JPH0886751A - Liquid dirtiness detecting device - Google Patents

Abstract

PURPOSE: To prevent a light emitting element and a photodevice from being deteriorated by a liquid to be detected and to enable improving assemblage. CONSTITUTION: This liquid dirtiness detecting device 10 has a housing 11 of T-shaped longitudinal section in which a base 12, a light transmitting part 17, a detecting part 20, and a cover part 30, etc., are enclosed. Light from a light-emitting diode 13 is allowed to pass through the emitting path 18 of the light transmitting part 17, then reach the end 21a of a prism 21 and go straight through an optical path Al before being reflected at the reflecting surface 21d of the prism 21. The light reflected at the reflecting surface 21d is reflected at reflecting surfaces 21e, 21f, then propagates through optical paths A2, A3, A4, passes through the incident path 19 of the light transmitting part 17, and is received by a photodiode 14. Because in the optical paths A1, A4 the light is transmitted through a liquid to be detected which fills a through hole 21c crossing the optical paths A1, A4, part of the light is absorbed and scattered by particles, etc., that are the cause of dirtiness of the liquid to be detected, resulting in a decrease in the amount by which the photodiode 14 receives the light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid pollution level detecting device, and more particularly, to a liquid pollution level detecting device for detecting dirt on lubricating oil or hydraulic oil of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as a method for detecting the degree of contamination of a liquid, there is known a light transmission type which transmits light through the liquid and detects the degree of contamination of the liquid by the amount of light received. For example, it is used to detect the degree of pollution due to carbon particles contained in the lubricating oil of diesel engines. As an example of this, in a lubricating oil pollution degree detecting device disclosed in Japanese Patent Laid-Open No. 61-213749, a pollution degree measuring means in which a light emitting element and a light receiving element are opposed to each other is immersed in lubricating oil, and a temperature detecting means is used. The temperature of the lubricating oil is detected, and the pollution degree of the lubricating oil is detected when the temperature reaches a predetermined temperature.

Further, in the optical sensor disclosed in Japanese Patent Laid-Open No. 60-111945, a light emitting element and a light receiving element are optically coupled to one end of separate optical fibers, and a V-shaped detection end portion is immersed in engine oil. The pollution degree of the engine oil is detected by making the other end of each optical fiber face the light reflection surface of.

[0004]

However, according to the lubricating oil pollution degree detecting device disclosed in Japanese Patent Laid-Open No. 61-213749, the pollution degree measuring means including the light emitting element and the light receiving element is immersed in the lubricating oil. Therefore, there is a problem that the mounting position is restricted by the physique of the pollution degree measuring means and a pressure loss increases when the lubricating oil flows. Further, since the light emitting element and the light receiving element are directly immersed in the lubricating oil, there is a problem that the life of the light emitting element and the light receiving element is shortened due to the temperature and corrosion of the lubricating oil. Further, since the light-emitting element and the light-receiving element are small in size, it is difficult to maintain the facing distance between the light-emitting element and the light-receiving element, which is determined by the concentration of the lubricating oil, with high accuracy, and the assembling property is not good. is there.

According to the optical sensor disclosed in JP-A-60-111945, the light from the light emitting element is reflected at the boundary between the light reflecting surface and the engine oil. When the reflecting surface is contaminated, there is a problem that the amount of reflected light is reduced and the contamination level cannot be accurately detected. The present invention has been made in order to solve such a problem, and provides a liquid pollution degree detection device capable of preventing deterioration of a light emitting element and a light receiving element due to a detection liquid and improving assemblability. The purpose is to Another object of the present invention is to provide a liquid pollution degree detection device that improves the light reflection efficiency of the reflection surface.

[0006]

In order to solve the above-mentioned problems, the liquid pollution degree detecting device according to claim 1 according to the present invention has a light-emitting element and a portion which can be immersed in the detection liquid, and which includes the light-emitting element. A prism that guides light, a light receiving element that receives light that travels through the prism, and a light reflection film that is formed on the outer peripheral surface that forms the contour of the prism and is immersed in the detection liquid. And a concave portion formed in the optical path of light traveling through the prism and filled with the detection liquid, the light emitted from the light emitting element is reflected by the light reflecting film, and passes through the concave portion. The light is received by the light receiving element.

According to a second aspect of the present invention, there is provided a liquid pollution degree detecting device, which has a light emitting element, a prism having a portion which can be immersed in the detection liquid, and which guides light from the light emitting element, and the prism. A light receiving element for receiving light, and a recess formed in the optical path of the light traveling through the prism and filled with the detection liquid, and the light emitted from the light emitting element forms the contour of the prism. It is reflected by the boundary surface between the outer peripheral surface and the detection liquid, and is received by the light receiving element through the recess.

A liquid pollution degree detecting device according to a third aspect of the present invention is characterized in that, in the liquid pollution degree detecting device according to the first or second aspect, a floating cleaning member is housed in the recess. The liquid pollution degree detecting device according to claim 4 of the present invention is the liquid pollution degree detecting device according to claim 1, 2 or 3, wherein the recess is a through hole formed in the prism. Characterize.

The liquid pollution degree detecting device according to a fifth aspect of the present invention is the liquid pollution level detecting device according to the first aspect, the second aspect or the third aspect, wherein the concave portion is formed in a concave shape on the outer wall of the prism. It is characterized by being a groove.

[0010]

ACTION AND EFFECT OF THE INVENTION Claims 1, 2, 3 of the present invention
According to the liquid pollution degree detection device of 4 or 5, since the prism immersed in the detection liquid and the light emitting element and the light receiving element are separately configured, the light emitting element and the light receiving element do not come into direct contact with the detection liquid. This has the effect of preventing deterioration of the light emitting element and the light receiving element.

Further, according to the liquid pollution degree detection device of the present invention, the optical path length of the light passing through the detection liquid depends on the width of the recess formed in the optical path. Since it is determined, it is not necessary to adjust the optical path length of the light that passes through the detection liquid during assembly. As a result, there is an effect that the assembling property can be improved. Furthermore, according to the liquid pollution degree detection device of the present invention, the light from the light emitting element travels in the prism and is reflected by the light reflecting film inside the prism. The part where the light is reflected is not contaminated by the detection liquid located outside the. This has the effect of improving the light reflection efficiency when the light traveling in the prism is reflected by the reflecting surface.

Further, according to the liquid pollution degree detecting device of the third aspect of the present invention, since the floating cleaning member is housed in the concave portion of the prism, dirt adheres to the wall portion of the concave portion which comes into contact with the detection liquid. Prevent. This has the effect of suppressing the attenuation of light due to dirt on the wall of the recess.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 12 show a liquid pollution degree detecting device according to a first embodiment of the present invention. As shown in FIG. 1, the liquid pollution degree detection device 10 has a housing 11 having a T-shaped vertical cross-section, and in this housing 11, a substrate 12, a light guide portion 17, a detection portion 20, and a lid portion 30. Etc. are housed.
Male screw part 1 provided on the outer peripheral wall of the convex part of the housing 11
1, the liquid pollution degree detection device 10 can be attached to an oil pan or the like (not shown) filled with the detection liquid.
When the liquid pollution degree detection device 10 is attached to an oil pan or the like, the tip of the convex portion is soaked in the detection liquid, and the detection unit 20 described later is located at the tip of the convex portion.

A light emitting diode 13, a photodiode 14, electronic parts (not shown), etc. are mounted on the substrate 12. The light emitting diode 13 which is a light emitting element and the photodiode 14 which is a light receiving element are arranged so as to be adjacent to each other on the same surface of the substrate 12, and are soldered to the circuit pattern formed on the opposite surface of the substrate 12. Has been done. On the surface of the substrate 12 on which this circuit pattern is formed,
A gel 15 is applied to prevent corrosion of the soldered portion.

The light guide section 17 is located between the substrate 12 and the detection section 20, and guides the light emitted from the light emitting diode 13 to the detection section 20 located at the tip of the protrusion of the housing 11, and the detection section. An incident path 19 that guides the light reflected by the reflecting surface 21f of 20 to the photodiode 14 is formed. The detection unit 20 is composed of, for example, a cylindrical prism 21 made of glass, and the prism 21 is inserted into the through hole 11a formed at the tip of the convex portion of the housing 11 together with the O-ring 27 that prevents the detection liquid from entering. ing. One end 21a of the prism 21 that is in contact with the light guide portion 17 is formed on a surface perpendicular to the exit path 18 and the entrance path 19 so that the incident light from the light emitting diode 13 to the prism 21 and the exit light from the prism 21 to the photodiode 14 are generated. I try not to generate unnecessary reflection.

As shown in FIG. 2, at the other end 21b of the prism 21 immersed in the detection liquid, the optical path A shown in FIG.
A through hole 21c is formed which vertically crosses the optical path A1 and the optical path A4. This through hole 21c has a rectangular cross section, and as shown in FIGS. 1 and 2, the length of the through hole 21c of the optical paths A1 and A4 is L1. The tip of the end 21b is formed into a tapered truncated cone. The reflected light is reflected on the optical path A2 on the wall surface of this truncated cone located on the extension of the optical path A1.
A reflecting surface 21d is formed by cutting out at a center of a reflecting surface 21e, which is an end surface of the prism 21, through a plane having an angle capable of reflecting light. Further, on the wall surface of the truncated cone facing the reflecting surface 21d, the reflecting surface 21 for reflecting the optical path A3 of the light reflected from the reflecting surface 21e in parallel with the optical path A1.
f is formed. The light reflected by the reflecting surface 21f passes through the optical path A4. These reflecting surfaces 21d, 21
A light reflection film, which is a metal film formed by aluminum vapor deposition, is coated on e and 21f to enable total reflection of light. The light reflected by the reflecting surfaces 21d, 21e, and 21f is reflected inside the light reflecting film of the prism 21 that is not in contact with the detection liquid, and therefore the reflecting surfaces 21d, 21e, and 21f is not contaminated.

In the annular groove provided around the lid portion 30,
An O-ring 31 is attached, and when the lid 30 is fitted into the housing 11, the O-ring 31 allows the lid 30 to be inserted.
The gap between the outer peripheral wall of the housing and the inner wall of the housing 11 is sealed. Further, the lid portion 30 is formed with an adjustment hole 30a and an external wiring hole 30b, and a lead wire 35 electrically connected to the substrate 12 is provided through the external wiring hole 30b.
1 is pulled out. The adjustment hole 30a and the external wiring hole 30b of the lid portion 30 fitted in the housing 11 are filled with potting agents 32 and 33, respectively, and the potting agents 32 and 33 are used to externally feed the housing 11 from the outside.
It prevents foreign matter from entering the inside.

The other end of the lead wire 35 whose one end is connected to the substrate 12 is connected to a pin (not shown) attached to the connector 37. The connector 37 electrically connects the liquid pollution degree detection device 10 to a control unit (not shown), and the drive is controlled by the control unit.
Next, the operation of the liquid pollution degree detection device 10 will be described with reference to FIG.

A voltage is applied to the light emitting diode 13 by drive control of a control unit (not shown), and the light emitting diode 13 emits light. This light passes through the emission path 18 of the light guide section 17 and reaches the end 21 a of the prism 21.
Incident on 1. The light incident on the prism 21 goes straight on the optical path A1 until it is reflected by the reflecting surface 21d of the prism 21. At this time, the through hole 21c of the prism 21 is passed through the optical path A1.
Crosses the length L1 so that the light is transmitted through the detection liquid filling the through hole 21c, and a part of the light is absorbed and scattered by particles or the like that cause the detection liquid to be contaminated, and the light amount is reduced. .

The light that is not absorbed or scattered by the particles in the detection liquid is reflected by the reflecting surface 21d, and then the optical path A2
And is reflected by the reflecting surface 21e. After further traveling along the optical path A3, the light is reflected by the reflecting surface 21f. By the three reflections, the traveling direction of light is changed by 180 °. That is, the optical path A4 after being reflected by the reflecting surface 21f is in the opposite direction to the optical path A1. The light traveling along the optical path A4 traverses the detection liquid filled in the through hole 21c while being absorbed and scattered by particles and the like, as described above. Light that is not absorbed or scattered by particles or the like passes through the incident path 19 of the light guide portion 17 and is received by the photodiode 14. A photodiode 14 to which a constant voltage is applied from a control unit (not shown)
Outputs a detection voltage that correlates with the amount of received light.

Therefore, the light quantity of the light received by the photodiode 14 is reduced by the particles in the detection liquid in the middle of the optical paths A1 and A4, and this reduction amount changes according to the equivalent quantity of the particles in the detection liquid. . That is, the amount of light received by the photodiode 14 changes according to the degree of contamination of the detection liquid. Here, when the detected liquid is hydraulic fluid,
The wavelength of light that is easily absorbed and scattered will be described.

FIG. 12 is a characteristic diagram showing the light transmittance of hydraulic fluid (for example, Cosmo Hydrofluid TS-32) with respect to the wavelength of the irradiated light. As can be seen from this characteristic diagram, in this hydraulic fluid, the transmission characteristics for light at a wavelength of 430 nm significantly change depending on the degree of deterioration of the hydraulic fluid. As described above, since the light transmission characteristics differ depending on the type of oil that is the detection liquid, unnecessary light receiving components are removed by selecting the light emitting element having the emission wavelength corresponding to the type for each detection liquid, and S / It becomes possible to improve the N ratio. In the case of hydraulic fluid (Cosmo Hydrofluid TS-32), the light emitting element that emits the light with the wavelength of 400 nm to 450 nm most strongly is the light emitting diode 1.
When used in No. 3, it becomes possible to effectively detect the degree of pollution.

According to the first embodiment, the light emitting diode 13
And the photodiode 14 are mounted on the same plane substrate without facing each other, and the contamination of the detection liquid is detected by the detection unit 20 located at a position distant from the light emitting diode 13 and the photodiode 14, so that the detection liquid is immersed in the detection liquid. The physical size of the detected detection unit 20 can be reduced. This has the effect of suppressing an increase in pressure loss due to the detection unit 20 when the detection liquid has a flow.

Further, according to the first embodiment, since the detection unit 20 immersed in the detection liquid is located at a position apart from the light emitting diode 13 and the photodiode 14, the detection liquid directly contacts the light emitting diode 13 and the photodiode 14. There is no contact. This has the effect of preventing the life of the light emitting diode 13 and the photodiode 14 from being shortened.

Further, according to the first embodiment, the light emitted from the light emitting diode 13 is reflected by the reflecting surface 21 inside the prism 21.
Since the light is reflected by d, 21e, and 21f, the prism 21
By the detection liquid on the outside of the surfaces 21d, 21e, 21
There is an effect that f is not contaminated. Furthermore, according to the first embodiment, the optical path length of the light passing through the detection liquid is equal to the optical path A1.
Since it is determined by the length L1 of the optical paths A1 and A4 that cross the through hole 21c formed in the middle of the optical path A4, it is not necessary to adjust the optical path length of the light passing through the detection liquid at the time of assembly. It is possible to improve the sex.

Further, according to the first embodiment, since the emission wavelength of the light emitting diode 13 is selected according to the detection liquid to remove the unnecessary light receiving component, there is an effect that the S / N ratio can be improved. Here, as a modified example of the prism 21, a modified example 1 is shown in FIGS. Modification 1 is an example in which the through hole 21c of the prism 21 is changed to the groove portion 22a. A rectangular groove portion 22a is formed substantially in the center of the prism 22 so as to vertically cross the optical path A1 and the optical path A4. Since the groove 22a is filled with the detection liquid, the contamination level of the detection liquid can be detected in the optical paths A1 and A4.

In the first modification, since the portion of the prism 22 that is filled with the detection liquid has a groove shape, the prism 22 is easily processed, and the liquid exchangeability of the detection liquid is improved as compared with the through hole. is there. Further, as a modified example of the prism 21, a modified example 2 is shown in FIGS. Modification 2 is an example in which the through hole 21c of the prism 21 is changed to the groove portions 23a and 23b. The optical path A1 is formed in the substantially central portion of the prism 23.
A rectangular groove portion 23a which vertically crosses the optical path A4 and a rectangular groove portion 23b which vertically crosses the optical path A4 are formed in a pair. As shown in FIG. 8, these groove portions 23a, 23b
Are located so as to face the center of the prism 23. Since the grooves 23a and 23b are filled with the detection liquid, the contamination level of the detection liquid can be detected in the optical paths A1 and A4.

In the second modification, since the portion of the prism 23 filled with the detection liquid has a groove shape, the prism 23 can be easily processed, and the liquid exchangeability of the detection liquid can be improved as compared with the through hole. is there. Furthermore, as a modified example of the prism 21, a modified example 3 is shown in FIGS. Modification 3
Is an example in which the grooves 23a and 23b of the prism 23 of Modification 2 are arcuate in the radial cross section of the prism.
A substantially rectangular center portion of the prism 24 is formed with a pair of a rectangular groove portion 24a vertically crossing the optical path A1 and a rectangular groove portion 24b vertically crossing the optical path A4. FIG.
As shown in FIG. 1, the groove portions 24a and 24b are located so as to face the center of the prism 24, and are formed in an arc shape so that the outside in the radial direction is wider than the center portion. Since the detection liquid is filled in the grooves 24a and 24b, respectively, the contamination level of the detection liquid can be detected in the optical paths A1 and A4.

In the third modification, since the portion of the prism 24 filled with the detection liquid has a groove shape, the prism 24 can be easily processed, and the liquid exchangeability of the detection liquid can be improved as compared with the through hole. is there. Further, in the radial cross section of the prism 24, since the grooves 24a and 24b are formed in an arc shape such that the outside in the radial direction is wider than the central portion, the strength of the prism 24 is higher than that of the prism 23 of Modification 2. effective.

(Second Embodiment) FIGS. 13 to 18 show a liquid pollution degree detecting device according to a second embodiment of the present invention. The same reference numerals are given to substantially the same components as those in the first embodiment. FIG.
As shown in FIG. 3, the second embodiment is different from the first embodiment in that the detection unit 50 is composed of a prism 51, a cap 61, and a floating cleaning member 64.

The liquid pollution degree detection device 40 has a housing 11 having a T-shaped vertical cross section, and the substrate 12, the light guide portion 17, the detection portion 40, the lid portion 30 and the like are accommodated in the housing 11. ing. The detection unit 50 includes a cylindrical prism 51 made of, for example, glass, a cap 61, and a floating cleaning member 64. The prism 51 is inserted into the through hole 11a formed at the tip of the convex portion of the housing 11 together with the O-ring 27 that prevents the detection liquid from entering.
One end 51a of the prism 51 that is in contact with the light guide portion 17 is formed on a surface perpendicular to the light guide portion 17, and the incident light from the light emitting diode 13 to the prism 51 and the emitted light from the prism 51 to the photodiode 14 are unnecessary reflections. Is trying not to occur.

As shown in FIGS. 13 and 14, the other end 51b of the prism 51 immersed in the detection liquid is provided with a groove 51c which vertically crosses the optical path B2 shown in FIG. The groove 51c has a rectangular cross section, and the length of the groove 51c in the optical path B1 direction is L2. The length L2 is determined by the type of the detection liquid. For example, when the detection liquid is hydraulic fluid, 5 mm to 10 mm is preferable. The tip of the end portion 51b located on the extension of the optical path B1 is cut out at 45 ° to form a reflecting surface 51d. Further, like the reflection surface 51b, the tip of the end portion 51b facing the reflection surface 51d is cut out at 45 °, and a reflection surface for reflecting the light path B2 of the light reflected from the reflection surface 51b in parallel with the light path B1. 51e is formed. The light reflected by the reflecting surface 51d passes through the optical path B3. A light reflection film, which is a metal film, is coated on these reflection surfaces 51d and 51e to enable total reflection of light. Since the light reflected by the reflecting surfaces 51d and 51e is reflected by the reflecting surfaces 51d and 51e inside the prism 51, the detecting liquid outside the prism 51 does not contaminate the reflecting surfaces 51d and 51e.

As shown in FIG. 13, the spherical floating cleaning member 64 has a size such that it can be freely moved in the groove portion 51c of the prism 51. The floating cleaning member 64 has the groove 51.
Since it is housed in c, it must be colorless and transparent, having a refractive index similar to that of the detection liquid that does not refract or scatter the light traveling along the optical path B2. Therefore, the material of the floating cleaning member 64 is, for example, glass, acrylic resin, or the like. When there is a flow of the detection liquid, the floating cleaning member 64 collides with the wall 51h of the groove 51c due to the flow, thereby preventing dirt from adhering to the wall 51h. Floating cleaning member 6 housed in the groove 51c
The number of 4 is preferably about 2.

Here, a modified example of the shape of the floating cleaning member 64, which is suitable for preventing dirt from adhering to the wall 51h, is shown in FIG.
Shown in (b) to (e). The modified example shown in FIG. 15 (b) is an example of the floating cleaning member 65 having a shape having a spherical surface having a plurality of small spherical recesses formed therein. The modified example shown in (c) is an example of the floating cleaning member 66 having a shape having a spherical surface in which a plurality of small spherical convex portions are formed. further,
The modified example shown in (d) is an example of the floating cleaning member 67 having a regular tetrahedron shape. Furthermore, the modified example shown in (e) is
Floating cleaning member 68 formed by combining two spheres
Is an example of.

The cap 61 plays a role of preventing the floating cleaning member 64 housed in the groove 51c from flowing out, and is attached to the tip of the convex portion of the housing 11 so as to cover the end 51b of the prism 51. . Since it is necessary that the detection liquid can pass through and the floating cleaning member 64 cannot pass through, the cap 61 is made of, for example, a metal net having a mesh to which the floating cleaning member 64 cannot pass.

Next, the operation of the liquid pollution degree detecting device 40 will be described with reference to FIG. A voltage is applied to the light emitting diode 13 by drive control to a control unit (not shown),
The light emitting diode 13 emits light. This light passes through the emission path 18 of the light guide unit 17, reaches the end 51 a of the prism 51, and enters the prism 51. The light incident on the prism 51 goes straight on the optical path B1 until it is reflected by the reflecting surface 51d of the prism 51. The light reflected by the reflecting surface 51d is 9
0 ° Change the traveling direction and proceed along the optical path B2. At this time,
Since the optical path B2 traverses the through hole 51c of the prism 51 by the length L2, light is transmitted through the detection liquid filling the through hole 51c, and part of the light is absorbed by particles or the like that are the cause of contamination of the detection liquid. It will be scattered and the amount of light will decrease.

The light that is not absorbed or scattered by the particles in the detection liquid is reflected by the reflecting surface 51e and changes its traveling direction by 90 °. By these two reflections, the traveling direction of light is 18
It is changed by 0 °. That is, the optical path B3 after being reflected by the reflecting surface 51e is in the opposite direction to the optical path B1. The light traveling along the optical path B3 passes through the incident path 19 of the light guide portion 17 and is received by the photodiode 14. The photodiode 14 to which a constant voltage is applied from a control unit (not shown) is
A detection voltage that correlates with the amount of received light is output.

Therefore, the light amount of the light received by the photodiode 14 is reduced by the particles in the detection liquid in the middle of the optical path B2, and this reduction amount changes according to the particle equivalent in the detection liquid. That is, the amount of light received by the photodiode 14 changes according to the degree of contamination of the detection liquid. Second
According to the embodiment, the reflecting surfaces 51d and 51e of the prism 51 are
Since the number of reflections for reflecting light in 2 is twice, there is an effect that light attenuation due to reflection can be suppressed as compared with the first embodiment in which the reflection surfaces 21d, 21e, and 21f of the prism 21 reflect three times. .

Further, according to the second embodiment, the prism 51
Since the floating cleaning member 64 is housed in the groove 51c, it has an effect of preventing dirt from adhering to the wall 51h of the groove 51c. Here, as a modified example of the prism 51, a modified example 1 is shown in FIG. Modification 1 is an example in which the position of the groove portion 51c of the prism 51 is changed in the middle of the optical path B1. The prism 52 is formed with a rectangular groove 52a that crosses the optical path B1 vertically. This groove 52a
Since the detection liquid is filled in the inside, the contamination level of the detection liquid can be detected in the optical path B1.

In the first modification, the groove 52a of the prism 52 is formed.
Since the formation position of the prism is the optical path B1 which is longer than the optical path B2, the prism 52 can be easily processed without requiring high precision in positioning. Here, as a modified example of the prism 51, a modified example 2 is shown in FIG. Modification 2 is
Without refracting light at the end 51b of the prism 51,
In this example, the light is refracted by the prism surface formed at the end portion 51a. One end of the prism 53 is cut out into a prism surface 53a having an angle at which light incident on the prism 53 can be reflected at the center of the reflecting surface 53d at the other end of the prism 53.
Further, one end of the prism 53 has a prism surface 53 with an angle such that the light reflected at the central portion of the reflecting surface 53d travels on an optical path C4 parallel to the optical path C1 of the light incident on the prism 53.
It is cut out in b. In the middle of the optical path C2 of the light refracted by the prism surface 53a, a rectangular groove portion 53c is formed which vertically crosses the optical path C2. Since the groove 53c is filled with the detection liquid, in the optical path C2,
It becomes possible to detect the contamination level of the detection liquid. In addition,
The reflection surface 53d is coated with a light reflection film which is a metal film, and enables total reflection of light.

In the second modification, the reflecting surface 53 of the prism 53
Since the number of reflections for reflecting the light at d is once, as compared with the first embodiment in which the reflection surfaces 21d, 21e, and 21f of the prism 21 reflect three times, the effect of suppressing the attenuation of the light due to the reflection is obtained. is there. In the second modification, the prism 5
Since there is only one reflection surface 53d formed on No. 3, it is effective in reducing the step of coating the light reflection film.

A modified example 3 of the prism 51 is shown in FIG. 17 (a). Modification 3 is a prism 51
This is an example in which the position of the groove portion 51c is added in the middle of the optical paths B1 and B3. The prism 54 is provided with a rectangular groove 54a that vertically crosses the optical path B1, a rectangular groove 54b that vertically crosses the optical path B2, and a rectangular groove 54c that vertically crosses the optical path B3. This groove 54a,
Since the detection liquid is filled in 54b and 54c, it becomes possible to detect the contamination level of the detection liquid in each of the optical path B1, the optical path B2, and the optical path B3.

In the third modification, since the contamination level of the detection liquid is detected by the three groove portions 54a, 54b, 54c formed on the prism 54, there is an effect of improving the detection accuracy of the contamination level. Here, as a modified example of the prism 51, a modified example 4 is shown in FIG. Modification 4 is an example in which a groove is added to the optical path C3 of the prism 53 of Modification 2. Optical path C2 of light refracted by the prism surface 55a
In the middle of, the rectangular groove 55 that crosses the optical path C2 vertically is formed.
c is formed. Further, in the middle of the optical path C3 of the light reflected by the reflecting surface 55e, a rectangular groove portion 55d which crosses the optical path C3 vertically is formed. Since the detection liquid is filled in the grooves 55c and 55d, the optical path C2,
In the optical path C3, it becomes possible to detect the contamination level of the detection liquid. The reflecting surface 55d is coated with a light-reflecting film that is a metal film to enable total reflection of light.

In the modified example 4, since the grooves 55c and 55d formed in the prism 55 are at two places, there is an effect of improving the detection accuracy of the pollution degree as compared with the modified example 2. Here, as a modified example of the prism 51, a modified example 5 is shown in FIG.
Shown in Modified Example 5 is an example in which light is reflected by a reflecting surface formed on a glass plate that is separate from the prism, without reflecting the light inside the prism 51. In the prism 56,
A prism surface 56a for refracting the light incident on the optical path D1 is formed, and the light emitted from the prism 56 is simultaneously refracted and advances to the optical path D2. Since the reflecting surface 57a is formed on the glass plate 57 which is a separate body from the prism 56, the light on the optical path D2 is reflected by the reflecting surface 57a and then the prism 56
Follow the optical path D3 toward. Since the light on the optical path D3 reflected by the reflecting surface 57a is incident on the prism 56 again, when the light is emitted from the prism 56, the prism 56 is formed on the prism surface 56b having an angle so as to proceed on the optical path D4 parallel to the optical path D1. It has been cut out.

Between the prism 56 and the glass plate 57,
Since the detection liquid filled in the detection chamber 58 defined by the prism 56, the glass plate 57, and the cap 61, the contamination level of the detection liquid can be detected in the optical paths D2 and D3. The reflective surface 57
A light reflecting film, which is a metal film, is coated on a to enable total reflection of light. Since this reflection of light is performed by the reflection surface 57a formed inside the glass plate 57 that is not in contact with the detection liquid, it is not affected by the contamination of the reflection surface 57a by the detection liquid.

In the modified example 5, the prism 56 and the glass plate 5
7, the detection chamber 58 is provided between the detection chamber 58 and the detection chamber 58, so that the optical path length can be secured longer than in the case where a through hole, a groove, or the like for detecting the contamination level of the detection liquid is formed in the prism. Further, it has the effect of improving the exchangeability of the detection liquid. In the present embodiment, the reflecting surface of the prism is coated with a light reflecting film, but the present invention is not limited to this, and a prism having a reflecting surface that totally reflects light incident at a predetermined incident angle is used. May be.

Further, although the light emitting diode 14 is used as the light emitting element in the present embodiment, the present invention is not limited to this, and for example, a white light source having a laser diode or a spectral filter may be used. Furthermore, in the present embodiment, the metal film formed by aluminum vapor deposition was used as the light reflecting film, but the present invention is not limited to this, and for example, a metal oxide film made of MgO ₂ or the like is used as the light reflecting film. May be.

[Brief description of drawings]

FIG. 1 is a sectional view showing the inside of a liquid pollution degree detection device according to a first embodiment of the present invention.

FIG. 2 is a side view of the prism as viewed in the direction of the arrow II in FIG.

FIG. 3 is a plan view showing a first modification of the prism.

4 is a view on arrow IV in FIG.

5 is a cross-sectional view showing a cross-sectional shape of the prism taken along the line VV in FIG.

FIG. 6 is a plan view showing a second modification of the prism.

FIG. 7 is a view taken in the direction of the arrow VII in FIG. 6;

8 is a cross-sectional view showing a cross-sectional shape of the prism taken along the line VIII-VIII in FIG.

FIG. 9 is a plan view showing a third modification of the prism.

FIG. 10 is a view on arrow in the X direction of FIG.

11 is a cross-sectional view showing a cross-sectional shape of the prism taken along line XI-XI in FIG.

FIG. 12 is a light transmission characteristic diagram showing the light transmittance with respect to the wavelength of light for each degree of deterioration of hydraulic oil.

FIG. 13 is a cross-sectional view showing the inside of the liquid pollution degree detection device according to the second embodiment of the present invention.

14 is a sectional view taken along line XIV-XIV in FIG.

FIG. 15 is a plan view of a floating cleaning member.

FIG. 16A is a plan view showing Modification Example 1 of the prism. (b) is a plan view showing a modified example 2 of the prism.

FIG. 17 (c) is a plan view showing Modification Example 3 of the prism. FIG. 9D is a plan view showing Modification Example 4 of the prism.

FIG. 18 is a plan view showing Modification Example 5 of the prism.

[Explanation of symbols]

10, 40 Liquid contamination detection device 11 Housing 12 Substrate 13 Light emitting diode (light emitting element) 14 Photodiode (light receiving element) 17 Light guide section 18 Exit path 19 Incident path 20, 50 Detection section 21, 22, 23, 24, 51 , 52, 53, 54, 5
5,56 Prism 21c Through hole (recess) 22a, 23a, 23b, 24a, 24b, 51c, 5
2a, 53c, 54a, 54c, 55c, 55d Groove portion (recessed portion, groove) 58 Detection chamber (recessed portion) 57 Glass plate 64, 65, 66, 67, 68, 69 Floating cleaning member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yurio Nomura 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. In-house (72) Inventor Shinji Hayada 1 Shindo, Takatana-cho, Anjo City, Aichi Prefecture

Claims (5)

[Claims] 1. A light emitting element, a prism having a portion that can be immersed in a detection liquid and guiding light from the light emitting element, a light receiving element for receiving light traveling through the prism, and a contour of the prism. And a light reflection film formed on the outer peripheral surface that is immersed in the detection liquid, and a concave portion that is formed in the optical path of the light traveling through the prism and that is filled with the detection liquid. The light emitted from the light emitting element is reflected by the light reflecting film and is received by the light receiving element via the recess, and the liquid pollution degree detecting device is characterized. 2. A light emitting element, a prism having a portion that can be immersed in the detection liquid and guiding light from the light emitting element, a light receiving element for receiving light traveling through the prism, and light traveling through the prism. And a recess filled with the detection liquid and formed in the optical path of the light emitted from the light emitting element is reflected at the boundary surface between the outer peripheral surface forming the contour of the prism and the detection liquid, A liquid pollution degree detecting device, wherein the light receiving element receives light through a recess. 3. The liquid pollution degree detection device according to claim 1, wherein a floating cleaning member is housed in the recess. 4. The concave portion is a through hole formed in the prism, wherein the concave portion is a through hole.
The liquid pollution degree detection device described. 5. The liquid pollution degree detection device according to claim 1, wherein the concave portion is a groove formed in a concave shape on the outer wall of the prism.