JP7101486B2 - Sensor - Google Patents

Description

The present invention relates to a sensor.

Mechanical devices such as speed reducers are usually housed in a housing in which lubricating oil is stored to prevent damage to mechanical parts such as gears and bearings. If the mechanical parts are worn during the operation of such a mechanical device, wear debris (mainly a conductor substance such as iron debris) will be mixed into the lubricating oil.

In general, it is known that the amount of wear debris (conductor material) generated in the lubricating oil increases when the wear of mechanical parts progresses and the wear failure period in the failure rate curve (bathtub curve) is entered. In order to properly perform preventive maintenance of such machine parts, it is indispensable to appropriately detect an increase in the amount of wear debris (conductor material) generated.

Patent Document 1 discloses an oil check sensor that is mounted on a transmission of an automobile or the like and checks the deterioration of oil in an oil container, the degree of friction of mechanical parts lubricated by oil, and the like. The sensor described in Patent Document 1 includes a sensor body having a conductive metallic cylinder bonded to the outer periphery of the rod-shaped body via an insulating gap, and the tip portion of the rod-shaped body protruding from the cylinder. In an oil check sensor in which a magnet is formed on the outer periphery, a pair of electrodes are fixed on the outer periphery of the magnet at predetermined intervals, and the amount of a conductor mixture such as iron powder contained in the oil is detected, the electrodes are used. It is disclosed that at least one of the above is used as a resistor.

Japanese Unexamined Patent Publication No. 2002-286697

However, if a facet adheres to the component member at the time of manufacturing the component member of the speed reducer, for example, at the time of cutting, such a facet remains inside the speed reducer, and the facet is used as a sensor. If it adheres to the detection area, it causes an erroneous signal to be transmitted, and there is a problem that it is difficult to prevent the occurrence of an erroneous signal with conventional sensors including the sensor as in Patent Document 1.

The present invention has been made in view of the above circumstances, and an object of the present invention is to transmit an erroneous signal in the detection area of the sensor by the facet or the like even when the facet or the like remains inside the speed reducer. The purpose is to provide a sensor that can be avoided.

The sensor according to the embodiment of the present invention includes a plurality of electrodes, applies a voltage between the plurality of electrodes, accumulates a conductor material between the electrodes, and detects a decrease in electrical resistance between the electrodes. The sensor is provided with a plurality of detection areas, and outputs a detection signal when the electrical resistance between the electrodes is reduced in at least two or more detection areas within the plurality of detection areas. It is configured as follows.

In the sensor according to the embodiment of the present invention, the plurality of electrodes include at least a first electrode, a second electrode, and a third electrode, and the plurality of detection areas include the first electrode. To include at least a first detection area formed between the electrode and the second electrode and a second detection area formed between the first electrode and the third electrode. It is composed of.

In the sensor according to the embodiment of the present invention, the plurality of electrodes further include a fourth electrode, a fifth electrode, and a sixth electrode, and the plurality of detection areas are the fourth electrode. Further include a third detection area formed between the electrode and the fifth electrode, and a fourth detection area formed between the fourth electrode and the sixth electrode. It is composed of.

The sensor according to the embodiment of the present invention is configured to circuit connect the plurality of detection areas in series.

The sensor according to the embodiment of the present invention is configured to connect the plurality of detection areas in parallel in a circuit and output a detection signal when the electrical resistance between the electrodes decreases in at least two or more areas. To.

In the sensor according to the embodiment of the present invention, a resistor for passing a minute current is arranged in each of the plurality of detection areas.

The sensor according to the embodiment of the present invention includes a voltage application control unit including a power supply to which a voltage is applied between the electrodes, a signal detection unit for detecting the output of the detection signal, and a case where the detection signal is output. A storage unit for storing the output of the detection signal, and the power supply application control unit are configured to cut off voltage application by the power supply while the output of the detection signal is stored in the storage unit. Will be done.

In the sensor arrangement according to the embodiment of the present invention, a plurality of sensors are arranged in a plurality of detection areas, and in the plurality of detection areas, a decrease in electrical resistance between the electrodes of the plurality of sensors is detected. It is configured as follows.

According to the sensor of one embodiment of the present invention, even if a facet or the like remains inside the speed reducer, it is possible to avoid sending an erroneous signal in the detection area of the sensor by the facet.

It is a side view of the mechanism 1 which concerns on one Embodiment of this invention. It is a top view and sectional view of the sensor 5 which concerns on one Embodiment of this invention. It is a schematic diagram which shows the connection mode of the sensor 5 which concerns on one Embodiment of this invention. It is a schematic diagram which shows the connection mode of the sensor 5 which concerns on one Embodiment of this invention. It is a schematic diagram which shows the connection mode of the sensor 5 which concerns on one Embodiment of this invention. It is a schematic diagram which shows the connection mode of the sensor 5 which concerns on one Embodiment of this invention. It is a top view and sectional view of the sensor 5 which concerns on one Embodiment of this invention. It is a schematic diagram of the signal processing circuit including the sensor 5 which concerns on one Embodiment of this invention. It is a schematic diagram of the signal processing circuit including the sensor 5 which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, a speed reducer will be described as an example of the device according to the embodiment of the present invention.

FIG. 1 is a side view (cross-sectional view) of the mechanism 1 according to the embodiment of the present invention. As shown in FIG. 1, the mechanism 1 includes a flange 3, in which at least a part of the speed reducer 2 is housed.

The flange 3 is an accommodating member for accommodating the speed reducer 2, and the servomotor 4 is attached to the flange 3. The flange 3 is a substantially cylindrical member having a hollow portion (space S). The openings at both ends of the flange 3 in the axial direction are closed by the speed reducer 2 and the servomotor 4, respectively, to form a closed space S. Lubricating oil is filled in the space S, and the flange 3 also functions as an oil bath.

The speed reducer 2 includes a case 12 attached to a flange 3, an input shaft 14 connected to an output shaft 13 of a servomotor 4, and an output shaft 15. The input shaft 14 and the output shaft 15 are rotatably supported around the rotation shaft AX with respect to the case 12.

The output of the servomotor 4 is input to the speed reducer 2 via the input shaft 14, decelerated by the speed reducer 2, and then transmitted to the output side device A1 via the output shaft 15.

The space in the case 12 in which the gear mechanism of the speed reducer 2 is housed is in contact with the space S in the flange 3. When the speed reducer 2 is operated, the lubricating oil circulates between the space in the case 12 and the space S in the flange 10 as the gear mechanism in the case 12 rotates. Due to the circulation of the lubricating oil, the wear debris (hereinafter referred to as the conductor substance) generated inside the speed reducer 2 is discharged to the space S in the flange 3.

In the space S, a sensor 5 for detecting an increase in the conductor substance floating in the lubricating oil is attached to the support member 16. The sensor 5 is a sensor in which a conductor substance is accumulated in a gap portion between electrodes by a magnet, and the amount of wear debris in the lubricating oil is detected by a change in electric resistance between the electrodes. A plurality of variations can be considered for the sensor 5. Part of various embodiments of the sensor 5 will be described with reference to FIGS. 2 to 6. Here, the sensor 5 may be configured to be arranged in the case 12, and may be appropriately arranged in any other place in the mechanism 1.

FIG. 2 is a diagram showing a configuration of a sensor 5 according to an embodiment of the present invention. The figure is shown as a top view of the sensor 5 and a cross-sectional view taken along the line AA of the top view, respectively.

As shown in FIG. 2, the sensor 5 has a first electrode (center electrode) 6 near the center, a second electrode (outer electrode) 7 located on the outside, a third electrode (outer electrode) 8, and a center. A fourth electrode (center electrode) 9 in the vicinity, a fifth electrode (outer electrode) 10 located on the outside, a sixth electrode (outer electrode) 11, a permanent magnet 40, a screw member 12, and a resin material 13 are provided. There is. The center electrode 6 may be configured to serve as both the magnet and the electrode without using the permanent magnet 40.

Here, the electrode is a member of a magnetic material formed of a conductive magnetic material such as iron, a ferrite core, or silicon steel. A resin material 13 which is a non-magnetic material (insulator) is arranged between these electrodes. In this way, each electrode and the permanent magnet 40 are formed so that at least a part of them is embedded in the central region of the resin material. The shape of each electrode and the permanent magnet 40 is not limited to the illustrated example, and various shapes can be adopted.

As shown in the cross-sectional view of FIG. 2, the center electrodes 6 and 9 are formed at intervals inside the outer electrodes 7, 8, 10 and 11. Therefore, a gap portion (detection area) GA is formed in the upper part of the resin material 13 between the center electrodes 6 and 9 and the outer electrodes 7, 8, 10 and 11.

An output line (not shown) is connected to each of the center electrodes 6 and 9 and the outer electrodes 7, 8, 10 and 11. The permanent magnet 40 may or may not be attached to the lower part of the center electrodes 6 and 9. Further, when the permanent magnet 40 is attached, the permanent magnet 40 is composed of a magnet or an electromagnet, but the magnet is coated with a non-magnetic material such as copper and a signal line (not shown) is connected to the coating layer. You may.

The sensor 5 is connected to a sensor drive circuit (not shown) that monitors the resistance value and predicts the failure of mechanical parts based on the fluctuation of the resistance value due to the accumulation of the conductor substance between the electrodes. When a certain amount of conductor material is accumulated in the gap portion (detection area), at least one of the electrical resistances between the electrodes 6 and 9 to which the voltage is applied and the electrodes 7, 8, 10 and 11 decreases. (Ie short-circuited), the output level of the output line changes. The sensor drive circuit makes it possible to predict the failure of mechanical parts by detecting this decrease in electrical resistance. Further, the decrease in electrical resistance includes an on / off signal by non-energization and electric communication, and may be detected in two states of non-energization and energization (hereinafter, referred to as "digital detection").

The sensor drive circuit is connected to a higher-level control device such as a manipulator by wire or wirelessly. The circuit board 43 of FIG. 1 may constantly transmit the output of the output line (output of the sensor 40A) to the upper control device, and intermittently (at predetermined time intervals) to the upper control device for power saving. ) May be sent.

When the host control device detects a change in the output level of the output line received from the circuit board 43, a predetermined notification means (display device or voice output device) issues a warning for urging maintenance of the speed reducer 2, for example. Can be configured.

The permanent magnet 40 is magnetized, and a magnetic flux path φA is formed in a predetermined direction. In particular, a strong magnetic flux flows in the gap portion (detection area) around the center electrodes 6 and 9. Due to the magnetic force of the permanent magnet 40, the conductor substance of the machine component (for example, the conductor substance of the machine component mixed in the lubricating oil) is attracted to the gap portion (detection area).

Next, with reference to FIG. 3, the connection mode of the sensor 5 in one embodiment of the present invention will be described. As shown in the figure, the fifth electrode (outer electrode) 10 located on the outside is connected to the detection circuit 17 by the connecting line 15, and the second electrode (outer electrode) 7 located on the outside is connected to the detection circuit 17 by the connecting line 16. It is connected to the detection circuit 17. Further, as shown in the figure, the third electrode (outer electrode) 8 and the sixth electrode (outer electrode) 11 are connected by a connecting wire 14. In this way, the fifth electrode (outer electrode) 10, the fourth electrode (center electrode) 9 near the center, the sixth electrode (outer electrode) 11, the third electrode (outer electrode) 8, and the vicinity of the center. The first electrode (center electrode) 6 and the second electrode (outer electrode) 7 can be configured to take the logical product of four circuits in this order. With this configuration, the number of lead wires can be reduced to two. When the first electrode (center electrode) 6 near the center and the fourth electrode (center electrode) 9 near the center are integrated, five electrodes are combined with the outer electrodes 7, 8, 10 and 11. Although lead wires are required, the number of lead wires can be significantly reduced by the above configuration.

In the configuration shown in FIG. 3, the first detection area 100 between the first electrode (center electrode) 6 near the center and the second electrode (outer electrode) 7, and the first electrode (center electrode) near the center ) 6 and the second detection area 200 between the third electrode (outer electrode) 8, the fourth electrode (center electrode) 9 near the center and the fifth electrode (outer electrode) 10. The detection area 300 of 3 and the fourth detection area 400 between the fourth electrode (center electrode) 9 near the center and the sixth electrode (outer electrode) 11 are configured in series. ..
As a result, even if a facet or the like remains inside the reducer, it is possible to avoid sending an erroneous signal by the detection circuit unless the facet adheres to all the detection areas. Therefore, it is possible to significantly reduce the transmission of such an erroneous signal.

Next, FIG. 4 will explain an example in which a sensor array (sensor group) composed of a plurality of sensors is provided in a plurality of detection areas. In the illustrated example, a sensor array (sensor group) composed of two sensors 5 is provided in the two detection areas, and each detection area is configured to be detected by each sensor 5. The number of detection areas and sensors is not limited to this, and may be changed as appropriate. For example, if the two detection areas are separated to some extent, it may be difficult to detect with one sensor, but by arranging one or more sensors in each area, the physical position of the detection area can be reached. It will be possible to respond accurately.

Further, in such a configuration, in one embodiment of the present invention, as shown in the figure, two sensors 5 are connected in series to form a circuit. Since the two sensors 5 are configured in series, no voltage is applied just by adhering the conductor substance to the sensor 5 in one detection area, and the conductor substance is also applied to the sensor 5 in the other detection area. The voltage will be applied only when it adheres. In this way, the sensor arrangement according to the embodiment of the present invention can surely prevent the output related to the failure prediction from being output even when the failure prediction is erroneously detected by one sensor 5.

Next, FIG. 5 describes a connection mode of the sensor 5 according to the embodiment of the present invention. As shown in the figure, among the plurality of detection areas described with reference to FIG. 3, the first detection area 100, the second detection area 200, and the third detection area 300 are the connection line 24, the connection line 25, and the connection line 26. These are connected in parallel, and the fourth detection area 400 is connected in series by the connection line 28, and is connected to the detection circuit 29.

As shown in FIG. 5, one of the four electrodes can be multiplexed (Gnd), and the remaining three electrodes can be used as signals. By connecting the two parts in two series via the circular electrode in the center and arranging one in three in parallel, the voltage can be reduced by about half and the robustness against disconnection can be improved.

Next, FIG. 6 describes a connection mode of the sensor 5 according to the embodiment of the present invention. As shown in the figure, the first detection area 100, the second detection area 200, the third detection area 300, and the fourth detection area 400 described in FIG. 3 are the connection line 18, the connection line 19, and the connection line. 20 and the connection line 21 are connected in parallel, and these are connected to the detection circuit 23.

As shown in FIG. 6, by connecting four electrodes in parallel, the voltage can be reduced to about one-fourth as compared with the connection mode shown in FIG. 3, and by multiplexing the Gnd line, the voltage can be reduced to about one-fourth. Robustness against disconnection can be improved.

Next, FIG. 7 shows a top view and a sectional view taken along the line AA of the sensor 5 according to another embodiment of the present invention.

As shown in FIG. 7, the sensor 5 in another embodiment of the present invention includes a first electrode (center electrode) 6 near the center, a second electrode (outer electrode) 7 located on the outside, and a third electrode. Electrode (outer electrode) 8, fourth electrode (center electrode) 9 near the center, fifth electrode (outer electrode) 10 located on the outside, sixth electrode (outer electrode) 11, permanent magnet 40, screw member 12 and a resin material 13 are provided. The center electrode 6 may be configured to serve as both the magnet and the electrode without using the permanent magnet 40.

In the illustrated example, between the first electrode (center electrode) 6 and the second electrode (outer electrode) 7, the first electrode (center electrode) 6 and the third electrode (outer electrode) 8 Between the fourth electrode (center electrode) 9 and the fifth electrode (outer electrode) 10, between the fourth electrode (center electrode) 9 and the sixth electrode (outer electrode) 11. The resistors 30 are arranged on the resin material 13. The arrangement of the illustrated resistor 30 is an example, and the shape, structure, arrangement location, arrangement mode, etc. of the resistor 30 are not particularly limited and can be appropriately changed.

In this way, by connecting the resistor 30 having a large resistance to the detection area of the sensor 5 so that a minute current can flow even if the conductor material is small, the copper wire (connecting wire, etc.) can be formed. Since a minute current does not flow when the circuit breaks, it is possible to detect a disconnection in the circuit. The resistance R of the resistor 30 is configured to be sufficiently larger than the resistance value Ω of the gap portion at the time of failure detection. Further, when the conductor material is collected due to the failure of the speed reducer, the resistance value in the detection area is lowered and a current having a large current value flows, so that a threshold value can be set for the current value and failure prediction can be performed. With the above configuration, both circuit disconnection and failure prediction can be reliably performed.

Next, the sensor according to the embodiment of the present invention has a structure in which a conductor substance adheres when the threshold value is exceeded and a current always flows when the sensor is turned on, which may waste energy. Further, since the life of the photo cover (PC) correlates with the time during which the photo is energized, it may affect the life of the PC and cause problems such as circuit breakage.

FIG. 8 is a diagram illustrating a configuration of a signal processing circuit for preventing such a problem. As shown in FIG. 8, a power supply application control unit 31 including a power supply 32 is connected to the sensor 5 by a connection line, and then connected to a voltage detection unit 33, a storage unit 34, and an output unit 35. The storage unit 34 is connected to the power supply application control unit 31 by a connection line.

The illustrated power supply application control unit 31 includes a power supply 32 to which a voltage is applied between the electrodes of the sensor 5, and is configured to be able to cut off the application of the voltage by the power supply. The voltage detection unit 33 detects the application of voltage by the power supply 32 and outputs a detection signal. The communication storage unit 34 stores the output of the detection signal when the detection signal is output by the signal detection unit 33. Although the illustrated storage unit 34 shows state storage by RS flip-flop, it may be an integrated device including a memory of a microcomputer or the like, or may be another embodiment. When the detection signal is stored in the storage unit 34, the output unit 35 outputs that the detection signal has been made and generates a trigger for a failure prediction alarm.

When the conductor material exceeding the threshold value adheres to the sensor 5 in one embodiment of the present invention, the sensor 5 is energized (ON state) with the power supply 32, and the detection unit 33 that detects this energizes the sensor 5 to the storage unit 34. It is output and the signal is stored in the storage unit 34. When the signal is stored in the storage unit 34, the signal is in the Hi state, and as a result, the power supply application control unit 31 is also in the Hi state, the voltage application is cut off, and the PC1 is in the OFF state. Then, since the energization of the sensor 5 is turned off, the output of the detection unit 33 to the storage unit 34 changes, but the output of the storage unit 34 is maintained by the circuit of the storage unit 34. Therefore, the output unit continues to generate a trigger for the failure prediction alarm.

In this way, it is possible to prevent the current from continuing to flow in the circuit, extend the life of the photocabber (PC), and avoid damage to the circuit.

Next, FIG. 9 is a diagram illustrating another configuration of the signal processing circuit. As shown in FIG. 9, a power supply application control unit 31 including a power supply 32 is connected to the sensor 5 by a connection line, and then connected to a voltage detection unit 33, a storage unit 34, and an output unit 35. The storage unit 34 is connected to the power supply application control unit 31 by a connection line. Unlike the case of FIG. 8, the timer circuit 36 is connected between the storage unit 34 and the power supply application control unit 31.

The illustrated power supply application control unit 31 includes a power supply 32 to which a voltage is applied between the electrodes of the sensor 5, and is configured to be able to cut off the application of the voltage by the power supply. The voltage detection unit 33 detects the application of voltage by the power supply 32 and outputs a detection signal. The communication storage unit 34 stores the output of the detection signal when the detection signal is output by the signal detection unit 33. Although the illustrated storage unit 34 shows state storage by RS flip-flop, it may be an integrated device including a memory of a microcomputer or the like, or may be another embodiment. When the detection signal is stored in the storage unit 34, the output unit 35 outputs that the detection signal has been made and generates a trigger for a failure prediction alarm.

When the conductor material exceeding the threshold value adheres to the sensor 5 in one embodiment of the present invention, the sensor 5 is energized (ON state) with the power supply 32, and the detection unit 33 that detects this energizes the sensor 5 to the storage unit 34. It is output and the signal is stored in the storage unit 34. However, since the conductor material usually tends to increase gradually, it is not always necessary to constantly apply a power source to the sensor 5 to continue monitoring, and it has been found that even intermittent monitoring is effective in predicting a failure.

In the signal processing circuit shown in FIG. 9, a timer circuit 36 is added, and power is applied at regular time intervals or fixed time intervals. In this way, it is possible to prevent the current from constantly flowing through the circuit, and thus it is possible to reduce energy consumption.

The above is the description of the exemplary embodiment of the present invention. The embodiments of the present invention are not limited to those described above, and various modifications can be made within the scope of the technical idea of the present invention. For example, the embodiment of the present application also includes the content of an appropriate combination of an embodiment or the like exemplarily specified in the specification or a trivial embodiment or the like.

1 Mechanism 2 Reducer 3 Flange part 4 Servo motor 5 Sensor 6 First electrode (center electrode)
7 Second electrode (outer electrode)
8 Third electrode (outer electrode)
9 Fourth electrode (center electrode)
10 Fifth electrode (outer electrode)
11 Sixth electrode (outer electrode)
12 Screw member 13 Resin 14 Connection line 15 Connection line 16 Connection line 17 Detection circuit 18 Connection line 19 Connection line 20 Connection line 21 Connection line 22 Connection line 23 Detection circuit 24 Connection line 25 Connection line 26 Connection line 28 Connection line 29 Detection circuit 30 Resistor 31 Power supply application control unit 32 Power supply 33 Voltage detection unit 34 Communication storage unit 35 Output unit 36 Timer circuit 40 Permanent magnet 43 Circuit board

Claims (8)

With multiple electrodes,
A power supply application control unit including a power supply that applies a voltage between the plurality of electrodes,
When the electrical resistance between the electrodes is reduced in at least two or more of the plurality of gaps due to the conductor material accumulated in each of the plurality of gaps between the plurality of electrodes, the plurality of electrodes. A signal detector that detects the output of a detection signal that indicates a decrease in electrical resistance between the electrodes of
When the detection signal is output, a storage unit that stores the output of the detection signal and
It is a sensor equipped with
The power supply application control unit is a sensor characterized in that the voltage application by the power supply is cut off while the output of the detection signal is stored in the storage unit. The plurality of electrodes include at least a first electrode, a second electrode, and a third electrode, and the plurality of gaps are formed between the first electrode and the second electrode. The sensor according to claim 1, further comprising a first gap portion formed and a second gap portion formed between the first electrode and the third electrode. The plurality of electrodes further include a fourth electrode, a fifth electrode, and a sixth electrode, and the plurality of gap portions are provided between the fourth electrode and the fifth electrode. The sensor according to claim 2, further comprising a third gap portion formed and a fourth gap portion formed between the fourth electrode and the sixth electrode. The sensor according to any one of claims 1 to 3, wherein the plurality of gap portions are connected by a circuit in series. The invention according to any one of claims 1 to 3, wherein the plurality of gap portions are connected in parallel in a circuit, and a detection signal is output when the electrical resistance between the electrodes decreases in at least two or more areas. Sensor. The sensor according to any one of claims 1 to 5, wherein a resistor for passing a minute current is arranged in each of the plurality of gap portions. The second electrode is arranged radially outside the first electrode.
The third electrode is arranged at a position radially outside the first electrode and separated from the second electrode in the circumferential direction.
The fourth electrode is arranged apart from the first electrode in the circumferential direction.
The fifth electrode is arranged radially outside the fourth electrode.
The sixth electrode is arranged radially outside the fourth electrode and at a position separated from the fifth electrode in the circumferential direction.
The first gap portion, the second gap portion, the third gap portion, and the fourth gap portion are connected in series.
The power supply applies a voltage between the second electrode and the fifth electrode.
The sensor according to claim 3. A sensor array comprising the sensor according to claim 1 in each of the plurality of detection areas, and detecting a decrease in electrical resistance between the electrodes of the plurality of sensors.

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