sensor

Abstract

The sensor of the present invention includes: a first electrode; a second electrode; an adsorption portion, which is arranged between the first electrode and the second electrode, and changes the resistance between the first electrode and the second electrode by adsorbing conductive particles smaller than the interval between the first electrode and the second electrode; and a short circuit suppression portion, which is used to suppress the short circuit between the first electrode and the second electrode caused by a large-diameter conductive sheet having a size larger than the interval between the first electrode and the second electrode.

Description

Technical Field

[0001] The invention relates to a sensor. Background Art

[0002] Mechanical devices such as speed reducers are housed in a housing containing lubricating oil in order to suppress damage to mechanical parts such as gears. When such a mechanical device is in operation, if the mechanical parts are worn, wear powder (for example, conductive materials such as iron powder) is mixed into the lubricating oil. The wear powder is, for example, a conductive material such as iron powder. If the wear of the mechanical parts progresses and enters the wear failure period in the failure rate curve (bathtub curve), the amount of wear powder mixed into the lubricating oil increases. Therefore, it is possible to accurately perform preventive protection of mechanical parts using a sensor for detecting the amount of wear powder in the lubricating oil.

[0003] As such a sensor, for example, Patent Document 1 discloses an oil detection sensor which is mounted on a transmission of an automobile and is used to detect the deterioration of oil in an oil container, the degree of wear of mechanical parts lubricated with oil, etc. The sensor includes a pair of electrodes and a magnet for adsorbing iron powder or the like (conductive material) contained in the oil, and detects the amount of conductive material in the oil based on the resistance value between the pair of electrodes which changes according to the adsorbed conductive material.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2002-286697 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, the wear powder detected in the reducer etc. increases due to initial wear, and then, after a certain normal operation, increases sharply before the failure occurs. The sensor detects the increase in the amount of wear powder before the failure, but in the case of a large reducer and other cases where the amount of wear powder generated by initial wear is large, the sensor may malfunction and fail to detect the increase in the amount of wear powder before the failure that should have been detected.

[0009] There are also demands for preventing malfunction of sensors and reliably stopping and replacing speed reducers by detecting before a failure.

[0010] Furthermore, when manufacturing mechanical devices such as reducers, large-sized foreign matter (e.g., chips) generated by cutting and the like may adhere to the components of the mechanical device and mix into the lubricating oil. If such large-sized foreign matter adheres to the sensor, a short circuit may occur between a pair of electrodes even if almost no wear powder is generated. In this way, in a sensor for detecting the amount of wear powder, the sensor may sometimes work unexpectedly even if the amount of wear powder is small.

[0011] The present invention has been made in view of the above circumstances, and aims to achieve the following object: to provide a sensor capable of suppressing unintended operation caused by the mixing of foreign matter or the difference between the amount of generated wear powder and the operation setting amount.

[0012] Solutions for solving problems

[0013] The sensor of the first technical solution of the present invention comprises:

[0014] 1st electrode;

[0015] The second electrode;

[0016] an adsorption portion disposed between the first electrode and the second electrode, and changing the resistance between the first electrode and the second electrode by adsorbing conductive particles smaller than the interval between the first electrode and the second electrode; and

[0017] The short circuit suppressing unit is configured to suppress a short circuit between the first electrode and the second electrode caused by a large-diameter conductor piece having a size larger than the interval between the first electrode and the second electrode.

[0018] The sensor includes a short circuit suppressing unit for suppressing a short circuit between the first electrode and the second electrode caused by a large-diameter conductor piece (i.e., a foreign object) having a size larger than the interval between the first electrode and the second electrode. Thus, the short circuit between the first electrode and the second electrode caused by the large-diameter conductor piece is suppressed, thereby suppressing unexpected operation of the sensor.

[0019] The sensor according to the first aspect of the present invention may include a detection unit for detecting a change in resistance between the first electrode and the second electrode.

[0020] In the sensor according to the first aspect of the present invention, the short circuit suppression portion may be an insulating protrusion provided on at least one of the first electrode and the second electrode.

[0021] According to this structure, even when the large-diameter conductor piece is attracted, the convex portion suppresses electrical contact with at least one of the first electrode and the second electrode. Therefore, a short circuit between the first electrode and the second electrode caused by the large-diameter conductor piece is suppressed, and unexpected operation of the sensor can be suppressed.

[0022] In the sensor according to the first aspect of the present invention, the short circuit suppression portion may be a convex portion provided on the adsorption portion.

[0023] By providing a convex portion between the first electrode and the second electrode, even when the large-diameter conductor piece is adsorbed, electrical contact with at least one of the first electrode and the second electrode can be suppressed. Therefore, a short circuit between the first electrode and the second electrode caused by the large-diameter conductor piece can be suppressed, and unexpected operation of the sensor can be suppressed.

[0024] In the sensor according to the first aspect of the present invention, the short circuit suppression portion and the adsorption portion may form a single-piece structure.

[0025] In the sensor according to the first aspect of the present invention, the short circuit suppression portion and the adsorption portion may be separate members.

[0026] In the sensor according to the first aspect of the present invention, the short circuit suppression unit may have insulating properties.

[0027] In the sensor according to the first aspect of the present invention, the short circuit suppression portion may be a wire extending in a direction intersecting a direction in which the first electrode and the second electrode face each other.

[0028] According to this structure, even when the large-diameter conductor piece is attracted, the wire material suppresses electrical contact with at least one of the first electrode and the second electrode. Therefore, the short circuit between the first electrode and the second electrode caused by the large-diameter conductor piece is suppressed, and unexpected operation of the sensor can be suppressed.

[0029] The sensor of the second technical solution of the present invention comprises:

[0030] A plurality of detection units including a pair of electrodes and an adsorption portion, the adsorption portion being disposed between the pair of electrodes and causing the resistance between the pair of electrodes to change by adsorbing conductive particles; and

[0031] The detection unit outputs a signal when the resistance changes in the set number of detection cells.

[0032] The sensor includes a plurality of detection units, and when the resistance in a set number of detection units decreases, the detection unit outputs a signal. Thus, the detection unit can be set so that even if the resistance in one detection unit changes due to the large-diameter conductor sheet, no signal is output. Thus, the unintended operation of the sensor caused by the large-diameter conductor sheet can be suppressed.

[0033] In the sensor according to the second aspect of the present invention, when the conductive particles are not adsorbed, the plurality of detection units may have the same resistance.

[0034] According to this configuration, the voltages applied to the plurality of detection units can be made the same, and thus the voltage applied to the sensor can be reduced.

[0035] In the sensor according to the second aspect of the present invention, the plurality of detection units may be connected in parallel to each other.

[0036] According to this configuration, compared with a case where a plurality of detection cells are connected in series, it is possible to reduce the voltage applied between a pair of electrodes of each detection cell.

[0037] The sensor of the third technical solution of the present invention has:

[0038] 1st electrode;

[0039] The second electrode;

[0040] an adsorption portion disposed between the first electrode and the second electrode, and causing the resistance between the first electrode and the second electrode to change by adsorbing the conductive particles;

[0041] a detection unit configured to detect that a predetermined amount of the conductive particles are adsorbed; and

[0042] The sensitivity adjustment unit adjusts the adsorption state of the conductive particles to change the detection sensitivity. This solves the above-mentioned problem.

[0043] According to the sensor of the third technical solution of the present invention, the adsorption state of the conductive particles is adjusted by the sensitivity adjustment unit. Therefore, even when the adsorption amount of the wear powder is large, the detection sensitivity of the sensor can be adjusted according to the adsorption of the conductive particles, and reliable detection can be performed. In particular, when the size of the reducer or the like provided with the sensor is large and the amount of initial wear powder generated is large, the adsorption of the initial wear powder can be limited, or the detection state can be changed when the adsorption amount is large, so that reliable detection can be performed.

[0044] In the sensor according to the third aspect of the present invention, the sensitivity adjustment unit may adjust the distance between the first electrode and the second electrode.

[0045] In the sensor according to the third aspect of the present invention, the sensitivity adjustment section may be a wall of an insulator disposed between the first electrode and the second electrode, and a group of the insulators having different wall heights may be formed.

[0046] In the sensor according to the third aspect of the present invention, the sensitivity adjustment unit may be an insulator disposed between the first electrode and the second electrode, and a group of insulators having different thicknesses between the first electrode and the second electrode may be formed.

[0047] In the sensor according to the third aspect of the present invention, the first electrode may have an end portion on the same surface as that of the second electrode.

[0048] In the sensor according to the third aspect of the present invention, the sensitivity adjusting portion may be another adsorption portion that adsorbs the conductive particles at least other than the adsorption portion.

[0049] In the sensor according to the third aspect of the present invention, the sensitivity adjustment unit may include a surface treatment layer of the first electrode and the second electrode.

[0050] The sensor of the fourth technical solution of the present invention has:

[0051] An outer electrode having a bottomed cylindrical shape;

[0052] an insulator, which is arranged on the outer electrode as an inner cylinder with a bottom;

[0053] A magnet disposed inside the insulator;

[0054] an inner electrode disposed inside the insulator and located closer to the opening of the outer electrode than the magnet in the axial direction;

[0055] a detection unit that detects that a predetermined amount of conductive particles are attracted by the magnet in such a manner as to short-circuit the outer electrode and the inner electrode; and

[0056] The sensitivity adjustment unit adjusts the adsorption state of the conductive particles to change the detection sensitivity. This solves the above-mentioned problem.

[0057] According to the sensor of the fourth technical solution of the present invention, the adsorption state of the conductive particles is adjusted by the sensitivity adjustment unit. Thus, even when the adsorption amount of the wear powder is large, the detection sensitivity of the sensor can be adjusted according to the adsorption of the conductive particles, and reliable detection can be performed. In particular, when the size of the reducer or the like provided with the sensor is large and the amount of initial wear powder generated is large, the adsorption of the initial wear powder can be limited, or the detection state can be changed when the adsorption amount is large, so that reliable detection can be performed.

[0058] In the sensor according to the fourth aspect of the present invention, the insulator may include a cylindrical portion and a sheet-shaped bottom portion.

[0059] In the sensor according to the fourth aspect of the present invention, the sensor may include a fastening portion that penetrates the inner electrode, the magnet, the bottom of the insulator, and the bottom of the outer electrode in the axial direction.

[0060] Effects of the Invention

[0061] According to the technical solution of the present invention, the following effect can be produced: a sensor can be provided that can suppress unexpected operations and improve operation reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a cross-sectional view showing an example of a mechanical device including the sensor according to the first embodiment of the present invention.

[0063] Figure 2 It is a top view and a cross-sectional view of the sensor according to the first embodiment of the present invention.

[0064] Figure 3 1 and 2 are a plan view and a cross-sectional view of a sensor having a short circuit suppression portion according to a modified example.

[0065] Figure 4 1 and 2 are a plan view and a cross-sectional view of a sensor having a short circuit suppression portion according to a modified example.

[0066] Figure 5 1 and 2 are a plan view and a cross-sectional view of a sensor having a short circuit suppression portion according to a modified example.

[0067] Figure 6 1 and 2 are a plan view and a cross-sectional view of a sensor having a short circuit suppression portion according to a modified example.

[0068] Figure 7 It is a diagram for explaining a sensor according to a second embodiment of the present invention.

[0069] Figure 8 It is a cross-sectional view showing a sensor according to a third embodiment of the present invention.

[0070] Fig. 9 It is a top view showing a sensor according to a fourth embodiment of the present invention.

[0071] Fig.10 It is a cross-sectional view showing a sensor according to a fifth embodiment of the present invention.

[0072] Fig.11 It is a diagram for explaining a sensor according to a sixth embodiment of the present invention.

[0073] Fig.12 It is a diagram for explaining a sensor according to a seventh embodiment of the present invention.

[0074] Description of Reference Numerals

[0075] 2…reducer; 5, 30, 60…sensor; 6, 61…first electrode (inner electrode); 8, 62…second electrode (outer electrode); 9, 69…fastening member (fastening portion); 10, 63…adsorption portion (insulator); 7, 64…magnet; 10a, 11, 12a, 12b, 12c, 15…short-circuit suppression portion; 14…wire; 31…center electrode; 32 (32A, 32B, 32C)…outer electrode; 50, 70…detection portion; 60a…detection surface; 61h, 62h…surface treatment layer; 66…cover. DETAILED DESCRIPTION

[0076] Hereinafter, a sensor according to a first embodiment of the present invention will be described with reference to the drawings.

[0077] In addition, the same reference numerals are given to common components in multiple drawings. It should be noted that, for the sake of convenience of description, the drawings are not necessarily shown to exact scale.

[0078] Figure 1 The diagram is a cross-sectional view showing an example of a mechanism 1 including a sensor 5 according to an embodiment of the present invention. The mechanism 1 is a movable part such as a robot arm, and includes a speed reducer 2, a flange 3 provided on the input side, a servo motor 4, and a device A1 on the output side.

[0079] The speed reducer 2 includes a housing 21 mounted on the flange 3 , an input shaft 23 connected to an output shaft 22 of the servomotor 4 , and an output shaft 24 connected to the device A1 on the output side.

[0080] The input shaft 23 and the output shaft 24 are supported so as to be rotatable about the axis AX relative to the housing 21. The output of the servo motor 4 is input to the reducer 2 via the input shaft 23, and after being decelerated by the reducer 2, is transmitted to the device A1 on the output side via the output shaft 24. Thus, the device A1 on the output side and the flange 3 can rotate relative to each other.

[0081] The flange 3 is a cylindrical member that accommodates at least a portion of the reducer 2. In addition, a servo motor 4 is mounted on the flange 3. The opening at one end of the flange 3 in the direction along the axis AX is blocked by the reducer 2, and the opening at the other end of the flange 3 is blocked by the servo motor 4. Thus, a closed hollow portion (space S) is formed in the flange 3.

[0082] Lubricating oil is stored in the space S, and the flange 3 also functions as an oil bath.

[0083] For example, a gear mechanism is housed in the housing 21 of the reducer 2. The space in the housing 21 is continuous with the space S in the flange 3. When the reducer 2 is in operation, the lubricating oil circulates between the space in the housing 21 and the space S in the flange 3 as the gear mechanism in the housing 21 rotates. Under the effect of the circulation of the lubricating oil, the conductor material such as the wear powder (conductor wear powder) generated inside the reducer 2 is discharged to the space S in the flange 3.

[0084] A sensor 5 for detecting the amount of conductive material contained in the lubricating oil is installed in the space S. The sensor 5 is fixed to the flange 3 by means of a support member 25, for example. The sensor 5 uses a magnet to gather the conductive material contained in the lubricating oil between a pair of electrodes, and detects the amount of conductive material in the lubricating oil based on the change in resistance between the pair of electrodes. The sensor 5 may be arranged, for example, in the housing 21, and may be arranged at any position in the mechanism 1 as long as it is in a space containing the lubricating oil.

[0085] Next, refer to Figure 2 , the structure of sensor 5 is described in detail. Figure 2 This is a diagram schematically showing the structure of a sensor according to a first embodiment of the present invention. Figure 2 A top view of the sensor 5 and a cross section along line AA of the top view are shown.

[0086] like Figure 2 As shown in FIG. 1 , the sensor 5 has a substantially cylindrical shape and includes a first electrode 6, a magnet 7, a second electrode 8, a fastening member 9, and an adsorption portion 10. Figure 2 As shown, when viewed from the upper surface of the sensor 5, the first electrode 6 is circular and is arranged at the center of the sensor 5. The second electrode 8 is a bottomed cylindrical member, including a bottom 8a extending approximately parallel to the first electrode 6, and a wall portion (cylindrical portion) 8b continuous with the bottom 8a and extending approximately perpendicularly to the bottom 8a.

[0087] The magnet 7 is roughly cylindrical and is disposed between the first electrode 6 and the bottom 8a of the second electrode 8. Through holes for fastening members 9 (bolts in the illustrated embodiment) to pass through are provided at the bottoms 8a of the first electrode 6, the magnet 7 and the second electrode 8, respectively. By passing the fastening member 9 through the through holes, the first electrode 6, the magnet 7 and the second electrode 8 are fixed to each other. The first electrode 6 and the second electrode 8 are fixed in a state separated from each other. The first electrode 6 and the second electrode 8 are made of, for example, a magnetic material having conductivity, such as iron, a ferrite core, or silicon steel. The magnet 7 is, for example, a permanent magnet, but it is also possible to configure the first electrode 6 to serve as both a magnet and an electrode instead of a permanent magnet.

[0088] The adsorption portion 10 is arranged in a manner to fill the space between the first electrode 6 and the second electrode 8, and is located between the first electrode 6 and the second electrode 8. The interval X1 between the wall portion 8b of the first electrode 6 and the second electrode 8 is larger than the size of the conductive material contained in the lubricating oil. As an example, the size of the conductive material is about 1.0μm to 100μm, and the interval X1 is preferably set to a distance that will not cause a short circuit due to initial wear of the iron powder. In the illustrated embodiment, the magnet 7 is in contact with the first electrode 6 and is surrounded by the adsorption portion 10. The adsorption portion 10 is made of an insulating non-magnetic material such as resin. The magnet 7 is used to form magnetic flux lines between the first electrode 6 and the second electrode 8. As a result, the conductive material contained in the lubricating oil gathers around the adsorption portion 10.

[0089] The sensor 5 includes a short circuit suppressing portion 10a for suppressing a short circuit between the first electrode 6 and the second electrode 8 caused by the large-diameter conductor piece. Here, the large-diameter conductor piece refers to, for example, a large-diameter conductor piece made by the manufacturing organization 1 (see Figure 1 ) and are conductive particles having a size larger than the interval X1 between the first electrode 6 and the second electrode 8. As an example, the size of the large-diameter conductive piece is about 2 mm to 5 mm.

[0090] exist Figure 2 In the embodiment shown, the short circuit suppression portion 10a is a convex portion provided on the adsorption portion 10, and is formed integrally with the adsorption portion 10. That is, a single-piece structure is formed between the short circuit suppression portion 10a and the adsorption portion 10. Therefore, the short circuit suppression portion 10a is formed of a non-magnetic material having insulating properties, such as resin, similarly to the adsorption portion 10. In addition, the adsorption portion 10 and the short circuit suppression portion 10a may also be separate bodies. Figure 2 In the cross-sectional view of , the width of the short circuit suppression portion 10a is substantially the same as the interval X1 between the first electrode 6 and the wall portion 8b of the second electrode 8. The short circuit suppression portion 10a is annular and is formed to surround the entire circumference of the first electrode 6 when viewed from the upper surface of the sensor 5.

[0091] The first electrode 6 and the second electrode 8 are respectively connected to output lines (not shown), and the first electrode 6 and the second electrode 8 are connected to the detection unit 50 (see Figure 1 )Electrical connection.

[0092] The detection unit 50 is used to detect the change in resistance between the first electrode 6 and the second electrode 8. The detection unit 50 includes, for example, a sensor drive circuit that predicts the failure of the parts of the mechanism 1 based on the change in resistance caused by the accumulation of the conductive material around the adsorption unit 10. When the conductive material contained in the lubricating oil accumulates around the adsorption unit 10, the resistance between the first electrode 6 and the second electrode 8 to which the voltage is applied decreases (or short-circuits), and the output level of the output line changes. The detection unit 50 predicts the failure of the parts of the mechanism 1 by detecting the change in resistance.

[0093] In addition, the reduction in resistance also includes the on-off signals caused by non-power supply and power supply, and the two states of non-power supply and power supply can also be detected (hereinafter referred to as "digital detection"). The detection unit 50 can also be connected to a higher-level control device (not shown) such as a manipulator by wire or wireless means. The higher-level control device can be configured to issue a warning to urge maintenance of the reducer 2, etc. using a predetermined notification component (for example, a notification unit such as a display device and a sound output device) when receiving a signal from the detection unit 50.

[0094] As described above, the sensor 5 includes the short circuit suppression portion 10a for suppressing the short circuit between the first electrode 6 and the second electrode 8 caused by the large-diameter conductor piece having a size larger than the interval X1 between the first electrode 6 and the second electrode 8. The short circuit suppression portion 10a is a convex portion provided on the adsorption portion 10. In this way, by providing the convex portion between the first electrode 6 and the second electrode 8, even when the large-diameter conductor piece is adsorbed on the periphery of the adsorption portion 10, at least one of the first electrode 6 and the second electrode 8 is suppressed from being in electrical contact with the large-diameter conductor piece. Therefore, by suppressing the short circuit between the first electrode 6 and the second electrode 8 caused by the large-diameter conductor piece, it is possible to suppress the unexpected operation of the sensor 5.

[0095] In addition, the short circuit suppression portion 10 a of the sensor 5 and the adsorption portion 10 form a single-piece structure.

[0096] Thus, the number of parts constituting the sensor 5 is reduced, so that the sensor 5 can be easily manufactured.

[0097] Next, refer to Figure 3 A modification of the short circuit suppression unit of the sensor 5 will be described.

[0098] like Figure 3As shown, the short circuit suppression portion 11 of the modified example is a convex portion provided on the adsorption portion 10, similarly to the short circuit suppression portion 10a, and is formed integrally with the adsorption portion 10. The short circuit suppression portion 11 is similarly formed of a non-magnetic material having insulating properties, such as resin, similarly to the short circuit suppression portion 10a. When viewed from the upper surface of the sensor 5, the short circuit suppression portion 11 is annular and is formed in a manner surrounding the entire circumference of the first electrode 6. The short circuit suppression portion 11 is different from the short circuit suppression portion 10a in that the width of the short circuit suppression portion 11 is smaller than the interval X1 between the first electrode 6 and the wall portion 8b of the second electrode 8.

[0099] As described above, even for the sensor 5 having the short circuit suppression portion 11 whose width is smaller than the interval X1, at least one of the first electrode 6 and the second electrode 8 can be suppressed from being in electrical contact with the large-diameter conductor piece. Therefore, by suppressing the short circuit between the first electrode 6 and the second electrode 8 caused by the large-diameter conductor piece, the unintended operation of the sensor 5 can be suppressed.

[0100] Next, refer to Figure 4 , another modification example of the short circuit suppression portion of sensor 5 is described.

[0101] like Figure 4 As shown, the short circuit suppression unit of the sensor 5 may also be divided into a plurality of parts. Figure 4 In the embodiment shown, the sensor 5 has three short circuit suppression parts 12a, 12b, and 12c. The plurality of short circuit suppression parts 12a, 12b, and 12c are convex parts provided on the adsorption part 10, and are formed integrally with the adsorption part 10. The short circuit suppression parts 12a, 12b, and 12c are formed of insulating non-magnetic materials such as resin, similar to the adsorption part 10. When viewed from the upper surface of the sensor 5, the plurality of short circuit suppression parts 12a, 12b, and 12c are arranged at equal intervals around the first electrode 6.

[0102] As described above, even if the short circuit suppression portion is divided into a plurality of parts, at least one of the first electrode 6 and the second electrode 8 can be suppressed from being in electrical contact with the large-diameter conductor sheet at the position where the short circuit suppression portions 12a, 12b, and 12c are provided. Therefore, the short circuit between the first electrode 6 and the second electrode 8 can be suppressed, and the unintended operation of the sensor 5 can be suppressed.

[0103] Next, refer to Figure 5 Still another modification of the short-circuit suppression unit of the sensor 5 will be described.

[0104] like Figure 5 As shown, the short circuit suppression portion of the sensor 5 may be a wire 14 extending in a direction intersecting the direction in which the first electrode 6 and the wall portion 8b of the second electrode 8 face each other. The wire 14 is supported by a plurality of support portions 13, separated from the adsorption portion 10, and provided on the adsorption portion 10.

[0105] exist Figure 5 In the embodiment, the plurality of support portions 13 are respectively pile-shaped components. One end of each support portion 13 is fixed in a state of being buried inside the adsorption portion 10. A through hole for the wire 14 to pass through is provided at the other end of each support portion 13. By passing the wire 14 through the through hole, the wire 14 is fixed in a state of being separated from the adsorption portion 10. When viewed from the upper surface of the sensor 5, the plurality of support portions 13 are arranged at equal intervals apart from each other in the circumferential direction of the first electrode 6, and the wire 14 is arranged in a manner of surrounding the entire circumference of the first electrode 6.

[0106] The material constituting the wire material 14 is not particularly limited, and may be a conductive material such as metal or an insulating material such as resin.

[0107] As described above, when the short circuit suppressing part is the wire 14, the wire 14 can also suppress at least one of the first electrode 6 and the second electrode 8 from making electrical contact with the large-diameter conductor sheet. Therefore, the short circuit between the first electrode 6 and the second electrode 8 is suppressed, and the unintended operation of the sensor 5 can be suppressed.

[0108] Next, refer to Figure 6 Still another modification of the short-circuit suppression unit of the sensor 5 will be described.

[0109] like Figure 6 As shown, the short circuit suppression portion 15 of the modified example may also be an insulating convex portion provided on at least one of the first electrode 6 and the second electrode 8. In the illustrated embodiment, the short circuit suppression portion 15 is provided at the wall portion 8b of the second electrode 8 along the inner edge where the wall portion 8b contacts the adsorption portion 10. In addition, the short circuit suppression portion 15 may be provided on the first electrode 6, or may be provided on the first electrode 6 and the second electrode separately.

[0110] As described above, when the short circuit suppression unit 15 is provided on at least one of the first electrode 6 and the second electrode 8, it is possible to suppress electrical contact between at least one of the first electrode 6 and the second electrode 8 and the large-diameter conductor sheet, similarly to the short circuit suppression unit 10a. Therefore, the short circuit between the first electrode 6 and the second electrode 8 is suppressed, and the unintended operation of the sensor 5 can be suppressed.

[0111] Hereinafter, a sensor according to a second embodiment of the present invention will be described with reference to the drawings.

[0112] Figure 7 It is a diagram for explaining the sensor according to this embodiment.

[0113] The sensor 30 of this embodiment is a sensor for detecting the amount of the conductive material contained in the lubricating oil, similarly to the sensor 5 of the first embodiment.

[0114] The sensor 30 has a substantially cylindrical outer shape, and includes a plurality of detection cells and a detection unit 50 that outputs a signal when the resistance of the detection cell changes.

[0115] More specifically, the sensor 30 includes a central electrode 31, a plurality of outer electrodes 32, an adsorption portion 33 disposed between the central electrode 31 and the outer electrodes 32, and a magnet 34. The plurality of outer electrodes 32 are insulated from each other, and a detection unit is formed by a pair of electrodes including the central electrode 31 and one outer electrode 32 and the adsorption portion 33 disposed between the pair of electrodes.

[0116] In the illustrated embodiment, the sensor 30 has four outer electrodes 32A, 32B, 32C, and 32D, constituting four detection units. The number of the outer electrodes 32 and the number of the detection units are not particularly limited. The magnet 34 of the sensor 30 forms magnetic flux lines between a pair of electrodes, so that the conductive material contained in the lubricating oil is adsorbed to the adsorption portion 33. In this way, when the conductive material gathers near the adsorption portion 33, the resistance of the detection unit changes. In the state where the conductive particles are not adsorbed, the resistance of each of the plurality of detection units is the same.

[0117] Output lines are connected to the central electrode 31 and the plurality of outer electrodes 32 , respectively, and the plurality of detection units are electrically connected to the detection unit 50 via the output lines.

[0118] In this embodiment, a plurality of detection units are connected in parallel to each other, and a voltage from the same voltage source is applied between the central electrode 31 and each outer electrode 32. When the resistance changes in any set number of detection units, the detection unit 50 outputs a signal.

[0119] For example, the detection unit 50 may be set to output a signal to a higher-level control device such as a manipulator when the resistance decreases in two or more detection cells, or may be set to output a signal when the resistance decreases in all detection cells.

[0120] As described above, the sensor 30 includes a plurality of detection cells, and the detection unit 50 outputs a signal when the resistance is reduced in any set number of detection cells.

[0121] Thus, the detection unit 50 can be set so that no signal is output even if the resistance in one detection unit changes due to the large-diameter conductor sheet. Therefore, the unexpected operation of the sensor caused by the large-diameter conductor sheet can be suppressed. In addition, by using the sensor 30, the condition for the detection unit 50 to output a signal can be set, so the timing of outputting a signal in one sensor 30 can be made consistent with the timing of the optimal fault prediction that varies according to the needs of each user.

[0122] In addition, when the conductive particles are not adsorbed, the resistances of the plurality of detection cells are equal to each other, thereby reducing the voltage applied to the sensor 30 .

[0123] In addition, the plurality of detection units are connected in parallel to each other, thereby making it possible to reduce the voltage applied between a pair of electrodes of each detection unit.

[0124] Hereinafter, a sensor according to a third embodiment of the present invention will be described with reference to the drawings.

[0125] Figure 8 is a cross-sectional view of a sensor according to this embodiment. In this embodiment, the difference from the above-mentioned embodiments is the adsorption portion. Figure 8 There are structures that are omitted from the illustration.

[0126] like Figure 8 As shown, the sensor 60 of this embodiment has a substantially cylindrical shape and includes a first electrode (inner electrode) 61 , a magnet 64 , a second electrode (outer electrode) 62 , a fastening member (fastening portion) 69 , an adsorption portion (insulator) 63 , and a housing 65 .

[0127] The first electrode (inner electrode) 61 is circular in shape when viewed from the upper surface of the sensor 60, and is disposed at the center of the sensor 60. The second electrode (outer electrode) 62 is a bottomed cylindrical member, and has a bottom 62a extending substantially parallel to the first electrode (inner electrode) 61, and a wall (cylindrical portion) 62b extending substantially perpendicularly to the bottom 62a and continuous with the bottom 62a. The first electrode (inner electrode) 61 is located at the opening of the second electrode (outer electrode) 62.

[0128] The magnet 64 is substantially cylindrical (substantially disc-shaped) and is disposed between the first electrode (inner electrode) 61 and the bottom 62a of the second electrode (outer electrode) 62. Through holes through which a fastening member (fastening portion) 69 (a bolt in the illustrated embodiment) passes are provided in the first electrode (inner electrode) 61, the magnet 64, and the bottom 62a of the second electrode (outer electrode) 62, respectively. By passing the fastening member (fastening portion) 69 through the through holes, the first electrode (inner electrode) 61, the magnet 64, and the second electrode (outer electrode) 62 are fixed to each other.

[0129] The outer diameter of the magnet 64 is formed to be smaller than the outer diameter of the second electrode (outer electrode) 62 .

[0130] The first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 are fixed in a state of being separated from each other. The first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 are made of, for example, a magnetic material having conductivity, such as iron, a ferrite core, or silicon steel. The magnet 64 is, for example, a permanent magnet, but it is also possible to configure the first electrode (inner electrode) 61 to serve as both a magnet and an electrode without using a permanent magnet.

[0131] The adsorption portion (insulator) 63 is provided so as to fill the space between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 , and is interposed between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 .

[0132] The adsorption portion (insulator) 63 has a bottom portion 63 a along the bottom portion 62 a of the second electrode (external electrode) 62 and a tube portion 63 b along the wall portion (tube portion) 62 b of the second electrode (external electrode) 62 .

[0133] The bottom portion 63a and the cylindrical portion 63b are separate bodies. The bottom portion 63a is formed in a sheet shape.

[0134] The bottom 63a of the adsorption part (insulator) 63 is made of insulating paper, for example, and its thickness can be 0.05 mm to 1 mm. The bottom 63a of the adsorption part (insulator) 63 can be made of circular paper having an outer diameter substantially the same as the inner diameter of the cylinder 63b.

[0135] In addition, the bottom 63a can be made of a circular paper having an outer diameter larger than the inner diameter of the cylinder 63b. In this case, the bottom 63a can be made of a circular paper having an outer diameter smaller than the outer diameter of the cylinder 63b. In addition, the bottom 63a can be made of a circular paper having an outer diameter equal to the outer diameter of the cylinder 63b.

[0136] A step 63c is formed on the inner surface of the cylindrical portion 63b of the adsorption portion (insulator) 63. The portion of the cylindrical portion 63b of the adsorption portion (insulator) 63 that is closer to the first electrode (inner electrode) 61 than the step 63c has an inner diameter dimension equal to the outer diameter of the first electrode (inner electrode) 61. The portion of the cylindrical portion 63b of the adsorption portion (insulator) 63 that is closer to the magnet 64 than the step 63c has an inner diameter dimension equal to the outer diameter of the magnet 64.

[0137] The thickness of the end of the cylindrical portion 63b of the adsorption portion (insulator) 63, that is, the interval X1 between the first electrode (inner electrode) 61 and the wall portion 62b of the second electrode (outer electrode) 62 is larger than the size of the conductive material contained in the lubricating oil. As an example, the size of the conductive material is about 1.0μm to 100μm, and the interval X1 is preferably set to a distance that does not cause a short circuit due to initial wear of iron powder. In the illustrated embodiment, the magnet 64 is in contact with the first electrode (inner electrode) 61 and is surrounded by the adsorption portion (insulator) 63.

[0138] The adsorption part (insulator) 63 is made of a non-magnetic material having insulating properties, such as resin. The magnet 64 forms magnetic flux lines between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62. As a result, the conductive material contained in the lubricating oil gathers around the adsorption part (insulator) 63. In addition, the range in which the lubricating oil circulates is set as the detection area.

[0139] The sensor 60 of this embodiment has a detection surface 60a formed on a plane connecting the end of the second electrode (outer electrode) 62 which is substantially coplanar with the surface of the first electrode (inner electrode) 61. That is, on the detection surface 60a, the conductor wear powder is attracted between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 in correspondence with the magnetic flux lines, and the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 are electrically connected. Thus, the sensor is used to detect changes in the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62.

[0140] In addition, the openings of the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 may not be arranged on the same plane.

[0141] By lengthening the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 drops to a threshold value or becomes a short-circuit state increases.

[0142] In addition, by shortening the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 is reduced to a threshold value or a short-circuit state.

[0143] The sensor 60 of the present embodiment includes a sensitivity adjustment unit that adjusts the adsorption state of the conductor wear powder to change the detection sensitivity.

[0144] In the present embodiment, the sensitivity adjustment portion is provided as the adsorption portion (insulator) 63. Furthermore, in the present embodiment, the sensitivity adjustment portion is provided as the cylindrical portion 63b of the adsorption portion (insulator) 63.

[0145] The adsorption portion (insulator) 63 of the present embodiment adjusts the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 , thereby adjusting the amount of conductor wear powder adsorbed by the adsorption portion (insulator) 63 .

[0146] Specifically, if Figure 8 As shown, the cylindrical portion 63b of the adsorption portion (insulator) 63 forms a group of varying protrusion heights from the detection surface 60a.

[0147] Figure 8 The detection surface 60a of the sensor 60A is at the same height HA as the end of the cylindrical portion 63b of the adsorption portion (insulator) 63A, that is, the detection surface 60a is coplanar with the cylindrical portion 63b of the adsorption portion (insulator) 63A.

[0148] for Figure 8 For the sensor 60B, the end of the cylindrical portion 63b of the adsorption portion (insulator) 63B is higher than the detection surface 60a by a height HB, that is, the cylindrical portion 63b of the adsorption portion (insulator) 63B protrudes from the detection surface 60a by a height HB.

[0149] for Figure 8 In the sensor 60C, the end of the cylindrical portion 63b of the adsorption portion (insulator) 63C is higher than the detection surface 60a by a height HC, that is, the cylindrical portion 63b of the adsorption portion (insulator) 63C protrudes from the detection surface 60a by a height HC.

[0150] for Figure 8 For the sensor 60D, the end of the cylinder 63b of the adsorption part (insulator) 63D is higher than the detection surface 60a by a height HD, that is, the cylinder 63b of the adsorption part (insulator) 63D protrudes from the detection surface 60a by a height HD.

[0151] Here, the relationship between the heights HA, HB, HC, and HD is set to HA (=0) <HB<HC<HD。

[0152] The sensor 60 of the present embodiment has a group of the cylindrical portion 63 b of the adsorption portion (insulator) 63 set to such different values, and can be selected and assembled from them.

[0153] That is, a group of the cylindrical portions 63 b of the plurality of adsorption portions (insulators) 63 having different heights (axial dimensions) constitutes a sensitivity adjustment portion.

[0154] Thus, by selecting the sensitivity adjustment portion, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 can be selected from a plurality of values.

[0155] Here, in Figure 8 In the sensor 60A, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 set by the end of the cylindrical portion 63b of the adsorption portion (insulator) 63A is used as a reference.

[0156] In contrast, Figure 8In the sensor 60B, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 set by the end of the cylinder 63b of the adsorption part (insulator) 63B is longer than the reference. Therefore, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 is reduced to a threshold value or a short circuit state is increased. As a result, even if the size of the reducer 2 is large, for example, it is not affected by the increase in the initial amount of wear powder of the reducer 2, and the fault detection of the reducer 2 can be reliably performed.

[0157] And, in Figure 8 In the sensor 60C, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 set by the end of the cylinder 63b of the adsorption part (insulator) 63C is longer than that of the sensor 60B. Therefore, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 is reduced to a threshold value or a short circuit state is increased. As a result, even if the size of the reducer 2 is larger, it is not affected by the increase in the initial wear powder amount of the reducer 2, and the fault detection of the reducer 2 can be reliably performed.

[0158] And, in Figure 8 In the sensor 60D, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 set by the end of the cylinder 63b of the adsorption part (insulator) 63D is longer than that of the sensor 60C. Therefore, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 is reduced to a threshold value or a short circuit state is increased. Therefore, even if the size of the reducer 2 is further increased, it is not affected by the increase in the initial wear powder amount of the reducer 2, and the fault detection of the reducer 2 can be reliably performed.

[0159] By appropriately selecting from the group of the adsorption portion (insulator) 63 in this manner, it is possible to reliably detect a failure of the speed reducer 2 without increasing the size of the sensor 60 or affecting other components.

[0160] That is, the center electrode (inner electrode) 61, the outer electrode (outer electrode) 62, the magnet 64, the shell 65, and the fastening member (fastening part) 69 are all common, and a sensor 60 with different sensitivities can be formed simply by replacing the adsorption part (insulator) 63.

[0161] In addition, in the present embodiment described above, the number of groups of the adsorption portions (insulators) 63 as the sensitivity adjustment portions is set to four, but the present invention is not limited thereto and can be set as appropriate.

[0162] The sensor 60 of the present embodiment is assembled as follows.

[0163] First, the outer electrode (outer electrode) 62 is placed inside the housing 65. Next, the bottom 63a of the adsorption part (insulator) 63 is arranged on the bottom 62a of the outer electrode (outer electrode) 62. Next, the cylinder 63b of the adsorption part (insulator) 63 having the selected height dimension is inserted into the outer electrode (outer electrode) 62. Next, the magnet 64 is inserted into the cylinder 63b, and the center electrode (inner electrode) 61 is inserted into the cylinder 63b. In this state, the sensor 60 is assembled by penetrating the fastening member (fastening part) 69 and fastening and fixing it.

[0164] The sensor 60 of the present embodiment includes a sensitivity adjustment unit, and can set the detection sensitivity to a predetermined state.

[0165] Specifically, the sensitivity adjustment unit is selected in response to the case where the amount of conductor wear powder generated is assumed to be large, so that the creepage distance of the wear powder adsorbed between the electrodes 61 and 62 can be increased, and the detection sensitivity of the sensor 60 is set to a predetermined state. In addition, the sensitivity adjustment unit is selected in response to the case where the amount of conductor wear powder generated is assumed to be small, so that the length of the wear powder adsorbed between the electrodes 61 and 62 can be reduced, and the detection sensitivity of the sensor 60 can be set to a predetermined state.

[0166] Thus, failure detection of the speed reducer 2 can be reliably performed without being affected by an increase in the amount of initial wear powder of the speed reducer 2 .

[0167] The amount of iron powder (wear powder) generated during initial wear varies depending on the type (size) of the reducer. In the case of a large reducer, the amount of initial wear iron powder is large, and the initial wear iron powder will fill the sensor electrical gap between electrodes 61 and 62 and react, which may cause malfunction. Therefore, it is necessary to design the sensor electrical gap corresponding to the reducer type, but there is a problem of enlarging the sensor in the diameter direction.

[0168] In contrast, the sensor 60 of the present embodiment has a sensitivity adjustment portion formed of an adsorption portion (insulator) 63 having different heights, thereby obtaining the same effect as extending in the radial direction, and thus the sensor 60 does not increase in size.

[0169] Hereinafter, a sensor according to a fourth embodiment of the present invention will be described with reference to the drawings.

[0170] Fig. 9 is a top view of a sensor according to this embodiment. In this embodiment, the difference from the third embodiment described above is in the adsorption portion and the external electrode. Fig. 9 There are structures that are omitted from the illustration.

[0171] like Fig. 9 As shown, the sensor 60 of this embodiment has a substantially cylindrical shape and includes a first electrode (inner electrode) 61 , a magnet 64 , a second electrode (outer electrode) 62 , a fastening member (fastening portion) 69 , an adsorption portion (insulator) 63 , and a housing 65 .

[0172] The first electrode (inner electrode) 61 is circular in shape when viewed from the upper surface of the sensor 60, and is disposed at the center of the sensor 60. The second electrode (outer electrode) 62 is a bottomed cylindrical member having a bottom 62a extending approximately parallel to the (inner electrode) 61 and a wall (cylindrical portion) 62b continuous with the bottom 62a and extending approximately perpendicularly to the bottom 62a.

[0173] The magnet 64 is substantially cylindrical (substantially disc-shaped) and is disposed between the first electrode (inner electrode) 61 and the bottom 62a of the second electrode (outer electrode) 62. Through holes through which a fastening member (fastening portion) 69 (a bolt in the illustrated embodiment) passes are provided in the first electrode (inner electrode) 61, the magnet 64, and the bottom 628a of the second electrode (outer electrode) 62, respectively. By passing the fastening member (fastening portion) 69 through the through holes, the first electrode (inner electrode) 61, the magnet 64, and the second electrode (outer electrode) 62 are fixed to each other.

[0174] The outer diameter of the magnet 64 is formed to be smaller than the outer diameter of the second electrode (outer electrode) 62 .

[0175] The first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 are fixed in a state of being separated from each other. The first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 are made of, for example, a magnetic material having conductivity, such as iron, a ferrite core, or silicon steel. The magnet 64 is, for example, a permanent magnet, but it is also possible to configure the first electrode (inner electrode) 61 to serve as both a magnet and an electrode without using a permanent magnet.

[0176] The adsorption portion (insulator) 63 is provided so as to fill the space between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 , and is interposed between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 .

[0177] The adsorption portion (insulator) 63 has a bottom portion 63 a along the bottom portion 62 a of the second electrode (external electrode) 62 and a tube portion 63 b along the wall portion (tube portion) 62 b of the second electrode (external electrode) 62 .

[0178] The bottom portion 63a and the cylindrical portion 63b are separate bodies. The bottom portion 63a is formed in a sheet shape.

[0179] The bottom 63a of the adsorption part (insulator) 63 is made of insulating paper, for example, and its thickness can be 0.05 mm to 1 mm. The bottom 63a of the adsorption part (insulator) 63 can be made of circular paper having an outer diameter substantially the same as the inner diameter of the cylinder 63b.

[0180] In addition, the bottom 63a can be made of a circular paper having an outer diameter larger than the inner diameter of the cylinder 63b. In this case, the bottom 63a can be made of a circular paper having an outer diameter smaller than the outer diameter of the cylinder 63b. In addition, the bottom 63a can be made of a circular paper having an outer diameter equal to the outer diameter of the cylinder 63b.

[0181] A step 63c is formed on the inner surface of the cylindrical portion 63b of the adsorption portion (insulator) 63. The portion of the cylindrical portion 63b of the adsorption portion (insulator) 63 that is closer to the first electrode (inner electrode) 61 than the step 63c has an inner diameter dimension equal to the outer diameter of the first electrode (inner electrode) 61. The portion of the cylindrical portion 63b of the adsorption portion (insulator) 63 that is closer to the magnet 64 than the step 63c has an inner diameter dimension equal to the outer diameter of the magnet 64.

[0182] The thickness of the end of the cylindrical portion 63b of the adsorption portion (insulator) 63, that is, the interval X1 between the first electrode (inner electrode) 61 and the wall portion 62b of the second electrode (outer electrode) 62 is larger than the size of the conductive material contained in the lubricating oil. As an example, the size of the conductive material is about 1.0μm to 100μm, and the interval X1 is preferably set to a distance that does not cause a short circuit due to initial wear of iron powder. In the illustrated embodiment, the magnet 64 is in contact with the first electrode (inner electrode) 61 and is surrounded by the adsorption portion (insulator) 63.

[0183] The adsorption part (insulator) 63 is made of a non-magnetic material having insulating properties, such as resin. The magnet 64 forms magnetic flux lines between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62. As a result, the conductive material contained in the lubricating oil gathers around the adsorption part (insulator) 63.

[0184] The sensor 60 of this embodiment has a detection surface 60a formed on a plane connecting the end of the second electrode (outer electrode) 62 which is substantially coplanar with the surface of the first electrode (inner electrode) 61. That is, on the detection surface 60a, the conductor wear powder is attracted between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 in correspondence with the magnetic flux lines, and the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 are electrically connected, thereby detecting a change in the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62.

[0185] By lengthening the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 drops to a threshold value or becomes a short-circuit state increases.

[0186] In addition, by shortening the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 drops to a threshold value or becomes a short-circuit state is reduced.

[0187] The sensor 60 of the present embodiment includes a sensitivity adjustment unit that adjusts the adsorption state of the conductor wear powder to change the detection sensitivity.

[0188] In the present embodiment, the sensitivity adjustment portion is provided as the adsorption portion (insulator) 63. Also, in the present embodiment, the sensitivity adjustment portion is provided as the cylindrical portion 63b of the adsorption portion (insulator) 63, the outer electrode (external electrode) 62, and the housing 65.

[0189] The adsorption portion (insulator) 63 of this embodiment adjusts the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 based on the large-diameter conductor sheet, thereby adjusting the amount of conductor wear powder to be adsorbed.

[0190] Specifically, if Fig. 9 As shown, there is a group in which the radial thickness of the cylindrical portion 63b of the adsorption portion (insulator) 63 changes.

[0191] Fig. 9 The sensor 60E has an adsorption portion (insulator) 63E, which becomes the interval X1 between the first electrode (inner electrode) 61 and the wall portion 62b of the second electrode (outer electrode) 62 on the detection surface 60a, that is, the thickness X1 of the end of the cylinder 63b on the detection surface 60a.

[0192] In addition, the sensor 60E includes an outer electrode (external electrode) 62E having a diameter size corresponding to the adsorption portion (insulator) 63E and a housing 65E.

[0193] Fig. 9 The sensor 60F has an adsorption portion (insulator) 63F, which becomes the interval X2 between the first electrode (inner electrode) 61 and the wall portion 62b of the second electrode (outer electrode) 62 on the detection surface 60a, that is, the thickness X2 of the end of the cylinder 63b on the detection surface 60a.

[0194] In addition, the sensor 60F includes an outer electrode (external electrode) 62F having a diameter size corresponding to the adsorption portion (insulator) 63F and a housing 65F.

[0195] Fig. 9 The sensor 60G has an adsorption portion (insulator) 63G, which becomes the interval X3 between the first electrode (inner electrode) 61 and the wall portion 62b of the second electrode (outer electrode) 62 on the detection surface 60a, that is, the thickness X3 of the end of the cylinder 63b on the detection surface 60a.

[0196] In addition, the sensor 60G includes an outer electrode (external electrode) 62G having a diameter size corresponding to the adsorption portion (insulator) 63G and a housing 65G.

[0197] Here, the relationship between the thicknesses X1, X2, and X3 is set as X1 <X2<X3。

[0198] The sensor 60 of the present embodiment has a group of the cylindrical portion 63 b of the adsorption portion (insulator) 63 set to such different values, and can be selected and assembled from them.

[0199] That is, a group of the cylindrical portions 63 b of the plurality of adsorption portions (insulators) 63 having different thicknesses (radial dimensions) constitutes a sensitivity adjustment portion.

[0200] Thus, by selecting the sensitivity adjustment portion, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 can be selected from a plurality of values.

[0201] Here, in Fig. 9 In the sensor 60E, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62E set by the end of the cylindrical portion 63b of the adsorption portion (insulator) 63E is used as a reference.

[0202] In contrast, Fig. 9 In the sensor 60F, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62F set by the end of the cylinder 63b of the adsorption part (insulator) 63F is longer than the reference. Therefore, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62F is reduced to a threshold value or a short circuit state is increased. As a result, even if the size of the reducer 2 is large, for example, it is not affected by the increase in the initial amount of wear powder of the reducer 2, and the fault detection of the reducer 2 can be reliably performed.

[0203] And, in Fig. 9In the sensor 60G, the creepage distance between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62G set by the end of the cylinder 63b of the adsorption part (insulator) 63G is longer than that of the sensor 60F. Therefore, the amount of conductor wear powder adsorbed until the resistance value between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62G is reduced to a threshold value or a short circuit state is increased. As a result, even if the size of the reducer 2 is larger, it is not affected by the increase in the initial wear powder amount of the reducer 2, and the fault detection of the reducer 2 can be reliably performed.

[0204] In this way, by appropriately selecting from the group of adsorption parts (insulators) 63, it is possible to reliably detect faults in the reducer 2 without increasing the axial size of the sensor 60 and without affecting the center electrode (inner electrode) 61, the magnet 64, and the fastening member (fastening part) 69.

[0205] That is, they are all universal, and by replacing the adsorption portion (insulator) 63, the outer electrode (external electrode) 62 and the shell 65, sensors 60 with different sensitivities can be made.

[0206] In addition, in the present embodiment described above, the number of groups of the adsorption portion (insulator) 63 as the sensitivity adjustment portion is set to three, but the present invention is not limited thereto and can be set as appropriate.

[0207] The sensor 60 of the present embodiment is assembled as follows.

[0208] First, the outer electrode (outer electrode) 62 is placed inside the housing 65 having the selected diameter size. Next, the bottom 63a of the adsorption part (insulator) 63 of the corresponding diameter size is arranged on the bottom 62a of the outer electrode (outer electrode) 62. Next, the cylinder 63b of the adsorption part (insulator) 63 having the selected diameter size is inserted into the outer electrode (outer electrode) 62. Next, the magnet 64 is inserted into the cylinder 63b, and the center electrode (inner electrode) 61 is inserted into the cylinder 63b. In this state, the sensor 60 is assembled by penetrating the fastening member (fastening part) 69 and fastening and fixing it.

[0209] Alternatively, a set of the housing 65 , the outer electrode (external electrode) 62 , and the adsorption portion (insulator) 63 having a selected diameter size may be set in advance.

[0210] The sensor 60 of the present embodiment includes a sensitivity adjustment unit, and can set the detection sensitivity to a predetermined state.

[0211] Specifically, the sensitivity adjustment unit is selected to increase the creepage distance of the wear powder adsorbed between the electrodes 61 and 62 in response to the assumed large amount of conductor wear powder generated, thereby setting the detection sensitivity of the sensor 60 to a predetermined state. In addition, the sensitivity adjustment unit is selected to reduce the length of the wear powder adsorbed between the electrodes 61 and 62 in response to the assumed small amount of conductor wear powder generated, thereby setting the detection sensitivity of the sensor 60 to a predetermined state.

[0212] Thus, failure detection of the speed reducer 2 can be reliably performed without being affected by an increase in the amount of initial wear powder of the speed reducer 2 .

[0213] Hereinafter, a sensor according to a fifth embodiment of the present invention will be described with reference to the drawings.

[0214] Fig.10 is a cross-sectional view of a sensor according to this embodiment. In this embodiment, the difference from the third and fourth embodiments is the aspect of the electrodes. Fig.10 There are structures that are omitted from the illustration.

[0215] like Fig.10 As shown, the sensor 60 of this embodiment is set to be substantially the same structure as the sensor 60 of the third and fourth embodiments.

[0216] The sensor 60 of the present embodiment includes a sensitivity adjustment unit that adjusts the adsorption state of the conductor wear powder to change the detection sensitivity.

[0217] In the present embodiment, the sensitivity adjustment unit is provided as a first electrode (inner electrode) 61 and a second electrode (outer electrode) 62 .

[0218] A surface treatment layer 61h is formed on the first electrode (inner electrode) 61 of the present embodiment. A surface treatment layer 62h is formed on the second electrode (outer electrode) 62 of the present embodiment.

[0219] The surface treatment layers 61h and 62h have good sliding properties and non-stickiness, are conductive, have low adhesion, are smooth, and have lubricity.

[0220] The surface treatment layers 61h and 62h can be formed by, for example, fluororesin composite electroless nickel plating, etc. Here, the fluororesin can be polytetrafluoroethylene particles, etc.

[0221] By utilizing the surface treatment layers 61h and 62h, the following situation can be prevented: sludge which may reduce the amount of wear powder that can be adsorbed on the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62 adheres to the first electrode (inner electrode) 61, the second electrode (outer electrode) 62 and the detection surface 60a, thereby reducing the amount of wear powder adsorbed between the first electrode (inner electrode) 61 and the second electrode (outer electrode) 62.

[0222] Thus, the detection sensitivity of the sensor 60 can be set to a predetermined state. Fig.10 In the figure, the state where sludge is attached is indicated by a dotted line.

[0223] In the case where the surface treatment layers 61h and 62h are not provided, sludge generated by the lubricant is deposited on the electrodes of the sensor to form an insulating film, which may cause malfunction. In contrast, in the present embodiment, by forming the surface treatment layers 61h and 62h, the accumulation of sludge is prevented by utilizing the improved sliding properties brought about by the surface treatment layers 61h and 62h and the good flow of the lubricant brought about thereby, and thus the stable operation of the fault prediction of the sensor 60 can be expected.

[0224] Hereinafter, a sensor according to a sixth embodiment of the present invention will be described with reference to the drawings.

[0225] Fig.11 It is a diagram for explaining the sensor according to this embodiment.

[0226] The sensor 60 of this embodiment is a sensor for detecting the amount of the conductive material contained in the lubricating oil, similarly to the sensor 30 of the second embodiment.

[0227] The sensor 60 has a substantially cylindrical outer shape, and includes a plurality of detection cells and a detection unit 70 that outputs a signal when resistance changes in the detection cells and prevents leakage.

[0228] More specifically, the sensor 60 includes a central electrode 61, a plurality of outer electrodes 62, an adsorption portion 63 disposed between the central electrode 61 and the outer electrodes 62, and a magnet 64. The plurality of outer electrodes 62 are insulated from each other, and a pair of electrodes including the central electrode 61 and one outer electrode 62 and the adsorption portion 63 disposed between the pair of electrodes constitute one detection unit.

[0229] In the illustrated embodiment, the sensor 60 has four outer electrodes 62A, 62B, 62C, and 62D, which constitute four detection units. The number of the outer electrodes 62 and the number of the detection units are not particularly limited. The magnet 64 of the sensor 60 forms magnetic flux lines between a pair of electrodes, so that the conductive material contained in the lubricating oil is adsorbed to the adsorption portion 63. In this way, when the conductive material gathers near the adsorption portion 63, the resistance of the detection unit changes. In the state where the conductive wear particles are not adsorbed, the resistance of each of the plurality of detection units is the same.

[0230] Output lines are connected to the central electrode 61 and the plurality of outer electrodes 62 , respectively, and the plurality of detection units are electrically connected to the detection unit 70 via the output lines.

[0231] In this embodiment, a plurality of detection units are connected in parallel to each other, and a voltage from the same voltage source is applied between the central electrode 61 and each outer electrode 62. When the resistance changes in any set number of detection units, the detection unit 70 outputs a signal.

[0232] For example, the detection unit 70 may be set to output a signal to a higher-level control device such as a manipulator when the resistance decreases in two or more detection cells, or may be set to output a signal when the resistance decreases in all detection cells.

[0233] Alternatively, the detection unit 70 sequentially switches any set detection unit, and outputs a signal when the resistance in the detection unit changes.

[0234] As described above, the detection unit 70 is set to output a signal when the resistance in the detection unit decreases, and then to cut off the detection power to the sensor 60 .

[0235] Specifically, as described above, the detection unit 70 is set to output a signal to light up the fault display when the resistance in the detection unit decreases, and then cut off the switch 71 to cut off the detection power to the sensor 60. In other words, the sensor 60 is not energized after detecting an increase in iron powder (a decrease in the resistance value of the gap portion) and determining that the reducer 2 has a fault.

[0236] Thus, even if the wear powder continues to accumulate and the sensor 60 comes into contact with the speed reducer 2 or the mechanism 1, leakage and electric shock can be prevented.

[0237] Therefore, even if the reducer 2 continues to be used after the sensor 60 transmits the fault of the reducer 2, the following possible situation can be prevented: iron powder is continuously generated inside the reducer 2 during operation, and conductor wear powder is continuously accumulated on the sensor 60. The size of the sensor 60 is expanded due to the accumulation of iron powder. As a result, the sensor 60 contacts and energizes the parts in the mechanism 1 through the wear powder, causing leakage and electric shock.

[0238] Hereinafter, a sensor according to a seventh embodiment of the present invention will be described with reference to the drawings.

[0239] Fig.12 It is a diagram for explaining the sensor according to this embodiment.

[0240] The sensor 60 of the present embodiment is a sensor for detecting the amount of the conductive material contained in the lubricating oil, similarly to the sensors 5 , 30 , and 60 of the above-described embodiments.

[0241] In this embodiment, if Fig.12 As shown, a cover 66 covering the sensor 60 is provided in the space S. The cover 66 accommodates the sensor 60 therein and has a plurality of through holes 67 formed at positions facing the detection surface 60 a of the sensor 60 .

[0242] The through hole 67 has an outer opening 67a on the space S side, which is the outside of the cover 66, having a larger diameter than the inner opening 67b on the surface side facing the sensor 60, which is the inside of the cover 66. That is, when the conductor wear powder enters the inside of the cover 66 from the space S, the through hole 67 reaches the sensor 60 through the through hole 67 with a reduced diameter. The cover 66 is arranged so that the inner opening 67b of the through hole 67 is separated from the detection surface 60a of the sensor 60. The cover 66 seals the inside except for the through hole 67.

[0243] Thus, even when the mechanism 1 and the reducer 2 are running violently and the lubricant is flowing violently, the sensor 60 can be protected by the cover 66. Thus, the conductor wear powder that has entered the cover 66 can be prevented from being released again into the external space S, and an accurate adsorption amount can be maintained, and reliable fault prediction can be performed. In addition, the conductor wear powder can be prevented from being released again from the cover 66, and the influence on the mechanism 1 and the reducer 2 can be reduced.

[0244] Furthermore, when viewed in the axial direction of the sensor 60 , the cover 66 may have an inner diameter that is substantially equal to the outer diameter of the sensor 60 .

[0245] Furthermore, according to the present embodiment, in the initial stage of operation of the reducer 2 with less wear powder, the cover 66 can be used to prevent a large amount of wear powder from being adsorbed on the sensor 60 at one time, thereby preventing malfunction of the sensor 60. Furthermore, compared to the initial stage of operation of the reducer 2 with less wear powder, before the reducer 2 is about to fail, when a large amount of wear powder is generated, sufficient wear powder can be adsorbed on the sensor 60 through the through hole 67, thereby performing detection.

[0246] In addition, in the present invention, it is also possible to appropriately combine the respective configurations of the above-described embodiments to cope with the present invention.

[0247] Furthermore, the sensitivity adjusting portion of the sensor of the present invention can include a group of the insulators having different axial heights relative to the opening of the external electrode.

[0248] This makes it possible to select from among insulators having a plurality of axial heights and set the detection sensitivity of the sensor to a predetermined state in accordance with the expected amount of conductor abrasion powder generated.

[0249] Specifically, in response to the situation where the amount of conductor wear powder generated is assumed to be large, an insulator with a higher axial height can be selected to increase the length of wear powder adsorbed between the electrodes, and the detection sensitivity of the sensor can be set to a predetermined state. In addition, in response to the situation where the amount of conductor wear powder generated is assumed to be small, an insulator with a lower axial height or coplanar with the electrode can be selected to reduce the length of wear powder adsorbed between the electrodes, and the detection sensitivity of the sensor can be set to a predetermined state.

[0250] The sensitivity adjustment part of the sensor of the present invention may have a group consisting of the insulator and the outer electrode corresponding to the outer diameter of the insulator, and the radial thickness of the insulator adjacent to the opening of the outer electrode is different relative to the outer diameter of the inner electrode.

[0251] This makes it possible to select from insulators having a plurality of radial thicknesses and set the detection sensitivity of the sensor to a predetermined state according to the expected amount of conductor abrasion powder generated.

[0252] Specifically, in response to the situation where the amount of conductor wear powder generated is assumed to be large, an insulator with a larger radial thickness can be selected to increase the length of wear powder adsorbed between electrodes, and the detection sensitivity of the sensor can be set to a predetermined state. In addition, in response to the situation where the amount of conductor wear powder generated is assumed to be small, an insulator with a smaller radial thickness can be selected to reduce the length of wear powder adsorbed between electrodes, and the detection sensitivity of the sensor can be set to a predetermined state.

[0253] The outer electrode of the sensor of the present invention can have an open end portion coplanar with the inner electrode.

[0254] The sensitivity adjustment unit of the sensor of the present invention may include another magnet provided in addition to the magnet.

[0255] In this case, it is also possible to select from a group of other magnets having a plurality of adsorption amounts, or to not provide other magnets.

[0256] Thus, by using other magnets to adsorb the wear powder according to the estimated amount of conductor wear powder generated, the amount of wear powder adsorbed between the electrodes can be reduced, and the detection sensitivity of the sensor can be set to a predetermined state.

[0257] Specifically, it is possible to select a strong or larger other magnet in response to a situation where the amount of conductor wear powder generated is assumed to be large, reduce the amount of wear powder adsorbed between the electrodes, and set the detection sensitivity of the sensor to a predetermined state. In addition, it is possible to select a weaker or smaller other magnet in response to a situation where the amount of conductor wear powder generated is assumed to be small, or not to provide other magnets, so that the wear powder adsorbed between the electrodes becomes a predetermined amount, and set the detection sensitivity of the sensor to a predetermined state.

[0258] The sensitivity adjustment portion of the sensor of the present invention may include surface treatment layers of the outer electrode and the inner electrode.

[0259] This can prevent sludge that may reduce the amount of adsorbable wear powder from being attached to the adsorption surface of the electrode, thereby reducing the amount of wear powder adsorbed between the electrodes and failing to exhibit the desired detection sensitivity.

[0260] Specifically, the surface treatment layer may have conductivity, low adhesion, smoothness, and lubricity.

[0261] The sensitivity adjustment portion of the sensor of the present invention may be a cover that covers at least a pair of electrodes and the adsorption portion disposed between the pair of electrodes.

Claims

1. A sensor, wherein: The sensor includes: 1st electrode; The second electrode; an adsorption portion disposed between the first electrode and the second electrode, and changing the resistance between the first electrode and the second electrode by adsorbing conductive particles smaller than the interval between the first electrode and the second electrode; a magnet disposed between the first electrode and the second electrode, and causing the conductive particles to gather near the adsorption portion by forming magnetic flux lines between the first electrode and the second electrode; and a short circuit suppressing portion for suppressing a short circuit between the first electrode and the second electrode caused by a large-diameter conductor piece having a size larger than the interval between the first electrode and the second electrode gathered near the adsorption portion, The short circuit suppression portion is a wire extending in a direction intersecting with a direction in which the first electrode and the second electrode face each other. The wire is supported by a plurality of supporting parts, each of which is a pile-shaped member, one end of each supporting part is fixed in a state of being buried inside the adsorption part, and the wire is fixed in a state of being separated from the adsorption part.

2. The sensor according to claim 1, wherein: The sensor includes a detection unit for detecting a change in resistance between the first electrode and the second electrode.

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