JP2002243681A - Oil detector and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil detector, capable of being miniaturized by reducing the number of parts and detecting the deterioration degree of oil, and a method for manufacutring the same. SOLUTION: A first electrode 20 and a second electrode 30 of the oil detector for detecting the deterioration degree of oil are formed into cylindrical shape. The first electrode 20 has fins 21, protruded outwardly toward the second electrode 30 in the diameter direction thereof. Communication holes 25 for allowing the inside and outside of the first electrode 20 to communicate with each other are formed to the first electrode 20 between the fines 21 adjacent to each other in the peripheral direction of the first electrode 20. The second electrode 30 has fins 31, protruded inwardly toward the first electrode 20 in the diameter direction and communication holes 35, for allowing the inside and outside of the second electrode 30 to communicate with each other are formed to the second electrode 30 between the fins 31 adjacent to each other in the peripheral direction of the second electrode 30. The fins 21 and 31 are arranged alternately in the peripheral direction, in such a state that the first and second electrodes 20 and 30 are assembled and the outer peripheral surface of the first electrode 20 and the inner peripheral surface of the second electrode 30 are made to be opposed to each other in the radial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil detector for detecting the degree of deterioration of oil.

[0002]

2. Description of the Related Art A hydraulic control or lubricating oil used in a vehicle or the like has an acidity or an alkalinity due to the incorporation of foreign matter or changes with time as the oil is used.
The H value changes. A change in the PH value indicates that the oil has deteriorated. Therefore, it is important to detect the degree of oil deterioration and to know when to change the oil. An oil detection device that detects the degree of oil deterioration has a reference electrode whose potential is almost constant irrespective of the PH value of oil and a comparison electrode whose potential changes according to the PH value of oil. The oil detection device detects the degree of deterioration of the oil by changing the PH value of the oil with the deterioration of the oil and changing the potential difference between the two electrodes.

[0003] In a conventional oil detector as disclosed in Japanese Patent Application Laid-Open No. 7-77514, as shown in FIG.
211 are formed by lamination, and the potential difference between the electrode 200 and the electrode 210 facing each other is output. Thin plate 201, 2
11 is electrically connected by conductive spacers 202 and 212. In addition, the housing 220 and a screw 2 for attaching the electrodes 200 and 210 to the housing 220.
03 and 213 and the thin plates 201 and 211 are insulated by insulating spacers 204 and 214.

[0004]

However, in the configuration of the oil detection device as shown in FIG.
210 is composed of a plurality of thin plates 201 and 211, respectively, and each thin plate must be electrically connected by conductive spacers 202 and 212. Therefore, there is a problem that the number of parts increases and the number of assembly steps increases. Further, the insulating spacers 204 and 214 are locations where current easily leaks, and it is desirable to reduce the number of such insulating members as much as possible.

Generally, if a current leaks between the electrodes, the accuracy of measuring the potential between the electrodes is reduced. Therefore, it is desirable to reliably insulate the electrodes. Further, if the resistance between the electrodes of the oil detection device is large, the accuracy of measuring the potential is reduced, so that the resistance between the electrodes is desirably small. The resistance between the electrodes becomes smaller as the facing area where the electrodes face each other is larger. In order to increase the area where the electrodes face each other in the oil detection device that constitutes each electrode by stacking the thin plates, it is conceivable to increase the area of each thin plate or increase the number of thin plates. However, when the area of the thin plate is increased, there is a problem that the diameter of the oil detector increases. Further, when the number of thin plates is increased, the number of parts increases, and there is a problem that the number of assembling steps increases.

In recent years, it has been desired not only to detect the degree of deterioration of oil but also to detect the remaining amount of oil with a single oil detector. The attachment of the oil detector is desirably a structure in which the deterioration sensor and the remaining amount sensor of the oil detector are inserted into the oil from outside the oil pan. In this case, it is desirable to reduce the diameter of the sensor of the oil detection device as much as possible and to reduce the insertion hole formed in the oil pan. However, in the conventional oil detecting device in which electrodes are formed by laminating thin plates, a space for the remaining amount sensor is required separately from the deterioration sensor, and the oil detecting device is increased in size, so that the insertion hole of the oil pan becomes large.

An object of the present invention is to provide an oil detecting device for detecting the degree of deterioration of oil, which can reduce the number of parts and reduce the size, and a method of manufacturing the same. Another object of the present invention is to provide an oil detection device that can be reduced in size and that detects the remaining amount of oil in addition to the degree of oil deterioration.

[0008]

According to the oil detecting device of the present invention, the first electrode and the second electrode formed in a cylindrical shape are arranged coaxially and face each other. Then, the first projections of the first electrode projecting toward the second electrode and the second projections of the second electrode projecting toward the first electrode have different directions of projection. Since the first projection and the second projection face each other except in the radial direction, the facing area between the first electrode and the second electrode increases. Since each electrode is formed in a cylindrical shape, each electrode can be constituted by a single component. Therefore, the number of parts is reduced and the number of assembling steps is reduced. Furthermore, if the axial length of the cylindrical electrode is increased, the facing area between the electrodes is easily increased without increasing the number of components, and the resistance between the electrodes of the oil detector is reduced. The detection accuracy of the degree of oil deterioration can be increased without increasing the size.

According to the oil detecting device of the present invention, the first protrusions and the second protrusions are alternately arranged in the circumferential direction, so that the second protrusions are provided on both sides of the first protrusion in the circumferential direction. The projection is located, and the first projection is located on both circumferential sides of the second projection. Since the facing area where the first projection and the second projection face each other increases and the resistance between the electrodes decreases, the degree of oil deterioration can be detected with high accuracy.

According to the oil detecting device of the third aspect of the present invention, since the first electrode and the second electrode are formed with the communication holes communicating the inside and the outside, the oil flows through the communication holes. I do. Since the stagnation of the oil around the electrodes is prevented, the degree of deterioration of the oil can be detected with high accuracy.

According to the oil detecting device of the fourth aspect of the present invention, the first electrode and the second electrode are a pair of electrodes,
Since a plurality of electrode pairs are arranged coaxially, the facing area between the electrodes increases. As a result, the resistance between the electrodes is reduced, so that the degree of deterioration of the oil can be detected with high accuracy.

According to the oil detecting device of the present invention, the remaining amount sensor for detecting the remaining amount of the oil is provided inside the innermost electrode. Since the degree of oil deterioration and the remaining amount of oil are detected by a single oil detection device, the number of mounting steps is reduced as compared with a case where the deterioration sensor and the remaining amount sensor are separately mounted on an oil pan or the like. Also,
Since the remaining amount sensor can be arranged in an empty space formed inside the cylindrical electrode, the outer diameter of the oil detecting device does not increase even if the remaining amount sensor is provided. Therefore, the insertion hole for inserting the oil detection device including the deterioration sensor and the remaining amount sensor into the oil pan from outside can be reduced.

Here, when the first protrusion and the second protrusion are in contact with the support member, the first protrusion and the second protrusion are larger than the distance between the mounting portions of the two electrodes mounted on the support member. The distance from the protruding portion is shorter, and current leaks easily. According to the oil detecting device of the sixth aspect of the present invention, since the first projection and the second projection are not in contact with the support member, it is possible to prevent leakage between the two projections.

According to the oil detecting device of the present invention, at least one of the mounting portions of the two electrodes is bent away from the other mounting portion.
The surface distance of the support member from one mounting portion to the other mounting portion, that is, the creepage distance increases. Even if conductive foreign matter mixed in oil, for example, adheres to the surface of the support member located between the attachment parts, the creepage distance of the support member becomes longer, thereby preventing conduction between the attachment parts via the foreign matter. I do.
Therefore, it is possible to prevent a leak current from flowing between the mounting portions, that is, between the electrodes.

According to the oil detecting device of the present invention, the surface of the support member on which the two electrodes are mounted has irregularities between the first electrode and the second electrode. Therefore, the creepage distance of the support member from one attachment portion to the other attachment portion is increased. Even if conductive foreign matter mixed in oil, for example, adheres to the surface of the support member located between the attachment parts, the creepage distance of the support member becomes longer, thereby preventing conduction between the attachment parts via the foreign matter. I do. Therefore, it is possible to prevent a leak current from flowing between the mounting portions, that is, between the electrodes.

According to the method for manufacturing an oil detecting device of the present invention, the first electrode base material and the second electrode base material are punched out by a press, and a plurality of fins are formed on one of the spread surfaces of both base materials. Since the first electrode and the second electrode are formed so as to protrude, manufacture of each electrode is easy. Further, since each electrode can be formed as a single component, the number of steps for assembling the oil detection device is reduced. According to the method for manufacturing an oil detecting device according to the twelfth aspect of the present invention, the fin of the first electrode and the fin of the second electrode are axially oriented in a state where the first electrode base material and the second electrode base material are rounded into a cylindrical shape. , The first electrode and the second electrode can be easily assembled.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIGS. 1, 2 and 3 show an oil detector according to a first embodiment of the present invention. Oil detector 10
Is mounted on, for example, an oil pan of a vehicle and detects the degree of deterioration of oil used for hydraulic control and lubrication.

The first electrode 20 and the second electrode 30 are formed in a cylindrical shape, and are attached to an insulating resin support member 11 shown in FIG. 3 with an adhesive or the like. The first electrode 20 and the second electrode 30 are immersed in oil such as an oil pan. The second electrode 30 is disposed coaxially with the first electrode 20 outside the first electrode 20. One of the two electrodes is formed of a metal whose potential does not substantially change irrespective of the pH value of the oil, and the other electrode is formed of a metal whose potential changes depending on the PH value of the oil.

A terminal 12 electrically connected to each electrode is embedded in the support member 11. The cover 15 is combined with the support member and covers the first electrode 20 and the second electrode 30. The cover 15 is formed with a communication hole 15 a so that oil flows inside and outside the cover 15.

As shown in FIGS. 1 and 2, the first electrode 2
Numeral 0 is formed in a cylindrical shape, and has a fin 21 as a first projection protruding radially outward toward the second electrode 30 and extending in the axial direction. Between the fins 21 that are adjacent in the circumferential direction, a communication hole 25 that communicates the inside and the outside of the first electrode 20 and through which oil can flow is formed. Second
The electrode 30 is formed in a cylindrical shape, and has a fin 31 as a second protrusion protruding radially inward toward the first electrode 20 and extending in the axial direction. The projecting direction of the fin 31 is shifted from the projecting direction of the fin 21. Between the fins 31 adjacent to each other in the circumferential direction, a communication hole 35 that communicates the inside and the outside of the second electrode 30 and through which oil can flow is formed. Since oil flows through the inside and outside of each electrode through the communication holes 25 and 35, the oil does not stay around the two electrodes. Therefore, the deterioration state of the entire oil can be detected with high accuracy.

As shown in FIG. 1, the first electrode 20 and the second
In a state where the electrode 30 is assembled, the fins 31 are located on both circumferential sides of the fin 21, and the fins 21 are located on both circumferential sides of the fin 31. That is, the fin 21 is 2
The fins 31 and the fins 31 face the two fins 21. Further, the outer peripheral surface of the first electrode 20 and the second
The inner peripheral surface of the electrode 30 faces radially. Therefore, the facing area where the first electrode 20 and the second electrode 30 face each other is large. When the opposing area between the two electrodes increases, the resistance between the electrodes decreases, so that the degree of oil deterioration can be detected with high accuracy.

Next, a method for manufacturing the first electrode 20 and the second electrode 30 will be described. As shown in FIGS. 4 and 6, the first electrode base material 100 and the second electrode base material 110 are rectangular thin plates. The first electrode base material 100 and the second electrode base material 110 each have bands 101 and 111 for welding and maintaining a cylindrical shape when rounded into a cylindrical shape.

(1) First, the fins 21 and 31 and the communication hole 2
The fins 21 and 3 are added to both base materials before the formation of the fins 5 and 35.
Through holes 102, 1 are provided at both ends in the Z direction at the position where
12 is formed. (2) A pair of unillustrated comb-shaped punches having blades extending in the Z direction which is the width direction of both base materials are formed on one side and the other side of both base materials in which through holes 102 and 112 are formed. The first electrode base material 100 and the second electrode base material 100
Fins 21 and 31 and communication holes 25 and 35 are formed in electrode base material 110.
Are formed.

(3) The first electrode base material 100 formed as shown in FIG. 4 is rolled into a cylindrical shape so that the fins 21 face outward and the fins 21 extend in the axial direction. The other parts are welded to form the first electrode 20 shown in FIG. The second electrode base material 110 formed as shown in FIG. 6 is rolled into a cylindrical shape so that the fins 31 face inward and the extending direction of the fins 31 is in the axial direction.
The second electrode 30 is formed by welding the portion other than the band 111.

(4) The first electrode 20 and the second electrode 30 are assembled so that the fins 21 and the fins 31 are alternately located in the circumferential direction. In addition to the above manufacturing method, a pipe-shaped inner cylinder and an outer cylinder having a larger diameter than the inner cylinder are prepared, the inner cylinder is directed outward, and the outer cylinder is formed with fins directed inward, and then combined. It is possible.

(Second Embodiment) FIG. 8 shows a second embodiment of the present invention.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. The method of manufacturing each electrode is the same as in the first embodiment. The first electrodes 40 and 60 and the second electrodes 50 and 70 are each formed in a cylindrical shape, and the first electrode 40 and the second electrode 5 are formed.
The first electrode 60 and the second electrode 70 are coaxially arranged. Further, the first electrode 40 and the second electrode 50,
If each of the first electrode 60 and the second electrode 70 is a pair of electrodes, the two pairs of electrodes are coaxially arranged. First
Electrode 40, second electrode 50, first electrode 60, second electrode 70
The second electrodes 50 and 70 are arranged outside the first electrodes 40 and 60, respectively. The first electrodes 40, 60 have fins 41, 61 as first protrusions that protrude radially outward toward the second electrodes 50, 70, respectively, and extend in the axial direction. Second electrodes 50, 70
Are fins 51 and 71 as second protrusions that protrude radially inward toward the first electrodes 40 and 60, respectively, and extend in the axial direction.
have. Communication holes 45, 55, 65, and 75 are formed between the fins adjacent to each electrode in the circumferential direction so as to communicate the inside and outside of each electrode and allow oil to flow therethrough.

As shown in FIG. 8, when the electrodes are assembled, the fins 51 and 71 are located on both sides in the circumferential direction of the fins 41 and 61, and the fins 41 and 61 are located on both sides in the circumferential direction of the fins 51 and 71, respectively. positioned. That is, each of the fins 41 and 61 has two fins 51 and 7 respectively.
1 and the fins 51 and 71 each have two fins 41,
It faces 61. Further, the first electrodes 40, 60
Are radially opposed to the inner peripheral surfaces of the second electrodes 50 and 70, respectively. Further, the outer peripheral surface of the second electrode 50 and the inner peripheral surface of the first electrode 60 are radially opposed. Therefore, the facing area where the first electrodes 40 and 60 face the second electrodes 50 and 70 is large. First electrodes 40, 6
When the facing area between 0 and the second electrodes 50 and 70 increases,
Since the resistance between the electrodes is reduced, the degree of oil deterioration can be detected with high accuracy.

(Third Embodiment) FIG. 9 shows a third embodiment of the present invention.
And FIG. Components substantially the same as those of the second embodiment are denoted by the same reference numerals. Oil detecting device 8 of third embodiment
0 has the first electrodes 40 and 60 and the second electrodes 50 and 70 shown in the second embodiment, and the remaining amount sensor 81 for detecting the remaining amount of oil. The remaining amount sensor 81 is a known remaining amount sensor that detects the remaining amount of oil, and is disposed inside the innermost first electrode 40. The oil detector 80 is inserted from the outside of the oil pan 90 through the insertion hole 91 of the oil pan 90 so that each electrode and the remaining amount sensor 81 are immersed in the oil of the oil pan 90.

Each of the electrodes, which is a deterioration sensor for detecting the degree of deterioration of oil, and a remaining amount sensor for detecting the remaining amount of oil are provided in one oil detecting device 80. The number of steps for attaching both sensors is reduced as compared with the case where the sensors are separately attached to the oil pan 90. further,
Since the remaining amount sensor 81 is disposed inside the innermost first electrode 40, the diameter of the oil detection device 80 does not increase. Therefore, the diameter of the insertion hole 91 for inserting the oil detection device 80 into the oil pan 90 can be reduced.

(Fourth Embodiment) FIG. 1 shows a fourth embodiment of the present invention.
It is shown in FIG. The first electrode 120 of the fourth embodiment has substantially the same configuration as the first electrode 20 of the first embodiment, and the second electrode 130 of the fourth embodiment has substantially the same configuration as the second electrode 30 of the first embodiment. In the fourth embodiment, the fins 121 as the first projections and the fins 131 as the second projections are formed by attaching the mounting portions 122 and 132, which are cylindrical ends, to the supporting member 140 made of insulating resin with the adhesive 145.
It is fixed at. Fins 121 and 131 are supporting members 1
40 and is not in contact with the support member 140.
Also, the surface of the support member 140 on the side where the mounting portions 122 and 132 of both electrodes are mounted is the mounting portion 122 and the mounting portion 13.
2, a concave portion 141 which is an uneven portion is formed.

Since the fins 121 and 131 do not contact the support member, the fin 121 and the fin 1
This prevents a current from leaking between the first and the second. Further, since the concave portion 141 is formed between the mounting portion 122 and the mounting portion 132, the surface distance of the support member 140 between the mounting portion 122 and the mounting portion 132, that is, the creepage distance is increased. Even if conductive foreign matter mixed in oil, for example, adheres to the surface of the support member 140 located between the mounting portions, the creepage distance of the support member 140 increases, so that the mounting portion 122 and the mounting portion are interposed through the foreign material. 132 is prevented from conducting. Since the leakage current is prevented from flowing between the mounting portion 122 and the mounting portion 132, that is, between the electrode 120 and the electrode 130, the accuracy of detecting the potential between the electrodes is improved.

The first, second, third and fourth described above
In the embodiment, the first electrode and the second electrode each formed in a cylindrical shape are used.
Fins are formed on the electrodes, and the fins of the first electrode and the fins of the second electrode alternately arranged in the circumferential direction face in addition to the outer peripheral surface of the first electrode and the inner peripheral surface of the second electrode. As a result, the facing area between the electrodes increases, and the resistance between the electrodes decreases.
Therefore, the degree of oil deterioration can be detected with high accuracy.
Further, since each electrode is formed by pressing one thin plate, the number of components of the deterioration sensor is reduced, and the man-hour for assembling the oil detection device is reduced.

In the above embodiments, the fins extend in the axial direction of each electrode formed in a cylindrical shape, but fins extending in a spiral shape may be formed. Further, each electrode may be formed by making the corrugated plate into a cylindrical shape. Although each electrode is formed in a cylindrical shape, the shape of each electrode may be a polygonal cylindrical shape as long as it is cylindrical. Further, although each electrode is formed by pressing a thin plate and rounding it into a cylindrical shape, each electrode may be formed by forming a projection while cutting a metal into a cylindrical shape. Further, the electrodes can be formed by extruding the finned inner cylinder and outer cylinder in the axial direction.

(Fifth embodiment, sixth embodiment, seventh embodiment,
Eighth Embodiment FIGS. 12, 13, 14, and 15 show fifth, sixth, seventh, and eighth embodiments of the present invention, respectively. In each embodiment, substantially the same components are denoted by the same reference numerals. The first electrode 150 and the second electrode 160 of the fifth embodiment shown in FIG. 12 are the same as the first electrode 120 and the second electrode 160 of the fourth embodiment.
The fin may have the same shape as the electrode 130, or may have a different shape. Although both electrodes are drawn in a cylindrical shape, they may be stacked electrodes having the same configuration as the conventional example shown in FIG. The support member 140 is
As in the embodiment, a concave portion 141 is formed between the mounting portion 151 and the mounting portion 161 on the surface where the mounting portions 151 and 161 are mounted.

The first electrode 150 and the second electrode 160
The mounting portion 151 and the mounting portion 161 are fixed to the support member 140 with an adhesive 145, and portions other than the mounting portions 151 and 161 are separated from the support member 140 and are not in contact. Further, similarly to the fourth embodiment, the concave portion 1 is formed on the surface of the support member 140 located between the mounting portion 151 and the mounting portion 161.
Since the base member 41 is formed, the creepage distance of the support member 140 is long. Therefore, the first electrode 150 and the second
Since leakage current is prevented from flowing between the electrodes 160, the accuracy of detecting the potential between the electrodes is improved.

In the sixth embodiment shown in FIG.
The mounting portion 161 of the first electrode 150 is bent in a direction away from the mounting portion 151 of the first electrode 150, and the mounting portion 161 is located farther from the mounting portion 151 than in the fifth embodiment.
Fixed to. Since the creepage distance of the support member 140 between the attachment portions 151 and the attachment portions 161 becomes longer, for example, conductive foreign matters mixed in oil adhere to the surface of the support member 140 located between the attachment portions. This also prevents conduction between the mounting portion 122 and the mounting portion 132 via foreign matter. Between the mounting portion 151 and the mounting portion 161, that is, the electrode 1
Since the leakage current is prevented from flowing between the electrode 50 and the electrode 160, the accuracy of detecting the potential between the electrodes is improved.

In the seventh embodiment shown in FIG.
50 mounting part 151 and second electrode 160 mounting part 16
1 are bent in directions away from the other mounting portions, and are fixed to the support member 140. Mounting part 151
Since the creepage distance of the support member 140 between the first electrode 15 and the mounting portion 161 increases, the first electrode 15 passes through the surface of the support member 140.
A leak current is prevented from flowing between the zero and the second electrode 160.

The eighth embodiment shown in FIG. 15 has attachment portions 151 and 161 having the same shape as the seventh embodiment. On the surface of the support member 140 to which the mounting portions 151 and 161 are mounted, irregularities 142 having a comb-like cross section are formed between the mounting portion 151 and the mounting portion 161. Mounting part 151 and mounting part 16
Since the creepage distance of the support member 140 between the first and second members becomes longer,
A leak current is prevented from flowing between the first electrode 150 and the second electrode 160 through the surface of the support member 140.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electrode of an oil detection device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an electrode according to the first embodiment.

FIG. 3A is a cross-sectional view showing the oil detecting device of the first embodiment, and FIG. 3B is a view taken in the direction of arrow B in FIG. 3A with the cover removed.

FIG. 4A is a plan view showing a first electrode base material of the first embodiment, and FIG. 4B is a cross-sectional view taken along line BB of FIG.

FIG. 5 is a cross-sectional view showing a first electrode formed by rolling a first electrode base material.

FIG. 6A is a plan view showing a second electrode base material of the first embodiment, and FIG. 6B is a cross-sectional view taken along line BB of FIG. 6A.

FIG. 7 is a cross-sectional view showing a second electrode formed by rolling a second electrode base material.

FIG. 8 is a cross-sectional view illustrating an electrode of an oil detector according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a state where an oil detection device according to a third embodiment of the present invention is attached to an oil pan.

FIG. 10 is an X-direction view of the oil detection device in FIG. 9 from which a cover is removed.

FIG. 11 is a schematic sectional view showing an oil detection device according to a fourth embodiment of the present invention.

FIG. 12 is a schematic sectional view showing an oil detection device according to a fifth embodiment of the present invention.

FIG. 13 is a schematic sectional view showing an oil detection device according to a sixth embodiment of the present invention.

FIG. 14 is a schematic sectional view showing an oil detection device according to a seventh embodiment of the present invention.

FIG. 15 is a schematic sectional view showing an oil detection device according to an eighth embodiment of the present invention.

FIG. 16 is a sectional view showing the periphery of an electrode of a conventional oil detection device.

[Explanation of symbols]

 10, 80 Oil detection device 20, 40, 60, 120, 150 First electrode 21, 41, 61, 121 Fin (first protrusion) 25, 35, 45, 55, 65, 75 Communication hole 30, 50, 70 , 130, 160 Second electrode 31, 51, 71, 131 Fin (second protrusion) 81 Remaining sensor 100 First electrode base material 110 Second electrode base material 140 Support member 141 Depression (irregularity) 142, Irregularity 122, 132, 151, 161 mounting part

Claims (12)

[Claims] 1. An oil detecting device for detecting a degree of oil deterioration based on a potential difference between electrodes, comprising: a first cylindrical electrode; and an outer peripheral side of the first electrode arranged substantially coaxially with the first electrode. A second electrode having a cylindrical shape, wherein the first electrode has a first protrusion protruding radially outward toward the second electrode, and the second electrode is provided on the first electrode side. An oil detection device, comprising: a second protrusion protruding radially inward, and wherein the first protrusion and the second protrusion have different protruding directions. 2. The oil detecting device according to claim 1, wherein the first protrusions and the second protrusions are alternately arranged in a circumferential direction. 3. The oil detecting device according to claim 1, wherein a communication hole communicating between the inside and the outside is formed in the first electrode and the second electrode. 4. The oil detection device according to claim 1, wherein the first electrode and the second electrode constitute a pair of electrode pairs, and a plurality of electrode pairs are arranged coaxially. apparatus. 5. The oil detecting device according to claim 1, further comprising a remaining amount sensor for detecting a remaining amount of the oil inside the electrode located at the innermost side. 6. A support member formed of an insulating material and having the first electrode and the second electrode attached thereto, wherein the first protrusion and the second protrusion are not in contact with the support member. The oil detection device according to any one of claims 1 to 5, characterized in that: 7. The device according to claim 6, wherein at least one of the attachment portions of the first electrode and the second electrode attached to the support member is bent away from the other attachment portion. The oil detection device as described in the above. 8. An oil detecting device for detecting a degree of oil deterioration based on a potential difference between electrodes, comprising: a first electrode and a second electrode which face each other and generate a potential difference when immersed in oil; and an insulating material. And a support member to which the first electrode and the second electrode are attached, wherein at least one of the attachment portions of the first electrode and the second electrode attached to the support member is the other attachment portion. An oil detector characterized by being bent away from the part. 9. The surface of the support member on which the two electrodes are attached has irregularities formed between the first electrode and the second electrode.
The oil detection device as described in the above. 10. An oil detecting device for detecting a degree of oil deterioration based on a potential difference between electrodes, comprising an insulating material and a first electrode and a second electrode facing each other to generate a potential difference when immersed in oil. And a support member to which the first electrode and the second electrode are attached, and a surface of the support member on the side to which the two electrodes are attached,
An oil detecting device, wherein irregularities are formed between the first electrode and the second electrode. 11. A step of punching a thin plate-shaped first electrode base material and a second electrode base material by a press, and projecting a plurality of fins on one spread surface side of both base materials, so that the fins face outward. Forming the first electrode base material into a cylindrical shape to form a first electrode; forming the second electrode base material into a cylindrical shape so that the fins face inward; forming a second electrode; Assembling the first electrode and the second electrode such that the fins of the first electrode and the fins of the second electrode are alternately located in the circumferential direction. Method. 12. The fin of the first electrode and the fin of the second electrode extend in the axial direction in a state where the first electrode base material and the second electrode base material are rolled into a cylindrical shape. 12. The method according to claim 11, wherein the first electrode base material and the second electrode base material are punched by a press.