JPH1047591A - Oil mist sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a proper amount of oil mist with confidence by providing a light emitting/receiving element and a light detection means detecting whether an oil mist is provided or not from the change of a light receiving amount, in the inside of a pipe unit serving as a conveying path of the atomized oil mist. SOLUTION: A pipe unit 32 having permeability is resin-molded, a light shielding environment is constituted, also the pipe unit 32 is interposed, while holding an LED33 and a phototransistor 34a oppositely facing, a phototransistor 34b is tilted to be arranged capable of photometry. When luminous intensity of the LED33 is left as controlled so as to fix light receiving intensity in the phototransistor 34a by a main circuit, a light receiving amount of the phototransistor 34b is changed by a scattering light beam of oil mist, so that whether an oil mist is provided or not can be detected. Besides, through utilizing shading and a refraction factor of the oil mist, whether the oil mist is provided or not in the pipe unit 32 can be well detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil mist sensor suitable for detecting the presence or absence of mist-like or fog-like lubricating oil (collectively referred to as oil mist).

[0002]

2. Description of the Related Art In recent years, lubricating oil to rotating parts and sliding parts of a mechanical device is not supplied in a so-called liquid state, but is supplied in a substantially gaseous state (oil mist) such as mist (micron fog). Things are starting to happen. As a result, there is an advantage that the amount of the lubricating oil used can be reduced or evenly supplied.

[0003] When the oil mist is supplied in this manner, it has been visually determined whether or not the oil mist is being supplied.

[0004]

As described above, conventionally, the presence or absence of an oil mist is visually determined, so that the following problems have been encountered. If the proper amount of the original oil mist is too small, the presence or absence of the oil mist is difficult to understand, and it tends to be set to a degree that it is clearly visible,
Use more oil mist than necessary. This is not preferable in terms of the amount of use and oil mist that floats unnecessarily in the factory.

[0005] Further, if an appropriate amount of oil mist is supplied, it is difficult to notice even if the oil mist is not supplied for some reason. The present invention has been made in view of the above problems, and has as its object to provide an oil mist sensor that can use an appropriate amount of oil mist with peace of mind.

[0006]

In order to achieve the above object, the invention according to claim 1 is directed to a tube which is a conveying path of a spray-like oil mist, a light emitting element which illuminates the inside of the tube, and an irradiation light. And a light detecting means for detecting the presence or absence of oil mist from a change in the amount of received light, and a main body case accommodating the tube and the light detecting means.

[0007] In the invention according to claim 1 configured as described above, the pipe and the light detecting means are housed in the main body case, and the oil mist in the form of a spray is passed through the pipe. It is being transported. In this case, the light detecting means includes a light emitting element illuminating the inside of the tube and a light receiving element receiving the irradiation light, and the presence or absence of the oil mist is determined based on the amount of received light that changes based on the presence or absence of the oil mist. Is detected. The above-mentioned tube may be any cylinder that can convey a spray-like oil mist, and the oil mist sensor may form a part of a conveyance path, or may support an external tube. . As an example of the former configuration, the invention according to claim 2 is the oil mist sensor according to claim 1, wherein the main body case supports the light-transmitting inner tube as the tube in a light-shielding environment, and The detecting means has a configuration in which the light emitting element and the light receiving element are arranged outside the translucent inner tube.

In the invention according to claim 2 configured as described above, a light-shielding environment is formed in the main body case, and a light-transmitting inner tube is supported in the light-shielding environment. In addition, since the light-transmitting inner tube has a light-transmitting property, if a light-emitting element is disposed outside the light-transmitting inner tube, the irradiation light passes through the light-transmitting inner tube and is illuminated to the passage of the oil mist. You. Then, similarly, light is received by a light-receiving element disposed outside the light-transmitting inner tube, and the presence or absence of oil mist is detected.

In this case, the light-emitting element and the light-receiving element are not affected by external light by forming a light-shielding environment.
Since the tube has an opening, external light may enter through the opening. Therefore, a third aspect of the present invention is the oil mist sensor according to the second aspect, wherein the outer tube connected to the translucent inner tube is formed of a non-translucent tube. Claim 3 configured as described above.
In the invention according to the present invention, since the non-light-transmitting tube is connected to the light-transmitting inner tube, a light-shielding environment is also formed at the opening of the light-transmitting inner tube, and external light is transmitted to the light-transmitting inner tube. It does not enter the tube.

On the other hand, as an example of supporting an external tube in the main body case, the invention according to claim 4 is the oil mist sensor according to claim 1, wherein the tube is formed of a translucent external tube. In addition, the main body case has a groove for guiding and supporting the translucent outer tube to the detection site of the light detection means. In the invention according to claim 4 configured as described above, the oil mist passes through the translucent outer tube, and the groove formed in the main body case supports the translucent outer tube. The groove guides the light-transmitting outer tube to the detection portion of the light detecting means, and irradiation light from the light-emitting element is radiated from the outside of the light-transmitting outer tube to the inside, and the light is received by the light-receiving element. To determine the presence or absence of oil mist.

According to a fifth aspect of the present invention, in the oil mist sensor according to the fourth aspect, the main body case has a mounting surface which is supported substantially in close contact with the external light-shielding member. The groove is formed in an open state. In the invention according to claim 5 configured as described above, since the groove portion is formed in an open state on the mounting surface of the main body case, the main body case is substantially adhered to the external light blocking member and supported by the mounting surface. In other words, the light-transmitting outer tube supported in the groove portion is surrounded and held around the entire circumference, and the entire circumference is surrounded by the light-shielding environment to form a light-shielding environment at the detection site of the detection means. .

According to a sixth aspect of the present invention, as an example of a configuration for supporting the light-transmitting outer tube, the oil mist sensor according to the fourth or fifth aspect,
An elastic pad is provided for pressing the translucent outer tube from the opening side while supporting the translucent outer tube in the groove. The external tube may be transmitting vibrations from other machines to itself,
If the translucent outer tube vibrates in the groove, the amount of light received by the light receiving element may change. However, in the invention according to claim 6 configured as described above, the light-transmitting outer tube is supported by the elastic pad and is supported by the elastic pad while being supported by the groove at the predetermined portion.
Therefore, the amount of light received by the light receiving element does not change due to the vibration of the light transmitting outer tube in the groove.

On the other hand, the detecting means detects the presence or absence of the oil mist from the change in the amount of received light while illuminating the inside of the tube, and various methods can be adopted as a method for detecting the change in the amount of received light. is there. As an example, the invention according to claim 7 is the oil mist sensor according to any one of claims 1 to 6, wherein the light detection unit includes a light measurement path that intersects an illumination path of the light emitting element. The light receiving element is arranged so as to be formed, and a change in the amount of received light is detected using scattered light due to oil mist.

In the invention according to claim 7, the light measuring path of the light receiving element intersects the illumination path of the light emitting element in the light detecting means. Therefore,
Even if the light emitting element is illuminated, the irradiation light does not directly irradiate the light receiving element. If there is nothing in the illumination path, the light receiving element is not illuminated as described above, but if an oil mist is present, the oil mist is illuminated and scattered. The scattered light has no directionality and is scattered almost uniformly, and a part of the scattered light irradiates the light receiving element. The presence or absence of oil mist is detected. Of course, it is sufficient that the photometric paths intersect in order to receive such scattered light, and it is not necessary that the optical axes intersect exactly.

According to another aspect of the present invention, there is provided an oil mist sensor according to any one of the first to sixth aspects, wherein the light detecting means includes the light emitting element and the light receiving element. The light-emitting path and the tube are arranged so as to intersect while facing the element, so that a change in the amount of received light due to the light shielding property of the oil mist is detected. In the invention according to claim 8 configured as described above, the light emitting element and the light receiving element are arranged to face each other, and the illumination path and the tube intersect. Although the path is not obstructed, the presence of oil mist blocks the illumination path, and the amount of received light changes due to the light shielding property of the oil mist, so that the oil mist is detected.

According to a ninth aspect of the present invention, in the oil mist sensor according to any one of the first to sixth aspects, the light detecting means includes:
The light emitting element and the light receiving element are arranged to detect a change in an optical path based on a change in a refractive index due to the presence or absence of the oil mist. In the invention according to claim 9 configured as described above, when the light is transmitted from the light emitting element to the tube, the refractive index changes depending on the presence or absence of oil mist in the tube. Accordingly, the optical path of the irradiation light changes, and if the light receiving element is arranged before or after the change, the amount of received light also changes, and the presence or absence of oil mist is detected.

When a light receiving element is arranged in an optical path when an oil mist is present to receive irradiation light, the positional relationship between the optical path and the light receiving element becomes important. Therefore, claim 1
The invention according to claim 0 is the oil mist sensor according to claim 9, wherein the light detecting means has an adjusting mechanism for adjusting a facing angle between the light emitting element and the light receiving element. In the invention according to claim 10 configured as described above, when the refractive index of the object to be measured changes, the optical path also changes, but by adjusting the facing angle between the light emitting element and the light receiving element by the adjusting mechanism. Thus, it is possible to cope with a change in the optical path.

On the other hand, the light detecting means detects the presence or absence of oil mist from the change in the amount of received light, but the change in the amount of received light here does not necessarily indicate only the presence or absence of the detection output of the light receiving element, but is interpreted in a broad sense. It should be. As an example, in the oil mist sensor according to any one of claims 1 to 10, the light detecting means performs feedback control of the light emission intensity of the light emitting element so as to keep the amount of light reception detected by the light receiving element constant. And a change rate detecting means for detecting the amount of received light from a change rate of the light emission intensity of the light emitting element.

In the invention having such a configuration, the illumination control means performs feedback control of the light emission intensity of the light emitting element so as to make the amount of light reception detected by the light receiving element constant. Therefore, the emission intensity is increased if the irradiation light does not easily reach the light receiving element due to being blocked by the oil mist. Conversely, if the oil mist disappears and there is no light blocking substance, the irradiation light easily reaches the light receiving element, so the emission intensity increases. Lower. Further, since the change rate detecting means detects the change rate of the light emission intensity of the light emitting element controlled in this manner, the presence or absence of oil mist can be detected from this change rate. For example, the amount of oil mist that passes through per unit time can be detected by integrating the rate of change. Also, assuming that the oil mist is conveyed in a pulsating flow, it can be determined that there is an oil mist when there is a change, and it can be determined that there is no oil mist when there is no change. That is, since the amount of received light is kept constant, it is possible to reduce the influence of the light transmittance of the tube and the aging of the element.

There are individual differences in such light detection means,
The amount of oil mist conveyed also varies depending on the use situation. Claim 11 is a preferred example in such a case.
According to the invention, in the oil mist sensor according to any one of claims 1 to 10, the light detection unit includes:
The light emitting device includes an adjusting unit that adjusts the light emission intensity of the light emitting element and a light receiving monitor that displays a light receiving state of the light receiving element. In the invention according to claim 11 configured as described above, the state of light reception by the light receiving element is displayed by the light receiving monitor. Therefore, if the light emission intensity of the light emitting element is adjusted by the adjusting means while referring to this display, a wide range is obtained. It can respond to various use environments. In this case, the light receiving monitor may indicate the change of ON / OFF or may quantitatively indicate the amount of received light.

Further, depending on the actual use environment, even if the oil mist temporarily disappears, it does not necessarily mean that the oil mist disappears permanently. As a preferred example of such a case, in the oil mist sensor according to any one of claims 1 to 11, the light detection unit is controlled for a predetermined period or more based on an operation state of the light emitting element and the light receiving element. It may be configured to have a determination stabilizing means for determining that there is no oil mist when the absence of oil mist continues for a long time.

According to the invention having the above-described structure, the determination and stabilization means of the light detection means determines the operating state of the light emitting element and the light receiving element, and the state in which no oil mist is present for a predetermined period or more based on the operating state. It is determined that there is no oil mist when is continued. Therefore, when a micron fog generator or the like generates oil mist in a pulsating flow, a section with oil mist and a section without oil mist are repeated, and erroneous determination may be caused by a section without oil mist that occurs repeatedly. Disappears.

That is, it can be used even when the oil mist is temporarily lost, and it is difficult to make an erroneous determination. Further, according to a twelfth aspect of the present invention, a light emitting means for irradiating the light to the passage of the oil mist, and a light radiated from the light emitting means and irregularly reflected by the oil mist in the passage is received at a predetermined position. A first light-receiving means, a second light-receiving means for receiving light emitted from the light-emitting means and traveling straight through the oil mist in the passage at a predetermined position, and the first light-receiving means Oil mist detecting means for detecting the presence or absence of oil mist in the passage based on the light receiving state of the irregularly reflected light; and irradiating light from the light emitting means based on the light receiving state of the straight light by the second light receiving means. And an adjusting means for adjusting the strength of the recording medium.

According to the present invention, light is applied to the passage through which the oil mist passes, and this light is irregularly reflected by the oil mist in the passage, and the irregularly reflected light is received at a predetermined position. While the presence or absence of oil mist in the passage is detected based on the light receiving condition, the light traveling straight through the oil mist is received at a predetermined position, and the oil mist passage is determined based on the light receiving condition of the straight traveling light. Is adjusted.

Further, according to a thirteenth aspect of the present invention, there is provided a light emitting means for irradiating light to a passage of the oil mist,
A light receiving means for receiving light radiated from the light emitting means and irregularly reflected by the oil mist in the passage at a predetermined position; and a light receiving means for receiving the oil mist in the passage based on the light receiving state of the irregularly reflected light by the light receiving means. Oil mist detection means for detecting the presence / absence of the oil mist detection means, and a delay means for immediately outputting the result of detection by the oil mist detection means for "no oil mist" and delaying and outputting the result of "oil mist present" for a predetermined time. There is a configuration.

According to the present invention, light is applied to the passage through which the oil mist passes, and the light is irregularly reflected by the oil mist in the passage, and the irregularly reflected light is received at a predetermined position. The presence or absence of oil mist in the passage is detected based on the light receiving condition. In this case, as for the detection result, “no oil mist” is output immediately, and “oil mist present” is output after a predetermined time delay.

[0027]

As described above, according to the present invention, an oil mist containing a lubricating oil different from air serving as a transporting medium is detected by using light, so that an oil which can be used with confidence. A mist sensor can be provided. Further, according to the second aspect of the present invention, since the tube through which the irradiation light is transmitted is held in the main body case, the light transmission performance is constant, and the presence or absence of oil mist can be easily detected.

Further, according to the third aspect of the invention,
Since external light is difficult to enter, erroneous determination is unlikely to occur. Further, according to the invention according to claim 4, since the light-transmitting outer tube for transporting the oil mist can be used as it is, there is no need to change the connection in order to intervene on the way, and the convenience is improved. Furthermore, according to the invention according to claim 5, the workability is improved by merely covering the translucent outer tube and mounting it.

Further, according to the invention according to claim 6,
The vibration can be cut off by using the elastic pad, and erroneous judgment can be prevented. Furthermore, according to the invention of claim 7, since the scattered light due to the oil mist is detected, the change between the state without the oil mist and the state with the oil mist is large, and it is easy to determine the presence or absence. Further, according to the invention of claim 8, the light emitting element and the light receiving element face each other, so that the optical axis alignment becomes easy. Further, according to the ninth aspect of the present invention, since the refractive index of the oil mist is used, the change appears in the optical path, which makes it easy to make a judgment, and the oil mist can be detected not only by the oil mist but also by other media. Become.

Further, according to the tenth aspect, it is possible to cope with a wide range of refractive index. Further, claim 1
ADVANTAGE OF THE INVENTION According to the invention concerning 1st, adjustment according to the amount of oil mist becomes possible, and usability improves. Further, according to the twelfth aspect of the present invention, light is applied to the oil mist passage, and the light is irregularly reflected by the oil mist in the passage, and the irregularly reflected light is received at a predetermined position. The presence or absence of oil mist in the passage is detected based on the state of receiving the irregularly-reflected light, and it is possible to prevent burning or the like of the rotating part or the sliding part based on the detection result. . In addition, light that travels straight through the oil mist is received at a predetermined position, and the intensity of irradiation light with respect to the passage of the oil mist is adjusted based on the light receiving state of the straight traveling light. In such a case, it is possible to minimize the influence of the fluctuation of the transmittance of the glass tube and improve the accuracy of detecting the oil mist.

According to the thirteenth aspect of the present invention, light is applied to the passage of the oil mist, and the light is irregularly reflected by the oil mist in the passage, and the irregularly reflected light is received at a predetermined position. The presence or absence of oil mist in the passage is detected based on the state of receiving the irregularly reflected light, and it is possible to prevent burning or the like of a rotating part or a sliding part based on the detection result. It becomes possible. Also, regarding the detection result, "No oil mist"
Is output immediately, and "oil mist is present" is output after a delay of a predetermined time, thereby making it possible to prevent erroneous determination due to a change in the density of the oil mist.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an oil mist circulation system employing an oil mist sensor according to an embodiment of the present invention. In the figure, a fog generating device 10 uses lubricating oil as fog oil (fog), mixes with pressurized air supplied from a compressor (not shown) via a line L1, and forms a line L as an oil mist.
Supply to 2. The pipeline L2 becomes pipelines L2a, L2b,... Branched at an equal pressure state, and supplies oil mist to the bearings 21a, 21b of the respective machine tools. The oil mist sensor 30 is installed at the tip of the pipes L2a and L2b, and detects whether oil mist is supplied to the ends of the pipes L2a and L2b.

FIG. 2 is a perspective view showing the appearance of the oil mist sensor 30, and FIG.
0 is shown in a block diagram. The oil mist sensor 30 includes a main body case 31 including a lower casing 31a and an upper casing 31b. In the lower casing 31a, an LED 33 as a light emitting element and a light receiving element together with a pipe 32 interposed in a pipe L2 and the like are provided. Phototransistors 34a and 34b as elements are supported, and a main circuit 35 is supported in the upper casing 31b. Note that LEDs 36a and 36b for monitoring are arranged on the upper surface of the upper casing 31b, and an adjustment volume 37 is arranged on the side surface.

In the lower casing 31a, FIG.
As shown in FIG. 1, a glass tube 32 is supported, and is entirely resin-molded except for both ends. In this resin mold, the LED 33 and the phototransistor 34a are held facing each other with the tube 32 interposed therebetween, and the phototransistor 34b is held facing the intersection of the facing path and the center of the tube 32. . Of course,
The path from each LED 33 and phototransistors 34a and 34b to the surface of the glass tube 32 is formed as a cavity, and normally, the irradiation light of the LED 33 is directly radiated to the phototransistor 34a through the cavity, and When the irradiation light is scattered in the tube 32, the scattered light is applied to the phototransistor 34b.

In this embodiment, the LED 33 illuminates the inside of the tube 32 from outside the tube 32, and the two phototransistors 34a and 34b also held outside the tube 32 receive irradiation light. For this reason, such irradiation light is not attenuated and the phototransistor 3
A glass tube having a high light transmittance is used so as to easily reach 4a and 34b. However, any material may be used as long as it has translucency corresponding to the required amount of received light. Even if the tube itself does not have translucency, each LED 33 and phototransistor 34a, 3a
It is sufficient that 4b can be directly installed in the tube. Further, in this embodiment, a light-shielding environment is formed by the resin mold.

FIG. 5 shows a drive circuit in the main circuit 35 for maintaining the intensity of light irradiated to the inside of the tube 32 at a predetermined level by using the LED 33 and the phototransistor 34a facing each other. The LED 33 is connected between the power supply line and the ground in series with the collector-emitter of the transistor 35a1 and the resistor 35a2.
The collector current is controlled according to the base current of the light emitting device, thereby emitting light with an intensity corresponding to the collector current. The base amplifier supplies the operational current to the operational amplifier 35a3. The operational amplifier 35a3 is connected to one input terminal of the operational amplifier 35a. The adjustment volume 37 allows a predetermined voltage to be supplied from a power supply line. The phototransistor 34a is connected in series between the power supply line and the ground together with the resistor 35a4.
The voltage between the two is supplied to the operational amplifier 35a through the resistor 35a5.
3 to the other input terminal.

According to this configuration, when the LED 33 emits light, a current flows through the resistor 35a4 according to the amount of light received by the phototransistor 34a, and a voltage corresponding to the current value is input to the operational amplifier 35a3 via the resistor 35a5. You.
The operational amplifier 35a3 compares the voltage set by the adjustment volume 37 with the voltage input via the resistor 35a5. If the voltage input via the resistor 35a5 is low, the output is increased. If the voltage input via 35a5 is high, the output is reduced. The output of the operational amplifier 35a3 becomes the base current and becomes the transistor 35
If the output is large because it is input to a1, the collector current of the transistor 35a1 is large, and as a result,
The emission intensity of the LED 33 increases, and conversely, if the output of the operational amplifier 35a3 decreases, the collector current of the transistor 35a1 decreases and the emission intensity of the LED 33 decreases. That is, feedback control for making the light receiving amount constant is performed such that the light emitting intensity of the LED 33 is increased when the light receiving amount of the phototransistor 34a is small, and the light emitting intensity of the LED 33 is reduced when the light receiving amount of the phototransistor 34a is large. Will be done.

Therefore, the feedback control system constitutes the illumination control means, and the adjustment volume 37 constitutes the adjustment means for adjusting the light emission intensity of the LED 33.
Of course, these are merely examples, and similar functions can be realized in various other configurations. For example, if the intensity is to be adjusted only on the light emitting side, as shown in FIG.
b1 and the collector-emitter current of LED3
3 and the resistor 35b2.

As described above, when the oil mist passes through the tube 32 while the irradiation light of a constant intensity is irradiated on the tube 32, the oil mist is scattered, shielded, and refracted by the three effects of the irradiation light. Affects course. The light detecting means detects the presence or absence of oil mist by paying attention to each of these, and the configuration of the corresponding embodiment will be described below. The property that the oil mist scatters the irradiation light is specifically expressed as a phenomenon that the oil mist emits light. The phototransistor 34b does not face the LED 33, and the photometric path of the phototransistor 34b merely intersects the illumination path of the LED 33. Therefore, as long as there is no light scattering substance in the tube 32, the LED 33
Is not received by the phototransistor 34b. However, when the oil mist is carried, the irradiated light is scattered, and a part of the light is incident on the phototransistor 34b.

FIG. 7 shows a drive circuit of the phototransistor 34b which receives light when oil mist is present. Phototransistor 34b and resistor 3
5c1 is connected in series between the power supply line and the ground, and the connection between the phototransistor 34b and the resistor 35c1 is connected to the base of the switching transistor 35c3 for output via the resistor 35c2. The switching transistor 35c3 is connected between the power line for output detection and the ground via the monitor LED 36b.

With this configuration, the light does not enter the phototransistor 34b without scattered light.
No collector current flows through the phototransistor 34b, and the switching transistor 3 is connected via the resistor 35c2.
No base current is supplied to 5c3. Therefore, the switching transistor 35c3 is off. However, when oil mist is present, scattered light enters the phototransistor 34b, so that a collector current flows and a base current is supplied to the switching transistor 35c3 via the resistor 35c2. Then, the switching transistor 35c3 is turned on, a collector current flows, and the monitor LED 36b is turned on. Using the collector current, the presence or absence of oil mist can be detected outside. Since the intensity of the scattered light is affected by the amount of oil mist, the light emission intensity of the LED 33 is adjusted by the adjusting volume 37 so that the switching transistor 35c3 is turned on by an appropriate amount of oil mist. Further, in this example, the light receiving state is displayed based on whether or not the monitor LED 36b is turned on. However, a numerical value may be displayed by an analog meter or a digital meter.

Since the scattered light is basically uniformly emitted toward the surroundings, the arrangement position of the phototransistor 34b may be any position where the irradiation light from the LED 33 does not directly enter, and can be changed as appropriate. . On the other hand, as long as there is no oil mist, a light-shielding environment is constituted by the above-described resin mold so as to prevent extra light from entering the phototransistor 34b. However, tube 32
Has an entrance and an exit at both ends, and it is meaningless if light enters from this part. For this reason, it is desirable to adopt a light-shielding tube for the tubes L2a and L2b connected to the tube 32.

When the presence or absence of the oil mist is detected based on the light-shielding property, the light detecting means can be constituted only by the LED 33 and the phototransistor 34a facing each other. In this case, the simplest configuration is shown in FIG.
As shown in (1), the intensity is adjusted on the light emitting side, and ON / OFF is determined only by the collector current flowing through the phototransistor 34b on the light receiving side. Also in this case, the emitter of the phototransistor 34b may be connected to the switching transistor 35c3 via the resistor 35b5. This configuration has an advantage that the configuration is simplified in that the presence or absence of oil mist is specifically handled as the ON / OFF of the phototransistor 34b.

Further, as shown in FIG.
While supplying the driving current of the LED 33 at 5d1, the AND circuit 35d is provided together with the detection result of the phototransistor 34a.
2 may be supplied. In this case, even if noise is likely to be added to the detection result of the phototransistor 34a, erroneous detection due to disturbance such as noise is reduced by masking via the AND circuit 35d2. On the other hand, even in the case of the feedback control system shown in FIG. 5, when the voltage value at the connection point between the emitter of the transistor 35a1 and the resistor 35a2 or the connection point between the phototransistor 34a and the resistor 35a4 is observed, the amount of oil mist becomes constant. Although the voltage value is constant in the equilibrium state, the voltage value follows and fluctuates when the amount of oil mist fluctuates. Therefore, assuming that the mist has a pulsating flow like an oil mist generated by a general fog generator 10, it can be determined that oil mist is present when such a voltage value fluctuates. Is constant, it can be determined that there is no oil mist. In this embodiment, the change rate detecting means is configured so that the fluctuating voltage value indicates the change rate of the light emission intensity of the light emitting element, but the presence or absence of the change is detected and the detection result is output. It can also be configured as follows. Of course, the current oil mist flow rate can be measured by integrating the voltage value.

Next, an example in which the presence or absence of an oil mist is detected based on the refractive index will be described. This will be described together with a modification of the main body case. FIG. 9 shows a modification of the main body case 131. In this modification, a groove 131a1 having a substantially U-shaped cross section and opening downward is formed in the lower casing 131a.
Has a transparent outer tube 132 for transporting oil mist.
Can be attached. The translucent outer tube 132
For example, a translucent tube made of nylon or the like is suitable, and a diameter is selected so as to be substantially in close contact with the inner peripheral surface of the groove 131a1. Since the cross-sectional shape of the groove 131a1 is U-shaped, a gap is created only by mounting the light-transmitting outer tube 132. Accordingly, the sponge-like elastic pads 141a to 141c are covered from the opening side so as to close the gap, and the mounting plate 142 made of a light-shielding member is further covered.
To close the lower surface of the lower casing 131a. FIG. 10 is a side view showing an attached state.

The wall surface of the groove 131a1 does not have light transmissivity.
133 and phototransistors 134a and 134b are shown in FIG.
1 are arranged in a positional relationship as shown in FIG. That is,
The LED 133 and the phototransistor 134a face each other,
The phototransistor 134b is disposed slightly inclined with respect to the optical axis of the irradiation light of the LED 133. This degree of inclination corresponds to the refractive index as shown in FIGS. That is, when there is no oil mist or the like in the translucent outer tube 132, the irradiation light of the LED
As shown in FIG. 2, the light basically refracts when passing through the translucent outer tube 132, and basically travels straight. In contrast,
If oil mist or the like is present in the translucent outer tube 132, the traveling direction changes due to a difference in refractive index. The phototransistor 134b is arranged at a position where the irradiation light whose traveling direction has changed can be received. LED13 in this sense
The optical axis of the phototransistor 3 and the optical axis of the phototransistor 134a are offset from the axis of the translucent outer tube 132.

The driving circuit may be realized by a circuit configuration equivalent to that shown in FIGS. In this case, the phototransistor 134a receives light without oil mist, and the phototransistor 134a with oil mist.
b will receive light. In terms of a change in the refractive index, a liquid material having the same configuration can be detected. In such a case, the phototransistor 134b must be able to receive light when the path of irradiation light changes due to a change in the refractive index, and it is preferable that the position can be finely adjusted. 14 to 16 show such an adjusting mechanism.

The first casing 231a and the second casing 231b are rotatable with respect to each other around a light-transmitting tube 232 within a small angle range. The first casing 231a is provided with an LED 233 on the side thereof. Along with illuminating the tube 232 with its axis removed,
Two phototransistors 234a and 234b are provided on the side of the second casing 231b, one of which receives straight traveling light and the other of which receives refracted light.
Here, the side receiving the straight light is a hollow portion 231b.
1, the cavity portion 231b2 on the side that receives refracted light has a size substantially corresponding to the irradiation light. Therefore, even when the position on the side that receives the refracted light is adjusted to an angular position corresponding to the actual refractive index, the straight traveling light passes through the wide hollow portion 231b1 and passes through the phototransistor 234.
a can be reached. FIG. 15 shows a case where the change in the course direction due to the difference in the refractive index is relatively small, and FIG. 16 shows a case where the change in the course direction is relatively large.

In this configuration, even if the refractive index does not change, if light scattering properties are present, scattered light may or may not be generated depending on the presence or absence of light. Is detectable. By the way, as shown in FIG. 9, the thickness of the elastic pads 141a to 141c varies depending on their positions. However, at both ends of the groove 131a1, a gap is formed by using soft and thick elastic pads 141a and 141c in consideration of light shielding properties. And the middle elastic pad 141b
The solid material is such that the transparent outer tube 132 can be pressed firmly into the groove 131a1.

The light-transmitting outer tube 132 may pick up vibration in the piping path, and
It may affect the irradiation light path of the ED 133. However, by pressing the translucent outer tube 132 against the groove 131a1 with the elastic pads 141a to 141c, vibration can be suppressed and good detection can be performed.
In particular, by setting the hardness to an appropriate value according to the portion to be pressed, the light-shielding properties and the holding properties are improved.

In this embodiment, the lower surface of the lower casing 131a is closed by the special mounting plate 142. For example, if the mounting position is a wall surface of a member having a light-shielding property, the light-transmitting outer tube 132 is used. It is also possible to hold it on this wall surface, cover it with the lower casing 131a, and fix it. The output as the light detection means appears as ON / OFF of the switching transistor 35c3 in FIGS. 3 and 7, and as the logical product output of the AND circuit 35d2 in FIG. In this case, if oil mist is generated at a time interval such as 10 times per minute, a warning may be issued during a period in which there is no oil mist even during normal operation. On the other hand, as shown in FIG. 17, by using a monostable multivibrator 302 or the like capable of setting the duration of a pulse in the time constant circuit 301, a configuration is made such that an off output is not generated in a normal operation state. You can also.
Here, the time constant circuit is set to a period slightly longer than the period without oil mist. With such a configuration, the monostable multivibrator is turned on when an oil mist is first detected, and turned off when a period originally determined by a time constant circuit has elapsed. However, since the next oil mist is detected before the output is turned off and a new time measurement is started, the on output is maintained. When the oil mist disappears for a time longer than the original interval, the output is turned off. Therefore, the detection side may determine that the oil mist has disappeared when the off output is detected except during the period immediately after the start.

The same determination can be realized by software on the sequencer side as shown in FIG. In step S100, the same period as that of the time constant circuit 301 is set, and the countdown is performed in step S110.
In the next step S120, the switching transistor 3
It is determined whether there is an ON output from 5c3, and if not, it is determined in step S130 whether a timeout has occurred. Steps S110 to S120 are repeated until the time-out occurs. However, if there is an ON output in the middle, the timer setting is reset in step S100, so that a new time measurement is started.
There is no timeout during normal operation. However, if an ON output is not output due to some abnormality, a timeout occurs, and an alarm is generated in step S140.

Needless to say, the decision stabilizing means is constituted by the combination of the time constant circuit 301 and the monostable multivibrator 302 shown in FIG. 17 by hardware, the software shown in FIG. 18, and the like. Needless to say, the same configuration can be realized. As described above, the light-transmitting tube 32 is resin-molded to form a light-shielding environment, and the LED 33 and the phototransistor 34a face each other with the tube 32 interposed therebetween, and the phototransistor 34b is inclined. If the light intensity of the LED 33 is controlled so that the light intensity at the phototransistor 34a is kept constant by the main circuit 35, the amount of light received by the phototransistor 34b changes due to the scattered light of the oil mist. The presence / absence of the oil mist can be detected, and in addition, the presence / absence of the oil mist in the tubular body 32 can be satisfactorily detected by utilizing the light shielding property and the refractive index of the oil mist.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an oil mist circulation system employing an oil mist sensor according to an embodiment of the present invention.

FIG. 2 is an external perspective view of an oil mist sensor.

FIG. 3 is a main circuit diagram of the oil mist sensor.

FIG. 4 is a partial sectional view of the oil mist sensor.

FIG. 5 is a main part circuit diagram of a drive circuit in the oil mist sensor.

FIG. 6 is a main part circuit diagram showing a modified example of the drive circuit in the oil mist sensor.

FIG. 7 is a main part circuit diagram of a drive circuit on the light receiving side in the oil mist sensor.

FIG. 8 is a main part circuit diagram of a drive circuit in an oil mist sensor using a pulse generator.

FIG. 9 is an exploded perspective view according to a modification of the oil mist sensor.

FIG. 10 is a side view of the oil mist sensor.

FIG. 11 is a partial sectional view of the oil mist sensor.

FIG. 12 is an explanatory diagram showing a traveling path of irradiation light of an oil mist sensor.

FIG. 13 is an explanatory diagram showing a traveling path of irradiation light when a refractive index changes.

FIG. 14 is an exploded perspective view showing an adjustment mechanism according to a refractive index.

FIG. 15 is a side view of the adjustment mechanism when a change in a traveling path is small.

FIG. 16 is a side view of the adjustment mechanism when a change in a traveling path is large.

FIG. 17 is a block diagram showing a configuration of a decision stabilizing means by hardware.

FIG. 18 is a flowchart illustrating a configuration of a determination stabilization unit using software.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 31 ... Main body case 31a ... Lower casing 31b ... Upper casing 32 ... Tube 33 ... LED 34a, 34b ... Phototransistor 35 ... Main circuit 36a, 36b ... LED 37 ... Adjustment volume 131 ... Main body case 131a ... Lower casing 131a1 ... Groove part 132 translucent outer tube 133 LED 134a, 134b phototransistor 141a-141c elastic pad 142 mounting plate 231a first casing 231b second casing 232 tube 233 LED 234a, 234b phototransistor 301 … Time constant circuit 302… Monostable multivibrator

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[Procedure amendment]

[Submission date] July 28, 1997

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for detecting the presence or absence of lubricating oil or cutting oil (collectively referred to as oil mist) consisting of mist, fog, or a small amount of oil fed together with air. It relates to a suitable oil mist sensor.

Claims (13)

[Claims] 1. A pipe which serves as a conveying path for a spray-like oil mist, a light-emitting element for illuminating the inside of the pipe, and a light-receiving element for receiving irradiation light. An oil mist sensor comprising: a light detecting means for detecting; and a main body case containing the tube and the light detecting means. 2. The oil mist sensor according to claim 1, wherein the main body case supports a light-transmitting inner tube as the tube in a light-shielding environment, and the detecting means includes a light-transmitting inner tube. An oil mist sensor, wherein the light emitting element and the light receiving element are arranged outside a tube. 3. The oil mist sensor according to claim 2, wherein the outer tube connected to the light-transmitting inner tube is formed of a non-light-transmitting tube. 4. The oil mist sensor according to claim 1, wherein the tube is formed of a light-transmitting outer tube, and the main body case is connected to the light-transmitting outer tube by the light detecting means. An oil mist sensor having a groove for guiding to and supporting a detection site. 5. The oil mist sensor according to claim 4, wherein the main body case has a mounting surface that is supported substantially in close contact with the external light-shielding member, and the groove portion is opened in the mounting surface. An oil mist sensor characterized by being formed. 6. The oil mist sensor according to claim 4, wherein the light transmitting outer tube is pressed from the opening side while the light transmitting outer tube is supported by the groove. An oil mist sensor having an elastic pad. 7. The oil mist sensor according to claim 1, wherein the light detecting means includes:
An oil mist sensor, wherein the light receiving element is arranged so as to form a photometric path that intersects the illumination path of the light emitting element, and a change in the amount of received light is detected by using light scattered by the oil mist. 8. The oil mist sensor according to claim 1, wherein said light detecting means comprises:
An oil characterized in that the light-emitting element and the light-receiving element face each other, and the illuminating path and the tube are arranged so as to intersect with each other, and a change in the amount of received light due to the light-shielding property of the oil mist is detected. Mist sensor. 9. The oil mist sensor according to claim 1, wherein said light detecting means comprises:
An oil mist sensor, wherein the light emitting element and the light receiving element are arranged to detect a change in an optical path based on a change in a refractive index due to the presence or absence of the oil mist. 10. The oil mist sensor according to claim 9, wherein said light detecting means has an adjusting mechanism for adjusting a facing angle between said light emitting element and said light receiving element. 11. The oil mist sensor according to any one of claims 1 to 10, wherein the light detecting means includes an adjusting means for adjusting a light emission intensity of the light emitting element, and a light receiving state of the light receiving element. An oil mist sensor having a light receiving monitor for displaying. 12. A light-emitting means for irradiating light to a passage of the oil mist, and a first light-receiving means for receiving at a predetermined position light emitted from the light-emitting means and irregularly reflected by the oil mist in the passage. And a second light receiving means for receiving at a predetermined position light emitted from the light emitting means and traveling straight through the oil mist in the passage, and a light receiving state of the irregularly reflected light at the first light receiving means. Oil mist detecting means for detecting the presence or absence of oil mist in the passage based on the light receiving means, and adjusting the intensity of the irradiation light from the light emitting means based on the light receiving condition of the straight light by the second light receiving means. An oil mist sensor comprising an adjusting unit. 13. A light emitting means for irradiating light to a passage of the oil mist, and a light receiving means for receiving at a predetermined position light emitted from the light emitting means and irregularly reflected by the oil mist in the passage. Oil mist detecting means for detecting the presence or absence of oil mist in the passage based on the light receiving state of the irregularly reflected light at the light receiving means, and immediately output when the result of detection by the oil mist detecting means is "no oil mist" An oil mist sensor, comprising: a delay means for outputting a "oil mist present" with a delay of a predetermined time.