JP7519797B2 - Detection Device - Google Patents

Description

The present invention relates to a detection device.

Devices such as reduction gears, in which internal parts mesh and slide with each other, generally generate conductive material consisting of wear particles and the like inside during operation. When the amount of conductive material generated between parts increases, the device will enter a period of wear failure and eventually reach the end of its life.

Conventionally, the device has been equipped with a box-shaped first electrode, a second electrode and a magnet arranged inside it via a resin material, and a sensor that applies a voltage between the first and second electrodes and detects the resistance value between the electrodes that fluctuates due to the conductive material that accumulates in the gap between the first and second electrodes.
The amount of wear between members within the device is detected from changes in the resistance value between the electrodes, and the life of the device is judged (see, for example, Japanese Patent Application Laid-Open No. 2003-233634).

JP 2019-95282 A

The sensor in Patent Document 1 has a built-in magnet for attracting conductive materials, but because the magnet is located behind the second electrode, there is a problem in that the conductive materials tend to gather unevenly at the second electrode, rather than in the gap between the electrodes.

The present invention aims to provide a detection device that can effectively collect conductive material in the gap between electrodes.

The present invention relates to a semiconductor device comprising: a first electrode;
a second electrode spaced apart from the first electrode;
A detection unit that detects a change in electrical resistance between the electrodes due to a conductive material accumulated in a gap between the first electrode and the second electrode,
A magnet is disposed at a position facing the gap between the first electrode and the second electrode;
The magnets are arranged at intervals and spaced apart from at least one of the first electrode and the second electrode adjacent thereto .
Another invention is:
A first electrode;
a second electrode spaced apart from the first electrode;
A detection unit that detects a change in electrical resistance between the electrodes due to a conductive material accumulated in a gap between the first electrode and the second electrode,
A magnet is disposed at a position facing the gap between the first electrode and the second electrode;
The first electrode is configured in a ring shape, the second electrode is arranged radially inside the first electrode, a ring-shaped gap is provided between the first electrode and the second electrode, and the magnets are arranged intermittently in the circumferential direction.

The present invention has the effect of making it possible to effectively accumulate conductive materials in the gaps between the electrodes.

1 is a cross-sectional view of a gear device to which a detection device according to an embodiment of the present invention is applied. FIG. 2 is a configuration diagram showing a detection device. 3A is a cross-sectional view of the sensor portion of the detection device taken along line BB in FIG. 3B, and FIG. 3B is a cross-sectional view taken along line AA in FIG. 3A. FIG. 4 is an enlarged cross-sectional view of the permanent magnet and its periphery in FIG. 5A is a cross-sectional view of another embodiment of the sensor portion of the detection device taken along line BB in FIG. 5B, and FIG. 5B is a cross-sectional view taken along line AA in FIG. 5A. 6A is a cross-sectional view of another embodiment of the sensor portion of the detection device taken along line BB in FIG. 6B, and FIG. 6B is a cross-sectional view taken along line AA in FIG. 6A. 7A is a cross-sectional view of another embodiment of the sensor portion of the detection device taken along line BB in FIG. 7B, and FIG. 7B is a cross-sectional view taken along line AA in FIG. 7A. 8A is a cross-sectional view of another embodiment of the sensor portion of the detection device taken along line BB in FIG. 8B, and FIG. 8B is a cross-sectional view taken along line AA in FIG. 8A. 9A is a cross-sectional view of another embodiment of the sensor portion of the detection device taken along line BB in FIG. 9B, and FIG. 9B is a cross-sectional view taken along line AA in FIG. 9A. 10A is a cross-sectional view of another embodiment of the sensor portion of the detection device taken along line BB in FIG. 10B, and FIG. 10B is a cross-sectional view taken along line AA in FIG. 10A. FIG. 11 is a cross-sectional view of a reducer showing a first modified example of an installation position of a detection device. FIG. 11 is a cross-sectional view of a reducer showing a second modified example of the installation position of the detection device.

The following describes an embodiment of the present invention in detail with reference to the drawings.

[Overall configuration of the gear device]
FIG. 1 is a cross-sectional view of a gear device 1 serving as a drive device to which a detection device according to an embodiment of the present invention is applied.
As shown in this figure, the gear device 1 is a reduction gear provided at a joint that connects two arm members A1, A2. In other words, the gear device 1 is attached to a robot having two arm members A1, A2 as a driven device. The driven device to which the gear device 1 is attached is not particularly limited, and the gear device can be used to drive various driven devices, and may be attached to the wheels of a machine tool or a transport cart, for example. Specifically, the gear device 1 includes a motor 10, a motor adapter 15, a reducer 20, and a detection device 40.

The motor 10 is the drive source for the reducer 20, and is, for example, a servo motor. The motor 10 has an output shaft 11 that is aligned in the up-down direction (vertical direction) exposed upward. In other words, the gear device 1 is attached to the driven device with the axial direction of the output shaft 11 of the motor 10 (output shaft of the reducer 20) facing vertically.

The motor adapter 15 is disposed between the reducer 20 and the motor 10, and supports the reducer 20 and the motor 10. The motor adapter 15 is formed in a generally cylindrical shape with both upper and lower ends open. The reducer 20 is bolted to the upper end of the motor adapter 15 so as to close the opening. Meanwhile, the motor 10 is bolted to the lower end of the motor adapter 15 so as to close the opening. In this way, both upper and lower ends of the internal space of the motor adapter 15 are closed by the motor 10 and the reducer 20, and a sealed space S is defined. Lubricating oil is sealed in this space S, and the motor adapter 15 also functions as an oil bath for this lubricating oil.
In addition, a flange protrudes from the outer periphery of the upper end of the motor adapter 15, and this flange is fixed to the arm member A1.

The reducer 20 includes an input shaft 21 connected to the output shaft 11 of the motor 10, an output shaft 22 fixed to the arm member A2, and a housing 25 attached to the motor adapter 15. The input shaft 21 and the output shaft 22 are supported rotatably around a rotation axis Ax along the up-down direction with respect to the housing 25. The output of the motor 10 is input from the input shaft 21 to the reducer 20, reduced in speed by the reducer 20, and then transmitted to the arm member A2 via the output shaft 22. As a result, when the motor 10 is driven, the arm member A2 is driven to rotate around the rotation axis Ax relative to the arm member A1.
In the following description, the direction along the rotation axis Ax is referred to as the "axial direction," the direction perpendicular to the rotation axis Ax is referred to as the "radial direction," and the rotation direction around the rotation axis Ax is referred to as the "circumferential direction."

[Detection device]
The detector 40 detects an increase in conductive material floating in the lubricating oil. The detector 40 is a sensor that uses a magnet to accumulate the conductive material in the gap between electrodes (gap portion) and detects the amount of conductive material consisting of wear powder and the like in the lubricating oil by the change in electrical resistance between the electrodes. When the reducer 20 operates, circulation of the lubricant occurs between the space in the housing 25 and the space S in the motor adapter 15. This circulation of the lubricant causes conductive material consisting of wear powder such as iron powder generated in the reducer 20 to be discharged into the space S in the motor adapter 15. The detector 40 detects this conductive material.

FIG. 2 is a diagram showing the configuration of the detection device 40. As shown in FIG.
As shown in this figure, the detection device 40 comprises a sensor unit 50 that detects a conductive material, a detection unit 45 that outputs a detection signal when a conductive material is detected, and a power supply 47 that supplies operating voltage to the sensor unit 50 and the detection unit 45.

The sensor unit 50 has a first electrode 51 and a second electrode 52, and when a conductive substance is accumulated between the electrodes, a voltage is applied from a power source 47 so that a weak current flows through the conductive wires 42, 43 connected to each electrode 51, 52.
The detection unit 45 detects the weak current flowing in the conductive wires 42, 43 connected to the first electrode 51 and the second electrode 52 by changes in the current resistance between the first electrode 51 and the second electrode 52, and when a current greater than a threshold value flows, it outputs a detection signal indicating the detection of a conductive material to the outside of the gear device 1.

Figure 3(A) is a cross-sectional view of the sensor unit 50 of the detection device 40 taken along line B-B in Figure 3(B), and Figure 3(B) is a cross-sectional view taken along line A-A in Figure 3(A). Note that, regardless of the orientation of the sensor unit 50 when it is installed in the gear device 1, the following explanation of each component of the sensor unit 50 will be based on the up, down, left and right directions in Figure 3(B).

As shown in the figure, the sensor portion 50 of the detection device 40 includes a first electrode 51 (box-shaped electrode), a second electrode 52 (center electrode), a permanent magnet 53, a screw member 54, a resin material (filler) 55, and a coating resin material 56.
The second electrode 52 is fixed to the first electrode 51 by a screw member 54. The conductive wire 42 shown in FIG.

The first electrode 51 and the second electrode 52 are made of a non-magnetic metal material. The first electrode 51 and the second electrode 52 may be made of a magnetic material, but from the viewpoint of uniformly collecting conductive material such as wear powder in the gap between the first electrode 51 and the second electrode 52, a weakly magnetic material is preferable, and a non-magnetic material is more preferable.
The first electrode 51 is configured to be substantially cylindrical, with one end side in the axial direction (the lower side in FIG. 3B ) closed at the bottom and configured to be cylindrical box-like with an opening on the top surface. Note that a through hole for inserting a screw member 54 is formed in the center of the bottom of the first electrode 51.

A resin material 55 , which is a non-magnetic material (insulating material), is disposed in the hollow portion of the first electrode 51 , and the second electrode 52 is disposed in a state of being embedded in the upper surface of the resin material 55 .
The second electrode 52 is embedded with its upper surface exposed from the resin material 55. The second electrode 52 is configured in a disk or columnar shape with an outer diameter smaller than the inner diameter of the first electrode 51, and is disposed inside the first electrode 51 so as to be concentric with the first electrode 51. A through hole for inserting a screw member 54 is formed in the center of the second electrode 52.

The height of the upper surface of the first electrode 51 and the second electrode 52 is approximately the same, and the height of the upper surface of the resin material 55 is somewhat lower than the upper surfaces of the first electrode 51 and the second electrode 52. The first electrode 51 and the second electrode 52 are disposed at a distance from each other by the resin material 55, and are insulated from each other.
Further, the permanent magnet 53 is embedded in the resin material 55, and the resin material 55 is interposed between the permanent magnet 53 and the first and second electrodes 51 and 52 so that they do not come into direct contact with each other.

As described above, the first electrode 51 has a cylindrical shape with an open upper portion, and the upper portion of the first electrode 51 has a ring shape when viewed from above.
Moreover, the second electrode 52 has a circular shape when viewed from above and is disposed concentrically with the first electrode 51, so that a gap G that has a ring shape when viewed from above is formed between these electrodes.

FIG. 4 is an enlarged cross-sectional view of the permanent magnet 53 and its periphery in FIG.
As shown in FIG. 3 , the permanent magnet 53 is ring-shaped and is disposed concentrically inside the first electrode 51 in a state where it is completely embedded in the resin material 55 .
The permanent magnet 53 is disposed at a position facing the gap G in the up-down direction. For example, the upper surface of the permanent magnet 53 is disposed so as to face the upper surface of the resin material 55 in the gap G.

Furthermore, the outer diameter of the permanent magnet 53 is set to be slightly smaller than the inner diameter of the first electrode 51, and the inner diameter of the permanent magnet 53 is set to be slightly larger than the outer diameter of the second electrode 52. Therefore, as shown in Fig. 3(A) , when viewed in a direction from the permanent magnet 53 toward the gap G (from below to above), the permanent magnet 53 is disposed so as not to overlap the first electrode 51 and the second electrode 52.
If viewed from above, the permanent magnet 53 is arranged so as to overlap the bottom of the first electrode 51. In other words, with reference to Fig. 4, the relationship of the arrangement of the permanent magnet 53 and the first and second electrodes 51, 52 is such that the permanent magnet 53 does not overlap either the opposing portion of the first electrode 51 (a part of the first electrode 51 that is in the same height range as the second electrode 52) that constitutes the gap G or the opposing portion of the second electrode 52 (the entire second electrode 52) when viewed from the top-bottom direction.

Also, as shown in FIG. 4, a portion of the upper part of the permanent magnet 53 is positioned in the gap G between the first electrode 51 and the second electrode 52. In other words, the upper part of the permanent magnet 53 is positioned so that it partially enters the range of the gap G formed by the first electrode 51 and the second electrode 52 facing each other.

As described above, the upper surface of the resin material 55 is lower than the upper surfaces of the first electrode 51 and the second electrode 52. Therefore, as shown in Fig. 4, the inside of the gap G has, in the vertical direction, a filled portion Ga filled with the resin material 55 and an accumulated portion Gb which is a void not filled with the resin material 55.
The integrated portion Gb is recessed in the up-down direction relative to the first electrode 51 and the second electrode 52 on both sides, and has a ring-shaped recessed groove structure when viewed from above.
The permanent magnet 53 is disposed so as to overlap the gap G when viewed from above and below, and therefore effectively attracts the conductive material into the accumulation portion Gb.

The coating resin material 56 covers the outer periphery and bottom surface of the first electrode 51 .
The screw member 54 penetrates the centers of the second electrode 52, the resin material 55, and the first electrode 51, and fastens and holds them together with a nut 541 provided on the bottom side of the first electrode 51. The coating resin material 56 is removed from around the center of the bottom surface of the first electrode 51 so as to avoid the nut 541.

As shown in FIG. 1, the sensor unit 50 of the detection device 40 is disposed in a space S within the motor adapter 15 through which the lubricant flows.
The motor adapter 15 has a mounting portion 151 for mounting the detection device 40 within the space S. The detection device 40 is attached to the mounting portion 151 via a support member 44. The location of the mounting portion 151 is not limited to the illustrated example, and it may be located further downward.

[Detection operation]
1 , in the gear device 1, the flow of lubricant accompanying the operation of the reducer 20 causes conductive material (e.g., iron powder) generated within the reducer 20 to be discharged together with the lubricant into the space S within the motor adapter 15. The conductive material within the space S is detected by the detection device 40.

In the detection device 40, the flow of the lubricant causes the conductive material to enter the gap G between the first electrode 51 and the second electrode 52 of the sensor unit 50. The conductive material is then attracted to the gap G between the first electrode 51 and the second electrode 52 by the magnetic force of the permanent magnet 53, and accumulates in the gap G. When the amount of accumulation exceeds a predetermined amount, the electrical resistance between the first electrode 51 and the second electrode 52 decreases through the accumulated conductive material, and when a certain amount is reached, electrical conduction occurs. Then, the minute current flowing between the first electrode 51 and the second electrode 52 increases. The detection unit 45 outputs a detection signal when the current exceeds a predetermined specified value. The detection signal is output to an external control device, for example, and is used for warning control, such as turning on a lamp indicating deterioration of the gear device 1 (reduction gear 20).

Technical Effects of the Invention Embodiments
In the detection device 40 of the gear device 1 described above, the permanent magnet 53 is disposed in the sensor unit 50 at a position facing the gap G between the first electrode 51 and the second electrode 52. Therefore, the attractive force of the permanent magnet 53 on the conductive material acts on the gap G, making it possible to effectively collect the conductive material in the gap G between the electrodes. This also makes it possible to more effectively detect the conductive material.

In addition, in the sensor unit 50, the permanent magnet 53 is arranged so as not to overlap the first electrode 51 and the second electrode 52 when viewed in the direction from the permanent magnet 53 toward the gap G. This makes it possible to suppress dispersion of the conductive material toward the first electrode 51 or the second electrode 52, and to more effectively collect the conductive material in the gap G.

In addition, in the sensor unit 50, a part of the permanent magnet 53 is disposed in the gap G where the first electrode 51 and the second electrode 52 face each other.
With the above-described arrangement, the permanent magnet 53 can be positioned closer to the bottom surface (top surface in FIG. 3B ) of the conductive material accumulation portion Gb in the gap G, making it possible to more effectively collect the conductive material in the gap G between the electrodes.

Furthermore, the sensor unit 50 has a filled portion Ga in which the gap G between the first electrode 51 and the second electrode 52 is filled with the resin material 55, and an accumulation portion Gb which is a gap that is not filled with the resin material 55. Therefore, a gap suitable for accumulation of the conductive material can be formed in the gap G, and the conductive material can be more effectively detected.
In addition, by adjusting the ratio between the filling portion Ga and the accumulation portion Gb of the gap G, it becomes possible to easily adjust the detection sensitivity.

[Another form of the sensor part of the detection device]
The sensor unit 50 of the detection device 40 is not limited to the example shown in Fig. 3, and can take various forms. Other examples of the sensor unit 50 will be described with reference to Figs. 5 to 10. (A) of each figure is a cross-sectional view of the sensor unit 50 taken along line B-B in (B) of each figure, and (B) of each figure is a cross-sectional view taken along line A-A in (A) of each figure. Note that, in the case of these sensor units 50, the description will be based on the up, down, left and right directions in (B) of each figure, regardless of the orientation when installed.
Regarding the sensor unit 50 in each figure, differences from the sensor unit 50 in FIG. 3 will be mainly described.

In the sensor unit 50 shown in Figures 5 and 6, the permanent magnets 53 are not ring-shaped, but are instead multiple columnar or block-shaped permanent magnets 53 arranged at equal intervals along the circumferential direction of a circle concentric with the first electrode 51. Each permanent magnet 53 in Figure 5 is cylindrical, which is circular when viewed from above, and each permanent magnet 53 in Figure 6 is rectangular, which is square when viewed from above. The shape of the permanent magnets 53 viewed from above is not limited to these, and may be, for example, elliptical or polygonal. Furthermore, they do not have to be columnar or block-shaped, and may be plate-shaped parallel to the bottom surface of the accumulation section Gb. Furthermore, they do not have to be spaced at equal intervals in the circumferential direction.

Each permanent magnet 53 shown in Figs. 5 and 6 is disposed in a position facing the gap G between the first electrode 51 and the second electrode 52, similar to the permanent magnet 53 in Fig. 3, and is disposed so as not to overlap the first electrode 51 and the second electrode 52 when viewed upward from the permanent magnet 53. Furthermore, a portion of each permanent magnet 53 is located in the gap G where the first electrode 51 and the second electrode 52 face each other. Therefore, the detection device 40 including these sensor units 50 can obtain the same technical effect as the detection device 40 including the sensor unit 50 in Fig. 3.

Furthermore, as shown in Figures 5 and 6, when permanent magnets 53 arranged intermittently in the circumferential direction are used, the conductive material can be concentrated and accumulated in each position of the accumulation section Gb corresponding to the arrangement of the permanent magnets 53 in the gap G, making it possible to more effectively detect the conductive material.

In addition, when determining whether a failure or end of life due to wear of components occurs, or when to replace components, for a device such as the gear device 1 in which internal components mesh and slide, the amount of conductive material generated varies depending on the size of the device, the number of parts, and the structure within the device. In such cases, multiple types of detection devices 40 are prepared, such as detection devices 40 having the sensor units 50 shown in Figures 3, 5, and 6, or detection devices 40 having sensor units 50 with different sizes and numbers of permanent magnets in these sensor units 50. Then, by selecting a detection device 40 equipped with a sensor unit 50 with appropriate sensitivity for devices with different amounts of conductive material generated, it becomes possible to more appropriately determine whether a failure or end of life due to wear of components occurs, or when to replace components.

The sensor section 50 shown in FIG. 7 has a configuration in which an insert member 57 made of an insulating material (such as ceramic) which is less susceptible to stress relaxation than the resin material 55 is added to the sensor section 50 shown in FIG.
7, a sensor unit 50 is formed by disposing an insert member 57 between a first electrode 51 and a second electrode 52 and fastening them together with a screw member 54. The insert member 57 is cylindrical and has a through hole formed in the center so that the screw member 54 passes through it.
The screw members 54 fasten the second electrode 52 , the insertion member 57 , and the first electrode 51 together, thereby holding these together with the resin material 55 as a single unit.
Furthermore, by making the insert member 57 smaller in diameter than the second electrode 52, the resin material 55 around the insert member 57 is also held between the first electrode 51 and the second electrode 52 by the screw member 54, via the second electrode 52.

The sensor unit 50 in FIG. 3 is fastened by the screw member 54 with only the resin material 55 present between the first electrode 51 and the second electrode 52. Therefore, the holding pressure due to fastening is constantly applied to the resin material 55. In this case, even if the fastening is initially performed with sufficient holding pressure, if stress relaxation occurs in the resin material 55 over time, the holding pressure will decrease, and there is a risk of misalignment of the first electrode 51, the second electrode 52, the resin material 55, and even the permanent magnet 53 held via the resin material 55.

In contrast, in the sensor unit 50 of FIG. 7, the holding pressure is applied by fastening to the insert member 57 instead of the resin material 55, so that the occurrence of stress relaxation is suppressed, and it is possible to perform good detection of conductive materials for a long period of time.
The insert member 57 can also be applied to the sensor unit 50 in FIGS.

The sensor unit 50 shown in Figures 3, 5, and 6 has a structure in which the first electrode 51, the second electrode 52, and the resin material 55 are integrally held by the screw member 54. However, as shown in Figures 8 to 10, instead of the screw member 54, the first electrode 51, the second electrode 52, and the resin material 55 may be integrally held by a pin member 58 with a snap-fit structure.

As shown in Figure 8, the pin member 58 having a snap-fit structure has a pair of leaf spring portions 581 extending side by side toward the tip end by a split-tip structure, and each leaf spring portion 581 has a protrusion portion 582 which protrudes in opposite directions.
When this pin member 58 is inserted into the through hole, a pair of leaf spring portions 581 extending side by side bend in the direction approaching each other, storing elastic force, and when the protrusion portion 582 passes through the through hole, the elastic force of each leaf spring portion 581 is released and they move away from each other, and each protrusion portion 582 prevents the pin member 58 from coming out of the through hole.

The pin member 58 may be configured so that the length from the bottom surface of the head 583 to the upper end of the protrusion 582 is equal to the distance from the top surface of the second electrode 52 to the bottom surface of the first electrode 51, thereby holding the first electrode 51, the second electrode 52 and the resin material 55 (including the permanent magnet 53) together.
8 to 10, however, a through hole into which the tip of the pin member 58 is inserted is provided in the upper wall surface of the support member 44 for mounting the detection device 40 to the above-mentioned gear device 1. The length from the bottom surface of the head 583 of the pin member 58 to the upper end of the protrusion 582 is set to be equal to the length from the upper surface of the second electrode 52 to the lower surface of the upper wall surface of the support member 44. As a result, the pin member 58 holds the first electrode 51, the second electrode 52, and the resin material 55 integrally, and enables the sensor unit 50 to be fixed to the support member 44.

The sensor unit 50 in Figures 8 to 10 is configured to integrally hold the first electrode 51, the second electrode 52, and the resin material 55 (including the permanent magnet 53) by the pin member 58. Therefore, unlike a configuration in which a holding pressure is always applied to the resin material 55 by fastening, such as the screw member 54, no holding pressure is constantly applied to the resin material 55, so stress relaxation of the resin material 55 is suppressed, making it possible to perform good detection of conductive materials over a long period of time.

[Modification 1]
The installation position of the detection device 40 is not limited to the example shown in FIG. 1, and may be changed to a more appropriate position.
For example, the detection device 40 may be disposed in an internal space of the reducer 20 that communicates with the space S in the motor adapter 15. Here, an example in which the detection device 40 is disposed in a so-called distribution type eccentric oscillation type reducer 20 will be described.

First, the reduction gear 20 will be described.
As shown in this figure, the reducer 20 has an input shaft 21, an eccentric body shaft 31 having eccentric bodies 31a and 31b, a first external gear 32A through which the eccentric body 31a passes and a second external gear 32B through which the eccentric body 31b passes and a through hole offset from the axis. The eccentric body shaft 31 has an eccentric body shaft gear 33 that meshes with the input shaft 21, and rotation is input from the input shaft 21 through the eccentric body shaft gear 33. The through holes of the external gears 32A and 32B are provided at multiple locations (for example, three locations) in the circumferential direction, and multiple eccentric body shafts 31 pass through them. The eccentric bodies 31a and 31b are rotatably arranged in the through holes of the external gears 32A and 32B via eccentric body bearings 37A.

The reducer 20 further includes an output shaft (carrier body) 22, a support plate 34 fixed to the input side of the output shaft 22, and a housing 25 having an internal gear 25g that meshes with the external gears 32A and 32B. The internal gear 25g has a plurality of outer pins p1 that function as internal teeth and an internal gear body having pin grooves that hold the plurality of outer pins p1. Between the eccentric body shaft 31 and the output shaft 22 and between the eccentric body shaft 31 and the support plate 34, eccentric body shaft bearings 37B are respectively arranged. The housing 25 rotatably supports the output shaft 22 and the support plate 34 via main bearings 38a and 38b. The housing 25 is fixed to the motor adapter 15, and the output shaft 22 is fixed to the arm member A2 (see FIG. 1).

The reducer 20 further includes an oil seal o1 and cap members c1 and c2 that seal lubricant inside the reducer 20 on the output side. The oil seal o1 seals between the output shaft 22 and the housing 25. The cap member c1 closes the output end of the central through hole 22a of the output shaft 22. The cap member c2 closes the output end of the through hole 22b of the output shaft 22, through which the eccentric shaft 31 is inserted.

In this configuration, when the input shaft 21 of the reducer 20 rotates due to the drive of the motor 10, the rotational motion is transmitted to the eccentric body shaft 31 via the eccentric body shaft gear 33. Then, the eccentric bodies 31a, 31b rotate, causing the external gears 32A, 32B to eccentrically oscillate. Due to this eccentric oscillation, the meshing positions of the external gears 32A, 32B and the internal gear 25g change in the circumferential direction, and because the number of teeth of both gears differs, the external gears 32A, 32B rotate (spin). Then, the rotation component of the external gears 32A, 32B is output to the arm member A2 via the output shaft 22.

In the reducer 20 having such a configuration, a relatively large surface pressure is applied to the eccentric bodies 31 a and 31 b, causing wear. Therefore, conductive material is likely to be generated between the eccentric bodies 31 a and 31 b and the eccentric body bearing 37 A. Also, conductive material is likely to be generated at the meshing portion of the eccentric body shaft gear 33.
Therefore, in this modification, the detector 40 is provided in the space S within the motor adaptor 15 (specifically, the motor adaptor 15) and at the output end within the through hole 22b of the output shaft 22 (specifically, the output shaft 22). Note that Fig. 11 shows the detector 40 in a simplified manner. The detector 40 is configured similarly to the detector 40 in the above embodiment, except for the installation position.
The detector 40 may be provided, for example, at the output end of the through hole 22 a in the center of the output shaft 22 .

[Modification 2]
Next, an example in which the detection device 40 is disposed inside a center crank type eccentric oscillating reducer 60 will be described.

First, the reduction gear 60 will be described.
As shown in this figure, the reducer 60 includes an output shaft 62, a reduction unit 63, and a housing (casing) 65 that covers the periphery of these. An oil seal o2 that seals a lubricant inside the reducer 60 is provided between the output shaft 62 and the housing 65. The housing 65 is fixed to the motor adapter 15 in place of the housing 25 of the above-mentioned modified example 1, and the output shaft 62 is fixed to the arm member A2 in place of the output shaft 22 of the above-mentioned modified example 1 (see FIG. 1).

The reduction gear unit 63 includes an eccentric shaft 71, multiple eccentric bodies 71a, 71b, and 71c provided on the eccentric shaft 71, and multiple external gears 72A, 72B, and 72C that oscillate with the rotation of the eccentric bodies 71a, 71b, and 71c. The external gears 72A, 72B, and 72C have multiple internal pin holes spaced apart in the circumferential direction at positions offset from the center, and a central through hole through which the eccentric shaft 71 passes. The eccentric shaft 71 is connected to an input shaft (not shown) that is connected to the output shaft 11 of the motor 10 (see FIG. 1).

The reduction gear 63 further includes an internal gear 65g provided on the inner periphery of the housing 65, an internal pin 62c that passes through an internal pin hole of the external gears 72A, 72B, and 72C, and a carrier body 74 that holds one end of the input side of the internal pin 62c. The internal gear 65g has an internal gear body having multiple external pins p2 that form internal teeth and multiple pin grooves that hold the multiple external pins p2, and is in inwardly meshed with the external gears 72A, 72B, and 72C. The internal pin 62c is provided so as to bulge out like a pin from the output shaft 62.

The reduction gear unit 63 further includes eccentric shaft bearings 76a and 76b, eccentric shaft bearings 77a, 77b, and 77c, and main bearings 78a and 78b. The eccentric shaft bearings 76a and 76b are disposed between the eccentric shaft 71 and the output shaft 62, and between the eccentric shaft 71 and the carrier body 74, respectively, to allow relative rotation between them. The eccentric bearings 77a, 77b, and 77c are disposed between the eccentric bodies 71a, 71b, and 71c, respectively, and the external gears 72A, 72B, and 72C, to allow relative rotation between them. The housing 65 rotatably supports the carrier body 74 and the output shaft 62 via the main bearings 78a and 78b.

With this configuration, in the reducer 60, when torque is input from the input shaft and the eccentric shaft 71 rotates, the eccentrics 71a, 71b, and 71c rotate inside the central through holes of the external gears 72A, 72B, and 72C, causing the external gears 72A, 72B, and 72C to oscillate in different phases. The external gears 72A, 72B, and 72C oscillate so that the external teeth farthest from the axis of the eccentric shaft 71 mesh with the internal gear 65g, and this meshing position changes in the circumferential direction as the oscillating motion occurs. Specifically, each time the eccentric shaft 71 rotates once, the meshing positions of the internal gear 65g and the external gears 72A, 72B, and 72C rotate once in the circumferential direction. There is a difference in the number of teeth between the external gears 72A, 72B, and 72C and the internal gear 65g, and each time the meshing position with the internal gear 65g rotates once, the external gears 72A, 72B, and 72C rotate by the difference in the number of teeth. This rotation is transmitted to the output shaft 62 via the inner pin 62c. As a result, the rotational motion of the input shaft is decelerated and taken out from the output shaft 62.

In the reducer 60 having such a configuration, a relatively large surface pressure is applied to the eccentric bodies 71a, 71b, and 71c, causing wear.
Therefore, it is preferable to dispose the detection device 40 at a position close to the eccentric bodies 71a, 71b, and 71c (eccentric body bearings 77a, 77b, and 77c). Here, "close" refers to a short distance in the communication passage in the reducer 60. In this modification, the detection device 40 is provided on the outer periphery of the recess 62a on the output side of the output shaft 62.
Further, the other detector 40 is provided in a drilled hole 71d on the output side of the eccentric shaft 71. Note that Fig. 12 shows each detector 40 in a simplified manner. The detector 40 is configured similarly to the detector 40 in the above embodiment, except for the installation position.
In addition, the detection device 40 may be disposed in the internal space of the reducer 60 or in the space S within the motor adapter 15 .

[others]
Although the embodiment and the modified examples of the present invention have been described above, the present invention is not limited to the above embodiment and the modified examples.
1 shows an example in which the gear device 1 is disposed with the output shaft 11 of the motor 10 facing upward, but the orientation of the gear device 1 is not limited to the above. For example, the gear device 1 can be used with the rotation axis Ax facing any direction, not limited to the up-down direction. Furthermore, the rotation axis Ax of the gear device 1 is not limited to being maintained in a fixed direction, and may be connected to another movable member and used in an environment in which the orientation of the rotation axis Ax fluctuates.

In addition, the detection device 40 is illustrated as being applied to a gear device, but is not limited to this, and the detection device 40 can be applied to any device in which components slide or mesh with each other internally, generating conductive material.

In addition, the detection device 40 has been described as having a ring-like shape when viewed from a certain direction, but is not limited thereto. For example, they may have a polygonal shape such as a square. However, in order to form a gap G between the first electrode 51 and the second electrode 52, and to arrange the permanent magnet 53 so as to overlap the gap G when viewed from above, it is preferable that the shapes of the first electrode 51, the second electrode 52, and the permanent magnet 53 when viewed from a certain direction are the same shape (with different dimensions).
Although the first electrode 51 has an opening at the top in the above example, the bottom may also be open. However, when the components of the sensor unit 50 are integrated by fastening them with the screw members 54, it is preferable that the bottom of the first electrode 51 is closed and an insertion hole is formed.

Furthermore, the configuration is not limited to one in which the first electrode 51 surrounds the second electrode 52. For example, the first electrode 51 and the second electrode 52 may be flat plates arranged opposite each other, and the permanent magnet 53 may be arranged to face the gap G.

Furthermore, the permanent magnet 53 may be disposed so that a portion of the permanent magnet 53 overlaps with the gap G when viewed from above (the depth direction of the accumulation portion Gb). In this case, the permanent magnet 53 may be disposed so that the remaining portion of the permanent magnet 53 overlaps with the second electrode 52 when viewed from above. Furthermore, in the case where the first electrode 51 does not have a shape that closes the bottom, the permanent magnet 53 may be disposed so that the remaining portion of the permanent magnet 53 overlaps with the first electrode 51 when viewed from above.
Furthermore, a part (upper part) of the permanent magnet 53 does not necessarily have to be disposed in the gap G between the first electrode 51 and the second electrode 52. Conversely, the entire permanent magnet 53 may be disposed in the gap G.

Although the detection device 40 includes the permanent magnet 53, an electromagnet may be used instead of the permanent magnet 53. The arrangement, number, shape, etc. of the electromagnet may be the same as those of the permanent magnet 53.
In addition, the permanent magnet 53 or the electromagnet may be arranged so as to be exposed upward from the bottom surface of the accumulation portion Gb of the gap G.

In addition, in the above embodiment, an example of an electrical connection form between the sensor unit, output unit, and power supply is shown, but this is merely a conceptual example, and various general connection forms may be applied.

In addition, in the above-mentioned modified examples 1 and 2, an eccentric oscillating type reduction gear is shown as an example of a reduction gear provided with a detection device 40, but the reduction gear may also be a simple planetary gear device, a flexible meshing gear device, various orthogonal axis gear devices, various parallel axis gear devices, a traction drive type reduction mechanism without gears, etc.
In addition, the details shown in the embodiment can be modified as appropriate without departing from the spirit of the invention.

REFERENCE SIGNS LIST 1 Gear device 10 Motor 15 Motor adapter 20 Reducer 40 Detector 42, 43 Conductive wire 44 Support member 45 Detector 47 Power source 50 Sensor 51 First electrode 52 Second electrode 53 Permanent magnet (magnet)
54 Screw member 55 Resin material (filler)
56: Resin coating material 57: Insertion member 58: Pin member 60: Reducer A1, A2: Arm member Ax: Rotation shaft G: Gap Ga: Filling portion Gb: Accumulation portion

Claims (5)

A first electrode;
a second electrode spaced apart from the first electrode;
A detection unit that detects a change in electrical resistance between the electrodes due to a conductive material accumulated in a gap between the first electrode and the second electrode,
A magnet is disposed at a position facing the gap between the first electrode and the second electrode;
The detection device includes a plurality of magnets arranged intermittently and spaced apart from at least one of the first electrode and the second electrode adjacent thereto . The detection device according to claim 1, wherein the magnet is arranged so as not to overlap the first electrode and the second electrode when viewed in a direction from the magnet toward the gap. The detection device according to claim 1 or 2, wherein the gap between the first electrode and the second electrode has a filling portion filled with a filler and an accumulation portion not filled with a filler. The detection device according to claim 3 , wherein a portion of the magnet is positioned so as to overlap the first electrode and the second electrode when viewed from the first electrode through the filling portion toward the second electrode. A first electrode;
a second electrode spaced apart from the first electrode;
A detection unit that detects a change in electrical resistance between the electrodes due to a conductive material accumulated in a gap between the first electrode and the second electrode,
A magnet is disposed at a position facing the gap between the first electrode and the second electrode;
A detection device in which the first electrode is configured in a ring shape, the second electrode is arranged radially inside the first electrode, a ring-shaped gap is provided between the first electrode and the second electrode, and the magnets are arranged intermittently in the circumferential direction.

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