JP6864584B2 - Metal foreign matter detector - Google Patents

Description

The present invention relates to a metal foreign matter detecting device, and more particularly to a metal foreign matter detecting device for detecting a metallic foreign matter contained in a fluid flowing through a piping line.

For example, in a device such as an internal combustion engine or a transmission that uses lubricating oil, the lubricating oil contains metal powder generated due to wear or the like of parts constituting the device. If the lubricating oil contains metal powder, not only the lubricating performance of the lubricating oil but also the operation and life of the device may be adversely affected.

Therefore, it is conceivable to detect the metal powder contained in the lubricating oil to grasp the state of the apparatus. For example, in Non-Patent Document 1 below, it is proposed to collect the lubricating oil in the rotating machine and measure the concentration of iron powder contained in the collected lubricating oil to use it for the maintenance of the rotating machine. There is. However, in Non-Patent Document 1, although it is possible to grasp the state of the rotating machine at the time when the lubricating oil is collected, it is difficult to grasp the state of the rotating machine at the present time.

In order to deal with such a problem, the following Patent Documents 1 and 2 propose to detect metal powder contained in the lubricating oil flowing through the piping line provided in the apparatus. In the following Patent Documents 1 and 2, it is determined whether or not the lubricating oil flowing through the piping line contains the metal powder by detecting the change in the inductance of the coil when the metal powder passes through. ..

Japanese Patent No. 4189966 Japanese Patent No. 4014605

Diagnosis of rotating machinery by iron powder densitometer: Journal of Marine Engineering Society of Japan, Vol.42, No.4, pp91-97

The magnitude of the change in the self-inductance of the coil when the metal powder passes depends on the size of the metal powder when the coil size is the same. Therefore, when the metal powder is small, the above change itself becomes small. As a result, it becomes difficult to distinguish the above change from noise, and it becomes difficult to determine whether or not the lubricating oil contains metal powder.

An object of the present invention is to provide a metal foreign matter detecting device capable of improving the detection accuracy of the metallic foreign matter even when the metallic foreign matter contained in the fluid is small.

In order to achieve the above object, the inventor of the present application has focused on the number of times a metallic foreign substance is detected. Then, it has been found that if a plurality of coils are arranged in the direction in which the fluid flows, the opportunity to detect a metallic foreign substance can be obtained a plurality of times. The present invention has been completed based on such findings.

The metallic foreign matter detecting device according to the present invention is a metallic foreign matter detecting device for detecting a metallic foreign matter contained in a fluid flowing through a piping line, and is made of a non-metallic material and constitutes at least a part of the piping line. A metal pipeline and a detection unit for detecting the metallic foreign matter contained in the fluid flowing through the non-metal pipeline are provided, and the detection unit is arranged in the middle of the non-metal pipeline, and the fluid is provided. A plurality of coils arranged in a flow direction, a detection circuit for detecting a change in self-inductivity when the metal foreign matter passes through each of the plurality of coils, and a velocimeter for measuring the flow velocity of a fluid flowing through the piping line. When the detection circuit detects a change in the self-fluid when the metal foreign matter passes through two or more predetermined coils among the plurality of coils, and these self When the change in inductance is at a time corresponding to the time difference in which the fluid sequentially passes through the two or more coils at the flow velocity measured by the flow meter, the metal foreign matter in the fluid flowing through the non-metal pipeline. Is included, and a determination circuit for determining that is included .

In the above-mentioned metal foreign matter detecting device, since a plurality of coils are arranged in the direction in which the fluid flows, there is an opportunity to detect the metallic foreign matter contained in the fluid a plurality of times. Therefore, the detection accuracy of metallic foreign matter is improved.

In the above aspect, when the change in self-inductance due to the passage of the metallic foreign matter is detected twice or more, and these detections are for the same metallic foreign matter, the metallic foreign matter is detected. Therefore, the reliability of the detection of the metallic foreign matter can be improved as compared with the case where the metal foreign matter is detected only once by detecting the change in the self-inductance due to the passage of the metallic foreign matter. This is because when the change in self-inductance due to the passage of a metallic foreign substance is detected only once, the change in self-inductance may be caused by noise, but as described above, the same metallic foreign substance is used. This is because it is unlikely that any of these changes in self-inductance is caused by noise if the change in self-inductance caused by the passage of noise is detected twice or more.

In the metal foreign matter detection device, preferably, the determination circuit detects a change in self-inductance when the metal foreign matter passes through more than half of the plurality of coils. Only when these changes in self-inductance are based on the same metallic foreign matter, it is determined that the fluid flowing through the non-metal pipeline contains the metallic foreign matter.

In the above aspect, the change in self-inductance due to the passage of the metallic foreign matter is detected in more than half of the coils, and the metallic foreign matter is detected when these detections are for the same metallic foreign matter. Therefore, the reliability for detecting metallic foreign substances can be further improved.

In the metal foreign matter detection device, preferably, the detection unit is further determined by the detection circuit when the metal foreign matter is determined to be contained in the fluid flowing through the non-metal conduit. A calculation circuit for calculating the size of the metallic foreign matter based on the detected value indicating the change in self-inductance is included.

In the above aspect, the size of the metal foreign matter can be grasped.

In the metal foreign matter detecting device, preferably, the detection unit further includes an information collecting circuit for collecting information on the size of the metallic foreign matter calculated by the calculation circuit.

In the above aspect, for example, it is possible to grasp how the total amount of the metallic foreign matter and the size of the metallic foreign matter change during the period from the start of collecting the size of the metallic foreign matter to the present.

In the metal foreign matter detection device, preferably, the detection unit further includes a switching circuit for selectively connecting each of the plurality of coils to the detection circuit.

In the above aspect, the detection circuit is shared by a plurality of coils. Therefore, it is not necessary to provide a detection circuit for each coil.

The metal foreign matter detecting device preferably further includes a shield covering the detecting unit.

In the above aspect, the signal indicating the change in the self-inductance of the coil when a metallic foreign substance passes through is less susceptible to noise.

According to the metal foreign matter detecting device according to the present invention, it is possible to improve the detection accuracy of the metallic foreign matter even when the metallic foreign matter contained in the fluid is small.

It is a schematic diagram which shows the schematic structure of the metal foreign matter detection apparatus by 1st Embodiment of this invention. It is a block diagram which shows the signal processing circuit provided in the metal foreign matter detection apparatus shown in FIG. It is a graph which shows the self-inductance of a coil detected by a detection circuit. It is a graph which shows the result of having calculated the rate of change of self-inductance. It is a graph which shows the rate of change of self-inductance corresponding to the extracted detection signal. It is a graph which shows that the self-inductance of each of three coils changed. It is a graph which shows that the self-inductance of each of three coils has changed, and is the graph which shows the state which aligned the time axis with the 3rd coil. It is a graph for demonstrating the error time range of a detection signal. It is a graph which shows that the self-inductance of each of three coils changed. It is a graph which shows that the self-inductance of each of the 1st coil and the 3rd coil of 3 coils changed. It is a graph which shows that the self-inductance of the 3rd coil of 3 coils changed. It is a signal detection process executed by a signal processing circuit, and is the flowchart which shows the signal detection process about the self-inductance of the first coil. It is a signal detection process executed by a signal processing circuit, and is the flowchart which shows the signal detection process about the self-inductance of a second coil. It is a signal detection process executed by a signal processing circuit, and is the flowchart which shows the signal detection process about the self-inductance of a third coil. It is a flowchart which shows the determination process which a signal processing circuit executes in 1st Embodiment of this invention. It is a flowchart which shows the determination process which a signal processing circuit executes in the application example of 1st Embodiment of this invention. It is a schematic diagram which shows the schematic structure of the metal foreign matter detection apparatus by 2nd Embodiment of this invention. It is a graph which shows that the self-inductance of each of two coils changed. It is a flowchart which shows the determination process which a signal processing circuit executes in 2nd Embodiment of this invention. It is a flowchart which shows the determination process which a signal processing circuit executes in the application example of the 2nd Embodiment of this invention. It is a schematic diagram which shows the schematic structure of the switching device provided in the detection unit provided in the metal foreign matter detection device according to the 3rd Embodiment of this invention. It is a schematic diagram which shows the schematic structure of the shield provided in the metal foreign matter detection apparatus according to 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The metal foreign matter detecting device 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing a schematic configuration of a metal foreign matter detecting device 10.

The metal foreign matter detecting device 10 detects metal foreign matter contained in the lubricating oil as a fluid flowing through the pipe 11 as a piping path. Here, the pipe 11 is provided in, for example, an internal combustion engine to allow the lubricating oil to flow. The metallic foreign matter is, for example, metal powder generated by wear of parts constituting an internal combustion engine.

In the following description, the cross section of the flow path of the pipe is a cross section of a portion (hollow portion) through which the lubricating oil flows in the pipe, and is a cross section in a direction perpendicular to the direction in which the lubricating oil flows.

The metal foreign matter detecting device 10 includes a non-metal pipe 12 as a non-metal pipe and a detection unit 13. These will be described below.

The non-metal pipe 12 is made of a non-metal material and forms a part of the pipe 11. The non-metal pipe 12 is located, for example, in the pipe 11, an upstream pipe located upstream of the non-metal pipe 12 in the direction in which the lubricating oil flows, and a position downstream of the non-metal pipe 12 in the direction in which the lubricating oil flows. It is arranged between the downstream pipes to be connected, and these upstream pipes and downstream pipes are connected. The flow path cross section of the non-metal pipe 12 has the same size and shape as the flow path cross sections of the upstream pipe and the downstream pipe. The flow path cross section of the non-metal tube 12 is, for example, circular. The non-metal material forming the non-metal tube 12 may be, for example, a metal material or a synthetic resin material.

The detection unit 13 includes a plurality of coils 141, 142, 143 (three in the present embodiment), a plurality of detection circuits 161, 162, 163 (three in the present embodiment), and a signal processing circuit 18. And.

The plurality of coils 141, 142, and 143 each allow the passage of metallic foreign matter contained in the lubricating oil flowing through the non-metal tube 12. The self-inductance of each of the plurality of coils 141, 142, and 143 changes as the metal foreign matter passes through them.

The plurality of coils 141, 142, and 143 are respectively arranged in the non-metal tube 12. The plurality of coils 141, 142, and 143 are arranged at equal intervals in the direction in which the lubricating oil flows.

The plurality of coils 141, 142, and 143 are formed by winding coil windings around the central axis of the non-metal tube 12, respectively. Each coil 141, 142, 143 is a so-called solenoid coil. The plurality of coils 141, 142, and 143 have the same shape and size as each other.

In the example shown in FIG. 1, the plurality of coils 141, 142, and 143 are each formed by winding coil windings around the outer peripheral surface of the non-metal tube 12. Therefore, when the lubricating oil flows through the non-metal tube 12 in which the plurality of coils 141, 142, and 143 are arranged, the metallic foreign matter contained in the lubricating oil passes through the inside of each of the plurality of coils 141, 142, and 143. It is designed to do.

The plurality of detection circuits 161, 162, and 163 detect changes in the self-inductance of the connected coil among the plurality of coils 141, 142, and 142, respectively. In the example shown in FIG. 1, the detection circuit 161 detects a change in the self-inductance of the coil 141, the detection circuit 162 detects a change in the self-inductance of the coil 142, and the detection coil 163 detects a change in the self-inductance of the coil 143. To do. The plurality of detection circuits 161, 162, and 163 may be formed on the same printed wiring board, or may be formed on different printed wiring boards, for example.

The plurality of detection circuits 161, 162, and 163 detect changes in the self-inductance of the connected coils, respectively, as follows. Here, since the method for each of the plurality of detection circuits 161, 162, and 163 to detect the self-inductance of the coil is the same, the following description only applies to the case where the detection circuit 161 detects the self-inductance of the coil 141. explain.

The detection circuit 161 measures the self-inductance of the coil 141 by, for example, measuring the resonance frequency of a resonance circuit composed of the coil 141 and a capacitor (not shown).

Here, when a metallic foreign substance formed of a magnetic material passes through the coil 141, the self-inductance of the coil 141 measured as described above increases. On the other hand, when a metallic foreign substance formed of a non-magnetic material passes through the coil 141, the self-inductance of the coil 141 measured as described above decreases. The detection circuit 161 detects such a change in the self-inductance of the coil 141.

The signal processing circuit 18 acquires information on the detected metallic foreign matter by using the self-inductance of the coil detected by each of the plurality of detection circuits 161, 162, and 163. The signal processing circuit 18 is connected to each of the plurality of detection circuits 161, 162, and 163. The signal processing circuit 18 may be formed on the same printed wiring board as the plurality of detection circuits 161, 162, 163, for example, or the printed wiring board on which the plurality of detection circuits 161, 162, 163 are formed. It may be formed on another printed wiring board.

The plurality of detection circuits 161, 162, 163 and the signal processing circuit 18 are realized, for example, by the central processing unit reading a program stored in the storage device and performing predetermined processing. A part of any of the plurality of detection circuits 161, 162, 163 and the signal processing circuit 18 may be realized by an integrated circuit such as an ASIC.

The signal processing circuit 18 will be described with reference to FIG. FIG. 2 is a block diagram showing a signal processing circuit 18.

The signal processing circuit 18 includes a signal extraction unit 181 as a signal extraction circuit, a determination unit 182 as a determination circuit, and an information collection unit 183 as an information collection circuit. These will be described below.

The signal extraction unit 181 extracts a detection signal indicating a change in self-inductance corresponding to the passage of a metallic foreign substance from the self-inductance of the coil detected by each of the plurality of detection circuits 161, 162, and 163, that is, the passage of the metallic foreign substance. To do.

Extraction of the detection signal by the signal extraction unit 181 will be described with reference to FIGS. 3, 4 and 5. Here, the extraction of the detection signal by the signal extraction unit 181 is the same regardless of which of the plurality of detection coils 161, 162, and 163 has detected the detection signal. Therefore, in the following description, the detection from the detection circuit 161 Only the case of extracting the signal will be described.

Note that FIG. 3 is a graph showing the self-inductance of the coil 141 detected by the detection circuit 161. FIG. 4 is a graph showing the result of calculating the rate of change of the self-inductance of the coil 141. FIG. 5 is a graph showing the rate of change of the self-inductance of the coil 141 corresponding to the extracted detection signal.

First, the signal extraction unit 181 calculates the baseline. The baseline is used to determine the presence or absence of a detection signal. The baseline is, for example, as shown in FIG. 3, the average value Ave of the self-inductance yy in the period immediately before the detection signal (1 second in the present embodiment).

Subsequently, the signal extraction unit 181 calculates the rate of change Yt as a value indicating the change in the detected self-inductance yt by the following equation (1).

According to the calculation result of the above equation (1), as shown in FIG. 4, the rate of change of the self-inductance becomes substantially zero in the portion corresponding to the baseline.

Subsequently, the signal extraction unit 181 sets the threshold value TH (see FIG. 4) so that the data near the baseline can be removed. The threshold TH is set to a value larger than the baseline.

Subsequently, the signal extraction unit 181 sets the data below the threshold value TH to zero, as shown in FIG. As a result, it is possible to extract a signal (detection signal) indicating a change in self-inductance due to the passage of a metallic foreign substance.

This will be described again with reference to FIG. The determination unit 182 confirms whether or not the plurality of detection signals extracted by the signal extraction unit 181 are caused by the passage of the same metallic foreign matter.

Here, a method of confirming whether or not the detection signal extracted by the signal extraction unit 181 is caused by the passage of the same metallic foreign matter will be described with reference to FIGS. 6 and 7. FIG. 6 is a graph showing that the self-inductance of each of the plurality of coils 141, 142, and 143 has changed. FIG. 7 is a graph showing that the self-inductance of each of the plurality of coils 141, 142, and 143 has changed, and is a graph showing a state in which the time axis is aligned with the coil 143.

When the metallic foreign matter passes through the plurality of coils 141, 142, 143 in sequence, the self-inductance of each of the plurality of coils 141, 142, 143 changes as shown in FIG. Here, the time difference between the passage of the metallic foreign matter through the coil 141 and the passage through the coil 143 is defined as ΔT13, and the time difference between the passage of the metallic foreign matter through the coil 142 and the passage through the coil 143 is defined as ΔT23.

It should be noted that ΔT13 and ΔT23 are determined by the flow velocity of the lubricating oil. The flow velocity of the lubricating oil is measured by a current meter 20 provided in the pipe 11 or the non-metal pipe 12.

It is assumed that the time axis of the self-inductance of the coil 141 is moved by ΔT13 and the time axis of the self-inductance of the coil 142 is moved by ΔT23. In such a case, as shown in FIG. 7, the change in self-inductance in coil 141 (detection signal) and the change in self-inductance in coil 142 (detection signal) are the changes in self-inductance in coil 143 (detection signal), respectively. ), It is confirmed that the change in self-inductance (detection signal) in each of the plurality of coils 141, 142, and 143 is caused by the same metallic foreign matter.

Here, the speed at which the metallic foreign matter flows (that is, the flow velocity of the lubricating oil) fluctuates. Therefore, even when the latest flow velocity is used, when the time axis of the self-inductance detected by the coils is moved as described above, the change in the self-inductance in each of the plurality of coils 141, 142, and 143 ( The detection signal) may not exist at the same time.

In consideration of such circumstances, a plurality of detection signals exist within a predetermined error time range Tx as shown in FIG. 8 in a state where the time axis of the self-inductance detected by the coil is moved as described above. By determining whether or not, it may be confirmed whether or not the change in self-inductance (detection signal) in each of the plurality of coils 141, 142, and 143 is caused by the same metallic foreign matter. .. The error time range Tx is, for example, about 1/10 of the time from when the metal foreign matter passes through one of the two adjacent coils to when it passes through the other.

This will be described again with reference to FIG. The determination unit 183 determines that the lubricating oil contains the metal foreign matter when the plurality of detection signals extracted by the signal extraction unit 181 are caused by the passage of the same metallic foreign matter.

Here, a method of determining whether or not the lubricating oil contains metallic foreign matter will be described with reference to FIGS. 9, 10 and 11. FIG. 9 is a graph showing that the self-inductances of the plurality of coils 141, 142, and 143 have changed. FIG. 10 is a graph showing that the self-inductances of the coils 141 and 143 have changed. FIG. 11 is a graph showing that the self-inductance of the coil 143 has changed.

The metallic foreign matter contained in the lubricating oil sequentially passes through the plurality of coils 141, 142, and 143. Therefore, as shown in FIG. 9, changes in self-inductance (detection signals) indicating the passage of metallic foreign matter are detected in all of the plurality of coils 141, 142, and 143, and these detection signals are the plurality of coils. If the detections are sequentially performed at predetermined intervals along the order of 141, 142, and 143, it is highly possible that the lubricating oil contains metallic foreign matter. However, for example, as shown in FIGS. 10 and 11, when a change in self-inductance (detection signal) indicating the passage of a metallic foreign substance is not detected in all of the plurality of coils 141, 142, and 143, the lubricating oil is used. May not contain metallic foreign matter. Therefore, in the present embodiment, changes in self-inductance (detection signal) indicating the passage of metallic foreign matter are detected in two or more of the plurality of coils 141, 142, and 143, and these are detected. If the signal is sequentially detected at predetermined intervals along the arrangement order of the plurality of coils 141, 142, and 143, it is determined that the lubricating oil contains metallic foreign matter. As a criterion for determining that the lubricating oil contains metallic foreign matter, a change in self-inductance (detection signal) indicating the passage of metallic foreign matter in at least one of the plurality of coils 141, 142, and 143. Of course, it is also possible to adopt the criterion that is detected.

This will be described again with reference to FIG. Since the plurality of detection signals extracted by the signal extraction unit 181 are caused by the passage of the same metallic foreign matter, the information collecting unit 183 is determined by the determination unit 182 that the lubricating oil contains the metallic foreign matter. In this case, information on the size of the passing metallic foreign matter is stored in a storage device (not shown) based on a plurality of detection signals (changes in self-lubrication) that are the basis of the determination. The information regarding the size of the metal foreign matter may be calculated based on, for example, the average value of the rate of change of self-inductance, or may be calculated based on the maximum value of the rate of change of self-inductance. Good.

The signal detection process executed by the signal processing circuit 18 will be described with reference to FIGS. 12, 13 and 14. FIG. 12 is a flowchart showing a signal detection process executed by the signal processing circuit 18 and showing a signal detection process for the self-inductance of the coil 141. FIG. 13 is a flowchart showing signal detection processing executed by the signal processing circuit 18 and showing signal detection processing for the self-inductance of the coil 142. FIG. 14 is a flowchart showing a signal detection process executed by the signal processing circuit 18 and showing a signal detection process for the self-inductance of the coil 143.

First, a signal detection process for the self-inductance of the coil 141 will be described with reference to FIG. In step S11, the signal processing circuit 18 acquires the self-inductance yy1x of the coil 141 at the time t1x from the detection circuit 161.

Subsequently, in step S12, the signal processing circuit 18 calculates the average value Ave1 of the self-inductance yy1x of the coil 141 for 1 second immediately before the time t1x when the self-inductance yy1x of the coil 141 is acquired from the detection circuit 161 in step S11. ..

Subsequently, in step S13, the signal processing circuit 18 calculates the rate of change Yt1 of the self-inductance yt1x of the coil 141 acquired from the detection circuit 161 in step S11.

Subsequently, in step S14, the signal processing circuit 18 determines whether or not the rate of change Yt1 of the self-inductance yy1x of the coil 141 calculated in step S13 is larger than the threshold value TH.

When the rate of change Yt1 of the self-inductance yt1x of the coil 141 calculated in step S13 is equal to or less than the threshold value TH (step S14: NO), the signal processing circuit 18 sets the value of the rate of change Yt1 of the self-inductance yy1x of the coil 141 in step S15. Is set to zero, and the time axis of the rate of change Yt1 of the self-inductance yy1x of the coil 141 is moved. After that, the signal processing circuit 18 executes the determination process in step S16. The details of the determination process will be described later.

Subsequently, the signal processing circuit 18 determines in step S17 whether or not an end command for terminating the detection of the self-inductance yy1x of the coil 141 has been input. When the end command is not input (step S17: NO), the signal processing circuit 18 executes the processes after step S11. When the end command is input (step S17: YES), the signal processing circuit 18 ends the signal detection process. The end command is output by, for example, a user operation.

When the rate of change Yt1 of the self-inductance yy1x of the coil 141 calculated in step S13 is larger than the threshold value TH (step S14: YES), the signal processing circuit 18 sets the rate of change Yt1 of the self-inductance yy1x of the coil 141 in step S18. After setting the value to the value of the rate of change Yt1 calculated in step S13, the processes after step S16 are executed.

Subsequently, a signal detection process for the self-inductance of the coil 142 will be described with reference to FIG. The signal detection process for the self-inductance of the coil 142 is different from the signal detection process for the self-inductance of the coil 141 in the amount of movement on the time axis. Specifically, in the signal detection process for the self-inductance of the coil 141, the movement amount on the time axis is ΔT13, whereas in the signal detection process for the self-inductance of the coil 142, the movement amount on the time axis is ΔT23. Is. Since this is the same as the signal detection process for the self-inductance of the coil 141, detailed description of the signal detection process for the self-inductance of the coil 142 will be omitted.

Subsequently, the signal detection process for the self-inductance of the coil 143 will be described with reference to FIG. The signal detection process for the self-inductance of the coil 143 is different from the signal detection process for the self-inductance of the coil 141 in that the time axis is not moved. Since this is the same as the signal detection process for the self-inductance of the coil 141, detailed description of the signal detection process for the self-inductance of the coil 143 will be omitted.

Subsequently, the determination process executed by the signal processing circuit 18 will be described with reference to FIG. FIG. 15 is a flowchart showing a determination process executed by the signal processing circuit 18.

First, in step S41, the signal processing circuit 18 determines whether or not a change (detection signal) in the self-inductance of the coil 141 due to the passage of a metallic foreign substance is detected. When a change (detection signal) in the self-inductance of the coil 141 due to the passage of the metal foreign matter is detected (step S41: YES), the signal processing circuit 18 is in step S42 of the coil 141 as the metal foreign matter passes. It is determined whether or not there is a change (detection signal) in the self-inductance of the coil 142 due to the passage of a metal foreign object within the error time range Tx based on the time when the self-inductance changes.

When there is a change (detection signal) in the self-inductance of the coil 142 due to the passage of the metal foreign matter (step S42: YES), the signal processing circuit 18 sets the self-inductance of the coil 141 due to the passage of the metal foreign matter in step S43. It is determined whether or not there is a change (detection signal) in the self-inductance of the coil 143 due to the passage of the metal foreign matter within the error time range Tx based on the time when the change is made.

When there is a change (detection signal) in the self-inductance of the coil 143 due to the passage of the metal foreign matter (step S43: YES), the signal processing circuit 18 is detected in the plurality of coils 141, 142, 143 in step S44. Calculate the average value of the rate of change of self-inductance.

Subsequently, in step S45, the signal processing circuit 18 calculates the size of the detected metallic foreign matter based on the average value of the rate of change of the self-inductance calculated in step S44. After that, in step S46, the signal processing circuit 18 stores the size of the metallic foreign matter calculated in step S45 in a storage device (not shown), and ends the determination process.

When there is no change (detection signal) in the self-inductance of the coil 143 due to the passage of the metal foreign matter (step S43: NO), the signal processing circuit 18 has the self-inductance detected in the coil 141 and the coil 142 in step S47. After calculating the average value of the rate of change, the processes after step S45 are executed.

When there is no change (detection signal) in the self-inductance of the coil 142 due to the passage of the metal foreign matter (step S42: NO), the signal processing circuit 18 sets the self-inductance of the coil 141 due to the passage of the metal foreign matter in step S48. It is determined whether or not there is a change (detection signal) in the self-inductance of the coil 143 due to the passage of the metal foreign matter within the error time range Tx based on the time when the change is made.

When there is a change (detection signal) in the self-inductance of the coil 143 due to the passage of a metallic foreign substance (step S48: YES), the signal processing circuit 18 determines the self-inductance detected in the coil 141 and the coil 143 in step S49. After calculating the average value of the rate of change, the processes after step S45 are executed.

When there is no change (detection signal) in the self-inductance of the coil 143 due to the passage of the metallic foreign matter (step S48: NO), the signal processing circuit 18 determines in step S50 that the metallic foreign matter has not been detected, and determines that the metal foreign matter has not been detected. End the process.

When the change (detection signal) of the self-inductance of the coil 141 due to the passage of the metallic foreign matter is not detected (step S41: NO), the signal processing circuit 18 self in the coil 142 due to the passage of the metallic foreign matter in step S51. It is determined whether or not a change in inductance (detection signal) is detected.

When a change (detection signal) in the self-inductance of the coil 142 due to the passage of the metal foreign matter is detected (step S51: YES), the signal processing circuit 18 is set in step 52 of the coil 142 due to the passage of the metallic foreign matter. It is determined whether or not there is a change (detection signal) in the self-inductance of the coil 143 due to the passage of a metal foreign object within the error time range Tx based on the time when the self-inductance changes.

When there is a change (detection signal) in the self-inductance of the coil 143 due to the passage of a metallic foreign substance (step S52: YES), the signal processing circuit 18 determines the self-inductance detected in the coil 142 and the coil 143 in step S53. After calculating the average value of the rate of change, the processes after step S45 are executed.

When there is no change (detection signal) in the self-inductance of the coil 143 due to the passage of the metallic foreign matter (step S52: NO), the signal processing circuit 18 determines in step S54 that the metallic foreign matter has not been detected, and determines that the metal foreign matter has not been detected. End the process.

When there is no change (detection signal) in the self-inductance of the coil 142 due to the passage of the metallic foreign matter (step S51: NO), the signal processing circuit 18 determines in step S55 that the metallic foreign matter has not been detected, and determines that the metal foreign matter has not been detected. End the process.

That is, in the present embodiment, as shown in Table 1, when the self-inductance of only one coil has changed, it is determined that no metal foreign matter has been detected, and the self-inductance of two or more coils has increased. If it changes, it is determined that a metallic foreign substance has been detected. Here, Table 1 shows the determination criteria (determination criteria for whether or not the lubricating oil contains metallic foreign matter) when the signal processing circuit 18 performs the determination process. In Table 1, the numerical value "1" indicates that there is a detection signal, and the numerical value "0" indicates that there is no detection signal.

In such a metal foreign matter detecting device 10, since it is determined that the metallic foreign matter is detected when the self-inductance changes in two or more coils, the reliability for detecting the metallic foreign matter is improved. Therefore, the detection accuracy of metallic foreign matter is improved.

Here, in the metal foreign matter detecting device 10, when the self-inductance changes in two or more coils, it is confirmed whether or not the change in these self-inductances is caused by the passage of the same metal foreign matter. , The reliability for detecting metallic foreign substances is further enhanced.

Further, in the metal foreign matter detecting device 10, since the size of the metallic foreign matter is calculated based on the detected rate of change of the self-inductance, the size of the detected metallic foreign matter can be grasped.

In addition, since the metal foreign matter detecting device 10 collects information on the size of the detected metallic foreign matter, the total amount of the metallic foreign matter and the size of the metallic foreign matter in the period from the start of collecting the information to the present. It is possible to grasp how the metal changes.

[Application example of the first embodiment]
Subsequently, the determination process executed by the signal processing circuit 18 in the application example of the first embodiment will be described with reference to FIG. FIG. 16 is a flowchart showing a determination process executed by the signal processing circuit 18 in the application example of the first embodiment.

The determination process according to the present application example is a metal foreign matter when the self-inductance of at least one of the plurality of coils 141, 142, 143 changes as compared with the determination process according to the first embodiment. Is different in that it is determined that the is detected. Specifically, it is as follows.

In the determination process according to the present application example, step S50A is performed instead of step S50 in the determination process according to the first embodiment. In step S50A, the signal processing circuit 18 sets the rate of change Yt1 of the self-inductance yt1 of the coil 141 as the rate of change Yt used to calculate the size of the metal foreign matter. After that, the signal processing circuit 18 ends the determination process.

In the determination process according to the present application example, step S54A is performed instead of step S54 in the determination process according to the first embodiment. In step S54A, the signal processing circuit 18 sets the rate of change Yt2 of the self-inductance yt2 of the coil 142 as the rate of change Yt used to calculate the size of the metal foreign matter. After that, the signal processing circuit 18 ends the determination process.

In the determination process according to the present application example, step S55A is performed instead of step S55 in the determination process according to the first embodiment. In step S55A, the signal processing circuit 18 determines whether or not a change in self-inductance (detection signal) of the coil 143 due to the passage of a metallic foreign substance is detected.

When the change (detection signal) of the self-inductance of the coil 143 due to the passage of the metal foreign matter is detected (step S55A: YES), the signal processing circuit 18 changes the self-inductance yt3 of the coil 143 Yt3 in step S56. Is the rate of change Yt used to calculate the size of the metal foreign matter, and then the determination process is terminated.

When the change (detection signal) of the self-inductance of the coil 143 due to the passage of the metallic foreign matter is not detected (step S55A: YES), the signal processing circuit 18 determines in step S57 that the metallic foreign matter is not detected. After that, the determination process ends.

That is, in this application example, as shown in Table 2, when the self-inductance changes in at least one coil, it is determined that a metallic foreign substance is detected, and the self in any of the plurality of coils 141, 142, and 143. If the inductance has not changed, it is determined that no metallic foreign matter has been detected. Here, Table 2 shows the determination criteria (determination criteria for whether or not the lubricating oil contains metallic foreign matter) when the signal processing circuit 18 performs the determination process in this application example. In Table 2, the numerical value "1" indicates that there is a detection signal, and the numerical value "0" indicates that there is no detection signal.

In this application example, since it is determined that the metal foreign matter is detected when the self-inductance of at least one coil changes, there is a high possibility that even a small detection signal can be detected. Therefore, in this application example, the detection accuracy of metallic foreign matter can be improved.

[Second Embodiment]
The metal foreign matter detecting device 10A according to the second embodiment of the present invention will be described with reference to FIG. FIG. 17 is a schematic view showing a schematic configuration of the metal foreign matter detecting device 10A.

The metal foreign matter detecting device 10A is different from the metal foreign matter detecting device 10 in that the coil 143 is not provided.

In the metal foreign matter detecting device 10A, as shown in FIG. 18, when a change in self-inductance (detection signal) due to the passage of the metallic foreign matter is detected in a plurality of (two in the present embodiment) coils 141 and 142. (See B1 and B2 in FIG. 18) or when a change in self-inductance (detection signal) due to the passage of a metallic foreign substance is detected in only one of the plurality of coils 141 and 142 (see C1 and D2 in FIG. 18). ).

Here, changes in self-inductance (detection signals) due to the passage of metallic foreign matter are detected in the plurality of coils 141 and 142, and these detection signals are predetermined according to the arrangement order of the plurality of coils 141 and 142. If it is detected sequentially at intervals, it is considered that there is almost no doubt that the lubricating oil contains metallic foreign matter, so it is easy to determine that the lubricating oil contains metallic foreign matter. However, if a change in self-inductance (detection signal) indicating the passage of metallic foreign matter is not detected in all of the plurality of coils 141 and 142, it is difficult to determine whether or not the lubricating oil contains metallic foreign matter. By the way. Therefore, in the present embodiment, changes in self-inductance (detection signals) indicating the passage of metallic foreign matter are detected in all of the plurality of coils 141 and 142, and these detection signals are the plurality of coils 141 and 142. If it is detected sequentially at predetermined intervals according to the order of the above, it is determined that the lubricating oil contains metallic foreign matter. As a criterion for determining that the lubricating oil contains metallic foreign matter, a change in self-inductance (detection signal) indicating the passage of metallic foreign matter is detected in at least one of the plurality of coils 141 and 142. Of course, it is also possible to adopt the standard of being done.

The determination process executed by the signal processing circuit 18 in the present embodiment will be described with reference to FIG. FIG. 19 is a flowchart showing a determination process executed by the signal processing circuit 18 in the present embodiment. The signal detection process executed by the signal processing circuit 18 in the present embodiment is the same as the signal detection process executed by the signal processing circuit 18 in the first embodiment (see FIGS. 12, 13 and 14). Therefore, the detailed description thereof will be omitted.

First, in step S81, the signal processing circuit 18 determines whether or not a change (detection signal) in the self-inductance of the coil 141 due to the passage of a metallic foreign substance is detected.

When a change (detection signal) in the self-inductance of the coil 141 due to the passage of a metallic foreign substance is detected (step S81: YES), the signal processing circuit 18 determines the time when the self-inductance of the coil 141 changes in step S82. It is determined whether or not there is a change (detection signal) in the self-inductance of the coil 142 due to the passage of a metallic foreign substance within the reference error time range Tx.

When a change (detection signal) in the self-inductance of the coil 142 due to the passage of a metallic foreign substance is detected (step S82: YES), the signal processing circuit 18 is detected by the plurality of coils 141 and 142 in step S83. Calculate the average value of the rate of change of self-inductance.

Subsequently, in step S84, the signal processing circuit 18 calculates the size of the detected metallic foreign matter based on the average value of the rate of change of the self-inductance calculated in step S83. After that, in step S85, the signal processing circuit 18 stores the size of the metallic foreign matter calculated in step S84, and ends the determination process.

When the change (detection signal) of the self-inductance of the coil 142 due to the passage of the metallic foreign matter is not detected (step S82: NO), the signal processing circuit 18 determines in step S86 that the metallic foreign matter is not detected. , Ends the judgment process.

When the change (detection signal) of the self-inductance of the coil 141 due to the passage of the metallic foreign matter is not detected (step S81: NO), the signal processing circuit 18 determines in step S87 that the metallic foreign matter is not detected. , Ends the judgment process.

That is, in the present embodiment, as shown in Table 3, it is determined that the metal foreign matter is detected only when the self-inductance changes in all of the plurality of coils 141 and 142. Here, Table 3 shows the determination criteria (determination criteria for whether or not the lubricating oil contains metallic foreign matter) when the signal processing circuit 18 performs the determination process in the second embodiment. In Table 3, the numerical value "1" indicates that there is a detection signal, and the numerical value "0" indicates that there is no detection signal.

In such a metal foreign matter detecting device 10A, since it is determined that the metal foreign matter is detected when the self-inductance changes in all of the plurality of coils 141 and 142, the reliability of the metal foreign matter detection itself can be improved. .. Therefore, the detection accuracy of metallic foreign matter can be improved.

[Application example of the second embodiment]
Subsequently, with reference to FIG. 20, the determination process executed by the signal processing circuit 18 in the application example of the second embodiment will be described. FIG. 20 is a flowchart showing a determination process executed by the signal processing circuit 18 in the application example of the second embodiment.

The determination process according to the present application example detects a metallic foreign substance when the self-inductance of at least one of the plurality of coils 141 and 142 changes as compared with the determination process according to the second embodiment. It differs in that it is judged to have been done. Specifically, it is as follows.

In the determination process according to the present application example, step S86A is performed instead of step S86 in the determination process according to the second embodiment. In step S86A, the signal processing circuit 18 sets the rate of change Yt1 of the self-inductance yt1 of the coil 141 as the rate of change Yt used to calculate the size of the metal foreign matter. After that, the signal processing circuit 18 ends the determination process.

In the determination process according to the present application example, step S87A is performed instead of step S87 in the determination process according to the second embodiment. In step S87A, the signal processing circuit 18 determines whether or not a change in the self-inductance of the coil 142 (detection signal) due to the passage of a metallic foreign substance is detected.

When a change (detection signal) in the self-inductance of the coil 142 due to the passage of a metallic foreign substance is detected (step S87A: YES), the signal processing circuit 18 changes the self-inductance yt2 of the coil 142 in step S88 in Yt2. Is the rate of change Yt used to calculate the size of the metal foreign matter, and then the determination process is terminated.

When the change (detection signal) of the self-inductance of the coil 142 due to the passage of the metallic foreign matter is not detected (step S87A: YES), the signal processing circuit 18 determines in step S89 that the metallic foreign matter is not detected. After that, the determination process ends.

That is, in this application example, as shown in Table 4, when the self-inductance changes in at least one coil, it is determined that a metallic foreign substance is detected, and the self-inductance is detected in any of the plurality of coils 141, 142, and 143. If the inductance has not changed, it is determined that no metallic foreign matter has been detected. Here, Table 4 shows the determination criteria (determination criteria for whether or not the lubricating oil contains metallic foreign matter) when the signal processing circuit 18 performs the determination process in this application example. In Table 4, the numerical value "1" indicates that there is a detection signal, and the numerical value "0" indicates that there is no detection signal.

In this application example, since it is determined that a metal foreign substance is detected when the self-inductance changes in at least one of the plurality of coils 141 and 142, there is a high possibility that even a small detection signal can be detected. Become. Therefore, in this application example, the detection accuracy of metallic foreign matter can be improved.

[Third Embodiment]
The metal foreign matter detecting apparatus according to the third embodiment of the present invention will be described with reference to FIG. 21. FIG. 21 is a schematic view showing a schematic configuration of a detection unit 13B included in the metal foreign matter detecting device according to the third embodiment.

The metal foreign matter detection device according to the present embodiment is different from the metal foreign matter detection device 10 in that the detection unit 13B is provided instead of the detection unit 13. The detection unit 13B is different from the detection unit 13 in that it includes one detection circuit 16 and one switching circuit 22 instead of including a plurality of detection circuits 161, 162, and 163.

The switching circuit 22 connects any one of the plurality of coils 141, 142, and 143 to the detection circuit 16. The switching circuit 22 includes two switch circuits 221 and 222. The switching circuit 22 selectively connects the coils 141, 142, and 143 to the detection circuit 16 by operating each of the two switch circuits 221 and 222 at appropriate timings.

Even in such a metal foreign matter detecting device, the same effect as that of the first embodiment can be obtained.

Further, in the above embodiment, since the switching circuit 22 is provided, one detection circuit 16 is shared by the plurality of coils 141, 142, and 143. As a result, it is not necessary to provide one detection circuit 16 for each of the plurality of coils 141, 142, and 143.

[Fourth Embodiment]
The metal foreign matter detecting device 10D according to the fourth embodiment of the present invention will be described with reference to FIG. 22. FIG. 22 is a schematic view showing a schematic configuration of a shield 24 included in the metal foreign matter detecting device 10D.

The metal foreign matter detecting device 10D differs from the metal foreign matter detecting device 10 in that it includes a shield 24. The shield 24 covers the detection unit 13.

Even in such a metal foreign matter detecting device 10D, the same effect as that of the metal foreign matter detecting device 10 can be obtained.

Further, in the metal foreign matter detecting device 10D, the shield 24 covers the detection unit 13. Therefore, when the detection circuits 161, 162, and 163 detect changes in the self-inductance of the coils 141, 142, and 143, they are less susceptible to noise.

Although the embodiments of the present invention have been described in detail above, these are merely examples, and the present invention is not to be interpreted in a limited manner by the above description of the embodiments.

The pipe line of the present invention may be formed only of a non-metal line.

The non-metal pipeline of the present invention may be arranged inside the pipeline. That is, the mode in which the non-metal pipeline constitutes at least a part of the pipe line includes a mode in which the non-metal pipeline is arranged inside the pipe line. In this case, the non-metal pipeline is realized, for example, by a hole extending along the pipeline. The coil may be arranged, for example, in a state of being inserted into the hole, or may be arranged in a state of being embedded around the hole.

The coil of the present invention may be arranged inside the non-metal pipeline, or may be arranged in a state of being embedded in the non-metal pipeline.

10 Metal foreign matter detection device 11 Piping line 12 Non-metal line 13 Detection unit 141 Coil 142 Coil 143 Coil 161 Detection circuit 162 Detection circuit 163 Detection circuit 182 Judgment circuit 183 Information collection circuit 22 Switching circuit 24 Shield

Claims (6)

A metal foreign matter detection device that detects metallic foreign matter contained in the fluid flowing through the piping line.
A non-metal pipeline formed of a non-metallic material and forming at least a part of the pipeline,
A detection unit for detecting the metallic foreign matter contained in the fluid flowing through the non-metal pipeline is provided.
The detection unit is
A plurality of coils arranged in the middle of the non-metal pipeline and arranged in the direction in which the fluid flows,
For each of the plurality of coils, a detection circuit that detects a change in self-inductance when the metal foreign matter passes through, and a detection circuit .
A current meter that measures the flow velocity of the fluid flowing through the piping line,
When the detection circuit detects a change in the self-inductance when the metal foreign matter passes through two or more predetermined coils among the plurality of coils, and these self-inductances are detected. When the change is at a time corresponding to the time difference in which the fluid sequentially passes through the two or more coils at the flow velocity measured by the flow meter, the metallic foreign matter is contained in the fluid flowing through the non-metal conduit. A metal foreign matter detection device including a determination circuit for determining that the mixture is included. The metal foreign matter detecting device according to claim 1.
The determination circuit is a case where the detection circuit detects a change in the self-inductance when the metal foreign matter passes through more than half of the plurality of coils, and these self A metal foreign matter detecting device that determines that the metal foreign matter is contained in the fluid flowing through the non-metal pipeline only when the change in inductance is based on the same metallic foreign matter. The metal foreign matter detecting device according to claim 1 or 2.
The detection unit further
When the determination circuit determines that the metal foreign matter is contained in the fluid flowing through the non-metal pipeline, the metal is based on a value indicating a change in the self-inductance detected by the detection circuit. A metal foreign matter detection device including a calculation circuit for calculating the size of foreign matter. The metal foreign matter detecting device according to claim 3.
The detection unit further
A metal foreign matter detection device including an information collecting circuit for collecting information on the size of the metallic foreign matter calculated by the calculation circuit. The metal foreign matter detecting device according to any one of claims 1 to 4.
The detection unit further
A metal foreign matter detection device including a switching circuit for selectively connecting each of the plurality of coils to the detection circuit. The metal foreign matter detecting device according to any one of claims 1 to 5, further comprising.
A metal foreign matter detection device including a shield covering the detection unit.

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