel to each other. The passage block (73) is made of a transparent synthetic resin (e.g., acrylic resin).

[0182] As shown in Figures 18 and 19, an oil passage (74) for flowing hydraulic oil is formed in the passage block (73). The oil passage (74) is a through-hole extending in the longitudinal direction of the passage block (73) (the vertical direction in Figure 18). The cross section of the oil passage (74) is circular. One end of the oil passage (74) opens to one end face (the upper end face in Figure 18) of the passage block (73). The other end of the oil passage (74) opens to the other end face (the lower end face in Figure 18) of the passage block (73).

[0183] As shown in Fig. 18, the passage block (73) is disposed in front of the base plate (72). The passage block (73) is in close contact with the photographed member (40) attached to the base plate (72). As shown in Fig. 20, the passage block (73) covers the entire photographed member (40).

[0184] 18 , the passage block (73) has a first side surface (73a) as its rear surface that comes into close contact with the photographed member (40), and a second side surface (73b) as its front surface opposite the photographed member (40). In the passage block (73), the oil passage (74) is disposed between the first side surface (73a) and the second side surface (73b) that are parallel to each other.

[0185] <Camera> The camera (35) of this embodiment is an imaging unit that captures an image of the photographed member (40), similar to the camera (35) of embodiment 1. The camera (35) of this embodiment includes a lens (35a) and captures a color image.

[0186] 17 and 18, the camera (35) is fixed to the case lid (71b) via a support plate (76), and is electrically connected to a coupler (77).

[0187] In the internal space of the case (71), the camera (35) is disposed in front of the passage block (73). The lens (35a) of the camera (35) faces the second side surface (73b) of the passage block (73). As shown in Figure 19, the lens (35a) of the camera (35) faces an area of ​​the second side surface (73b) near the center in the vertical direction.

[0188] The camera (35) faces the second side surface (73b) of the passage block (73) and captures, as the determination image (50), an image of the photographed member (40) that is disposed on the other side of the passage block (73). In other words, the camera (35) captures, as the determination image (50), an image of the photographed member (40) viewed from the second side surface (73b) of the passage block (73).

[0189] <First Light Source, Second Light Source> The first light source (36a) and the second light source (36b) are light-emitting light sources (36). Each of the first light source (36a) and the second light source (36b) is a white LED lamp.

[0190] The first light source (36a) and the second light source (36b) are fixed to the support plate (76) together with the camera (35). The first light source (36a) and the second light source (36b) are electrically connected to a coupler (77).

[0191] In the internal space of the case (71), the first light source (36a), the camera (35), and the second light source (36b) are aligned in a row in this order in the extension direction of the oil passage (74) (the up-and-down direction in Figures 17 and 18). In Figures 17 and 18, the first light source (36a) is located above the camera (35), and the second light source (36b) is located below the camera (35).

[0192] <First Joint Member, Second Joint Member> As shown in FIGS. 18 and 19, each of the first joint member (75a) and the second joint member (75b) is a cylindrical member made of metal.

[0193] The first joint member (75a) penetrates the upper side of the case body (71a) in Fig. 18. One end (the lower end in Fig. 18) of the first joint member (75a) is inserted into the opening of the oil passage (74) in the upper surface of the passage block (73) in Fig. 18. The other end (the upper end in Fig. 18) of the first joint member (75a) is connected to the return pipe (63) through which the hydraulic oil flows.

[0194] The second joint member (75b) passes through the lower side of the case body (71a) in Figure 18. One end (upper end in Figure 18) of the second joint member (75b) is inserted into the opening of the oil passage (74) in the lower surface of the passage block (73) in Figure 18. The other end (lower end in Figure 18) of the second joint member (75b) is connected to the return pipe (63) through which the hydraulic oil flows.

[0195] -Determination Unit- As shown in FIG. 16, the determination unit (80) includes a determination section (25) and a display section (21).

[0196] <Determination Unit> The determination unit (25) of this embodiment has the same configuration as the determination unit (25) of embodiment 1. Specifically, the determination unit (25) of this embodiment includes a CPU (26) and a memory device (27).

[0197] The determination unit (25) of this embodiment performs the same operations as the determination unit (25) of embodiment 1. Specifically, the determination unit (25) of this embodiment performs a color determination operation, a turbidity determination operation, and a cause determination operation using the determination image (50).

[0198] <Display> The display (21) of this embodiment is one or more LED lamps, similar to the display (21) of the first embodiment.

[0199] - Operation of the Turbidity Determining Device - The operation of the turbidity determining device (10) will be described.

[0200] The turbidity determining device (10) performs the operation described below while hydraulic oil passes through the imaging unit (70). The hydraulic oil flowing through the return pipe (63) passes through the first joint member (75a) and flows into the oil passage (74) of the passage block (73), and then flows through the oil passage (74). After passing through the oil passage (74), the hydraulic oil passes through the second joint member (75b) and flows out of the imaging unit (70), and then passes through the return pipe (63) again and flows into the hydraulic oil tank (60).

[0201] In the turbidity determination device (10), a camera (35) serving as an imaging unit captures an image of the photographed member (40) as a determination image (50). In the turbidity determination device (10), the determination unit (25) performs a color determination operation, a turbidity determination operation, and a cause determination operation based on the determination image (50). The determination unit (25) sequentially performs the color determination operation and the turbidity determination operation. Furthermore, if the determination unit (25) determines in the turbidity determination operation that the hydraulic oil is highly turbid (in other words, that the state of the hydraulic oil is poor), it performs the cause determination operation. These operations are the same as those performed by the turbidity determination device (10) of the first embodiment.

[0202] <Image for Determination> As described above, the camera (35) acquires an image of the photographed member (40) as the image for determination (50). The camera (35) transmits the acquired image for determination (50) to the determination unit (25). The determination unit (25) stores the image for determination (50) received from the camera (35) in the memory device (27) as a color image with 256 gradations for each of R (red), G (green), and B (blue). Note that the RGB gradations shown here are merely an example.

[0203] The light emitted by the first light source (36a) and the second light source (36b) passes through the transparent passage block (73) and is reflected by the photographed member (40). The light reflected by the photographed member (40) passes through the passage block (73) and the hydraulic oil flowing through the oil passage (74), and enters the camera (35).

[0204] An example of the determination image (50) acquired by the camera (35) is shown in Figures 22 and 23. The determination image (50) is a planar image of the photographed member (40). In the photographed member (40), the portion corresponding to the black determination figure (46) drawn on the surface of the photographed member (40) is a dark area (52) with a relatively low brightness. In addition, in the photographed member (40), the portion corresponding to the white area of ​​the surface of the photographed member (40) other than the determination figure (46) is a bright area (51) with a relatively high brightness.

[0205] <Color Determination Operation> The color determination operation will be described. The color determination operation is "an operation in which the determination unit (25) determines the color of the hydraulic oil based on the determination image (50)."

[0206] As shown in Figure 22, the determination unit (25) sets four first regions (56) in the determination image (50), which is a color image. The first regions (56) are portions of the determination image (50) and include only the bright portions (51). Note that the number of first regions (56) is merely an example, and there may be only one. The determination unit (25) sets the first regions (56) in portions of the determination image (50) that correspond to areas other than the determination figure (46) of the photographed member (40).

[0207] The determination unit (25) determines the color of the hydraulic oil based on the ASTM color. The process for determining the color of the hydraulic oil is the same as the process performed by the determination unit (25) in the first embodiment. Specifically, the determination unit (25) calculates the average value of each of the RGB gradation values ​​for all of the first regions (56). Then, the determination unit (25) determines whether the color of the hydraulic oil corresponds to "transparent," "yellow," "bright yellow," or "black" based on the calculated average value of each of the RGB gradation values ​​for the first regions (56).

[0208] <Turbidity Determining Operation> The turbidity determining operation will be described. The turbidity determining operation is "an operation in which the determining unit (25) determines the degree of turbidity of the hydraulic oil based on the determination image (50)."

[0209] The turbidity determination operation performed by the determination unit (25) of this embodiment is the same as the turbidity determination operation performed by the determination unit (25) of embodiment 1. However, the second region (57) set by the determination unit (25) of this embodiment in the turbidity determination operation is different from the second region (57) set by the determination unit (25) of embodiment 1 in the turbidity determination operation.

[0210] The second region (57) set by the determining section (25) of this embodiment in the turbidity determining operation will be described with reference to FIG.

[0211] The second region (57) is a part of the determination image (50). The second region (57) is a linear region located at the center in the left-right direction of the determination figure (46) reflected in the determination image (50). The second region (57) is located in a portion of the determination figure (46) reflected in the determination image (50) that overlaps with the oil passage (74) when viewed from the second side surface (73b) of the passage block (73).

[0212] The second region (57) crosses the horizontal lines that make up the determination graphic (46). Therefore, in the second region (57), dark areas (52) formed by the determination graphic (46) and light areas (51) formed by the parts of the photographed member (40) other than the determination graphic (46) appear alternately from one end of the second region (57) to the other end.

[0213] In the turbidity determination operation, the determination unit (25) of the present embodiment, like the determination unit (25) of the first embodiment, calculates the gradation difference ΔVC (=VC1−VC2) between the light portion (51) and the dark portion (52) in the second region (57) and determines to which of the levels shown in Fig. 11 the calculated gradation difference ΔVC belongs. Then, the determination unit (25) determines whether the degree of turbidity of the hydraulic oil is "substantially none," "low," or "high," depending on the level to which the gradation difference ΔVC belongs.

[0214] <Cause Determining Operation> The determining unit (25) performs a cause determining operation when it determines that “the hydraulic oil is highly turbid and is in a state where the hydraulic oil is unsuitable for use.” The cause determining operation is “an operation in which the determining unit (25) determines the cause of the turbidity of the hydraulic oil based on the determination image (50).”

[0215] In the cause identification operation, the judgment unit (25) of this embodiment, like the judgment unit (25) of embodiment 1, calculates the average value VC_ave of the gradation values ​​in the second region (57) of the judgment image (50), and determines the cause of the turbidity of the hydraulic oil by comparing the calculated average value VC_ave of the gradation values ​​of the second region (57) with a reference gradation value.

[0216] Specifically, when the average value VC_ave of the gradation values ​​of the second region (57) is higher than the reference gradation value (VC_max(n)<VC_ave), the determination unit (25) of the present embodiment determines that the cause of the turbidity of the hydraulic oil is “inclusion of water.” Furthermore, when the average value VC_ave of the gradation values ​​of the second region (57) is equal to or lower than the reference gradation value (VC_ave≦VC_max(n)), the determination unit (25) of the present embodiment determines that the cause of the turbidity of the hydraulic oil is “inclusion of solid matter such as sludge.”

[0217] - Overall flow of operation of the turbidity determination device - The overall flow of operation of the turbidity determination device (10) of this embodiment is the same as the overall flow of operation of the turbidity determination device (10) of embodiment 1 shown in the flowchart of Figure 12. The turbidity determination device (10) of this embodiment performs a color determination operation, a turbidity determination operation, and a cause determination operation, and displays the results obtained by the turbidity determination operation and the cause determination operation on a display unit (21) formed of an LED lamp.

[0218] Feature (1) of Embodiment 2 Like the turbidity determination device (10) of Embodiment 1, the turbidity determination device (10) of this embodiment can determine the degree of turbidity of hydraulic oil if the hydraulic oil to be determined for turbidity is located between the imaging unit (35) and the photographed member (40). Therefore, by using this turbidity determination device (10), the degree of turbidity of hydraulic oil can be determined without collecting a test sample of the hydraulic oil from the hydraulic equipment.

[0219] In particular, the turbidity determining device (10) of this embodiment determines the degree of turbidity of the hydraulic oil returning to the hydraulic oil tank (60) through the return pipe (63). Therefore, it is possible to continuously determine the condition of the hydraulic oil actually being used and to promptly notify the user or manager of the hydraulic equipment if the condition of the hydraulic oil deteriorates. Therefore, the turbidity determining device (10) of this embodiment can provide the user or manager of the hydraulic equipment with information that is useful for preventing problems in the hydraulic equipment caused by the continued use of degraded hydraulic oil.

[0220] Furthermore, the turbidity determining device (10) of the present embodiment provides the same effects as the turbidity determining device (10) of the first embodiment.

[0221] Feature (2) of Second Embodiment In the turbidity determining device (10) of this embodiment, the hydraulic oil to be determined for turbidity flows through an oil passage (74) formed in the passage block (73), and the camera (35) and the photographed member (40) are disposed outside the passage block (73). Therefore, in the turbidity determining device (10) of this embodiment, the hydraulic oil to be determined for turbidity does not come into contact with the photographed member (40) and the camera (35).

[0222] Here, if foreign matter contained in the hydraulic oil adheres to the photographed member (40) or the camera (35), it will not be possible to obtain an evaluation image (50) that accurately reflects the state of the hydraulic oil, and there is a risk of misjudging the state of the hydraulic oil.

[0223] On the other hand, in the turbidity determining device (10) of the present embodiment, the hydraulic oil to be determined for turbidity does not come into contact with the photographed member (40) and the camera (35), and therefore foreign matter contained in the hydraulic oil does not adhere to the photographed member (40) and the imaging unit (35). Therefore, according to the present embodiment, it is possible to improve the accuracy of determining the state of the hydraulic oil.

[0224] Feature (3) of Embodiment 2 In the turbidity determination device (10) of this embodiment, the first side surface (73a) of the passage block (73) that contacts the photographed member (40) is flat. The camera (35) faces the second side surface (73b) of the passage block (73) and captures an image of the photographed member (40) located on the other side of the passage block (73) as the determination image (50). The second side surface (73b) of the passage block (73) is a flat surface that is parallel to the first side surface (73a). This allows the camera (35) to capture an image of the photographed member (40) with relatively little distortion as the determination image (50).

[0225] Therefore, according to this embodiment, the turbidity determination device (10) can determine the state of the hydraulic oil using a determination image (50) with little distortion, thereby improving the accuracy of determining the state of the hydraulic oil.

[0226] Feature (4) of Embodiment 2 In the turbidity determination device (10) of this embodiment, the photographed member (40), the camera (35), the passage block (73), the first light source (36a), and the second light source (36b) are disposed in a case (71). The case (71) is opaque to light. Inside the case (71), the camera (35) captures, as the determination image (50), an image of the photographed member (40) that receives only the light emitted by the first light source (36a) and the second light source (36b). Therefore, the camera (35) can capture an image of the photographed member (40) without being affected by light outside the case (71).

[0227] Therefore, according to the turbidity determination device (10) of this embodiment, the state of the hydraulic oil can be determined using a determination image (50) that accurately reflects the state of the hydraulic oil, thereby improving the accuracy of determining the state of the hydraulic oil.

[0228] Feature (5) of Embodiment 2 In the turbidity determining device (10) of the present embodiment, the first light source (36a), the camera (35), and the second light source (36b) are arranged in a line along the linear oil passage (74) in the internal space of the case (71). The camera (35) captures, as the determination image (50), an image of the photographed member (40) that has received light emitted by the first light source (36a) and the second light source (36b). Therefore, the camera (35) can capture, as the determination image (50), an image of the photographed member (40) that has received light of a relatively uniform intensity.

[0229] If the intensity of light incident on the photographed member (40) is uniform, the camera (35) can acquire the determination image (50) that accurately reflects the state of the hydraulic oil. Therefore, according to the turbidity determining device (10) of the present embodiment, the state of the hydraulic oil can be determined using the determination image (50) that accurately reflects the state of the hydraulic oil, thereby improving the accuracy of determining the state of the hydraulic oil.

[0230] -Modifications of Embodiment 2- The following modifications may be applied to the turbidity determining device (10) of Embodiment 2. Note that the following modifications may be combined or substituted as appropriate, as long as the functionality of the turbidity determining device (10) is not impaired.

[0231] 18 , in the imaging unit (70) of the turbidity determining device (10) of the present embodiment, the lens (35a) of the camera (35) is spaced apart from the second side surface (73b) of the passage block (73). However, the arrangement of the camera (35) and the passage block (73) in the imaging unit (70) is not limited to the arrangement shown in FIG.

[0232] For example, in the imaging unit (70), the camera (35) may be disposed so that its lens (35a) is in contact with the second side surface (73b) of the passage block (73). Alternatively, as shown in Fig. 24, a cylindrical lens hood (38) may be provided at the tip of the lens (35a) of the camera (35). In this case, it is desirable to dispose the camera (35) at a position where the tip of the lens hood (38) (the end opposite to the lens (35a)) is in contact with the second side surface (73b) of the passage block (73).

[0233] When the lens (35a) or the lens hood (38) is in contact with the second side surface (73b) of the passage block (73), light reflected by the second side surface (73b) of the passage block (73) is not incident on the camera (35). Therefore, the camera (35) can acquire an image of the photographed member (40) without being affected by light reflected by the second side surface (73b) of the passage block (73). Therefore, the turbidity determining device (10) of this modified example can determine the state of the hydraulic oil using the determination-use image (50) that accurately reflects the state of the hydraulic oil, thereby improving the accuracy of determining the state of the hydraulic oil.

[0234] Second Modification In the turbidity determining device (10) of the present embodiment, the determining figure (46) drawn on the photographed member (40) is not limited to the grid-like figure shown in FIG.

[0235] For example, the determination figure (46) may be the figure shown in FIG. 25 or FIG. 26. The determination figures (46) shown in FIG. 25 and FIG. 26 are composed of a rectangular frame and multiple horizontal lines that are parallel to each other. In these determination figures (46), the multiple horizontal lines are arranged at regular intervals. In the determination figure (46) shown in FIG. 25, the multiple horizontal lines are substantially parallel to the short sides of the frame. In the determination figure (46) shown in FIG. 26, the multiple horizontal lines are inclined with respect to the short sides of the frame.

[0236] 27 , in the turbidity determination device (10) of the present embodiment, the imaging unit (70) may be provided with a determination section (25) and a display section (21). In the turbidity determination device (10) of this modification, the determination section (25) is disposed in the internal space of the case (71), the display section (21) is disposed on the outer surface of the case (71), and the determination unit (80) is omitted.

[0237] <Fourth Modification> The turbidity determining device (10) of this embodiment may be configured to display the determination results obtained in the turbidity determining operation and the cause determining operation of the determining unit (25) on an external device such as a smartphone. In this case, the turbidity determining device (10) is configured to be able to wirelessly communicate with the external device such as a smartphone.

[0238] 16 , the imaging unit (70) of the turbidity determining device (10) is installed in the return pipe (63) in an orientation in which the first joint member (75a) is located at the top and the second joint member (75b) is located at the bottom. However, the orientation of the imaging unit (70) when installed in the return pipe (63) is not limited to the orientation shown in FIG. 16 . The orientation of the imaging unit (70) may be, for example, an orientation in which the extension directions of the first joint member (75a) and the second joint member (75b) are substantially horizontal, or an orientation in which the extension directions of the first joint member (75a) and the second joint member (75b) are inclined with respect to the vertical.

[0239] Other Embodiments The following modifications may be applied to the turbidity determining device (10) of the above-described Embodiments 1 and 2. Note that the following modifications may be combined or substituted as appropriate, as long as the functionality of the turbidity determining device (10) is not impaired.

[0240] First Modification In the turbidity determination device (10) of the first and second embodiments, the determination unit (25) may be configured by a general-purpose computer that executes an application program. In this specification, the term "computer" refers to a machine that stores a program describing a calculation procedure (algorithm) and executes calculations in accordance with the stored program. Therefore, the term "computer" in this specification includes mainframe computers, personal computers, tablet computers, smartphones, etc.

[0241] Fig. 28 shows a turbidity determination device (10) of embodiment 2 to which this modification is applied. This turbidity determination device (10) also serves as a turbidity determination system (15). In the turbidity determination device (10) shown in Fig. 28, the determination unit (80) is omitted, and a smartphone (92) constitutes the determination section (25).

[0242] In the turbidity determination device (10) shown in Fig. 28, the imaging unit (70) includes a communication module (91). The communication module (91) performs wireless communication based on a communication standard such as Wi-Fi (registered trademark). The imaging unit (70) of this modification transmits the determination image (50) acquired by the camera (35) to a smartphone (92) constituting the determination unit (25) via a communication line (93) such as the Internet.

[0243] An application program for causing the smartphone (92) to function as the determination unit (25) and the display unit (21) is installed in the smartphone (92). The smartphone (92) functioning as the determination unit (25) determines the state of the hydraulic oil based on the determination image (50) and displays the determination result on the display of the smartphone (92). In this modification, the display of the smartphone (92) constitutes the display unit (21).

[0244] Second Modification In the turbidity determining device (10) of the first and second embodiments, the determining section (25) may be configured to determine the state of the hydraulic oil by so-called machine learning.

[0245] In the turbidity determination device (10) of this modified example, a learned model is recorded in the memory device (27) of the determination unit (25). This learned model is generated by machine learning using, as input data, a large number of determination images (50) for hydraulic oils in various states and, as training data, the states of hydraulic oil corresponding to each determination image (50).

[0246] The judgment unit (25) of this modified example inputs the judgment image (50) acquired by the camera (35) into the learned model to judge whether the degree of turbidity of the hydraulic oil is “substantially none,” “low,” or “high,” and, if the degree of turbidity of the hydraulic oil is “high,” to judge whether the cause of the turbidity of the hydraulic oil is “inclusion of water” or “inclusion of solid matter.”

[0247] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first" and "second" in the specification and claims are used to distinguish between terms to which these terms are attached, and do not limit the number or order of the terms.

[0248] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for a turbidity determination device and a turbidity determination system that determine the degree of turbidity of hydraulic oil.

[0249] 10 Turbidity determination device 15 Turbidity determination system 25 Determination unit 31 Partition member 35 Camera (imaging unit) 36 Light source 36a First light source 36b Second light source 40 Photographed member 43 Through hole 50 Determination image 51 Light area 52 Dark area 56 First region 57 Second region 71 Case 73 Intermediate member 73a First side surface 73b Second side surface 74 Oil passage 75a First joint member 75b Second joint member

Claims

1. A turbidity determination device (10) for determining the turbidity of hydraulic oil of a hydraulic equipment, comprising: an imaged member (40) forming a light portion (51) and a dark portion (52); an imaging unit (35) that is provided at a position away from the imaged member (40) so that the hydraulic oil is present between the imaged member (40) and the imaged member (40) and obtains an image of the imaged member (40) as an image for determination (50); and a determination unit (25) that performs a turbidity determination operation for determining the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portion (51) and the dark portion (52) in the image for determination (50) obtained by the imaging unit (35).

2. The turbidity determination device as described in claim 1, wherein in the turbidity determination operation, the determination unit (25) determines that the degree of turbidity of the hydraulic oil is higher as the gradation difference between the light areas (51) and the dark areas (52) in the determination image (50) is smaller.

3. The turbidity determination device according to claim 1 or 2, wherein the turbidity determination operation is an operation in which the determination unit (25) determines the degree of turbidity of the hydraulic oil by comparing the gradation difference between the light areas (51) and the dark areas (52) in the determination image (50) with a reference gradation difference.

4. The turbidity determination device as described in claim 3, wherein the reference gradation difference is the gradation difference between the bright area (51) and the dark area (52) in the determination image (50) acquired by the imaging unit (35) when the unturbidified hydraulic oil is present between the photographed member (40) and the imaging unit (35).

5. The turbidity determination device as described in claim 3 or 4, wherein the determination unit (25) performs a color determination operation to determine the color of the hydraulic oil based on the determination image (50), and in the turbidity determination operation, compares the reference gradation difference corresponding to the color of the hydraulic oil determined in the color determination operation with the gradation difference between the light area (51) and the dark area (52) in the determination image (50).

6. The turbidity determination device as described in claim 5, wherein a portion of the determination image (50) that includes only the bright portion (51) is a first region (56), and the color determination operation is an operation in which the determination unit (25) determines the color of the hydraulic oil based on the first region (56) of the determination image (50).

7. The turbidity determination device as claimed in any one of claims 1 to 6, wherein the photographed member (40) forms a plurality of the bright portions (51) and the dark portions (52), and an area of ​​the determination image (50) which includes a plurality of the bright portions (51) and the dark portions (52) is a second area (57), and in the turbidity determination operation, the determination unit (25) determines the degree of turbidity of the hydraulic oil based on the difference between the maximum gradation value of the bright portions (51) and the minimum gradation value of the dark portions (52) in the second area (57).

8. The turbidity determining device according to any one of claims 1 to 6, wherein the determining section (25) performs a cause determining operation for determining the cause of the turbidity of the hydraulic oil.

9. The turbidity determination device as described in claim 8, wherein an area of ​​the determination image (50) that includes both the bright areas (51) and the dark areas (52) is a second area (57), and the cause determination operation is an operation in which the determination unit (25) determines the cause of the turbidity of the hydraulic oil based on the average value of the gradation values ​​in the second area (57) of the determination image (50).

10. The turbidity determination device as described in claim 9, wherein the photographed member (40) forms a plurality of the bright areas (51) and the dark areas (52), and the second area (57) is an area of ​​the determination image (50) that includes a plurality of the bright areas (51) and the dark areas (52).

11. The turbidity determination device as described in claim 9 or 10, wherein the cause determination operation is an operation in which the determination unit (25) determines the cause of turbidity of the hydraulic oil by comparing the average gradation value in the second region (57) of the determination image (50) with a reference gradation value.

12. The turbidity determination device as described in Claim 11, wherein the reference gradation value is the gradation value of the bright portion (51) in the determination image (50) acquired by the imaging unit (35) when the unturbidified hydraulic oil is present between the photographed member (40) and the imaging unit (35).

13. A turbidity determination device as described in claim 11 or 12, wherein in the cause determination operation, the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is the mixing of water into the hydraulic oil when the average value of the gradation values ​​in the second region (57) of the determination image (50) is higher than the reference gradation value.

14. A turbidity determination device as described in any one of claims 11 to 13, wherein in the cause determination operation, the determination unit (25) determines that the cause of the turbidity of the hydraulic oil is the inclusion of solid matter in the hydraulic oil when the average value of the gradation values ​​in the second region of the determination image (50) is lower than the reference gradation value.

15. A turbidity determination device as described in any one of claims 1 to 14, wherein the photographed member (40) has a through hole (43) that opens onto a surface facing the imaging section (35), and the portion of the photographed member (40) other than the through hole (43) forms the bright portion (51), and the through hole (43) forms the dark portion (52).

16. The turbidity determining device according to claim 15, wherein a plurality of the through holes (43) are formed in the photographed member (40).

17. The turbidity determination device according to claim 15 or 16, wherein the photographed member (40) is white in color.

18. The turbidity determining device according to any one of claims 1 to 17, wherein the photographed member (40) is fixed relative to the imaging section (35).

19. The turbidity determining device according to claim 18, further comprising a mesh-like partition member (31) surrounding the space (32) between the photographed member (40) and the imaging section (35).

20. A turbidity determination device as described in any one of claims 1 to 14, comprising an intermediate member (73) arranged between the photographed member (40) and the imaging unit (35), made of a transparent material, and having an oil passage (74) formed therein for flowing hydraulic oil.

21. The turbidity determining device as described in claim 20, wherein the intermediate member (73) has a first side surface (73a) and a second side surface (73b), each of the first side surface (73a) and the second side surface (73b) being flat, the first side surface (73a) and the second side surface (73b) being parallel to each other, the oil passage (74) being disposed in the intermediate member (73) between the first side surface (73a) and the second side surface (73b), the photographed member (40) being provided in contact with the first side surface (73a) of the intermediate member (73), and the imaging unit (35) being provided in a position facing the second side surface (73b) of the intermediate member (73).

22. A turbidity determining device as described in claim 20 or 21, comprising: a first coupling member (75a) communicating with one end of the oil passage (74) and connected to an oil piping (63) through which the hydraulic oil flows; and a second coupling member (75b) communicating with the other end of the oil passage (74) and connected to the oil piping (63).

23. The turbidity determining device according to any one of claims 20 to 22, comprising a case (71) that houses the photographed member (40), the imaging unit (35), and the intermediate member (73).

24. The turbidity determining device according to claim 23, further comprising a light source (36) that is housed in said case (71) and emits light, said case (71) being made of a material that does not transmit light.

25. The turbidity determining device as described in Claim 24, wherein the oil passage (74) of the intermediate member (73) is a linear passage, the light source (36) includes a first light source (36a) and a second light source (36b), and the first light source (36a), the imaging unit (35), and the second light source (36b) are arranged in a row in sequence along the extension direction of the oil passage (74).

26. A turbidity determination system (15) for determining the turbidity of hydraulic oil of a hydraulic device, comprising: an imaged member (40) forming a light portion (51) and a dark portion (52); an imaging unit (35) that is provided at a position away from the imaged member (40) such that the hydraulic oil is present between the imaged member (40) and the imaged member (40) and obtains an image of the imaged member (40) as an image for determination (50); and a determination unit (25) that performs a turbidity determination operation to determine the degree of turbidity of the hydraulic oil based on the difference in gradation between the light portion (51) and the dark portion (52) in the image for determination (50) obtained by the imaging unit (35).

Images