sensor

Abstract

The present invention provides a sensor. The sensor comprises: a first electrode; a second electrode disposed with a gap therebetween; a sensor body in which the first and second electrodes are disposed; and a capturing portion disposed in the gap, the outer peripheral surface of the capturing portion being formed of an insulator. The sensor of the present invention conducts electricity in the peripheral direction via conductive particles gathered in the capturing portion.

Description

Technical Field

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

[0002] In order to prevent damage to mechanical parts such as gears, mechanical devices such as speed reducers are housed in a housing containing lubricating oil. When mechanical parts wear out during the operation of such a mechanical device, wear powder (e.g., conductive materials such as iron powder) is mixed into the lubricating oil. This 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, a sensor that detects the amount of wear powder in the lubricating oil can be used to appropriately perform preventive maintenance on mechanical parts.

[0003] As such a sensor, for example, as disclosed in Patent Document 1, the following structure is known: the sensor has a cup-shaped electrode located on the outer peripheral side of a permanent magnet, and an electrode formed by circumferentially arranging a plurality of rod-shaped conductors in a manner opposite to the electrode, and detects the amount of metal powder that short-circuits between the electrodes to check the degree of oil contamination.

[0004] Furthermore, the present applicant has applied for a sensor described in Patent Document 2.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-331324

[0008] Patent Document 2: Japanese Patent Application Publication No. 2019-128311 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, the structure described in Patent Document 1 requires multiple electrodes to be arranged in the circumferential direction. Considering the amount of metal powder that can be detected, it cannot be miniaturized beyond a certain level. Therefore, there is a problem that the structure may be too large to be accommodated in a small oil pan.

[0011] In particular, recent demands for miniaturization of speed reducers and other equipment have led to a demand for compact sensors that can accommodate these miniaturizations. At the same time, sensors are required to provide both operational reliability and accurate fault prediction and detection. There is a demand for sensors that achieve both of these performance characteristics.

[0012] Furthermore, in Patent Document 2, a detection gap is formed between the electrodes in the radial direction. However, in order to suppress malfunction due to initial wear powder, the size of the gap cannot be reduced. Therefore, there is a demand for further miniaturization.

[0013] The present invention aims to achieve the object of providing a sensor that can be miniaturized and has high operational reliability.

[0014] Solutions for solving problems

[0015] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: it comprises: a first electrode; a second electrode, which is arranged with a gap between it and the first electrode; a sensor body, which is provided with the first electrode and the second electrode; and a capturing portion, which is arranged in the gap, the outer peripheral surface of the capturing portion being composed of an insulator, in which the sensor is energized in the peripheral direction by means of conductive particles gathered in the capturing portion.

[0016] In a sensor according to one aspect of the present invention, the gaps between the detecting conductive particles are provided along the outer peripheral surface of the adsorption portion. This allows for a more compact sensor without compromising detection sensitivity, compared to a sensor with gaps between the detecting conductive particles provided radially relative to the sensor's end face.

[0017] Furthermore, since the detection direction can be set to the outer peripheral direction, the sensor can be miniaturized without reducing the detection sensitivity, compared with a case where a plurality of detection gaps are provided in the axial direction in the circumferential direction of the sensor.

[0018] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: comprising: a first electrode; a second electrode, which is separated from the first electrode by a gap in the circumferential direction; and an adsorption portion, which is arranged in the gap, the outer circumferential surface of the adsorption portion being composed of an insulator, the first electrode, the adsorption portion and the second electrode being arranged in the circumferential direction, and by adsorbing conductive particles on the outer circumferential surface of the adsorption portion, the first electrode and the second electrode are short-circuited in the circumferential direction, thereby changing the resistance between the first electrode and the second electrode.

[0019] In a sensor according to one aspect of the present invention, the gaps between the detecting conductive particles are arranged circumferentially along the outer peripheral surface of the adsorption portion. This allows for a more compact sensor without compromising detection sensitivity, compared to a sensor with gaps between the detecting conductive particles arranged radially along the sensor's end face.

[0020] Furthermore, the detection direction can be set along the circumferential direction of the outer peripheral surface of the adsorption portion, so the sensor can be miniaturized without reducing the detection sensitivity, compared with the case where multiple detection gaps are provided in the axial direction in the circumferential direction of the sensor.

[0021] A sensor according to one technical solution of the present invention may also comprise: a third electrode, which is separated from the first electrode and the second electrode by a gap in the circumferential direction; and an adsorption portion, which is arranged in the gap, the outer circumferential surface of the adsorption portion being composed of an insulator, and the resistance between the first electrode and the third electrode is changed by causing conductive particles to be adsorbed on the outer circumferential surface of the adsorption portion so as to short-circuit the first electrode and the third electrode in the circumferential direction.

[0022] A sensor according to one technical solution of the present invention may also comprise: a fourth electrode, which is circumferentially separated from the first electrode, the second electrode, and the third electrode by a gap; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion being composed of an insulator, and the first electrode and the fourth electrode being short-circuited in the circumferential direction by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, thereby changing the resistance between the first electrode and the fourth electrode.

[0023] In the sensor according to one aspect of the present invention, the outer peripheral surface of the electrode may form a side surface of a columnar body.

[0024] In the sensor according to one aspect of the present invention, the electrodes may be magnets and arranged so as to form a magnetic flux extending from an outer peripheral surface toward the radially outer side.

[0025] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: it has a cylindrical sensor body, and the sensor comprises: a magnet, which divides the sensor body into four parts in the circumferential direction; an adsorption portion, which is configured to fill the gap between the magnets in the sensor body, and the adsorption portion protrudes radially outward relative to the outer circumferential surface of the magnet, and the magnets are magnetized in the radial direction, and the magnets adjacent to each other in the circumferential direction are magnetized in opposite directions. The magnets are set as electrodes, and by adsorbing conductive particles on the outer circumferential surface of the adsorption portion, the magnets are short-circuited with each other in the circumferential direction, thereby changing the resistance between the magnets set as electrodes.

[0026] In a sensor according to one aspect of the present invention, the gaps between the detecting conductive particles are arranged circumferentially along the outer peripheral surface of the adsorption portion. This allows for a more compact sensor without compromising detection sensitivity, compared to a sensor with gaps between the detecting conductive particles arranged radially along the sensor's end face.

[0027] Furthermore, the detection direction can be set along the circumferential direction of the outer peripheral surface of the adsorption portion, so the sensor can be miniaturized without reducing the detection sensitivity, compared with the case where multiple detection gaps are provided in the axial direction in the circumferential direction of the sensor.

[0028] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: it comprises a first electrode, a second electrode and a third electrode, a first capturing portion is arranged between the first electrode and the second electrode, a second capturing portion is arranged between the second electrode and the third electrode, and the first electrode, the second electrode and the third electrode are arranged in the axial direction of the sensor body.

[0029] In a sensor according to one embodiment of the present invention, the gaps for detecting the conductive particles are arranged along the axial direction of the outer peripheral surface of the capture portion. This allows for a more compact sensor without compromising detection sensitivity, compared to a case where the gaps for detecting the conductive particles are arranged radially along the end face of the sensor.

[0030] In addition, the detection direction can be set to the axial direction along the outer peripheral surface of the capture portion. Therefore, compared with the case where multiple detection gaps in the axial direction are provided in the circumferential direction of the sensor, the sensor can be miniaturized without reducing the detection sensitivity.

[0031] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: comprising: a first electrode; a second electrode, which is separated from the first electrode by a gap in the axial direction; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion being composed of an insulator, the first electrode, the adsorption portion and the second electrode being stacked in the axial direction, and by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, the first electrode and the second electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the second electrode.

[0032] In a sensor according to one aspect of the present invention, the gaps between the detecting conductive particles are arranged along the axial direction of the outer peripheral surface of the adsorption portion. This allows for a more compact sensor without compromising detection sensitivity, compared to a case where the gaps between the detecting conductive particles are arranged radially along the sensor's end face.

[0033] In addition, the detection direction can be set along the axial direction of the outer peripheral surface of the adsorption portion. Therefore, compared with the case where multiple detection gaps in the axial direction are provided in the circumferential direction of the sensor, the sensor can be miniaturized without reducing the detection sensitivity.

[0034] A sensor according to one technical solution of the present invention may also comprise: a third electrode, which is separated from the first electrode and the second electrode by a gap in the axial direction; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion being composed of an insulator, the first electrode, the second electrode and the third electrode being overlapped with each of the adsorption portions in the axial direction, and the resistance between the first electrode and the third electrode being changed by adsorbing conductive particles on the outer peripheral surface of the adsorption portion so as to short-circuit the first electrode and the third electrode in the axial direction.

[0035] A sensor according to one technical solution of the present invention may also include: a fourth electrode, which is separated from the first electrode, the second electrode, and the third electrode by a gap in the axial direction; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion is composed of an insulator, the first electrode to the fourth electrode are overlapped with each of the adsorption portions in the axial direction, and the first electrode and the fourth electrode are short-circuited in the axial direction by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, thereby changing the resistance between the first electrode and the fourth electrode.

[0036] In the sensor according to one aspect of the present invention, the outer peripheral surface of the electrode may be located on a side surface of the columnar body.

[0037] In the sensor according to one aspect of the present invention, the electrodes may be magnets and arranged so as to form a magnetic flux extending from an outer peripheral surface toward the radially outer side.

[0038] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: it has a cylindrical sensor body, and the sensor comprises: a magnet, which divides the sensor body into three in the axial direction; an adsorption portion, which is configured to fill the axial gap between the magnets in the sensor body, the magnet and the adsorption portion are overlapped in the axial direction, the adsorption portion protrudes radially outward relative to the outer peripheral surface of the magnet, the magnet is magnetized in the radial direction, and the magnets adjacent in the axial direction are magnetized in opposite directions to each other, the magnet is set as an electrode, and by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, the magnets are short-circuited with each other in the axial direction, thereby changing the resistance between the magnets set as the electrodes.

[0039] In a sensor according to one aspect of the present invention, the gaps between the detecting conductive particles are arranged along the axial direction of the outer peripheral surface of the adsorption portion. This allows for a more compact sensor without compromising detection sensitivity, compared to a case where the gaps between the detecting conductive particles are arranged radially along the sensor's end face.

[0040] In addition, the detection direction can be set along the axial direction of the outer peripheral surface of the adsorption portion. Therefore, compared with the case where multiple detection gaps in the axial direction are provided in the circumferential direction of the sensor, the sensor can be miniaturized without reducing the detection sensitivity.

[0041] A sensor according to one aspect of the present invention solves the aforementioned problem by comprising: a first electrode; a second electrode spaced axially from the first electrode with a gap therebetween; and a capture portion disposed in the gap, the outer circumferential surface of the capture portion being formed of an insulator. The capture portion has different axial lengths.

[0042] According to one aspect of the sensor of the present invention, the first electrode, the adsorption portion, and the second electrode are stacked and separated in the axial direction, and the gaps between the detecting conductive particles are provided along the outer peripheral surface of the adsorption portion in the axial direction. This allows for a more compact sensor without compromising detection sensitivity, compared to a case where the gaps between the detecting conductive particles are provided radially relative to the end face of the sensor.

[0043] Furthermore, the adsorption state of the conductive particles is adjusted using different types of capture units with different axial lengths. This allows reliable detection even when a large amount of conductive particles are adsorbed, by adjusting the sensor's detection sensitivity accordingly. In particular, when the sensor's reducer, etc., is large and the initial amount of conductive particles generated is high, reliable detection can be achieved by limiting the adsorption of conductive particles or by changing the detection state to reflect the high adsorption amount.

[0044] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: comprising: a first electrode; a second electrode, which is separated from the first electrode by a gap in the axial direction; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion being composed of an insulator, the first electrode, the adsorption portion and the second electrode being stacked in the axial direction, and by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, the first electrode and the second electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the second electrode.

[0045] According to one aspect of the sensor of the present invention, the first electrode, the adsorption portion, and the second electrode are stacked and separated in the axial direction, and the gaps between the detecting conductive particles are provided along the outer peripheral surface of the adsorption portion in the axial direction. This allows for a more compact sensor without compromising detection sensitivity, compared to a case where the gaps between the detecting conductive particles are provided radially relative to the end face of the sensor.

[0046] A sensor according to one technical solution of the present invention may also be provided with: a third electrode, which is separated from the first electrode with a gap in the axial direction and is separated from the second electrode with a gap in the axial direction; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion is composed of an insulator, the first electrode, the adsorption portion and the third electrode are stacked in the axial direction, and the first electrode and the third electrode are short-circuited in the axial direction by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, thereby changing the resistance between the first electrode and the third electrode.

[0047] A sensor according to one technical solution of the present invention may also comprise: a fourth electrode, which is separated from the first electrode by a gap in the axial direction, and is separated from the second electrode and the third electrode by a gap in the axial direction; and an adsorption portion, which is arranged in the gap, the outer peripheral surface of the adsorption portion being composed of an insulator, and the first electrode and the fourth electrode being short-circuited in the axial direction by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, thereby changing the resistance between the first electrode and the fourth electrode.

[0048] In the sensor according to one aspect of the present invention, the second electrode, the fourth electrode, and the third electrode may be arranged spaced apart in the circumferential direction, and the adsorption portion may be disposed in a gap between the electrodes.

[0049] In the sensor according to one aspect of the present invention, the outer peripheral surface of the electrode may be located on a side surface of the columnar body.

[0050] In the sensor according to one aspect of the present invention, a magnet may be arranged at least at a position closer to the first electrode than the second electrode in the axial direction, and the magnet may be arranged so as to form a magnetic flux in the axial direction.

[0051] In the sensor according to one aspect of the present invention, the first electrode may be a magnet.

[0052] A sensor according to one technical solution of the present invention solves the above-mentioned problem by the following means: it has a cylindrical sensor body, the sensor body comprising: a first electrode, an adsorption portion, and a second electrode stacked in the axial direction; and a magnet, which is magnetized in the axial direction, and by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, the outer peripheral surfaces of the first electrode and the second electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the second electrode.

[0053] According to one aspect of the sensor of the present invention, the first electrode, the adsorption portion, and the second electrode are stacked and separated in the axial direction, and the gaps between the detecting conductive particles are provided along the outer peripheral surface of the adsorption portion in the axial direction. This allows for a more compact sensor without compromising detection sensitivity, compared to a case where the gaps between the detecting conductive particles are provided radially relative to the end face of the sensor.

[0054] In the sensor according to one aspect of the present invention, the second electrode may be divided in a circumferential direction of the sensor body.

[0055] Effects of the Invention

[0056] According to one aspect of the present invention, the sensor can be miniaturized while maintaining accurate detection without reducing detection sensitivity by providing a detection gap along the outer peripheral surface at the outermost position of the columnar sensor body. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] 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.

[0058] Figure 2 It is a perspective view showing a sensor according to a first embodiment of the present invention.

[0059] Figure 3 It is a cross-sectional view showing the direction of magnetic flux in the sensor according to the first embodiment of the present invention.

[0060] Figure 4 It is an explanatory diagram showing the arrangement of electrodes in the sensor according to the first embodiment of the present invention.

[0061] Figure 5 It is a cross-sectional view showing a detection state in the sensor according to the first embodiment of the present invention.

[0062] Figure 6A This is an explanatory diagram showing another example of the magnet in the sensor according to the first embodiment of the present invention.

[0063] Figure 6B This is an explanatory diagram showing another example of the magnet in the sensor according to the first embodiment of the present invention.

[0064] Figure 7 It is a perspective view showing another example of the sensor according to the first embodiment of the present invention.

[0065] Figure 8 It is a perspective view showing a sensor according to a second embodiment of the present invention.

[0066] Figure 9 It is a cross-sectional view showing the direction of magnetic flux in a sensor according to a second embodiment of the present invention.

[0067] Figure 10 It is a cross-sectional view perpendicular to the axial direction, showing another example of the sensor according to the second embodiment of the present invention.

[0068] Figure 11 It is a cross-sectional view taken along the axial direction, showing another example of the sensor according to the second embodiment of the present invention.

[0069] Figure 12 It is a cross-sectional view along the axial direction of a sensor showing a third embodiment of the present invention.

[0070] Figure 13 It is an explanatory diagram showing a magnet in a sensor according to a third embodiment of the present invention.

[0071] Figure 14 It is an explanatory diagram showing the arrangement of electrodes in a sensor according to a third embodiment of the present invention.

[0072] Figure 15 It is a cross-sectional view showing a detection state in a sensor according to a third embodiment of the present invention.

[0073] Figure 16 It is a cross-sectional view taken along the axial direction, showing another example of the sensor according to the third embodiment of the present invention.

[0074] Figure 17 It is a perspective view showing a sensor according to a fourth embodiment of the present invention.

[0075] Figure 18 It is a cross-sectional view taken along the axial direction, showing another example of the sensor according to the fourth embodiment of the present invention.

[0076] Figure 19 This is an exploded perspective view showing another example of the sensor according to the fifth embodiment of the present invention.

[0077] Figure 20 This is an exploded perspective view showing another example of the sensor according to the fifth embodiment of the present invention.

[0078] Figure 21 It is a cross-sectional view perpendicular to the axial direction, showing another example of the sensor according to the fifth embodiment of the present invention.

[0079] Figure 22 It is a cross-sectional view taken along the axial direction, showing the electrode arrangement of a sensor according to a sixth embodiment of the present invention.

[0080] Figure 23It is a cross-sectional view along the axial direction of a sensor showing a seventh embodiment of the present invention.

[0081] Figure 24 It is an explanatory diagram showing a magnet in a sensor according to a seventh embodiment of the present invention.

[0082] Figure 25 It is a cross-sectional view along the axial direction of a sensor showing an eighth embodiment of the present invention.

[0083] Figure 26 It is an explanatory diagram showing the electrode arrangement of a sensor according to the eighth embodiment of the present invention.

[0084] Figure 27 It is a cross-sectional view taken along the axial direction, showing another example of the sensor according to the ninth embodiment of the present invention.

[0085] Description of Reference Numerals

[0086] 10, 20, 30, 40, sensor; 10a, 20a, end surface; 11, 21, 31, 41, first electrode; 11a, 12a, 13a, 14a, 21a, 22a, 23a, 24a, 31a, 32a, 33a, 41a, 42a, outer peripheral surface; 11f, 12f, 13f, 14f, 31f, 32f, 33f, Flexible substrate; 12, 22, 32, 42, 42A, 42B, 42C, 42D, second electrode; 13, 23, 33, third electrode; 14, 24, 34, fourth electrode; 15, 25, 35, 45, adsorption portion (capture portion); 15G1, 15G2, 15G3, 15G4, 25G1, 25G2, 25G3, 25G4, 35 G1, 35G2, 35G3, 35G4, 45G1, adsorption convex portion; 25c, central portion; 25m, groove portion; 26a, 26b, 26c, 26d, electrode; 30a, top; 35a, top portion; 35b, base portion; 35B, 46, 46b, shell; 35Ba, 35Bb, 35Bc, window portion; 35Bg, threaded portion; 35C, upper shell; 35D, lower shell; 35Df, wire passage; 37, 47, cylinder; 38, screw (fastening member); 40a, upper end face; 41b, electrode plate; 48, fastening member; 48, bolt (fastening member); 48a, nut; 49, magnet; axd, axis; G1, G2, G3, G4, gap; mp, conductor particles (wear powder). DETAILED DESCRIPTION

[0087] Hereinafter, a sensor according to a first embodiment of the present invention will be described with reference to the drawings.

[0088] Figure 11 is a cross-sectional view showing an example of a mechanism including a sensor according to the first embodiment of the present invention. Figure 1 In the figure, reference numeral 1 is a mechanism.

[0089] In addition, the same reference numerals are given to components that are common to multiple drawings. For the sake of convenience, the drawings are not necessarily shown to scale.

[0090] The mechanism 1 of this embodiment is a movable part such as a robot arm. Figure 1 As shown, the mechanism 1 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.

[0091] The speed reducer 2 comprises a housing 2a mounted on the flange 3; an input shaft 2c connected to the output shaft 2b of the servo motor 4; and an output shaft 2d connected to the output-side device A1. The input shaft 2c and the output shaft 2d are supported so as to be rotatable relative to the housing 2a about the axis AX. The output of the servo motor 4 is input to the speed reducer 2 via the input shaft 2c, and after being reduced in speed by the speed reducer 2, it is transmitted to the output-side device A1 via the output shaft 2d. This allows the output-side device A1 and the flange 3 to rotate relative to each other.

[0092] The flange 3 is a cylindrical member that houses at least a portion of the reducer 2. A servo motor 4 is also mounted on the flange 3. The opening at one end of the flange 3, along the axis AX, is blocked by the reducer 2, while the opening at the other end is blocked by the servo motor 4. This creates a sealed hollow portion (space S) within the flange 3. Lubricating oil is contained within the space S, and the flange 3 also functions as an oil bath.

[0093] The housing 2a of the speed reducer 2 houses, for example, a gear mechanism. The space inside the housing 2a is continuous with the space S inside the flange 3. When the speed reducer 2 is in operation, the gear mechanism inside the housing 2a rotates, causing lubricating oil to circulate between the space inside the housing 2a and the space S inside the flange 3. This circulation of lubricating oil removes conductor particles mp (see [Illegible]) such as wear powder (conductor wear powder) generated inside the speed reducer 2. Figure 5 ) is discharged into the space S inside the flange 3.

[0094] A sensor 10 for detecting the amount of conductive particles mp contained in the lubricating oil is installed within space S. Sensor 10 is secured to flange 3 via, for example, support member 2e. Sensor 10 uses a magnet to attract conductive particles (iron powder) mp contained in the lubricating oil between a pair of electrodes, and detects the amount of conductive particles mp in the lubricating oil based on changes in the resistance between the electrodes. Sensor 10 can be located, for example, within housing 2a, or anywhere within mechanism 1 as long as it is within a space containing lubricating oil.

[0095] Then, based on Figures 2 to 4 The sensor according to this embodiment will be described in detail.

[0096] Figure 2 It is a perspective view showing the sensor according to this embodiment. Figure 3 This is an end view showing the sensor according to this embodiment. Figure 4 : is an explanatory diagram showing the electrode arrangement in the sensor of this embodiment. Figure 2 , reference numeral 10 denotes a sensor.

[0097] like Figure 2 As shown in FIG, the sensor 10 has a substantially cylindrical outer shape (columnar body) having an axis axd. The sensor 10 includes a first electrode 11 , a second electrode 12 , a third electrode 13 , a fourth electrode 14 , and an adsorption portion (capturing portion) 15 .

[0098] The end surface 10 a of the sensor 10 has a substantially circular contour in a direction orthogonal to the axis axd.

[0099] The first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14 have a substantially sector-shaped cross-section having a quadrant arc when viewed from the end face 10a of the sensor 10. The first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14 are all formed in substantially the same shape.

[0100] The first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14 are arranged so as to be symmetrical about the axis axd. When viewed from the end surface 10a, the electrodes 11 to 14 are arranged in a clockwise direction in the circumferential direction rtd, in the order of the first electrode 11, the second electrode 12, the fourth electrode 14, and the third electrode 13.

[0101] The first electrode 11 , the second electrode 12 , the fourth electrode 14 , and the third electrode 13 are all arranged at the same position in the direction along the axis axd.

[0102] The first electrode 11 , the second electrode 12 , the fourth electrode 14 , and the third electrode 13 are arranged so that their outer peripheral surfaces 11 a to 14 a are flush with each other and form the same cylindrical surface.

[0103] The first electrode 11 , the second electrode 12 , the third electrode 13 , and the fourth electrode 14 are all set to have the same length in the direction along the axis axd.

[0104] The first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14 are spaced apart from each other in a direction along the end surface 10a. Gaps G1 to G4 are formed between the electrodes 11 to 14.

[0105] The separation distance between the first electrode 11 and the second electrode 12 in the circumferential direction RTD is defined as a gap G1. The separation distance between the first electrode 11 and the third electrode 13 in the circumferential direction RTD is defined as a gap G2. The separation distance between the second electrode 12 and the fourth electrode 14 in the circumferential direction RTD is defined as a gap G3. The separation distance between the third electrode 13 and the fourth electrode 14 in the circumferential direction RTD is defined as a gap G4.

[0106] The first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14 are all formed as magnetic bodies. The magnetic bodies are formed of, for example, permanent magnets.

[0107] The first electrode 11 , the second electrode 12 , the third electrode 13 , and the fourth electrode 14 are all provided so that their magnetization directions are in the radial direction of the sensor 10 .

[0108] The first electrode 11 and the fourth electrode 14, located symmetrically with respect to the axis axd, are magnetized so that the same polarity appears on their outer peripheral surfaces 11a and 14a. The second electrode 12 and the third electrode 13, located symmetrically with respect to the axis axd, are magnetized so that the same polarity appears on their outer peripheral surfaces 12a and 13a. Furthermore, adjacent electrodes 11-14 are magnetized to have different polarities.

[0109] For example, Figure 3 As shown, the second electrode 12 and the third electrode 13 are magnetized so that their north poles are located on their outer peripheral surfaces 12a and 13a. The first electrode 11 and the fourth electrode 14 are magnetized so that their south poles are located on their outer peripheral surfaces 11a and 14a. Furthermore, the directions of magnetization can be set so that all electrodes 11 to 14 have opposite polarities.

[0110] By adopting such an arrangement, the electrodes 11 to 14 of the magnetic body are attracted to each other by their respective magnetic forces and can be fixed to the cross-shaped attraction portion 15 without using an adhesive or other adhesive.

[0111] An adsorption portion 15 is disposed between the electrodes 11 to 14. The adsorption portion 15 is made of an insulating non-magnetic material such as resin. The adsorption portion 15 has a cross-shaped cross section when viewed from the end face 10a along the axis axd.

[0112] The adsorption portion 15 includes an adsorption projection 15G1 provided to fill the gap G1 between the first electrode 11 and the second electrode 12 and projecting radially outward relative to the outer peripheral surfaces 11 a and 12 a .

[0113] The adsorption portion 15 includes an adsorption projection 15G2 that is provided to fill the gap G2 between the first electrode 11 and the third electrode 13 and that protrudes radially outward relative to the outer peripheral surfaces 11 a and 13 a .

[0114] The adsorption portion 15 includes an adsorption projection 15G3 provided to fill the gap G3 between the second electrode 12 and the fourth electrode 14 and projecting radially outward relative to the outer peripheral surfaces 12 a and 14 a .

[0115] The adsorption portion 15 includes an adsorption projection 15G4 provided to fill the gap G4 between the third electrode 13 and the fourth electrode 14 and projecting radially outward relative to the outer peripheral surfaces 13 a and 14 a .

[0116] The suction protrusions 15G1 to 15G4 are formed so that their radial protrusion heights are all the same. Alternatively, the suction protrusions 15G1 to 15G4 can be formed to any desired size, such as varying radial protrusion heights. The radial protrusion heights of the suction protrusions 15G1 to 15G4 can be used to adjust the detection sensitivity, which will be discussed later.

[0117] The dimensions of the gaps G1 to G4 between the electrodes 11 to 14 in the circumferential direction (rtd) are larger than the dimensions of the conductive material contained in the lubricating oil. For example, the dimensions of the conductive material are approximately 1.0 μm to 100 μm. The spacing between the gaps G1 to G4 is preferably set to a distance sufficient to prevent short-circuiting of iron powder due to initial wear. The dimensions of the gaps G1 to G4 in the circumferential direction (rtd) are all set to the same value.

[0118] like Figure 3 As shown, magnetic flux lines are formed between the electrodes 11 to 14 as magnetic bodies so as to be connected via the radially outer sides of the attraction projections 15G1 to 15G4 .

[0119] Between the first electrode 11 and the second electrode 12 , magnetic flux lines are formed from the outer peripheral surface 12 a of the second electrode 12 as the north pole toward the outer peripheral surface 11 a of the first electrode 11 as the south pole via the radially outer side of the attraction projection 15G1 .

[0120] Between the first electrode 11 and the third electrode 13 , magnetic flux lines are formed from the outer peripheral surface 13 a of the third electrode 13 as the north pole toward the outer peripheral surface 11 a of the first electrode 11 as the south pole via the radially outer side of the attraction projection 15G2 .

[0121] Between the fourth electrode 14 and the second electrode 12 , magnetic flux lines are formed from the outer peripheral surface 12 a of the second electrode 12 as the north pole toward the outer peripheral surface 14 a of the fourth electrode 14 as the south pole via the radially outer side of the attraction projection 15G3 .

[0122] Between the fourth electrode 14 and the third electrode 13 , magnetic flux lines are formed from the outer peripheral surface 13 a of the third electrode 13 as the north pole toward the outer peripheral surface 14 a of the fourth electrode 14 as the south pole via the radially outer side of the attraction projection 15G4 .

[0123] Furthermore, each of the electrodes 11 to 14 may also have a non-magnetic conductor portion on the side opposite to the end face 10a. In this case, the magnet and the conductor portion are in contact with each other and have conductivity in each of the electrodes 11 to 14. Figure 2 A conductor portion 12b corresponding to the second electrode 12 is shown in FIG.

[0124] Output lines are connected to the first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14. The first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode 14 are connected to the detection unit 5 (see Figure 1 ) electrical connection.

[0125] The multiple electrodes 11 to 14 are insulated from each other. Figure 4 As shown, one detection unit is composed of a pair of electrodes, which are composed of a first electrode 11 and any one of electrodes 12 to 14 other than the first electrode 11 , and an adsorption portion 15 disposed between the pair of electrodes.

[0126] exist Figure 4 In FIG. 1 , “+” is written for the output line of the first electrode 11 , and “−” is written for the output lines of the electrodes 12 to 14 other than the first electrode 11 , thereby indicating a pair of detection units.

[0127] Figure 5 It is a cross-sectional view showing a detection state in the sensor of this embodiment.

[0128] In this embodiment, the sensor 10 is composed of three detection units corresponding to the second electrode 12, the third electrode 13, and the fourth electrode 14. The number of electrodes 12 to 14 and the number of detection units are not particularly limited.

[0129] The magnets serving as electrodes 11 to 14 of the sensor 10 form magnetic flux lines between the paired electrodes 11 to 14. Figure 5 As shown, the conductive particles (wear powder) mp contained in the lubricating oil are attracted to the attracting portion 15. At this time, the electrodes 11 to 14 form magnetic flux in the radial direction from the position closest to the attracting portion 15, thereby increasing the attraction efficiency of the conductive particles mp.

[0130] The resistance of the detection cell changes when the conductive particles mp gather in the vicinity of the adsorption portion 15. In a state where the conductive particles (wear powder) mp are not adsorbed, the resistance of each of the plurality of detection cells may be the same.

[0131] In this embodiment, a plurality of detection units corresponding to the second electrode 12 and the third electrode 13 are connected in parallel. A voltage from the same voltage source is applied between the first electrode 11 and the second electrode 12. Furthermore, a voltage from the same voltage source is applied between the first electrode 11 and the third electrode 13.

[0132] When the conductive particles mp gather in the region near the adsorption projection 15G1 , the resistance of the detection cell corresponding to the second electrode 12 changes.

[0133] When the conductive particles mp gather in the region near the adsorption projection 15G2 , the resistance of the detection cell corresponding to the third electrode 13 changes.

[0134] The detection unit 5 detects changes in the resistance between the first electrode 11 and the second electrode 12. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusion 15G1. When conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusion 15G1, the resistance between the first electrode 11 and the second electrode 12, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0135] Similarly, the detection unit 5 detects changes in the resistance between the first electrode 11 and the third electrode 13. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusion 15G2. When conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusion 15G3, the resistance between the first electrode 11 and the third electrode 13, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0136] Furthermore, a voltage from the same voltage source is applied between the first electrode 11 and the fourth electrode 14 .

[0137] When the conductive particles mp are all gathered in the vicinity of the adsorption convex portion 15G1 and the adsorption convex portion 15G3 , the resistance of the detection cell corresponding to the fourth electrode 14 changes.

[0138] Furthermore, when the conductive material is gathered in the vicinity of the adsorption projection 15G2 and the adsorption projection 15G4 , the resistance of the detection cell corresponding to the fourth electrode 14 changes.

[0139] The detection unit 5 detects changes in the resistance between the first electrode 11 and the fourth electrode 14. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the areas surrounding the adsorption protrusions 15G1 and 15G3. If conductive particles mp contained in the lubricating oil accumulate around both the areas surrounding the adsorption protrusions 15G1 and 15G3, the resistance between the first electrode 11 and the fourth electrode 14, to which voltage is applied, decreases (or shorts), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0140] This detection can be started in a state where the conductive particles mp are gathered around both the periphery of the attraction convex portion 15G1 and the periphery of the attraction convex portion 15G3 .

[0141] Similarly, the detection unit 5 includes, for example, a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the areas surrounding the adsorption protrusions 15G2 and 15G4. When conductive particles mp contained in the lubricating oil accumulate around both the areas surrounding the adsorption protrusions 15G2 and 15G4, the resistance between the first electrode 11 and the fourth electrode 14, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0142] This detection can be started in a state where the conductive particles mp are gathered around both the periphery of the attraction convex portion 15G2 and the periphery of the attraction convex portion 15G4 .

[0143] In this way, the resistance change at the detection cell corresponding to the second electrode 12 and the detection cell corresponding to the third electrode 13 detects the resistance change at one adsorption convex portion 15G1 or one adsorption convex portion 15G2. In contrast, the resistance change at the detection cell corresponding to the fourth electrode 14 detects the resistance change at two adsorption convex portions 15G1 and 15G3, or at two adsorption convex portions 15G2 and 15G4. Therefore, different states can be detected in the multiple detection cells. In other words, resistance change is detected in two stages.

[0144] Furthermore, two-stage, two-system detection units are provided, thereby improving the reliability of fault prediction.

[0145] The detection unit 5 outputs a signal when the resistance changes in a set detection unit. For example, the detection unit 5 may be configured to output a signal to a higher-level control device such as a manipulator when the resistance decreases in two or more detection units, or may be configured to output a signal when the resistance decreases in all detection units.

[0146] Alternatively, the reduction in resistance may include detecting both the non-energized and energized states based on the connection and disconnection signals of the non-energized and energized states (hereinafter referred to as "digital detection"). The detection unit 5 may also be connected to a higher-level control device (not shown) such as a manipulator by wire or wirelessly. The higher-level control device may be configured to issue a warning prompting maintenance of the reducer 2, etc., using a predetermined notification device (e.g., a display device, a sound output device, etc.) upon receiving a signal from the detection unit 5.

[0147] As described above, the sensor 10 of this embodiment has a plurality of detection units, and the detection unit 5 outputs a signal when the resistance is reduced in any set detection unit. Thus, the detection unit 5 can be set so that even if the resistance changes in one detection unit due to initial wear powder and the resistance does not change in other detection units, no signal is output. Thus, unexpected operation of the sensor can be suppressed. In addition, according to the sensor 10, the conditions for the detection unit 5 to output a signal can be set, so that the time when the signal is output in one sensor 10 can be made consistent with the time of optimal fault prediction that is different according to the user's expectations.

[0148] Furthermore, when the conductive particles mp are not adsorbed, the resistance of each of the multiple detection cells can be the same. This can reduce the voltage applied to the sensor 10. Furthermore, the multiple detection cells can be connected in parallel. This can reduce the voltage applied between the pair of electrodes of each detection cell.

[0149] Furthermore, it is preferable to set the arrangement of the sensor 10 so that the first electrode 11 forming a detection unit relative to all the other electrodes 12 to 14 corresponds to a portion where the amount of the conductive particles mp is large.

[0150] In sensor 10 of this embodiment, gaps G1 to G4 for detecting conductive particles mp are provided along outer peripheral surfaces 11a to 14a in the circumferential direction rtd. This allows for a more compact sensor 10 without compromising detection sensitivity, compared to a case where gaps for detecting conductive particles are provided radially relative to end surface 10a of sensor 10.

[0151] In addition, the detection direction of the detection unit can be set to the circumferential direction rtd along the outer peripheral surface 11a~14a. Therefore, compared with the case where multiple detection gaps are provided in the axis axd direction in the circumferential direction of the sensor, the sensor can be miniaturized without reducing the detection sensitivity.

[0152] Furthermore, the electrodes 11 to 14 as magnetic bodies form magnetic flux in the radial direction from the position closest to the attraction portion 15 , so the attraction efficiency of the conductive particles mp is high and does not decrease even if the size is reduced.

[0153] Furthermore, according to the sensor 10 of this embodiment, the number of components can be reduced, assembling can be facilitated, and manufacturing costs can be reduced.

[0154] Figure 6A and Figure 6B This is an explanatory diagram showing another example of the magnet in the sensor according to this embodiment.

[0155] In the sensor 10 of this embodiment, the magnetic bodies forming the electrodes 11 to 14 are configured so that their cross sections are sector-shaped. Figure 6A and Figure 6B As shown, it is also possible to have a structure having an annular cross section divided into four in the circumferential direction.

[0156] In this case, each electrode 11-14 is also magnetized in the radial direction of the sensor 10. The second electrode 12 and the third electrode 13 are magnetized so that the same polarity is present on their outer peripheral surfaces 12a and 13a. The first electrode 11 and the fourth electrode 14 are magnetized so that the same polarity is present on their outer peripheral surfaces 11a and 14a. Furthermore, adjacent electrodes 11-14 are magnetized so that they have different polarity.

[0157] By adopting such an arrangement, the electrodes 11 to 14 of the magnetic body are attracted to each other by their respective magnetic forces and can be fixed to the cross-shaped attraction portion 15 without using an adhesive or other adhesive.

[0158] Figure 7This is a perspective view showing another example of the sensor according to this embodiment.

[0159] In the sensor 10 of this embodiment, as Figure 7 As shown, flexible substrates 11f to 14f can be used as output lines from the electrodes 11 to 14 .

[0160] The output line connected to the first electrode 11 is provided as a flexible substrate 11f, which is sandwiched between the first electrode 11 and the adsorption portion 15. The portion of the flexible substrate 11f in contact with the first electrode 11 is made conductive by peeling off the coating, etc., and maintains electrical continuity with the first electrode 11. Furthermore, the electrodes 11 to 14, which are magnetic bodies, attract each other using their respective magnetic forces, so that the flexible substrate 11f is fixed in place while being sandwiched between the first electrode 11 and the adsorption portion 15.

[0161] Therefore, the flexible substrate 11 f and the first electrode 11 can be fixedly connected while maintaining the conductive state without using an adhesive or the like.

[0162] Similarly, in the sensor 10 of this embodiment, the flexible substrate 12 f is fixedly connected to the second electrode 12 , the flexible substrate 13 f is fixedly connected to the third electrode 13 , and the flexible substrate 14 f is fixedly connected to the fourth electrode 14 .

[0163] In addition, Figure 7 In the embodiment, the flexible substrate 11f is sandwiched between the first electrode 11 and the adsorption projection 15G2, but may also be sandwiched between the first electrode 11 and the adsorption projection 15G1.

[0164] Hereinafter, a sensor according to a second embodiment of the present invention will be described with reference to the drawings.

[0165] Figure 8 It is a perspective view showing the sensor according to this embodiment. Figure 9 FIG is an end view of the sensor according to this embodiment. Figure 8 , reference numeral 20 denotes a sensor.

[0166] In this embodiment, the difference from the first embodiment mentioned above is the point related to the outer shape of the sensor and the magnet. Figure 1 The structure of the mechanism 1 shown is described.

[0167] like Figure 8 As shown in FIG, the sensor 20 has a substantially prismatic outer shape (columnar body) having an axis axd. The sensor 20 includes a first electrode 21 , a second electrode 22 , a third electrode 23 , a fourth electrode 24 , and an adsorption portion (capturing portion) 25 .

[0168] The end surface 20 a of the sensor 20 has a substantially rectangular outline in a direction orthogonal to the axis axd.

[0169] The first electrode 21 , the second electrode 22 , the third electrode 23 , and the fourth electrode 24 form side surfaces of the prism.

[0170] The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 have a substantially rectangular cross-sectional shape when viewed from the end surface 20a of the sensor 20. These electrodes 21 to 24 are formed into rectangular flat plates. The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are all formed into substantially the same shape.

[0171] The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are arranged so as to be symmetrical about the axis axd. When viewed from the end surface 20a, the electrodes 21 to 24 are arranged in a clockwise direction in the circumferential direction rtd, in the order of the first electrode 21, the second electrode 22, the fourth electrode 24, and the third electrode 23.

[0172] The first electrode 21 , the second electrode 22 , the fourth electrode 24 , and the third electrode 23 are all arranged at the same position in the direction along the axis axd.

[0173] The first electrode 21 , the second electrode 22 , the fourth electrode 24 , and the third electrode 23 are arranged so that their outer peripheral surfaces 21 a to 24 a have cross-sectional shapes such that each side of the square is located at the same distance from the axis axd.

[0174] The first electrode 21 , the second electrode 22 , the third electrode 23 , and the fourth electrode 24 are all set to have the same length in the direction along the axis axd.

[0175] The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are spaced apart from each other in a direction along the end surface 20a. Gaps G1 to G4 are formed between the electrodes 21 to 24.

[0176] The separation distance between the first electrode 21 and the second electrode 22 in the circumferential direction rtd is defined as a gap G1. The separation distance between the first electrode 21 and the third electrode 23 in the circumferential direction rtd is defined as a gap G2. The separation distance between the second electrode 22 and the fourth electrode 24 in the circumferential direction rtd is defined as a gap G3. The separation distance between the third electrode 23 and the fourth electrode 24 in the circumferential direction rtd is defined as a gap G4.

[0177] The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are all formed as magnetic bodies. The magnetic bodies are formed of, for example, permanent magnets.

[0178] The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are all magnetized in the radial direction of the sensor 20. In other words, each of the electrodes 21 to 24 is a thin plate-shaped magnet magnetized to have two polarities on the front and back surfaces of the main flat surface.

[0179] The first electrode 21 and the fourth electrode 24, which are symmetrically positioned and opposite to each other about the axis axd, are magnetized so that the same polarity appears on their outer peripheral surfaces 21a and 24a. The second electrode 22 and the third electrode 23, which are symmetrically positioned and opposite to each other about the axis axd, are magnetized so that the same polarity appears on their outer peripheral surfaces 22a and 23a. Furthermore, adjacent electrodes 21 to 24 are magnetized so that they have different polarity.

[0180] For example, Figure 9 As shown, the second electrode 22 and the third electrode 23 are magnetized so that their north poles are located on their outer peripheral surfaces 22a and 23a. The first electrode 21 and the fourth electrode 24 are magnetized so that their south poles are located on their outer peripheral surfaces 21a and 24a. Furthermore, the directions of magnetization can also be set so that all electrodes 21 to 24 have opposite polarities.

[0181] By setting this arrangement, the electrodes 21 to 24 of the magnet are arranged in a parallel state with their north and south poles facing each other, so that they are attracted to each other by their respective magnetic forces. As a result, the electrodes 21 to 24 of the magnet can be fixed to the center portion 25c of the cross-shaped attraction portion 25 without using an adhesive or other bonding portion.

[0182] An adsorption portion 25 is positioned between each of the electrodes 21 to 24. The adsorption portion 25 is formed from an insulating, non-magnetic material such as resin. The adsorption portion 25 has a cross-shaped cross section when viewed from the end face 20a along the axis axd, with a central portion 25c having a larger diameter than the radial end portions. Furthermore, the central portion 25c is formed in a prismatic shape. The space between each of the electrodes 21 to 24 is filled with the central portion 25c.

[0183] The adsorption portion 25 has an adsorption projection 25G1 provided to fill the gap G1 between the first electrode 21 and the second electrode 22 and projecting radially outward relative to the outer peripheral surfaces 21 a and 22 a .

[0184] The adsorption portion 25 has an adsorption projection 25G2 that is provided to fill the gap G2 between the first electrode 21 and the third electrode 23 and that protrudes radially outward relative to the outer peripheral surfaces 21 a and 23 a .

[0185] The adsorption portion 25 has an adsorption projection 25G3 provided to fill the gap G3 between the second electrode 22 and the fourth electrode 24 and projecting radially outward relative to the outer peripheral surfaces 22 a and 24 a .

[0186] The adsorption portion 25 has an adsorption projection 25G4 provided to fill the gap G4 between the third electrode 23 and the fourth electrode 24 and projecting radially outward relative to the outer peripheral surfaces 23 a and 24 a .

[0187] The adsorption projections 25G1 to 25G4 are formed in a shape such that the diagonal lines of the rectangle (square) formed by the electrodes 21 to 24 are extended radially outward, when viewed in cross section in the axis axd direction.

[0188] The adsorption convex portions 25G1 to 25G4 are formed so that their radial protrusion heights are all the same. Alternatively, the adsorption convex portions 25G1 to 25G4 may be formed so that their radial protrusion heights are of any desired size, such as varying in size. The radial protrusion heights of the adsorption convex portions 25G1 to 25G4 can be used to adjust the detection sensitivity, which will be discussed later.

[0189] The dimensions of the gaps G1 to G4 between the electrodes 21 to 24 in the circumferential direction (rtd) are larger than the dimensions of the conductive material contained in the lubricating oil. For example, the dimensions of the conductive material are approximately 1.0 μm to 100 μm. The spacing between the gaps G1 to G4 is preferably set to a distance sufficient to prevent short-circuiting of iron powder due to initial wear. The dimensions of the gaps G1 to G4 in the circumferential direction (rtd) are all set to the same value.

[0190] like Figure 9 As shown, magnetic flux lines are formed between the electrodes 21 to 24 as magnetic bodies so as to be connected via the radially outer sides of the attraction projections 25G1 to 25G4 .

[0191] Between the first electrode 21 and the second electrode 22 , magnetic flux lines are formed from the outer peripheral surface 22 a of the second electrode 22 as the north pole toward the outer peripheral surface 21 a of the first electrode 21 as the south pole via the radially outer side of the attraction projection 25G1 .

[0192] Between the first electrode 21 and the third electrode 23 , magnetic flux lines are formed from the outer peripheral surface 23 a of the third electrode 23 as the north pole toward the outer peripheral surface 21 a of the first electrode 21 as the south pole via the radially outer side of the attraction projection 25G2 .

[0193] Between the fourth electrode 24 and the second electrode 22 , magnetic flux lines are formed from the outer peripheral surface 22 a of the second electrode 22 as the north pole toward the outer peripheral surface 24 a of the fourth electrode 24 as the south pole via the radially outer side of the attraction projection 25G3 .

[0194] Between the fourth electrode 24 and the third electrode 23 , magnetic flux lines are formed from the outer peripheral surface 23 a of the third electrode 23 as the north pole toward the outer peripheral surface 24 a of the fourth electrode 24 as the south pole via the radially outer side of the attraction projection 25G4 .

[0195] In addition, the electrodes 21 to 24 and the adsorption protrusions 25G1 to 25G4 may not be in contact with each other. Figure 9 As shown, the distances between the electrodes 21 to 24 and the adsorption projections 25G1 to 25G4 may increase from the central portion 25 c toward the radially outer side.

[0196] Furthermore, a non-magnetic conductor portion may be provided on the side opposite to the end face 20a of each of the electrodes 21 to 24. In this case, the magnet and the conductor portion of each of the electrodes 21 to 24 are in contact with each other and have conductivity.

[0197] Output lines are connected to the first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24. The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are connected to the detection unit 5 (see the first embodiment) via the output lines. Figure 1 ) electrical connection.

[0198] The plurality of electrodes 21 to 24 are insulated from each other, and one detection unit is composed of a pair of electrodes and an adsorption portion 25 disposed between the pair of electrodes. The pair of electrodes is composed of the first electrode 21 and any one of the other electrodes 22 to 24 .

[0199] In this embodiment, the sensor 20 is composed of three detection units corresponding to the second electrode 22, the third electrode 23, and the fourth electrode 24. The number of electrodes 22 to 24 and the number of detection units are not particularly limited. The magnets serving as the electrodes 21 to 24 of the sensor 20 form magnetic flux lines between the paired electrodes 21 to 24. Therefore, the wear powder mp contained in the lubricating oil (see the first embodiment) is Figure 5 ) is adsorbed on the adsorption portion 25. When the conductive particles mp gather in the area near the adsorption portion 25, the resistance of the detection unit changes. In the state where the conductive particles (wear powder) mp are not adsorbed, the resistance of each of the plurality of detection units may be the same.

[0200] The plurality of detection units are electrically connected to the detection section 5 in correspondence with the output lines connected to the plurality of electrodes 22 to 24 .

[0201] In this embodiment, a plurality of detection units corresponding to the second electrode 22 and the third electrode 23 are connected in parallel. A voltage from the same voltage source is applied between the first electrode 21 and the second electrode 22. Furthermore, a voltage from the same voltage source is applied between the first electrode 21 and the third electrode 23.

[0202] When the conductive particles mp gather in the region near the adsorption projection 25G1 , the resistance of the detection cell corresponding to the second electrode 22 changes.

[0203] When the conductive particles mp gather in the region near the adsorption projection 25G2 , the resistance of the detection cell corresponding to the third electrode 23 changes.

[0204] The detection unit 5 detects changes in the resistance between the first electrode 21 and the second electrode 22. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusion 25G1. When conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusion 25G1, the resistance between the first electrode 21 and the second electrode 22, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0205] Similarly, the detection unit 5 detects changes in the resistance between the first electrode 21 and the third electrode 23. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusion 25G2. When conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusion 25G3, the resistance between the first electrode 21 and the third electrode 23, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0206] Furthermore, a voltage from the same voltage source is applied between the first electrode 21 and the fourth electrode 24 .

[0207] When the conductive particles mp are all gathered in the vicinity of the adsorption convex portion 25G1 and the adsorption convex portion 25G3 , the resistance of the detection cell corresponding to the fourth electrode 24 changes.

[0208] Furthermore, when the conductive material is gathered in the vicinity of the adsorption projection 25G2 and the adsorption projection 25G4 , the resistance of the detection cell corresponding to the fourth electrode 24 changes.

[0209] The detection unit 5 detects changes in the resistance between the first electrode 21 and the fourth electrode 24. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusions 25G1 and 25G3. If the conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusions 25G1 and 25G3, the resistance between the first electrode 21 and the fourth electrode 24, to which voltage is applied, decreases (or shorts), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0210] This detection can be started in a state where the conductive particles mp are gathered around both the periphery of the adsorption convex portion 25G1 and the periphery of the adsorption convex portion 25G3 .

[0211] Similarly, the detection unit 5 includes, for example, a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the areas surrounding the adsorption protrusions 25G2 and 25G4. If the conductive particles mp contained in the lubricating oil accumulate around the areas surrounding the adsorption protrusions 25G2 and 25G4, the resistance between the first electrode 21 and the fourth electrode 24, to which voltage is applied, decreases (or shorts), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0212] This detection can be started in a state where the conductive particles mp are gathered around both the periphery of the attraction convex portion 25G2 and the periphery of the attraction convex portion 25G4 .

[0213] In this manner, the resistance changes at the detection cells corresponding to the second electrode 22 and the detection cells corresponding to the third electrode 23 detect the resistance changes at either one adsorption convex portion 25G1 or one adsorption convex portion 25G2, respectively. In contrast, the resistance change at the detection cell corresponding to the fourth electrode 24 detects either the resistance changes at two adsorption convex portions 25G1 and 25G3 or at two adsorption convex portions 25G2 and 25G4. Thus, different states can be detected in the multiple detection cells. In other words, resistance changes are detected in two stages.

[0214] Furthermore, two-stage, two-system detection units are provided, thereby improving the reliability of fault prediction.

[0215] The detection unit 5 outputs a signal when the resistance changes in a set detection cell. For example, the detection unit 5 may be configured to output a signal to a higher-level control device such as a manipulator when the resistance decreases in both the detection cell corresponding to the second electrode 22 and the detection cell corresponding to the third electrode 23. Alternatively, the detection unit 5 may be configured to output a signal when the resistance decreases in all detection cells, including the detection cell corresponding to the fourth electrode 24.

[0216] Alternatively, the reduction in resistance may include detecting both the non-energized and energized states based on the connection and disconnection signals of the non-energized and energized states (hereinafter referred to as "digital detection"). The detection unit 5 may also be connected to a higher-level control device (not shown) such as a manipulator by wire or wirelessly. The higher-level control device may be configured to issue a warning prompting maintenance of the reducer 2, etc., using a predetermined notification device (e.g., a display device, a sound output device, etc.) upon receiving a signal from the detection unit 5.

[0217] As described above, the sensor 20 of this embodiment has a plurality of detection units, and the detection unit 5 outputs a signal when the resistance is reduced in any set detection unit. Thus, the detection unit 5 can be set so that even if the resistance changes in one detection unit due to initial wear powder and the resistance does not change in other detection units, no signal is output. Thus, unexpected operation of the sensor can be suppressed. In addition, according to the sensor 20, the conditions for the detection unit 5 to output a signal can be set, so that the time when the signal is output in one sensor 20 can be made consistent with the time of optimal fault prediction that is different according to the user's expectations.

[0218] Furthermore, when the conductive particles mp are not adsorbed, the resistance of each of the multiple detection cells can be the same. This can reduce the voltage applied to the sensor 20. Furthermore, the multiple detection cells are connected in parallel. This can reduce the voltage applied between the pair of electrodes of each detection cell.

[0219] Furthermore, it is preferable to set the arrangement of the sensor 20 so that the first electrode 21 forming the detection unit corresponds to a portion where the amount of the conductive particles mp is large relative to all the other electrodes 22 to 24 .

[0220] In the sensor 20 of this embodiment, the gaps G1 to G4 for detecting the conductive particles mp are provided along the outer peripheral surfaces 21a to 24a in the circumferential direction rtd. This allows the sensor 20 to be miniaturized without reducing detection sensitivity, compared to a case where the gaps for detecting the conductive particles are provided radially relative to the end surface 20a of the sensor 20.

[0221] In addition, the detection direction of the detection unit can be set to the circumferential direction rtd along the outer peripheral surface 21a~24a. Therefore, compared with the case where multiple detection gaps in the axis axd direction are provided in the circumferential direction of the sensor, the sensor can be miniaturized without reducing the detection sensitivity.

[0222] Furthermore, the electrodes 21 to 24 as magnetic bodies generate magnetic flux in the radial direction from the position closest to the attracting portion 25, so the attracting efficiency of the conductive particles mp is high and does not decrease even when the size is reduced, thus enabling further miniaturization.

[0223] Furthermore, according to the sensor 20 of this embodiment, the number of components is reduced, thereby facilitating assembly, and an inexpensive plate-shaped magnet can be used, thereby reducing manufacturing costs.

[0224] Figure 10 It is a cross-sectional view perpendicular to the axial direction, showing another example of the sensor according to the present embodiment.

[0225] In the sensor 20 of this embodiment, the magnets forming the electrodes 21 to 24 are configured so as to have portions separated from the adsorption projections 25G1 to 25G4. Figure 10 As shown, a structure may be adopted in which grooves 25m into which magnets serving as the electrodes 21 to 24 are fitted are provided at the bases of the adsorption projections 25G1 to 25G4 and the central portion 25c.

[0226] In this case, it is preferable that the groove portion 25 m does not cover the outer peripheral surfaces 21 a to 24 a of the electrodes 21 to 24 .

[0227] Here, even when grooves 25m are provided, it is preferable that the extension length of the adsorption protrusions 25G1 to 25G4 in the circumferential direction rtd, that is, the surface distance from the adjacent outer peripheral surface 21a to the outer peripheral surface 22a of the adsorption protrusion 25G1, is such that the amount of accumulation of the conductive particles mp is the same as when the grooves 25m are not provided. Thus, the detection sensitivity of each detection unit can be set independently of the presence or absence of the grooves 25m.

[0228] At the same time, it is preferable that the size of the circumferential direction rtd of each of the gaps G1 to G4 does not change even if the groove portion 25 m is provided.

[0229] In this example, the electrodes 21 to 24 are inserted into the grooves 25m along the axis axd from the end surface 20a, making it easier to assemble the sensor 20. This allows the electrodes 21 to 24 to be more firmly fixed to the adsorption portion 25 than when the electrodes 21 to 24 are fixed to the adsorption portion 25 solely by their magnetic force.

[0230] Figure 11It is a cross-sectional view taken along the axial direction, showing another example of the sensor according to the present embodiment.

[0231] In the sensor 20 of this embodiment, the electrodes 21 to 24 and the adsorption portion 25 are flush with each other on the end surface 20a. Figure 11 As shown, the end surface 20d can be formed as an inclined surface with the center portion protruding outward in the axis axd direction, and further, a structure can be adopted in which the electrodes 26a to 26d serving as magnetic bodies are provided.

[0232] In this case, the electrodes 26 a to 26 d and the electrodes 21 to 24 are also arranged so as to have polarities different from the polarities of the adjacent magnetic bodies.

[0233] Thus, on end surface 20a, which is a plane perpendicular to axis axd, the weaker magnetic flux leaking from the magnets of electrodes 21 to 24 can be used to form a further detection unit by utilizing the stronger magnetic flux generated by electrodes 26a to 26d. This ensures the reliability of detection by sensor 20 and allows the detection sensitivity to be set to a predetermined level.

[0234] In addition, in the sensor 20 of this embodiment, as in the first embodiment, Figure 7 As shown, flexible substrates 11f to 14f may be used as output lines from the electrodes 21 to 24 .

[0235] In this case, the magnetic electrodes 21 to 24 are arranged in parallel with their north and south poles facing each other. Therefore, the pressure applied to the flexible substrates 11f to 14f against the adsorption portion 25 is greater than in the first embodiment, allowing for more secure fixation and maintaining good contact.

[0236] Hereinafter, a sensor according to a third embodiment of the present invention will be described with reference to the drawings.

[0237] Figure 12 1 is a cross-sectional view taken along the axial direction showing the sensor in this embodiment. Figure 13 : is an explanatory diagram showing the magnet of the sensor of this embodiment. Figure 12 , reference numeral 30 denotes a sensor.

[0238] In this embodiment, the difference from the first embodiment mentioned above is the point related to the structure of the sensor. Figure 1 The structure of the mechanism 1 shown is described.

[0239] like Figure 12 As shown in FIG, the sensor 30 has a substantially cylindrical outer shape having an axis axd. The sensor 30 includes a first electrode 31 , a second electrode 32 , a third electrode 33 , and an adsorption portion (capturing portion) 35 .

[0240] The tip 30a of the sensor 30 is formed in a substantially hemispherical shape.

[0241] The first electrode 31, the second electrode 32, and the third electrode 33 are plates having a circular outline centered on the axis axd when viewed in the direction of the axis axd. The first electrode 31, the second electrode 32, and the third electrode 33 have substantially the same outline and substantially the same thickness.

[0242] The second electrode 32 , the first electrode 31 , and the third electrode 33 are stacked in the axis axd direction and arranged in this order from the distal end 30 a toward the proximal end along the axis axd direction.

[0243] The second electrode 32 , the first electrode 31 , and the third electrode 33 are coaxially arranged in parallel in the direction along the axis axd.

[0244] The second electrode 32 , the first electrode 31 , and the third electrode 33 are arranged so that their outer peripheral surfaces 31 a to 33 a are flush with each other and form the same cylindrical surface.

[0245] The second electrode 32 , the first electrode 31 , and the third electrode 33 are set so that their diameters in a direction perpendicular to the axis axd are all equal.

[0246] The second electrode 32 , the first electrode 31 , and the third electrode 33 are spaced apart from each other in the direction along the axis axd. Gaps G1 and G2 are formed between the electrodes 31 to 33 .

[0247] The distance between the first electrode 31 and the second electrode 32 in the direction along the axis axd is referred to as a gap G1. The distance between the first electrode 31 and the third electrode 33 in the direction along the axis axd is referred to as a gap G2.

[0248] The first electrode 31, the second electrode 32, and the third electrode 33 are all formed as magnets. The magnets are formed of, for example, permanent magnets.

[0249] The magnetization directions of the first electrode 31 , the second electrode 32 , and the third electrode 33 are all set to the radial direction of the sensor 30 .

[0250] The first electrode 31 is magnetized so that the polarity varies along the half-circumference of the radially outer peripheral surface 31a. The second electrode 32 and the third electrode 33 are magnetized so that the polarity varies along the half-circumference of the outer peripheral surfaces 32a and 33a.

[0251] The first electrode 31 has an outer surface 31a with polarity opposite to that of the outer surfaces 32a and 33a of the second electrode 32 and the third electrode 33. That is, the electrodes 31, 32, and 33 adjacent to each other along the axis axd are magnetized to have different polarities.

[0252] That is, the first electrode 31 is arranged so that a magnet magnetized to the same polarity rotates half a circle around the axis axd relative to the second electrode 32 and the third electrode 33 .

[0253] For example, Figure 12 As shown, the first electrode 31 is magnetized so that its north pole is located in the lower half of its outer peripheral surface 31a. The second electrode 32 and the third electrode 33 are magnetized so that their north poles are located in the upper half of their outer peripheral surfaces 32a and 33a, respectively. Furthermore, the magnetization directions can be set so that all electrodes 31 to 33 have opposite polarities.

[0254] With this arrangement, the electrodes 31 to 33 of the magnets attract each other in the axis axd direction by their respective magnetic forces. Therefore, the electrodes 31 to 33 can be stacked in the axis axd direction and fixed to the attraction portion 35 without using adhesives or other bonding agents.

[0255] An adsorption portion 35 is disposed between each of the electrodes 31 to 33. The adsorption portion 35 is formed of an insulating non-magnetic material such as resin. The adsorption portion 35 is formed as a plate having a circular outline when viewed from the tip 30a along the axis axd.

[0256] The adsorption portion 35 includes an adsorption projection 35G1 provided to fill the gap G1 between the first electrode 31 and the second electrode 32 and projecting radially outward relative to the outer peripheral surfaces 31 a and 32 a .

[0257] The adsorption portion 35 includes an adsorption projection 35G2 that is provided to fill the gap G2 between the first electrode 31 and the third electrode 33 and that protrudes radially outward relative to the outer peripheral surfaces 31 a and 33 a .

[0258] The suction protrusions 35G1 and 35G2 are formed so that their radial projections relative to the outer peripheral surfaces 31a to 33a are the same. Alternatively, the suction protrusions 35G1 and 35G2 can be formed to any desired size, such as having different radial projection heights. The radial projection heights of the suction protrusions 35G1 and 35G2 can be used to adjust the detection sensitivity, which will be discussed later.

[0259] The thickness of the gaps G1 and G2 between the electrodes 31 to 33, along the axis axd, is greater than the size of the conductive material contained in the lubricating oil. As an example, the size of the conductive material is approximately 1.0 μm to 100 μm. The spacing between the gaps G1 and G2 is preferably set to a distance sufficient to prevent short-circuiting of iron powder due to initial wear. The dimensions of the gaps G1 and G2 along the axis axd are set to the same value.

[0260] like Figure 12 As shown, magnetic flux lines are formed between the electrodes 31 to 33 as magnetic bodies so as to be connected in the direction along the axis axd via the radially outer sides of the attraction projections 35G1 and 35G2 .

[0261] like Figure 12 As shown on the lower side of the paper, magnetic flux lines are formed between the first electrode 31 and the second electrode 32, extending from the outer peripheral surface 31a of the first electrode 31 as the N pole through the radially outer side of the adsorption protrusion 35G1 toward the outer peripheral surface 32a of the second electrode 32 as the S pole. Figure 12 As shown on the upper side of the paper, magnetic flux lines are formed between the first electrode 31 and the second electrode 32, extending from the outer peripheral surface 32a of the second electrode 32 as the N pole through the radially outer side of the adsorption protrusion 35G1 toward the outer peripheral surface 31a of the first electrode 31 as the S pole.

[0262] like Figure 12 As shown on the lower side of the paper, magnetic flux lines are formed between the first electrode 31 and the third electrode 33, extending from the outer peripheral surface 31a of the first electrode 31 as the N pole through the radially outer side of the adsorption protrusion 35G2 toward the outer peripheral surface 33a of the third electrode 33 as the S pole. Figure 12 As shown on the upper side of the paper, magnetic flux lines are formed between the first electrode 31 and the third electrode 33, extending from the outer peripheral surface 33a of the third electrode 33 as the N pole through the radially outer side of the adsorption protrusion 35G2 toward the outer peripheral surface 31a of the first electrode 31 as the S pole.

[0263] A tip portion 35a made of the same material as the adsorption portion 35 is formed at the outer position of the second electrode 32 in the direction along the axis axd, that is, at the tip 30a. The tip portion 35a has a contour identical to that of the adsorption projections 35G1 and 35G2 when viewed in the direction of the axis axd. The tip portion 35a has a spherical surface.

[0264] A base end portion 35b made of the same material as the adsorption portion 35 is formed on the outside of the third electrode 33 in the direction along the axis axd, that is, on the base side of the sensor 30. The base end portion 35b has a contour identical to that of the adsorption projections 35G1 and 35G2 when viewed in the direction of the axis axd. Furthermore, the base end portion 35b has a thickness along the axis axd identical to that of the adsorption projections 35G1 and 35G2.

[0265] The base portion 35b, third electrode 33, suction protrusion 35G2, first electrode 31, suction protrusion 35G1, and second electrode 32, stacked along axis axd, are each provided with a center hole aligned with axis axd, through which a fastening member 38 (a screw in the illustrated embodiment) passes. The fastening member 38 passing through the center hole along axis axd secures the electrodes 31-33, suction protrusions 35G1 and 35G2, and the tip portion 35a and base portion 35b to one another.

[0266] A cylinder 37 is provided radially around the screw 38. The cylinder 37 has the function of maintaining mutual insulation between the electrodes 31 to 33 and the screw 38, and setting radially fixed positions between the electrodes 31 to 33, the adsorption projections 35G1 and 35G2, the tip portion 35a, and the base portion 35b.

[0267] The first electrode 31, the second electrode 32, and the third electrode 33 are connected to output lines. The first electrode 31, the second electrode 32, and the third electrode 33 are connected to the detection unit 5 (see FIG. Figure 1 ) electrical connection.

[0268] The plurality of electrodes 31 to 33 are insulated from each other, and one detection unit is composed of a pair of electrodes and an adsorption portion 35 disposed between the pair of electrodes. The pair of electrodes is composed of the first electrode 31 and any one of the other electrodes 32 to 33 .

[0269] exist Figure 14 In FIG. 1 , “+” is written for the output line of the first electrode 31 , and “−” is written for the output lines of the other electrodes 32 and 33 , thereby indicating a pair of detection units.

[0270] Figure 15 It is a cross-sectional view showing a detection state in the sensor of this embodiment.

[0271] In this embodiment, the sensor 30 is composed of two detection units corresponding to the second electrode 32 and the third electrode 33. The number of electrodes 32-33 and the number of detection units are not particularly limited. The magnets serving as the electrodes 31-33 of the sensor 30 form magnetic flux lines between the paired electrodes 31-33. Figure 15 As shown, conductive particles (wear powder) mp contained in the lubricating oil are adsorbed by the adsorption portion 35. As the conductive particles mp gather in the area near the adsorption portion 35, the resistance of the detection cell changes. When the conductive particles (wear powder) mp are not adsorbed, the resistance of each of the multiple detection cells may be the same.

[0272] In this embodiment, a plurality of detection units corresponding to the second electrode 32 and the third electrode 33 are connected in parallel. A voltage from the same voltage source is applied between the first electrode 31 and the second electrode 32. Furthermore, a voltage from the same voltage source is applied between the first electrode 31 and the third electrode 33.

[0273] When the conductive particles mp gather in the region near the adsorption projection 35G1 , the resistance of the detection cell corresponding to the second electrode 32 changes.

[0274] When the conductive particles mp gather in the region near the adsorption projection 35G2 , the resistance of the detection cell corresponding to the third electrode 33 changes.

[0275] The detection unit 5 detects changes in the resistance between the first electrode 31 and the second electrode 32. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusion 35G1. When conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusion 35G1, the resistance between the first electrode 31 and the second electrode 32, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0276] Similarly, the detection unit 5 detects changes in the resistance between the first electrode 31 and the third electrode 33. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusion 35G2. When conductive particles mp contained in the lubricating oil accumulate around the adsorption protrusion 35G2, the resistance between the first electrode 31 and the third electrode 33, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0277] In this manner, the resistance change at the detection unit corresponding to the second electrode 32 and the detection unit corresponding to the third electrode 33 is detected by detecting the resistance change at either one adsorption protrusion 35G1 or one adsorption protrusion 35G2. Therefore, different states can be detected using multiple detection units. In other words, resistance changes are detected using two systems of detection units.

[0278] The detection unit 5 outputs a signal when the resistance changes in a set detection unit. For example, the detection unit 5 may be configured to output a signal to a higher-level control device such as a manipulator when the resistance decreases in two or more detection units, or may be configured to output a signal when the resistance decreases in all detection units.

[0279] Alternatively, the reduction in resistance may include detecting both the non-energized and energized states based on the connection and disconnection signals of the non-energized and energized states (hereinafter referred to as "digital detection"). The detection unit 5 may also be connected to a higher-level control device (not shown) such as a manipulator by wire or wirelessly. The higher-level control device may be configured to issue a warning prompting maintenance of the reducer 2, etc., using a predetermined notification device (e.g., a display device, a sound output device, etc.) upon receiving a signal from the detection unit 5.

[0280] As described above, the sensor 30 of this embodiment has a plurality of detection units, and the detection unit 5 outputs a signal when the resistance is reduced in any set detection unit. Thus, the detection unit 5 can be set so that even if the resistance changes in one detection unit due to initial wear powder and the resistance does not change in other detection units, no signal is output. Thus, unexpected operation of the sensor can be suppressed. In addition, according to the sensor 30, the conditions for the detection unit 5 to output a signal can be set, so that the time when the signal is output in one sensor 30 can be made consistent with the time of optimal fault prediction that is different according to the user's expectations.

[0281] Furthermore, when the conductive particles mp are not adsorbed, the resistance of each of the multiple detection cells can be set to be the same. This can reduce the voltage applied to the sensor 30. Furthermore, the multiple detection cells can be connected in parallel. This can reduce the voltage applied between the pair of electrodes of each detection cell.

[0282] Furthermore, it is preferable to set the arrangement of the sensor 30 so that the first electrode 31 forming the detection unit relative to all the other electrodes 32 and 33 corresponds to a portion where the amount of the conductive particles mp is large.

[0283] In sensor 30 of this embodiment, gaps G1 and G2 for detecting conductive particles mp are provided along outer peripheral surfaces 31a to 33a in a direction along axis axd. This allows for a more compact sensor 30 without compromising detection sensitivity, compared to a case where gaps for detecting conductive particles are provided radially relative to the end face of sensor 30.

[0284] In addition, the detection units along the axis axd along the outer peripheral surfaces 31a to 33a can be adjacent to each other, and the detection direction can be set to the direction along the axis axd. Therefore, compared with the case where multiple detection gaps in the direction of the axis axd are provided in the circumferential direction of the sensor, the sensor can be miniaturized without reducing the detection sensitivity.

[0285] In addition, the magnet is exposed on the sensor surface and serves also as electrodes 31 to 33, forming a magnetic flux in the radial direction from the position closest to the adsorption portion 35. Therefore, the adsorption efficiency of the conductive particles mp is high and will not decrease even if miniaturized.

[0286] Furthermore, according to the sensor 30 of this embodiment, the number of components can be reduced, assembling can be facilitated, and manufacturing costs can be reduced.

[0287] Figure 16 This is an explanatory diagram showing another example of the sensor according to this embodiment.

[0288] Furthermore, in the sensor 30 of this embodiment, the detection units for the electrodes 31 to 33 are configured as two systems in parallel. Figure 16 As shown, the detection unit can also be formed in two stages.

[0289] Specifically, the first-stage detection unit is composed of the second electrode 32 located on the tip 30a side and the first electrode 31 located at the center position in the axis axd direction. The second-stage detection unit is composed of the second electrode 32 located on the tip 30a side and the third electrode 33 located on the opposite side in the axis axd direction.

[0290] exist Figure 16 In FIG. 1 , “+” is written for the output line of the second electrode 32 , and “−” is written for the output lines of the other electrodes 31 and 33 , indicating that they form a pair of detection units.

[0291] In this example, the detection unit 5 detects changes in the resistance between the second electrode 32 and the first electrode 31. When the conductive particles mp contained in the lubricating oil of the mechanism 1 gather around the adsorption protrusion 15G1, the resistance between the second electrode 32 and the first electrode 31, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0292] In this example, the detection unit 5 predicts failures in components of the mechanism 1 based on changes in resistance caused by the accumulation of conductive particles mp around the areas surrounding the adsorption projections 35G1 and 35G2. When conductive particles mp contained in the lubricating oil accumulate around both the adsorption projections 35G1 and 35G2, the resistance between the second electrode 32 and the third electrode 33, to which voltage is applied, decreases (or short-circuits), causing a change in the output level of the output line. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0293] This detection can be started in a state where the conductive particles mp are gathered around both the periphery of the attraction convex portion 35G1 and the periphery of the attraction convex portion 35G2 .

[0294] In this way, for the resistance change at the detection unit corresponding to the first electrode 31, the resistance change of one adsorption protrusion 35G1 is detected. Conversely, for the resistance change at the detection unit corresponding to the third electrode 33, the resistance changes of two adsorption protrusions 35G1 and 35G2 are detected. Therefore, different states can be detected in multiple detection units. In other words, resistance changes are detected in two stages. This improves the reliability of fault prediction.

[0295] In addition, the second electrode 32, the first electrode 31, and the third electrode 33 arranged in the axis axd direction are described as follows: Figure 14 The “―”, “+”, “―”, and Figure 16 The detection unit settings shown are "+", "-", and "-". However, the detection unit settings can also be set to "-", "-", and "+".

[0296] Hereinafter, a sensor according to a fourth embodiment of the present invention will be described with reference to the drawings.

[0297] Figure 17 It is a perspective view showing the sensor according to this embodiment.

[0298] The present embodiment differs from the third embodiment described above in the shape of the adsorption portion. Therefore, corresponding structures are denoted by the same reference numerals and their descriptions are omitted.

[0299] like Figure 17 As shown, the adsorption portion 35 of the sensor 30 of this embodiment covers a portion of the electrodes 31 to 33 in the circumferential direction.

[0300] Specifically, the adsorption protrusions 35G1 and 35G2 in the gaps G1 and G2 are provided to cover approximately half of the circumference, and the remaining circumferential portions of the electrodes 31 to 33 are covered with the same resin as that of the adsorption portion 35. Specifically, the adsorption portion 35 is configured to include a substantially cylindrical housing 35B.

[0301] The housing 35B is provided with windows 35Ba to 35Bc that expose approximately half of the outer peripheral surfaces 31 a to 33 a of the electrodes 31 to 33 .

[0302] The windows 35Ba to 35Bc are provided in the same circumferential rtd position when viewed in the axis axd direction. Figure 13 This prevents detection failures caused by magnetic flux that circulates along the circumference of the electrodes 31 to 33 and has nothing to do with the gaps G1 and G2.

[0303] In addition, the housing 35B can be provided with a threaded portion 35Bg that is enlarged in diameter in the direction of the axis axd of the base end portion 35b. The threaded portion 35Bg can fix the sensor 30 to the flange 3 (see FIG. 2 ) without using the support member 2e, for example. Figure 1 The screw portion 35Bg is coaxial with the housing 35B and extends from the housing 35B in the direction of the axis axd. Alternatively, the screw portion 35Bg and the housing 35B may be formed integrally.

[0304] The sensor 30 of this embodiment can also produce effects equivalent to those of the third embodiment described above.

[0305] Figure 18 It is a cross-sectional view taken along the axial direction, showing another example of the sensor according to the present embodiment.

[0306] In the sensor 30 of this embodiment, the housing 35B is described as being integral, but as Figure 18 As shown, the housing 35B may be divided into two by a plane parallel to the axis axd.

[0307] In this example, windows 35Ba to 35Bc are provided in upper housing 35C, and a wire passage 35Df is provided in lower housing 35D in a direction along axis axd, so as to be in contact with outer peripheral surfaces 31a, 32a, and 33a. Wire passage 35Df is open on the proximal end portion 35b side and closed on the distal end portion 30a side.

[0308] In this example, flexible substrates 31f, 32f, and 33f are provided as output lines.

[0309] The output line connected to the first electrode 31 is provided as a flexible substrate 31f, which is sandwiched between the first electrode 31 and the adsorption portion 35. The portion of the flexible substrate 31f in contact with the first electrode 31 is made conductive by peeling off the coating, etc., and maintains electrical continuity with the first electrode 31. Furthermore, the electrodes 31 to 33, which are magnetic bodies, attract each other using their respective magnetic forces, so that the flexible substrate 31f is fixed while being sandwiched between the first electrode 31 and the adsorption portion 35.

[0310] Therefore, the flexible substrate 31 f and the first electrode 31 can be fixedly connected while maintaining the conductive state without using an adhesive or the like.

[0311] Similarly, in the sensor 30 of this embodiment, the flexible substrate 32 f is fixedly connected to the second electrode 32 , and the flexible substrate 33 f is fixedly connected to the third electrode 33 .

[0312] Furthermore, these flexible substrates 31f, 32f, and 33f are connected to the detection unit 5 via the inside of the wire path 35Df.

[0313] This example also can produce the same effects as those of the above-described embodiments.

[0314] Hereinafter, a sensor according to a fifth embodiment of the present invention will be described with reference to the drawings.

[0315] Figure 19 It is an exploded perspective view showing the sensor in this embodiment.

[0316] The present embodiment differs from the fourth embodiment described above in the shape of the magnet. Therefore, corresponding structures are denoted by the same reference numerals and their descriptions are omitted.

[0317] In the sensor 30 of this embodiment, the first electrode 31, the second electrode 32, and the third electrode 33 have a substantially rectangular outline when viewed along the axis axd. These electrodes 31-33 are rectangular flat plates. The first electrode 31, the second electrode 32, and the third electrode 33 are all substantially the same shape.

[0318] In the sensor 30 of the present embodiment, the magnetization directions of the electrodes 31 to 33 and the arrangement state relative to the adsorption portion 35 formed as a housing 35B are substantially the same as those of the third embodiment described above.

[0319] Specifically, the first electrode 31, the second electrode 32, and the third electrode 33 are formed into rectangular plates centered on the axis axd. The first electrode 31, the second electrode 32, and the third electrode 33 are stacked in the direction of the axis axd, and are arranged in the order of the second electrode 32, the first electrode 31, and the third electrode 33 along the axis axd from the distal end 30a toward the proximal end.

[0320] The second electrode 32 , the first electrode 31 , and the third electrode 33 are coaxially arranged in parallel in the direction along the axis axd.

[0321] The second electrode 32 , the first electrode 31 , and the third electrode 33 are arranged so that the four sides of their outer peripheral surfaces 31 a to 33 a are flush with each other to form the same prism-shaped surfaces.

[0322] The second electrode 32 , the first electrode 31 , and the third electrode 33 are all set to have the same diameter in a direction perpendicular to the axis axd (the length of one side of the corresponding rectangle or the length of the diagonal of the rectangle).

[0323] The first electrode 31 , the second electrode 32 , and the third electrode 33 , which are magnetic bodies, are all arranged so that their magnetization directions are in the radial direction of the sensor 30 .

[0324] The first electrode 31 is magnetized so that the polarities of the radially outer peripheral surfaces 31a of the first electrode 31 are different. Furthermore, the second electrode 32 and the third electrode 33 are magnetized so that the polarities of the radially outer peripheral surfaces 32a and 33a of the second electrode 32 and the third electrode 33 are different.

[0325] The polarity of the outer peripheral surface 31a of the first electrode 31 is opposite to the polarity of the outer peripheral surfaces 32a and 33a of the second electrode 32 and the third electrode 33. In other words, the electrodes 31, 32, and 33 adjacent to each other along the axis axd are magnetized to have different polarities.

[0326] That is, the first electrode 31 is arranged so that a magnet magnetized to the same polarity as the second electrode 32 and the third electrode 33 rotates half a circle around the axis axd.

[0327] For example, Figure 19 As shown, the first electrode 31 is magnetized so that its north pole is located at the lower end of its outer peripheral surface 31a. The second electrode 32 and the third electrode 33 are magnetized so that their north poles are located at the upper end of their outer peripheral surfaces 32a and 33a, respectively. Furthermore, the directions of magnetization can also be set so that all electrodes 31 to 33 have opposite polarities.

[0328] With this arrangement, the electrodes 31 to 33 of the magnet attract each other in the axis axd direction by their respective magnetic forces. Therefore, the electrodes 31 to 33 can be stacked in the axis axd direction and fixed to the attraction portion 35 without using adhesives or other bonding agents.

[0329] Furthermore, since each of the electrodes 31 to 33 has a rectangular outline shape, when each of the electrodes 31 to 33 is attached to the housing 35B, it is possible to fix the electrodes 31 to 33 in a state in which the magnetization direction can be easily set.

[0330] Furthermore, in this embodiment, the third electrode 33, the first electrode 31, and the second electrode 32 stacked along the axis axd are each provided with a center hole through which a fastening member 38 (a screw in the illustrated embodiment) passes, so as to have a center axis that coincides with the axis axd.

[0331] This embodiment can also produce effects equivalent to those of the above-described embodiments.

[0332] Figure 20 This is an exploded perspective view showing another example of the sensor according to this embodiment.

[0333] In addition, in the sensor 30 of this embodiment, the outer shape of the housing 35B is formed in a substantially cylindrical shape, but as shown in FIG. Figure 20 As shown, the outer shape of the housing 35B may be configured to be substantially prismatic.

[0334] In this example, the electrodes 31 to 33 can be arranged so that the sides of the electrodes 31 to 33 having a rectangular outline are parallel to the sides of the housing 35B having a substantially prismatic shape.

[0335] Thereby, when each of the electrodes 31 to 33 is attached to the housing 35B, it is possible to fix the electrodes 31 to 33 in a state in which the setting of the magnetization direction is further facilitated.

[0336] This example also can produce the same effects as those of the above-described embodiments.

[0337] Figure 21 This is an exploded perspective view showing another example of the sensor according to this embodiment.

[0338] Furthermore, in the sensor 30 of this embodiment, the housing 35B is described as being integral, but Figure 21 As shown, the housing 35B may be divided into two parts along a plane parallel to the axis axd.

[0339] In this example, each of the electrodes 31 to 33 as a magnetic body is in the shape of a flat plate with a rectangular outline, has a wire path 35Df, and is provided with flexible substrates 31f, 32f, and 33f as output wires.

[0340] In this example, the upper housing 35C is provided with windows 35Ba to 35Bc. Figure 21 As shown, the windows 35Ba to 35Bc are formed so that their circumferential dimensions are slightly narrower than the circumferential dimensions of the electrodes 31 to 33 .

[0341] Furthermore, a wire passage 35Df is formed in the lower housing 35D in the direction along the axis axd so as to be in contact with the outer peripheral surfaces 31a, 32a, and 33a. The wire passage 35Df is open on the base end portion 35b side and is closed on the tip end 30a side.

[0342] In this example, the output line connected to the first electrode 31 is also formed as a flexible substrate 31f, which is sandwiched between the first electrode 31 and the adsorption portion 35. The portion of the flexible substrate 31f that contacts the first electrode 31 is made conductive by removing the coating, etc., and maintains electrical continuity with the first electrode 31. Furthermore, the electrodes 31 to 33, each of which is a magnet, attract each other using their respective magnetic forces, so that the flexible substrate 31f is fixed while being sandwiched between the first electrode 31 and the adsorption portion 35.

[0343] Therefore, the flexible substrate 31 f and the first electrode 31 can be fixedly connected while maintaining the conductive state without using an adhesive or the like.

[0344] Similarly, in the sensor 30 of this example, the flexible substrate 32 f is fixedly connected to the second electrode 32 , and the flexible substrate 33 f is fixedly connected to the third electrode 33 .

[0345] Furthermore, these flexible substrates 31f, 32f, and 33f are connected to the detection unit 5 via the inside of the wire path 35Df.

[0346] In this example, the electrodes 31 to 33 are inserted into the upper case 35C, and the flexible substrates 31f, 32f, and 33f are inserted through the wire passages 35Df to assemble the lower case 35D. This improves the ease of assembly.

[0347] This example also can produce the same effects as those of the above-described embodiments.

[0348] Hereinafter, a sixth embodiment of the sensor according to the present invention will be described with reference to the drawings.

[0349] Figure 22 It is a cross-sectional view taken along the axis, showing the arrangement of electrodes in the sensor according to this embodiment.

[0350] The present embodiment differs from the third embodiment described above in terms of the number of electrodes. Therefore, corresponding components are denoted by the same reference numerals and their descriptions are omitted.

[0351] The sensor 30 of this embodiment includes, in addition to the electrodes 31 to 33 , an adsorption projection 35G3 forming a gap G3 and a fourth electrode 34 on the base end portion 35 b side of the third electrode.

[0352] The electrodes 31 to 34 are stacked in the axis axd direction, and are arranged in the order of the second electrode 32 , the first electrode 31 , the third electrode 33 , and the fourth electrode 34 from the distal end 30 a toward the proximal end 35 b along the axis axd direction.

[0353] In this embodiment, the fourth electrode 34 has a configuration whose shape and arrangement relative to the gap G4 and the adsorption projections 35G3 are based on the first electrode 31 , the adsorption projections 35G1 and 35G2 , and the gaps G1 and G2 .

[0354] In the present embodiment, the magnetization direction of the fourth electrode 34 is the same as that of the first electrode 31 , and the magnetization direction of the adjacent third electrode 33 is opposite to that of the first electrode 31 .

[0355] Furthermore, in the sensor 30 of this embodiment, the detection units for the electrodes 31 to 34 are configured as two systems in parallel. Figure 22 As shown, the detection unit is formed in two stages.

[0356] Specifically, the first-stage detection unit is composed of the second electrode 32 located on the tip 30a side and the first electrode 31 located at the center in the axis axd direction. The second electrode 32 located on the tip 30a side and the third electrode 33 located on the opposite side in the axis axd direction form a parallel detection unit. Furthermore, the first electrode 31 and the fourth electrode 34 form the second-stage detection unit.

[0357] exist Figure 22 In FIG. 1 , “+” is written on the output line of the first electrode 31 , and “−” is written on the output lines of the other electrodes 32 to 34 , indicating a pair of detection units.

[0358] In this embodiment, the detection unit 5 detects changes in the resistance between the first electrode 31 and the second electrode 32. When the conductive particles mp contained in the lubricating oil of the mechanism 1 gather around the adsorption protrusion 15G1, the resistance between the first electrode 31 and the second electrode 32, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0359] In this embodiment, the detection unit 5 detects changes in the resistance between the second electrode 32 and the third electrode 33. When the conductive particles mp contained in the lubricating oil of the mechanism 1 gather around the adsorption protrusion 35G2, the resistance between the first electrode 31 and the third electrode 33, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0360] Furthermore, in this embodiment, the detection unit 5 predicts failures in components of the mechanism 1 based on, for example, changes in resistance caused by the accumulation of conductive particles mp around the adsorption protrusions 35G1 and 35G3. When conductive particles mp contained in the lubricating oil accumulate around both the adsorption protrusions 35G1 and 35G3, the resistance between the second electrode 32 and the fourth electrode 34, to which voltage is applied, decreases (or short-circuits), causing a change in the output level of the output line. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0361] This detection can be started in a state where the conductive particles mp are gathered around both the periphery of the attraction convex portion 35G1 and the periphery of the attraction convex portion 35G3 .

[0362] Thus, the resistance change at one adsorption convex portion 35G1 is detected for the resistance change at the detection unit corresponding to the first electrode 31. Similarly, the resistance change at one adsorption convex portion 35G2 is detected for the resistance change at the detection unit corresponding to the third electrode 33.

[0363] In contrast, the resistance change at the detection unit corresponding to the fourth electrode 34 is detected by detecting the resistance change at two locations, namely, the adsorption protrusions 35G1 and 35G3. Therefore, different states can be detected in the multiple detection units. In other words, resistance changes are detected in two stages. This improves the reliability of fault prediction.

[0364] In addition, the second electrode 32, the first electrode 31, the third electrode 33, and the fourth electrode 34 arranged in the axis axd direction are described as follows: Figure 22 The detection unit settings of “-”, “+”, “-”, and “-” shown above can also be set to “-”, “-”, “+”, and “-”.

[0365] Furthermore, the detection unit settings can be set to "+", "-", "-", "-", and "-", "-", "-", and "+". In this case, three stages of resistance change can be detected.

[0366] This embodiment can also produce effects equivalent to those of the above-described embodiments.

[0367] Hereinafter, a sensor according to a seventh embodiment of the present invention will be described with reference to the drawings.

[0368] Figure 23 1 is a cross-sectional view taken along the axial direction showing the sensor in this embodiment. Figure 24 : is an explanatory diagram showing the magnet of the sensor of this embodiment. Figure 23 , reference numeral 40 denotes a sensor.

[0369] In this embodiment, the difference from the third embodiment mentioned above is the point related to the structure of the sensor. Figure 1 The structure of the mechanism 1 shown is described.

[0370] like Figure 23 As shown in FIG, the sensor 40 of this embodiment has a substantially cylindrical outer shape having an axis axd. The sensor 40 includes a first electrode 41, a second electrode 42, a fastening member 48, and an adsorption portion (capturing portion) 45.

[0371] In the sensor 40, the first electrode 41, the second electrode 42, and the adsorption portion 45 are formed as plates having a circular outline centered on the axis axd when viewed in the direction of the axis axd. The first electrode 41, the adsorption portion 45, and the second electrode 42 all have substantially the same outline and substantially the same thickness.

[0372] The first electrode 41 , the adsorption portion 45 , and the second electrode 42 are stacked in the axis axd direction and arranged in this order from the upper end surface 40 a along the axis axd direction.

[0373] The first electrode 41 , the adsorption portion 45 , and the second electrode 42 are coaxially arranged in parallel in the direction along the axis axd.

[0374] The first electrode 41 and the second electrode 42 are arranged so that their outer peripheral surfaces 41a and 42a are flush with each other and form the same cylindrical surface. An electrode plate 41b, such as a washer, is arranged on the upper end surface 40a side of the first electrode 41.

[0375] The first electrode 41 and the second electrode 42 are spaced apart from each other in a direction along the axis axd. A gap G1 is formed between the first electrode 41 and the second electrode 42.

[0376] The first electrode 41 is a magnet. The magnet is composed of a permanent magnet.

[0377] like Figure 24 As shown, the magnetization direction of the first electrode 41 is set to be along the axis axd.

[0378] The second electrode 42 is made of a conductive magnetic material such as iron, a ferrite core, or silicon steel.

[0379] The adsorption portion 45 is formed in a disk shape having a diameter larger than the diameters of the first electrode 41 and the second electrode 42 .

[0380] The adsorption portion 45 includes an adsorption projection 45G1 provided to fill the gap G1 between the first electrode 41 and the second electrode 42 and projecting radially outward relative to the outer peripheral surfaces 31 a and 32 a .

[0381] The thickness of the gap G1 between the first electrode 41 and the second electrode 42, along the axis axd, is greater than the size of the conductive material contained in the lubricating oil. As an example, the size of the conductive material is approximately 1.0 μm to 100 μm. The gap G1 is preferably spaced such that short circuits in the iron powder due to initial wear are prevented. If the gap G1 is formed by multiple components, the dimensions of the gap G1 along the axis axd are set to the same value for each of the components.

[0382] The first electrode 41, the adsorption portion 45, and the second electrode 42 are each provided with a through-hole for inserting a fastening member 48 (a bolt in the illustrated embodiment). The fastening member 48 is inserted into the through-hole to secure the first electrode, the adsorption portion 45, and the second electrode 42 to each other. The bolt (fastening member) 48 is secured with a nut 48a.

[0383] A cylinder 47 is provided radially around the bolt (fastening member) 48. The cylinder 47 has the function of maintaining mutual insulation between the first electrode 41, the second electrode 42, and the bolt 48, and of fixing the radial positions of the first electrode 41, the second electrode 42, and the adsorption projection 45G1. The cylinder 47 may not be provided.

[0384] like Figure 23 As shown, magnetic flux lines are formed between the second electrode 42 and the first electrode 41 as a magnet so as to connect in the direction along the axis axd via the radially outer side of the attraction projection 45G1 .

[0385] The first electrode 41 and the second electrode 42 are connected to output lines. The first electrode 41 and the second electrode 42 are connected to the detection unit 5 (see Figure 1 ) electrical connection.

[0386] The first electrode 41 and the second electrode 42 are insulated from each other, and one detection unit is composed of a pair of electrodes consisting of the first electrode 41 and the second electrode 42 , and an adsorption portion 45 disposed between the pair of electrodes.

[0387] The detection unit 5 detects changes in the resistance between the first electrode 41 and the second electrode 42. For example, the detection unit 5 includes a sensor drive circuit that predicts failures in components of the mechanism 1 based on changes in resistance along the axis axd direction caused by the accumulation of conductive material around the adsorption portion 45. When conductive material contained in the lubricating oil accumulates around the adsorption portion 45, the resistance between the first electrode 41 and the second electrode 42, to which voltage is applied, decreases (or short-circuits), causing the output level of the output line to change. The detection unit 5 detects this change in resistance to predict failures in components of the mechanism 1.

[0388] Alternatively, the reduction in resistance may include detecting both the non-energized and energized states based on the connection and disconnection signals of the non-energized and energized states (hereinafter referred to as "digital detection"). The detection unit 5 may also be connected to a higher-level control device (not shown) such as a manipulator by wire or wirelessly. The higher-level control device may be configured to issue a warning prompting maintenance of the reducer 2, etc., using a predetermined notification device (e.g., a display device, a sound output device, etc.) upon receiving a signal from the detection unit 5.

[0389] In sensor 40 of this embodiment, gaps G1 for detecting conductive particles mp are provided along outer peripheral surfaces 41a and 42a in a direction along axis axd. This allows for miniaturization of sensor 40 without compromising detection sensitivity, compared to a case where gaps for detecting conductive particles are provided radially relative to the end face of sensor 40.

[0390] Furthermore, the magnet is exposed on the sensor surface and also serves as the first electrode 41, generating a magnetic flux radially outward of the adsorption portion 45. This results in a high adsorption efficiency for the conductive particles mp, which is maintained even with miniaturization. Furthermore, by adjusting the dimensions along the axis axd, the detection sensitivity can be adjusted, preventing malfunctions caused by initial wear powder while also preventing an increase in the diameter.

[0391] Furthermore, according to the sensor 40 of this embodiment, the number of components can be reduced, assembling can be facilitated, and manufacturing costs can be reduced.

[0392] Hereinafter, a sensor according to an eighth embodiment of the present invention will be described with reference to the drawings.

[0393] Figure 25 1 is a cross-sectional view taken along the axial direction showing the sensor in this embodiment. Figure 26 It is an explanatory diagram showing the electrode arrangement of the sensor according to this embodiment.

[0394] The present embodiment differs from the seventh embodiment described above in the structures of the second electrode and the housing. Other corresponding structures are denoted by the same reference numerals and their description is omitted.

[0395] The sensor 40 of this embodiment is a sensor for detecting the amount of the conductive material contained in the lubricating oil, similarly to the sensor 40 of the seventh embodiment described above.

[0396] like Figure 25 As shown, the sensor 40 has a substantially cylindrical outer shape and includes a plurality of detection cells and a detection section 5 that outputs a signal when the resistance in the detection cell changes.

[0397] More specifically, the sensor 40 includes a first electrode 41, a plurality of second electrodes 42, and an adsorption portion 45 disposed between the electrodes 41 and 42. The plurality of second electrodes 42 are insulated from one another by a housing 46 or the like, and a single detection unit is composed of a pair of electrodes, the pair of electrodes being composed of the first electrode 41 and the single second electrode 42, and the adsorption portion 45 disposed between the pair of electrodes.

[0398] In addition, if Figure 26 As shown, the housing 46 is embedded in each of the four circumferentially divided second electrodes 42A, 42B, 42C, and 42D, enabling positional adjustment and insulating the four second electrodes 42A, 42B, 42C, and 42D from one another. The housing 46 can also be formed of the same resin as the material of the adsorption portion 45.

[0399] In the illustrated embodiment, the sensor 40 includes four circumferentially divided second electrodes 42A, 42B, 42C, and 42D, forming four detection units. The number of second electrodes 42 and the number of detection units are not particularly limited. The magnet serving as the first electrode 41 in the sensor 40 forms magnetic flux lines between the paired first electrode 41 and each of the divided second electrodes 42A, 42B, 42C, and 42D. Consequently, the conductive material contained in the lubricating oil is attracted to the adsorption portion 45. The first electrode 41 and the divided second electrodes 42A, 42B, 42C, and 42D correspond to the detection units located on the side surfaces of the sensor body.

[0400] The resistance of the detection cells changes when the conductive material gathers in the vicinity of the adsorption portion 45. When the conductive material is not adsorbed, the resistance of the plurality of detection cells is the same.

[0401] The detection directions of the plurality of detection units are set by the gap G1 and are all along the axis axd.

[0402] like Figure 26As shown, output lines are connected to the first electrode 41 and the plurality of second electrodes 42A, 42B, 42C, and 42D, respectively, and the plurality of detection units are electrically connected to the detection section 5 via the output lines.

[0403] In this embodiment, multiple detection cells are connected in parallel, and a voltage from the same voltage source is applied between the first electrode 41 and the multiple second electrodes 42A, 42B, 42C, and 42D. The detection unit 5 outputs a signal when the resistance changes in any number of detection cells. For example, the detection unit 5 can be configured 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 it can be configured to output a signal when the resistance decreases in all detection cells.

[0404] As described above, sensor 40 includes multiple detection cells, and detection unit 5 outputs a signal when the resistance decreases in any number of the detection cells. This allows detection unit 5 to be configured so that no signal is output even if the resistance changes in a single detection cell due to a large-diameter conductor sheet. Furthermore, the conditions for signal output from detection unit 5 can be configured based on sensor 40, allowing the timing of signal output from a single sensor 40 to coincide with the optimal time for fault prediction, which varies depending on the user's needs.

[0405] In addition, when no conductive particles are adsorbed, the resistance of each of the multiple detection cells is the same. This reduces the voltage applied to the sensor 40. Furthermore, the multiple detection cells are connected in parallel. This reduces the voltage applied between the pair of electrodes of each detection cell.

[0406] This embodiment can also produce effects equivalent to those of the above-described embodiments.

[0407] Hereinafter, a sensor according to a ninth embodiment of the present invention will be described with reference to the drawings.

[0408] Figure 27 1 is a cross-sectional view taken along the axial direction showing the sensor in this embodiment.

[0409] The present embodiment differs from the seventh and eighth embodiments described above in terms of the attracting portion and the magnet. Other corresponding structures are denoted by the same reference numerals and their description is omitted.

[0410] In this embodiment, magnet 49 is embedded within adsorption portion 45, with its outer peripheral surface not exposed to the outside. Furthermore, magnet 49 contacts the portion of first electrode 41, a disc-shaped conductor, that is located on the side closest to second electrode 42, along axis axd. Preferably, magnet 49 is located close to first electrode 41 and second electrode 42. Alternatively, magnet 49 may be in contact with second electrode 42.

[0411] Moreover, the housing 46b is provided on the upper end surface 40a side of the first electrode 41. The housing 46b covers the upper end surface 40a side of the first electrode 41.

[0412] That is, the first electrode 41 , the magnet 49 , the attracting portion 45 , the second electrode 42 , and the housing 46 are stacked in a direction along the axis axd.

[0413] The first electrode 41 and the second electrode 42 have approximately the same diameter, and the outer peripheral surfaces 41a and 42a form flush cylindrical surfaces. The magnet 49 has a diameter smaller than that of the first electrode 41 and the second electrode 42. Furthermore, the adsorption portion 45 includes an adsorption protrusion 45G1 having a larger diameter than that of the first electrode 41 and the second electrode 42.

[0414] The adsorption portion (insulator) 45 is formed from an insulating, non-magnetic material such as resin. Magnet 49 generates magnetic flux lines between the first electrode 41 and the second electrode 42. This causes the conductive material contained in the lubricating oil to gather around the adsorption protrusion 45G1. The range of the lubricating oil's circulation is defined as the detection area.

[0415] The sensor 40 of this embodiment has a detection surface formed by the surface of an adsorption projection 45G1 that protrudes radially outward relative to a cylinder connecting the outer circumferential surface 41a of the first electrode 41 and the outer circumferential surface 42a of the second electrode 42, which is substantially flush with the outer circumferential surface 41a of the first electrode 41. Specifically, on the detection surface, conductive wear powder is attracted between the first and second electrodes 41, 42, in response to magnetic flux lines. This electrically connects the first and second electrodes 41, 42, and thus detects changes in the resistance between the first and second electrodes 41, 42.

[0416] Furthermore, the outer peripheral surface 41 a of the first electrode 41 and the outer peripheral surface 42 a of the second electrode 42 may not be flush with each other.

[0417] As the creeping distance between the first electrode 41 and the second electrode 42 increases, the amount of adsorbed conductor wear powder increases until the resistance between the first electrode 41 and the second electrode 42 drops to a threshold value or a short circuit occurs.

[0418] Furthermore, the creeping distance between the first electrode 41 and the second electrode 42 is shortened, and the amount of adsorbed conductor wear powder is reduced until the resistance between the first electrode 41 and the second electrode 42 drops to a threshold value or a short circuit occurs.

[0419] Here, the creeping distance between the first electrode 41 and the second electrode 42 for setting the detection sensitivity of the detection unit is defined by the protrusion amount of the adsorption convex portion 45G1 in the adsorption portion 45 .

[0420] That is, by increasing or decreasing the radial protrusion amount of the adsorption projection 45G1 and the thickness of the adsorption projection 45G1 along the axis axd, the creeping distance between the first electrode 41 and the second electrode 42 that is short-circuited when the conductive particles are deposited can be changed.

[0421] Furthermore, the thickness dimension of the adsorption projection 45G1 in the direction along the axis axd depends on the thickness dimensions of the gap G1 and the magnet 49 .

[0422] The sensor 40 of this embodiment includes a group of adsorption portions 45 having different protrusion amounts and thickness dimensions, and can be selected and mounted from the group.

[0423] That is, a group of a plurality of adsorption portions 45 having different thicknesses (dimensions in the axis axd direction) and / or radial protrusion amounts constitutes a sensitivity adjustment portion.

[0424] Thus, by selecting the sensitivity adjustment portion, the creeping distance between the first electrode 41 and the second electrode 42 can be selected from a plurality of values.

[0425] The sensor 40 in this embodiment includes a sensitivity adjustment unit, and can set the detection sensitivity to a predetermined state.

[0426] The amount of iron powder (wear dust) generated by initial wear varies depending on the model (size) of the reducer. Large reducers often contain a higher amount of iron powder, which can fill the sensor's electrical clearance between electrodes 41 and 42 and cause a reaction, potentially leading to malfunction. Consequently, the sensor's electrical clearance must be designed to match the reducer model, resulting in an increased sensor diameter.

[0427] In contrast, the sensor 40 in this embodiment includes a sensitivity adjustment portion composed of a group of adsorption portions 45 having different sizes, thereby achieving the same effect as the effect of extension in the diameter direction, and thus the sensor 40 does not increase in size.

[0428] This embodiment can also produce effects equivalent to those of the above-described embodiments.

Claims

1. A sensor comprising: 1st electrode; 2nd electrode; a columnar sensor body having the first electrode and the second electrode arranged on a side surface thereof with a gap therebetween in a circumferential direction; and A capture portion is disposed in the gap, wherein the outer peripheral surface of the capture portion is formed of an insulator. In this sensor, The sensor is electrified in the peripheral direction by the conductive particles gathered in the capture part. The first electrode and the second electrode are magnets, the magnets are magnetized in the radial direction, and the magnets adjacent to each other in the circumferential direction are magnetized in opposite directions. The capture portion protrudes radially outward relative to the outer peripheral surface of the magnet.

2. A sensor comprising: 1st electrode; a second electrode; and The first adsorption part has an outer peripheral surface made of an insulator. The first electrode and the second electrode are arranged to be spaced apart from each other with a first gap in the circumferential direction. The first adsorption portion is arranged in the first gap, By causing the conductive particles to be adsorbed on the outer peripheral surface of the first adsorption portion, the first electrode and the second electrode are short-circuited in the circumferential direction, thereby changing the resistance between the first electrode and the second electrode. The first electrode and the second electrode are magnets, the magnets are magnetized in the radial direction, and the magnets adjacent to each other in the circumferential direction are magnetized in opposite directions. The first attraction portion protrudes radially outward relative to the outer peripheral surface of the magnet.

3. The sensor according to claim 2, wherein The sensor features: a third electrode spaced apart from the first electrode with a second gap in the circumferential direction, the third electrode being located on a side of the first electrode opposite to the second electrode; and a second adsorption portion disposed in the second gap, wherein the outer peripheral surface of the second adsorption portion is formed of an insulator; By causing the conductive particles to be adsorbed on the outer peripheral surface of the second adsorption portion, the first electrode and the third electrode are short-circuited in the circumferential direction, thereby changing the resistance between the first electrode and the third electrode.

4. The sensor according to claim 3, wherein The sensor features: a fourth electrode spaced apart from the second electrode at a third gap in the circumferential direction and spaced apart from the third electrode at a fourth gap in the circumferential direction; a third adsorption portion disposed in the third gap, wherein the outer peripheral surface of the third adsorption portion is formed of an insulator; and a fourth adsorption portion disposed in the fourth gap, wherein the outer peripheral surface of the fourth adsorption portion is formed of an insulator; By causing the conductive particles to be adsorbed on the outer peripheral surface of the third adsorption portion, the second electrode and the fourth electrode are short-circuited in the circumferential direction, thereby changing the resistance between the second electrode and the fourth electrode, and By allowing the conductive particles to be adsorbed on the outer peripheral surface of the fourth adsorption portion, the third electrode and the fourth electrode are short-circuited in the circumferential direction, thereby changing the resistance between the third electrode and the fourth electrode.

5. The sensor according to any one of claims 2 to 4, wherein The outer peripheral surface of the electrode forms a side surface of the columnar body.

6. The sensor according to any one of claims 2 to 4, wherein The magnet is arranged so as to form a magnetic flux extending from an outer peripheral surface toward the radially outer side.

7. A sensor having a cylindrical sensor body, The sensor features: a magnet that divides the sensor body into four parts in the circumferential direction; and an adsorption portion configured to fill gaps between the magnets in the sensor body, The adsorption portion protrudes radially outward relative to the outer peripheral surface of the magnet. The magnets are magnetized in the radial direction, and the magnets adjacent to each other in the circumferential direction are magnetized in directions opposite to each other. The magnets serve as electrodes, and by adsorbing conductive particles onto the outer peripheral surface of the adsorption portion, the magnets are short-circuited in the circumferential direction, thereby changing the resistance between the magnets serving as electrodes.

8. A sensor comprising: 1st electrode; a second electrode spaced apart from the first electrode with a first gap in the axial direction; and a first adsorption portion disposed in the first gap, wherein the outer peripheral surface of the first adsorption portion is formed of an insulator; The first electrode, the first adsorption portion, and the second electrode are stacked in the axial direction. By causing the conductive particles to be adsorbed on the outer peripheral surface of the first adsorption portion, the first electrode and the second electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the second electrode. The first electrode and the second electrode are magnets, the magnets are magnetized in the radial direction, and the magnets adjacent to each other in the axial direction are magnetized in opposite directions. The first attraction portion protrudes radially outward relative to the outer peripheral surface of the magnet.

9. The sensor according to claim 8, wherein The sensor features: a third electrode spaced apart from the second electrode with a second gap in the axial direction; and a second adsorption portion disposed in the second gap, wherein the outer peripheral surface of the second adsorption portion is formed of an insulator; The first electrode, the second electrode, and the third electrode overlap with the first adsorption portion and the second adsorption portion in the axial direction. By causing the conductive particles to be adsorbed on the outer peripheral surface of the second adsorption portion, the second electrode and the third electrode are short-circuited in the axial direction, thereby changing the resistance between the second electrode and the third electrode.

10. The sensor according to claim 9, wherein The sensor features: a fourth electrode spaced apart from the third electrode with a third gap in the axial direction; and The third adsorption portion is arranged in the third gap, and the outer peripheral surface of the third adsorption portion is composed of an insulator. The first electrode to the fourth electrode and the first adsorption part to the third adsorption part are overlapped in the axial direction. By causing the conductive particles to be adsorbed on the outer peripheral surface of the third adsorption portion, the third electrode and the fourth electrode are short-circuited in the axial direction, thereby changing the resistance between the third electrode and the fourth electrode.

11. The sensor according to any one of claims 8 to 10, wherein The outer peripheral surface of the electrode is located on the side of the columnar body.

12. The sensor according to any one of claims 8 to 10, wherein: The magnet is arranged so as to form a magnetic flux extending from an outer peripheral surface toward the radially outer side.

13. A sensor having a cylindrical sensor body, The sensor features: a magnet that divides the sensor body into three parts in the axial direction; and an adsorption portion configured to fill the gap between the magnets in the sensor body in the axial direction, The magnet and the adsorption portion are overlapped in the axial direction, The adsorption portion protrudes radially outward relative to the outer peripheral surface of the magnet. The magnets are magnetized in the radial direction, and the magnets adjacent to each other in the axial direction are magnetized in opposite directions. The magnets serve as electrodes, and by adsorbing conductive particles on the outer peripheral surface of the adsorption portion, the magnets are short-circuited in the axial direction, thereby changing the resistance between the magnets serving as electrodes.

14. A sensor comprising: 1st electrode; a second electrode spaced apart from the first electrode with a first gap in the axial direction; a third electrode spaced apart from the first electrode in the axial direction with the first gap therebetween, and spaced apart from the second electrode in the circumferential direction with a gap therebetween; and an adsorption portion disposed in the first gap, wherein the outer peripheral surface of the adsorption portion is formed of an insulator, The first electrode, the adsorption portion, and the second electrode are stacked in the axial direction. By causing the conductive particles to be adsorbed on the outer peripheral surface of the adsorption portion, the first electrode and the second electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the second electrode. The first electrode, the adsorption portion, and the third electrode are stacked in the axial direction. By causing the conductive particles to be adsorbed on the outer peripheral surface of the adsorption portion, the first electrode and the third electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the third electrode. The adsorption portion protrudes radially outward relative to the first electrode, the second electrode, and the third electrode.

15. The sensor according to claim 14, wherein The sensor includes a fourth electrode spaced apart from the first electrode in the axial direction with the first gap therebetween, and spaced apart from the second electrode and the third electrode in the circumferential direction with the gap therebetween. By causing the conductive particles to be adsorbed on the outer peripheral surface of the adsorption portion, the first electrode and the fourth electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the fourth electrode.

16. The sensor according to claim 15, wherein The second electrode, the fourth electrode, and the third electrode are arranged spaced apart in the circumferential direction, and adsorption portions are arranged in gaps between the second electrode, the fourth electrode, and the third electrode.

17. The sensor according to any one of claims 14 to 16, wherein: The outer peripheral surface of the electrode is located on the side of the columnar body.

18. The sensor according to any one of claims 14 to 16, wherein: A magnet is arranged at least at a position closer to the first electrode than the second electrode in the axial direction. The magnets are arranged so as to form a magnetic flux directed in the axial direction.

19. The sensor according to claim 18, wherein The first electrode is a magnet.

20. A sensor comprising a cylindrical sensor body, The sensor body comprises: A first electrode, an adsorption portion, and a second electrode stacked in the axial direction; and a magnet, which is magnetized in the axial direction, By causing the conductive particles to be adsorbed on the outer peripheral surface of the adsorption portion, the outer peripheral surfaces of the first electrode and the second electrode are short-circuited in the axial direction, thereby changing the resistance between the first electrode and the second electrode. The second electrode is divided in the circumferential direction of the sensor body. The adsorption portion protrudes radially outward relative to the first electrode and the second electrode.

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