Sensor

Abstract

The present invention provides a sensor. The sensor (5, 30, 60) of the present invention includes: a first electrode (6, 61); a second electrode (8, 62); a first adsorption portion (10, 63) disposed between the first electrode (6, 61) and the second electrode (8, 62) to adsorb conductor wear powder in the detection region; a detection portion (50) that detects a change in resistance between the first electrode (6, 61) and the second electrode (8, 62) caused by the conductor wear powder; and a second adsorption portion (64B) disposed in the detection region to adsorb conductor wear powder in the detection region.

Description

Technical Field

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

[0002] In order to suppress damage to mechanical components such as gears, a mechanical device such as a speed reducer is housed in a housing storing lubricating oil. When mechanical components are worn during operation of such a mechanical device, wear powder (e.g., a conductive substance such as iron powder) mixes into the lubricating oil. The wear powder is a conductive substance such as iron powder. If the wear of the mechanical components 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 appropriately perform preventive maintenance of mechanical components.

[0003] As such a sensor, for example, an oil inspection sensor is disclosed in Patent Document 1. The oil inspection sensor is installed in a transmission of an automobile or the like, and inspects the deterioration of the oil in an oil container, the wear degree of mechanical components lubricated with the oil, and the like. The sensor includes a pair of electrodes and a magnet that adsorbs iron powder or the like (conductive substance) contained in the oil, and detects the amount of the conductive substance in the oil based on the resistance value between the pair of electrodes that changes due to the adsorbed conductive substance.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-286697

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2005-331324 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, the wear powder detected in a speed reducer or the like increases due to initial wear. After that, after roughly a certain normal operation, it increases sharply before a failure occurs. Sensors for detecting an increase in the amount of wear powder before such a failure have been conventionally known. However, in the case of a conventional sensor, when the amount of wear powder generated due to initial wear is large, such as when the size of the speed reducer is large, there is a case where the sensor malfunctions and cannot detect an increase in the amount of wear powder before a failure that should originally be detected.

[0010] In addition, there is a requirement to reliably stop and replace a speed reducer or the like through pre-failure detection in order to prevent malfunction of the sensor.

[0011] Moreover, when manufacturing mechanical devices such as speed reducers, there is a possibility that large-sized foreign matters (such as chips, etc.) generated due to cutting processes, etc. adhere to the constituent members of the mechanical device or mix into the lubricating oil. If such large-sized foreign matters adhere to the sensor, even if almost no wear powder is generated, the two electrodes are short-circuited. Thus, in a sensor for detecting the amount of wear powder, there is a situation where the sensor unexpectedly operates even when the amount of wear powder is small.

[0012] The present invention is made in view of the above situation and aims to achieve the following object: to provide a sensor capable of suppressing the mixing-in of foreign matters and unexpected operation caused by the difference between the generated amount of wear powder and the operation set amount.

[0013] Solutions for Solving the Problems

[0014] A sensor according to one aspect of the present invention includes: a first electrode; a second electrode; a first adsorption portion disposed between the first electrode and the second electrode for adsorbing conductor wear powder in the detection region; a detection portion for detecting a change in the resistance between the first electrode and the second electrode caused by the conductor wear powder; and a second adsorption portion disposed in the detection region for adsorbing conductor wear powder in the detection region.

[0015] In this sensor, due to the conductor wear powder adsorbed between the first electrode and the second electrode, the first electrode and the second electrode are short-circuited, or the resistance between the first electrode and the second electrode changes. Thus, the detection portion can detect the amount of conductor wear powder in the detection region. In addition, the second adsorption portion adsorbs the conductor wear powder in the detection region. Thus, the short-circuit or resistance change between the first electrode and the second electrode corresponding to the amount of conductor wear powder in the detection region is adjusted, and therefore, unexpected operation of the sensor can be suppressed.

[0016] A sensor according to one aspect of the present invention may be such that the second adsorption portion is disposed at a position separated from the first electrode, the second electrode, and the first adsorption portion.

[0017] Alternatively, a sensor according to one aspect of the present invention may have a sensitivity adjustment portion for changing the detection sensitivity by adjusting the adsorption state of the conductor wear powder, and the sensitivity adjustment portion is a plurality of the second adsorption portions having different adsorption capabilities for adsorbing the conductor wear powder.

[0018] A sensor according to one aspect of the present invention includes: a bottomed cylindrical outer electrode; an insulator disposed as a bottomed inner cylinder within the outer electrode; a first magnet disposed within the insulator; an inner electrode disposed within the insulator and axially located on the opening side of the first magnet closer to the outer electrode; a detection unit that detects the adsorption of conductor wear powder that changes the resistance value between the outer electrode and the inner electrode; and a second magnet disposed outside the outer electrode that adsorbs the conductor wear powder.

[0019] In the sensor according to one aspect of the present invention, the adsorption state of the conductor wear powder is adjusted using another magnet as a sensitivity adjustment unit. Thus, even when the adsorption amount of the wear powder is large, it is possible to reliably detect by adjusting the detection sensitivity of the sensor according to the adsorption of the conductor wear powder. In particular, in the case where the size of a speed reducer or the like where the sensor is provided is large and the amount of initial wear powder generated is large, it is set in such a way as to limit the adsorption of the initial wear powder or change the detection state when the adsorption amount is large, and reliable detection can be performed.

[0020] Thus, a second adsorption unit with a higher adsorption ability is selected corresponding to the case where the amount of conductor wear powder generated is expected to be large, reducing the amount of wear powder adsorbed between the electrodes, and the detection sensitivity of the sensor can be set to a predetermined state. Additionally, a second adsorption unit with a lower adsorption ability is selected corresponding to the case where the amount of conductor wear powder generated is expected to be small, increasing the amount of wear powder adsorbed between the electrodes, and the detection sensitivity of the sensor can be set to a predetermined state.

[0021] Alternatively, the sensor according to one aspect of the present invention may include a first electrode and a second electrode, and the first magnet forms magnetic induction lines between the first electrode and the second electrode.

[0022] Moreover, it is possible that the sensitivity adjustment unit includes another magnet (another adsorption unit, second magnet) provided outside the outer electrode.

[0023] In this case, it is also possible to select from a group of other magnets having multiple adsorption amounts or not provide other magnets. Additionally, by selecting from other adsorption units having multiple adsorption abilities, the detection sensitivity of the sensor can be set to a predetermined state corresponding to the amount of conductor wear powder generated as expected.

[0024] Thus, the wear powder is adsorbed using another magnet corresponding to the amount of conductor wear powder generated as expected, reducing the amount of wear powder adsorbed between the electrodes, and the detection sensitivity of the sensor can be set to a predetermined state.

[0025] Specifically, corresponding to a case where the amount of generated conductor wear powder is assumed to be large, a strong magnetic force or a larger other magnet is selected to reduce the amount of wear powder adsorbed between the electrodes, and the detection sensitivity of the sensor can be set to a predetermined state. In addition, corresponding to a case where the amount of generated conductor wear powder is assumed to be small, a magnet with a weaker magnetic force or a smaller other magnet, or no other magnet is provided, so as to set the amount of wear powder adsorbed between the electrodes to a predetermined amount, and the detection sensitivity of the sensor can be set to a predetermined state.

[0026] In the sensor according to one aspect of the present invention, the other magnets may be separately arranged within the detection region.

[0027] Effects of the Invention

[0028] According to the present invention, the following effect can be achieved: a sensor capable of suppressing unexpected operations and improving operation reliability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 2A It is a top view of the sensor according to the first embodiment of the present invention.

[0031] Figure 2B It is a cross-sectional view of the sensor according to the first embodiment of the present invention.

[0032] Figure 3 It is a diagram for explaining the sensor according to the second embodiment of the present invention.

[0033] Figure 4 It is a cross-sectional view showing an example of a mechanical device including the sensor according to the third embodiment of the present invention.

[0034] Figure 5 It is a diagram for explaining the sensor according to the third embodiment of the present invention.

[0035] Explanation of Reference Signs

[0036] 2. Reducer; 5, 30, 60. Sensors; 6, 61. First electrode (inner electrode); 8, 62. Second electrode (outer electrode); 9, 69. Fastening member (fastening part); 10, 63. Adsorbing part (insulator); 7, 34, 64. Magnets; 10a, 10b. Protrusions; 31. Central electrode; 32(32A, 32B, 32C). Outer electrodes; 50. Detection part; 60a. Detection surface; 64B. Other magnet (other adsorbing part). Detailed Embodiments

[0037] Hereinafter, a first embodiment of the sensor of the present invention will be described based on the drawings.

[0038] Components common to a plurality of drawings are denoted by the same reference numerals in the plurality of drawings. Note that, for convenience of explanation, each drawing is not necessarily drawn to an accurate scale.

[0039] Figure 1 FIG. is a cross-sectional view showing an example of a mechanism 1 including a sensor 5 according to an embodiment of the present invention. The mechanism 1 is a movable part such as a robotic arm, and includes a speed reducer 2, a flange 3 provided on the input side, a servo motor 4, and a device A1 on the output side.

[0040] The speed reducer 2 includes: a housing 21 that is attached to the flange 3; an input shaft 23 that is connected to the output shaft 22 of the servo motor 4; and an output shaft 24 that is connected to the device A1 on the output side. The input shaft 23 and the output shaft 24 are supported so as to be rotatable about an axis AX with respect to the housing 21. The output of the servo motor 4 is input to the speed reducer 2 via the input shaft 23, and after being reduced in speed by the speed reducer 2, is transmitted to the device A1 on the output side via the output shaft 24. Thus, the device A1 on the output side and the flange 3 can rotate relative to each other.

[0041] The flange 3 is a cylindrical member that houses at least a part of the speed reducer 2. In addition, the servo motor 4 is attached to the flange 3. An opening at one end of the flange 3 in the direction along the axis AX is blocked by the speed reducer 2, and an opening at the other end is blocked by the servo motor 4. Thus, a sealed hollow portion (space S) is formed in the flange 3. Lubricating oil is housed in the space S, and the flange 3 also functions as an oil bath.

[0042] For example, a gear mechanism is housed in the housing 21 of the speed reducer 2. The space inside the housing 21 is continuous with the space S inside the flange 3. When the speed reducer 2 operates, as the gear mechanism inside the housing 21 rotates, a circulation of lubricating oil is generated between the space inside the housing 21 and the space S inside the flange 3. Due to this circulation of the lubricating oil, conductor substances such as wear powder (conductor wear powder) generated inside the speed reducer 2 are discharged into the space S inside the flange 3.

[0043] A sensor 5 for detecting the amount of conductive substances contained in lubricating oil is installed in the space S. The sensor 5 is fixed to the flange 3 by means of, for example, a support member 25. The sensor 5 uses a magnet to gather the conductive substances contained in the lubricating oil between a pair of electrodes, and detects the amount of conductive substances in the lubricating oil based on the change in the resistance between the pair of electrodes. The position where the sensor 5 is arranged can also be, for example, inside the housing 21, and as long as it is within the space where the lubricating oil is stored, it can be arranged at any place within the mechanism 1. The range where the lubricating oil circulates is set as the detection area of the sensor 5.

[0044] Next, the structure of the sensor 5 will be described in detail with reference to Figures 2A to 2B FIGS. Figures 2A to 2B FIG. 1 is a diagram schematically showing the structure of the sensor according to the first embodiment of the present invention. Figure 2A 、 Figure 2B FIGS. 2 and 3 respectively show a top view of the sensor 5 and a cross-section along the line A-A of the top view.

[0045] As Figures 2A to 2B shown in FIGS. 4 and 5, the sensor 5 has a generally cylindrical outer shape, and includes a first electrode 6, a magnet 7, a second electrode 8, a fastening member 9, an adsorption portion 10 (first adsorption portion), and another magnet (second adsorption portion, other adsorption portions) 64B. As Figures 2A to 2B shown in FIG. 6, when viewed from the upper surface of the sensor 5, the first electrode 6 is circular in shape and is arranged at the center of the sensor 5. The second electrode 8 is a bottomed cylindrical member, including: a bottom portion 8a that extends substantially parallel to the first electrode 6; and a wall portion (cylindrical portion) 8b that is continuous with the bottom portion 8a and extends substantially perpendicular to the bottom portion 8a.

[0046] The magnet 7 is generally cylindrical and is arranged between the first electrode 6 and the bottom portion 8a of the second electrode 8. Through holes through which the fastening member 9 (a bolt in the illustrated embodiment) passes are respectively provided in each of the first electrode 6, the magnet 7, and the bottom portion 8a of the second electrode 8. By passing the fastening member 9 through these through holes, the first electrode 6, the magnet 7, and the second electrode 8 are fixed to each other. The first electrode 6 and the second electrode 8 are fixed in a state of being separated from each other. The first electrode 6 and the second electrode 8 are made of a conductive magnetic material such as iron, a ferrite core, or silicon steel. The magnet 7 is, for example, a permanent magnet, but it can also be configured such that the first electrode 6 serves as both a magnet and an electrode without using a permanent magnet.

[0047] The adsorption part 10 is arranged so as to fill the space between the first electrode 6 and the second electrode 8, and is interposed between the first electrode 6 and the second electrode 8. The interval X1 between the wall part 8b of the first electrode 6 and the second electrode 8 is larger than the size of the conductive substance contained in the lubricating oil. As an example, the size of the conductive substance is about 1.0 μm to 100 μm, and preferably the interval X1 is set to a distance that will not cause a short circuit due to initial wear iron powder. In the illustrated embodiment, the magnet 7 is in contact with the first electrode 6 and is surrounded by the adsorption part 10. The adsorption part 10 is made of a non-magnetic material having insulation properties such as resin. The magnet 7 forms magnetic induction lines between the first electrode 6 and the second electrode 8. Thereby, the conductive substances contained in the lubricating oil gather around the adsorption part 10.

[0048] The sensor 5 has another magnet 64B (refer to Figure 1 ) that is separated from the second electrode 8.

[0049] The position where the sensor 5 is arranged can also be, for example, inside the housing 21. As long as it is within the space where the lubricating oil is stored, it can be arranged at any place within the mechanism 1.

[0050] The other magnet 64B is arranged at the position farthest from the sensor 5 within the space S. Therefore, the position where the other magnet 64B is arranged can also be, for example, inside the housing 21 corresponding to the arrangement of the sensor 5. As long as it is within the space where the lubricating oil is stored, it can be arranged at any place within the mechanism 1.

[0051] The other magnet 64B forms magnetic induction lines within the space S (refer to Figure 1 ). Thereby, the conductive wear powder contained in the lubricating oil is adsorbed onto the other magnet 64B.

[0052] The other magnet 64B is exposed within the space S. Therefore, the conductive wear powder contained in the lubricating oil is adsorbed onto the other magnet 64B and is adsorbed onto the adsorption part (insulator) 10 by the magnet 7. That is, compared with the case where there is no other magnet 64B, the amount of conductive wear powder adsorbed onto the adsorption part 10 is reduced.

[0053] The other magnet 64B has an adsorption force that resists the flow of the lubricating oil caused by the operation of the speed reducer 2 or the like and does not release the once-adsorbed conductive wear powder again. In addition, the other magnet 64B sets the magnetic force intensity or its surface area so that the amount of conductive wear powder adsorbed by the adsorption part 10 using the magnet 7 is reduced by a predetermined amount.

[0054] As long as the other magnet 64B has the adsorption ability of the conductive wear powder, it can also be configured as a non-magnetic structure.

[0055] In Figures 2A to 2BIn the illustrated embodiment, a convex portion 10a is provided on the adsorption portion 10, and the convex portion 10a is integrally formed with the adsorption portion 10. That is, the convex portion 10a and the adsorption portion 10 have a single-piece structure. Therefore, the convex portion 10a is made of a non-magnetic material having insulation properties such as resin, like the adsorption portion 10. The adsorption portion 10 and the convex portion 10a may also be separate. In Figure 2B In the cross-sectional view of, the width of the convex portion 10a is substantially the same as the interval X1 between the wall portion 8b of the first electrode 6 and the second electrode 8. When viewed from the upper surface of the sensor 5, the convex portion 10a is annular and is formed so as to surround the entire circumference of the first electrode 6.

[0056] Output lines (not shown) are respectively connected to the first electrode 6 and the second electrode 8, and the first electrode 6 and the second electrode 8 are electrically connected to the detection unit 50 (refer to Figure 1 ) via the output lines.

[0057] The detection unit 50 detects a change in the resistance between the first electrode 6 and the second electrode 8. The detection unit 50 includes, for example, a sensor drive circuit that predicts a failure of the components of the mechanism 1 based on the change in resistance caused by the aggregation of the conductive substance around the adsorption portion 10. If the conductive substance contained in the lubricating oil in the detection area aggregates around the adsorption portion 10, the resistance between the first electrode 6 and the second electrode 8 to which a voltage is applied decreases (or is short-circuited), and the output level of the output line changes. The detection unit 50 detects this change in resistance, thereby predicting a failure of the components of the mechanism 1.

[0058] Alternatively, in the decrease in resistance, it may also include detecting two states of non-energization and energization based on the connection and disconnection signals of non-energization and energization (hereinafter, referred to as "digital detection"). The detection unit 50 may be connected to a host control device (not shown) such as a manipulator by wire or wirelessly. The host control device can be configured to, if it receives a signal from the detection unit 50, issue a warning urging maintenance of the speed reducer 2 or the like using a predetermined reporting unit (for example, a display device, a sound output device, etc.).

[0059] The sensor 5 of the present embodiment increases the adsorbable amount of the conductive wear powder of the other magnet 64B by enhancing the magnetic force of the other magnet 64B or increasing the surface area of the other magnet 64B. In the case where the adsorbable amount of the conductive wear powder of the other magnet 64B is increased, in the sensor 5, the same effect as the following is achieved: extending the creep distance along the surface between the first electrode 6 and the second electrode 8 and reducing the amount of the conductive wear powder adsorbed by the adsorption portion 10.

[0060] That is, by enhancing the magnetic force of the other magnet 64B or increasing the surface area of the other magnet 64B, the amount of conductor wear powder adsorbed increases until the resistance value between the first electrode 6 and the second electrode 8 in the adsorption portion 10 decreases to the threshold value or a short-circuit state.

[0061] In addition, when the adsorbable amount of the conductor wear powder of the other magnet 64B is reduced by weakening the magnetic force of the other magnet 64B or decreasing the surface area of the other magnet 64B, the same effect as the following situation is achieved: shortening the creep distance along the surface between the first electrode 6 and the second electrode 8, and increasing the amount of conductor wear powder adsorbed by the adsorption portion 10.

[0062] In this case, as the selection of the adsorption capacity when weakening the magnetic force of the other magnet, it is also possible not to provide the other magnet 64B.

[0063] That is, by weakening the magnetic force of the other magnet 64B or decreasing the surface area of the other magnet 64B, the amount of conductor wear powder adsorbed decreases until the resistance value between the first electrode 6 and the second electrode 8 in the adsorption portion 10 decreases to the threshold value or a short-circuit state.

[0064] Therefore, according to the sensor 5 of the present embodiment, even when the size of the speed reducer 2 is larger, the failure detection of the speed reducer 2 can be reliably performed without being affected by the increase in the initial amount of wear powder in the speed reducer 2.

[0065] In this way, by appropriately selecting from a group of other magnets 64B with different magnetic forces or shapes, without changing the sensor 5 and without affecting other component parts, the sensor 5 with different sensitivities can be set and the failure detection of the speed reducer 2 can be reliably performed.

[0066] In the present embodiment, the wear powder is adsorbed by the other magnet 64B located at a separated position from the adsorption portion 10 in the detection area corresponding to the generated amount of the assumed conductor wear powder. By the other magnet 64B adsorbing the wear powder, the amount of wear powder adsorbed between the first electrode 6 and the second electrode 8 is reduced, and the detection sensitivity of the sensor 5 can be set to a predetermined state.

[0067] In the present embodiment, the other magnet 64B is a sensitivity adjustment portion that changes the detection sensitivity of the sensor 5 by adjusting the adsorption state of the conductor wear powder adsorbed by the adsorption portion 10.

[0068] The sensitivity adjustment portion of the present embodiment can adjust the amount of conductor wear powder adsorbed between the first electrode 6 and the second electrode 8 by the adsorption portion 10.

[0069] Specifically, the other magnet 64B adjusts the adsorption capacity of the conductor wear powder. That is, (1-i) adjusting the strength of the magnetic force in the other magnet 64B, or (1-ii) increasing or decreasing the surface area of the other magnet 64B, and (2) moreover, by increasing or decreasing the thickness of the non-magnetic body layer laminated on the surface of the other magnet 64B, the adsorbable amount of the conductor wear powder of the other magnet 64B is adjusted.

[0070] Moreover, the sensitivity adjustment unit has a plurality of other magnets 64B with different adsorption capacities of the conductor wear powder.

[0071] The sensor 5 of the present embodiment has a set of a plurality of other magnets 64B with such different adsorption capacity values, and the other magnet selected from the set can be arranged in the space S.

[0072] That is, a plurality of other magnets 64B with different adsorption capacities constitute the sensitivity adjustment unit.

[0073] In the present embodiment, the other magnet 64B is used for collecting the initial wear iron powder, so that the excess initial wear iron powder can be collected. As a result, the initial wear iron powder attached to the adsorption portion 10 of the sensor 5 is reduced, and thus, malfunction caused by the initial wear iron powder can be prevented. Therefore, it is not necessary to increase the gap length between the first electrode 6 and the second electrode 8 in the sensor 5.

[0074] On the other hand, the wear powder generated when the speed reducer 2 fails is generated in a large amount that cannot be compared with the initial wear iron powder, so it does not affect the fault prediction performance in the sensor 5. Therefore, reliable fault prediction can be performed.

[0075] Hereinafter, a second embodiment of the sensor of the present invention will be described based on the drawings.

[0076] Figure 3 It is a diagram for explaining the sensor in the present embodiment.

[0077] The sensor 30 of the present embodiment is a sensor for detecting the amount of the conductor substance contained in the lubricating oil, similarly to the sensor 5 in the above-described first embodiment.

[0078] The sensor 30 has a substantially cylindrical outer shape, and includes a plurality of detection units and a detection unit 50 that outputs a signal when the resistance changes in the detection unit.

[0079] More specifically, the sensor 30 has a center electrode 31, a plurality of outer electrodes 32, an adsorption portion 33 disposed between the center electrode 31 and the outer electrodes 32, a magnet 34, and other magnets 64B (refer to Figure 1)。The plurality of outer electrodes 32 are insulated from each other. A pair of electrodes composed of the center electrode 31 and one outer electrode 32, and the adsorption portion 33 disposed between the pair of electrodes constitute one detection unit.

[0080] In the illustrated embodiment, the sensor 30 has four outer electrodes 32A, 32B, 32C, and 32D, constituting four detection units. The number of the outer electrodes 32 and the number of the detection units are not particularly limited. The magnet 34 of the sensor 30 forms magnetic induction lines between a pair of electrodes. Therefore, the conductive substances contained in the lubricating oil are adsorbed on the adsorption portion 33. Thus, if the conductive substances gather near the adsorption portion 33, the resistance in the detection unit changes. In the state where no conductive particles are adsorbed, the resistances of the plurality of detection units are the same.

[0081] Output lines are connected to the center electrode 31 and the plurality of outer electrodes 32 respectively, and the plurality of detection units are electrically connected to the detection unit 50 through the output lines respectively.

[0082] In the present embodiment, the plurality of detection units are connected in parallel with each other, and a voltage from the same voltage source is applied between the center electrode 31 and each outer electrode 32. When the resistance changes in any set number of detection units, the detection unit 50 outputs a signal. For example, the detection unit 50 can be set to output a signal to an upper control device such as a controller when the resistance decreases in two or more detection units, or can be set to output a signal when the resistance decreases in all the detection units.

[0083] As described above, the sensor 30 includes a plurality of detection units, and the detection unit 50 outputs a signal when the resistance decreases in any set number of detection units. Thus, the detection unit 50 can be set so that even if the resistance changes in one detection unit due to a large-diameter conductive sheet, no signal is output. Therefore, the unexpected operation of the sensor caused by the large-diameter conductive sheet can be suppressed. In addition, according to the sensor 30, the conditions for the detection unit 50 to output a signal can be set. Therefore, the timing for the signal to be output in one sensor 30 can be made to coincide with the optimal failure prediction timing that is different according to each user.

[0084] In addition, in the state where no conductive particles are adsorbed, the resistances of the plurality of detection units are the same. Thus, the voltage applied to the sensor 30 can be reduced.

[0085] In addition, the plurality of detection units are connected in parallel with each other. Thus, the voltage applied between a pair of electrodes of each detection unit can be reduced.

[0086] In the present embodiment, another magnet 64B is provided for collecting initial wear iron powder, so that excess initial wear iron powder can be collected. As a result, the initial wear iron powder adhering to the adsorption portion 33 of the sensor 30 is reduced, and thus malfunction caused by the initial wear iron powder can be prevented. Therefore, it is not necessary to increase the gap length between the first electrode (inner electrode) 31 and the second electrode (outer electrode) 32 in the sensor 30.

[0087] On the other hand, wear powder generated when the speed reducer 2 fails is generated in a large amount to an extent that cannot be compared with the initial wear iron powder, so it does not affect the fault prediction performance in the sensor 30. Therefore, reliable fault prediction can be performed.

[0088] Hereinafter, a third embodiment of the sensor of the present invention will be described based on the drawings.

[0089] Figure 4 It is a cross-sectional view showing an example of the mechanism 1 of the sensor 5 according to an embodiment of the present invention.

[0090] Figure 5 It is a view for explaining the sensor in the present embodiment.

[0091] As Figure 5 shown, the sensor 60 in the present embodiment has a substantially cylindrical outer shape and includes a first electrode (an example of the inner electrode in the claims) 61, a magnet 64 (an example of the first magnet in the claims), a second electrode (an example of the outer electrode in the claims) 62, a fastening member (fastening portion) 69, an adsorption portion (first adsorption portion, an example of the insulator in the claims) 63, and a housing 65.

[0092] When viewed from the upper surface of the sensor 60, the first electrode 61 is circular and is disposed at the central portion of the sensor 60. The second electrode 62 is a bottomed cylindrical member having: a bottom portion 62a that extends substantially parallel to the first electrode 61; and a wall portion (tubular portion) 62b that is continuous with the bottom portion 62a and extends substantially perpendicular to the bottom portion 62a. The first electrode 61 is located at the opening of the second electrode 62.

[0093] The magnet 64 is substantially cylindrical (substantially disc-shaped) and is disposed between the first electrode 61 and the bottom portion 62a of the second electrode 62. Through holes for the fastening member 69 (a bolt in the illustrated embodiment) to pass through are respectively provided in each of the first electrode 61, the magnet 64, and the bottom portion 62a of the second electrode 62. By passing the fastening member 69 through these through holes, the first electrode 61, the magnet 64, and the second electrode 62 are fixed to each other.

[0094] The outer diameter of the magnet 64 is formed smaller than the outer diameter of the second electrode 62.

[0095] The first electrode 61 and the second electrode 62 are fixed in a separated state from each other. The first electrode 61 and the second electrode 62 are made of a conductive magnetic material such as iron, a ferrite core, or silicon steel. The magnet 64 is, for example, a permanent magnet, but it can also be configured such that the first electrode 61 serves as both a magnet and an electrode without using a permanent magnet.

[0096] The adsorption part 63 is provided in such a way as to fill the space between the first electrode 61 and the second electrode 62 and is interposed between the first electrode 61 and the second electrode 62.

[0097] The adsorption part 63 has a bottom part 63a along the bottom 62a of the second electrode 62 and a cylindrical part 63b along the wall part 62b of the second electrode 62. The bottom part 63a and the cylindrical part 63b are provided as separate bodies. The bottom part 63a is provided as a sheet.

[0098] The bottom part 63a of the adsorption part 63 is, for example, insulating paper, and its thickness can be set to 0.05 mm to 1 mm. The bottom part 63a of the adsorption part 63 can be set as a circular paper with an outer diameter approximately the same as the inner diameter of the cylindrical part 63b.

[0099] Moreover, the bottom part 63a can be set as a circular paper with an outer diameter larger than the inner diameter of the cylindrical part 63b. At this time, the bottom part 63a can be set as a circular paper with an outer diameter smaller than the outer diameter of the cylindrical part 63b. Moreover, the bottom part 63a can be set as a circular paper with an outer diameter the same as the outer diameter of the cylindrical part 63b.

[0100] A step 63c is formed on the inner surface of the cylindrical part 63b of the adsorption part 63. The part of the cylindrical part 63b of the adsorption part 63 on the side closer to the first electrode 61 than the step 63c has an inner diameter dimension equal to the outer diameter of the first electrode 61. The part of the cylindrical part 63b of the adsorption part 63 on the side closer to the magnet 64 than the step 63c has an inner diameter dimension equal to the outer diameter of the magnet 64.

[0101] The thickness of the end part of the cylindrical part 63b of the adsorption part 63, that is, the distance between the first electrode 61 and the wall part 62b of the second electrode 62, is larger than the size of the conductive substance contained in the lubricating oil. As an example, the size of the conductive substance is on the order of 1.0 μm to 100 μm, and preferably the thickness of the end part of the cylindrical part 63b of the adsorption part 63 is set to a distance that does not cause a short circuit due to initial wear of iron powder. In the illustrated embodiment, the magnet 64 is in contact with the first electrode 61 and is surrounded by the adsorption part 63.

[0102] The adsorption part 63 is made of a non-magnetic material with insulating properties such as resin. The magnet 64 forms magnetic induction lines between the first electrode 61 and the second electrode 62. As a result, the conductive substances contained in the lubricating oil gather around the adsorption part 63.

[0103] In the sensor 60 of the present embodiment, the plane connecting the ends of the first electrode 61 and the second electrode 62 is defined as the detection surface 60a. That is, the reason is that in the detection surface 60a, in correspondence with the magnetic induction lines, the conductor wear powder is adsorbed between the first electrode 61 and the second electrode 62, electrically connecting the first electrode 61 and the second electrode 62, thereby detecting the change in the resistance value between the first electrode 61 and the second electrode 62.

[0104] Since the creep distance along the surface between the first electrode 61 and the second electrode 62 becomes longer, the amount of conductor wear powder adsorbed until the resistance value between the first electrode 61 and the second electrode 62 decreases to the threshold value or the short-circuit state becomes larger.

[0105] In addition, since the creep distance along the surface between the first electrode 61 and the second electrode 62 becomes shorter, the amount of conductor wear powder adsorbed until the resistance value between the first electrode 61 and the second electrode 62 decreases to the threshold value or the short-circuit state becomes smaller.

[0106] The sensor 60 of the present embodiment has a sensitivity adjustment unit that adjusts the adsorption state of the conductor wear powder to change the detection sensitivity.

[0107] In the present embodiment, the sensitivity adjustment unit is set as another adsorption unit (second adsorption unit, other magnet) 64B (refer to Figure 4 ). Moreover, in the present embodiment, the sensitivity adjustment unit can be selected from a group of multiple other adsorption units (other magnets) 64B having different adsorption capabilities.

[0108] The other adsorption unit (other magnet) 64B of the present embodiment can adjust the amount of conductor wear powder adsorbed between the first electrode 61 and the second electrode 62 by selecting the adsorption ability.

[0109] Thereby, by selecting the other adsorption unit (other magnet) 64B as the sensitivity adjustment unit, the amount of conductor wear powder adsorbed between the first electrode 61 and the second electrode 62 can be selected from multiple values.

[0110] Here, Figure 4 the mechanism 1 shown is set to have the same structure as the structure of the first embodiment shown in Figure 1 .

[0111] In Figure 4 , the position where the sensor 60 is disposed within the detection region may also be, for example, within the housing 21. As long as it is within the space containing the lubricating oil, it can be disposed at any place within the mechanism 1.

[0112] The position where the other magnet 64B is disposed may be a position separated from the sensor 60 within the space S. In the present embodiment, in Figure 1As compared with the mechanism 1, the position of the other magnet 64B is configured to be slightly closer to the sensor 60.

[0113] The assembly of the sensor 60 in this embodiment can be carried out as follows.

[0114] First, the outer electrode (external electrode) 62 is placed inside the housing 65. Next, the bottom 63a of the adsorption portion 63 is disposed on the bottom 62a of the outer electrode 62. Next, the cylindrical portion 63b having a selected height dimension of the adsorption portion 63 is inserted into the outer electrode 62. Next, the magnet 64 and the center electrode (internal electrode) 61 are inserted into the cylindrical portion 63b. In this state, the through-fastening member 69 is tightened and fixed, thereby assembling the sensor 60.

[0115] The sensor 60 in this embodiment has a sensitivity adjustment portion, so that the detection sensitivity can be set to a predetermined state.

[0116] Specifically, corresponding to the case where the amount of conductor wear powder generated is assumed to be large, the sensitivity adjustment portion is selected, the creep distance along the surface for adsorbing the wear powder between the electrodes 61 and 62 is increased, and the detection sensitivity of the sensor 60 can be set to a predetermined state. In addition, corresponding to the case where the amount of conductor wear powder generated is assumed to be small, the sensitivity adjustment portion is selected, the length of the wear powder adsorbed between the electrodes 61 and 62 is reduced, and the detection sensitivity of the sensor 60 can be set to a predetermined state.

[0117] Thereby, the failure detection of the speed reducer 2 can be reliably performed without being affected by the increase in the initial wear powder amount in the speed reducer 2.

[0118] Due to the difference in the model (size) of the speed reducer, the amount of iron powder (wear powder) generated due to initial wear varies. In the case of a large speed reducer, the amount of initial wear iron powder is large, and the electrical clearance of the sensor between the electrodes 61 and 62 is filled with the initial wear iron powder and reacts, there is a possibility of malfunction. Therefore, there is a problem that it is necessary to design the electrical clearance of the sensor corresponding to the speed reducer model, but it leads to the enlargement of the sensor in the diameter direction.

[0119] In contrast, the sensor 60 in this embodiment does not become large-sized by having a sensitivity adjustment portion constituted by other adsorption portions (other magnets) 64B having different adsorption capabilities. The other adsorption portion 64B may be a filter or the like in addition to the magnet.

[0120] In the present invention, it is also possible to appropriately combine the structures in the above-described respective embodiments to cope with the situation.

Claims

1. A sensor, comprising: A first electrode; A second electrode; An insulator disposed between the first electrode and the second electrode, adsorbing conductor wear powder in the detection region, the conductor wear powder being adsorbed to the insulator due to the first electrode or a first magnet disposed between the first electrode and the second electrode; A detection unit that detects a change in resistance between the first electrode and the second electrode caused by the conductor wear powder; And A plurality of second magnets disposed in the detection region, adsorbing conductor wear powder in the detection region, The plurality of second magnets are disposed at positions separated from the first electrode, the second electrode, and the insulator, A sensitivity adjustment unit that adjusts the adsorption state of the conductor wear powder and changes the detection sensitivity is constituted by the plurality of second magnets, The sensitivity adjustment unit has a plurality of second magnets with different adsorption capabilities for adsorbing the conductor wear powder.

2. A sensor, having: A bottomed cylindrical outer electrode; An insulator disposed as a bottomed inner cylinder in the outer electrode; A first magnet disposed inside the insulator; An inner electrode disposed inside the insulator and axially located on the opening side of the outer electrode with respect to the first magnet; A detection unit that detects the adsorption of conductor wear powder that changes the resistance value between the outer electrode and the inner electrode; And A plurality of second magnets disposed outside the outer electrode, adsorbing conductor wear powder, The plurality of second magnets are disposed at positions separated from the inner electrode, the outer electrode, and the insulator, A sensitivity adjustment unit that adjusts the adsorption state of the conductor wear powder and changes the detection sensitivity is constituted by the plurality of second magnets, The sensitivity adjustment unit has a plurality of second magnets with different adsorption capabilities for adsorbing the conductor wear powder.

3. The sensor according to claim 2, wherein The sensor includes a first electrode and a second electrode, The first magnet forms magnetic induction lines between the first electrode and the second electrode.

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