JP2021032381A - Sealing device and sealing structure - Google Patents

Abstract

To provide a sealing device which can exactly detect the leakage of a sealed liquid, and can reduce a time and labor for an arrangement of equipment.SOLUTION: A sealing device is arranged between an inside member and an outside member which relatively rotate, and seals a clearance between the inside member and the outside member. The inside member is at least partially formed of a conductive material. The sealing device comprises: an attachment part attached to the outside member; a circular disc-shaped lip arranged inside the attachment part in a radial direction, and extending toward the inside member; an elastic material-made elastic ring arranged between the lip and the inside member, and interference-fit with the inside member; at least two electrodes arranged at an internal peripheral face of the elastic ring; a measuring instrument arranged at the elastic ring, and measuring an electricity conductive state between the electrodes; and a radio transmitter arranged at the elastic ring, and repeatedly or continuously transmitting a signal indicating a measurement result of the measuring instrument.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sealing device and a sealing structure.

Conventionally, a sealing device that seals a gap between a relatively rotating inner member and an outer member has been used in various applications. The sealing device has a limited life and is replaced regularly.

Patent Document 1 discloses a device for monitoring a decrease in the sealing function of a sealing device, that is, a leak of a liquid to be sealed. With such a device, the sealing device can be replaced before the end of the life of the sealing device. For example, sealing devices used in dusty environments have a shorter lifespan than those used in clean environments, but by using such techniques, individual sealing devices can be replaced in a timely manner. it can.

Japanese Unexamined Patent Publication No. 2004-308905

It is desirable to be able to detect leaks of the sealed liquid more accurately. In addition, it is desirable that there is no need to deploy equipment for monitoring the leakage of the sealed liquid.

Therefore, the present invention provides a sealing device and a sealing structure that can more accurately detect the leakage of the liquid to be sealed and reduce the labor of deploying the equipment.

The sealing device according to an aspect of the present invention is a sealing device that is arranged between a relatively rotating inner member and an outer member and seals a gap between the inner member and the outer member. The inner member is at least partially formed of a conductive material. The sealing device is arranged between a mounting portion attached to the outer member, an annular lip extending radially inside the mounting portion, and an annular lip extending toward the inner member, and between the lip and the inner member. An elastic ring made of an elastic material to which the inner member is tightly fitted, at least two electrodes arranged on the inner peripheral surface of the elastic ring, and electrical conduction between the electrodes arranged on the elastic ring. It has a measuring instrument for measuring a state and a wireless transmitter arranged on the elastic ring and repeatedly or continuously transmitting a signal indicating a measurement result of the measuring instrument.

In this embodiment, the electrical conduction state between at least two electrodes located on the inner peripheral surface of the elastic ring interposed between the lip and the inner member reflects the sealed state between the elastic ring and the inner member. To do. For example, if the sealed liquid does not enter between the elastic ring and the inner member, the electrodes come into contact with the inner member, which is partially formed of a conductive material, and the resistance or impedance between the electrodes is low and flows between the electrodes. The current is large, and if the sealed liquid enters between the elastic ring and the inner member (if there is a leak of the sealed liquid), the resistance or impedance between the electrodes is high and the current flowing between the electrodes is small. Therefore, by measuring the state of electrical conduction between the electrodes, it is possible to accurately detect whether or not there is a leak of the sealed liquid. The measuring instrument measures the state of electrical conduction between the electrodes, and the wireless transmitter transmits a signal indicating the measurement result of the measuring instrument. A signal indicating the measurement result of the measuring instrument is received by an external receiving device, and it is possible to recognize whether or not there is a leak of the sealed liquid by analyzing the measurement result. Since the transmitter is a wireless transmitter arranged in an elastic ring, there is no need to deploy cables.

It is sectional drawing of the sealed structure which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 showing a cross section of an elastic ring having a sealed structure and a rotating shaft in normal times. It is a partially broken enlarged perspective view of an elastic ring and its surroundings in normal times. It is a partially broken enlarged perspective view of the elastic ring and its surroundings at the time of abnormality. It is a graph which shows the example of the measurement result of the measuring instrument of the sealed structure which concerns on embodiment. It is sectional drawing which shows the cross section of the elastic ring and the rotating shaft of the sealing structure in normal times which concerns on the modification of embodiment of this invention. It is a graph which shows the example of the measurement result of the measuring instrument of the sealed structure which concerns on the modification of FIG. It is sectional drawing of the sealed structure which concerns on other modification of embodiment of this invention.

Hereinafter, various embodiments according to the present invention will be described with reference to the accompanying drawings. Drawing scales are not always accurate and some features may be exaggerated or omitted.

As shown in FIG. 1, the sealing structure according to the embodiment of the present invention has a columnar rotating shaft (inner member) 2 and a housing (outer member) 4 of the rotating shaft 2. Most of the rotating shaft 2 is made of a conductive material, for example steel. The housing 4 has a cylindrical shaft hole 4A in which the rotating shaft 2 is arranged. While the housing 4 is stationary, the rotating shaft 2 rotates around the central axis Ax.

A sealing device 1 which is a packing is arranged in the gap between the rotating shaft 2 and the housing 4.

Although the sealing device 1 is annular, only the upper portion thereof is shown in the figure. In the figure, the right side is the liquid side on which the sealed liquid (for example, oil) is arranged, and the left side is the atmosphere side. The sealing device 1 seals the gap between the rotating shaft 2 and the housing 4, suppresses the leakage of the liquid from the liquid side to the atmosphere side, and suppresses the intrusion of water and dust from the atmosphere side to the liquid side.

The sealing device 1 has a composite structure having an elastic ring 12 and a rigid ring 14. The elastic ring 12 is made of an elastic material, for example, an elastomer. The rigid ring 14 is made of a rigid material, for example metal, to reinforce the elastic ring 12. In this embodiment, the rigid ring 14 has a substantially L-shaped cross section. In this embodiment, almost the entire rigid ring 14 is embedded in the elastic ring 12, and is in close contact with the elastic ring 12.

The sealing device 1 has an outer cylindrical portion 16, an inner cylindrical portion 17, and a connecting ring portion 18.

The outer cylindrical portion (mounting portion) 16 is composed of an elastic ring 12 and a rigid ring 14, and is mounted in the shaft hole 4A of the housing 4. The mounting method is not limited, but for example, the outer cylindrical portion 16 is fitted (that is, press-fitted) into the shaft hole 4A of the housing 4 by a tightening method.

The connecting ring portion 18 connects the outer cylindrical portion 16 and the inner cylindrical portion 17 arranged radially inside the outer cylindrical portion 16. The connecting ring portion 18 is also composed of an elastic ring 12 and a rigid ring 14.

The inner cylindrical portion 17 is composed of only the elastic ring 12, and surrounds the rotating shaft 2. The inner cylindrical portion 17 has a main lip (seal lip) 20 and a dust strip 21. The main lip 20 is an annular protrusion that protrudes inward in the radial direction, and the tip of the main lip 20 slidably contacts the outer peripheral surface of the rotating shaft 2. The main lip 20 mainly serves to seal the liquid to be sealed.

The dust strip 21 is an annular protrusion having a truncated cone shape that extends radially inward and toward the atmosphere. The tip of the dust strip 21 slidably contacts the outer peripheral surface of the rotating shaft 2. The dust strip 21 mainly plays a role of suppressing the intrusion of water and dust from the atmospheric side to the liquid side.

A dust strip 22 further extends from the connecting portion between the inner cylindrical portion 17 and the connecting ring portion 18. The dust strip 22 is an annular protrusion having a truncated cone shape that extends radially inward and toward the atmosphere. The dust strip 22 extends toward the rotating shaft 2, and an elastic ring 40, which will be described later, is interposed between the tip of the dust strip 22 and the rotating shaft 2. The dust strip 22 also plays a role of suppressing the intrusion of water and dust mainly from the atmospheric side to the liquid side. Since the main lip 20 and the dust strip 21 are located on the liquid side of the dust strip 22, the liquid to be sealed is not present in the vicinity of the dust strip 22 in normal times, or even if it is present, the amount is very small.

In the figure, the rotating shaft 2 is shown by a virtual line, but the lips 20, 21, and 22 are shown as being deformed by receiving a reaction force from the rotating shaft 2. The lips 20, 21, 22 are made of an elastic material.

Although not essential, a garter spring 24 is wound around the outer circumference of the inner cylindrical portion 17. The garter spring 24 compresses the inner cylindrical portion 17 inward in the radial direction and presses the main lip 20 against the rotating shaft 2.

An elastic material, for example, an elastic ring 40 made of an elastomer, is arranged between the tip of the dust strip 22 arranged on the most atmospheric side of the lips 20, 21 and 22 and the rotating shaft 2. The rotating shaft 2 is tightly fitted to the elastic ring 40. Therefore, in normal times, the elastic ring 40 rotates together with the rotating shaft 2.

As shown in FIGS. 1 and 2, two electrodes 42 are arranged (for example, embedded) on the inner peripheral surface of the elastic ring 40, and the electrodes 42 are brought into contact with the outer peripheral surface of the rotating shaft 2. In FIG. 2, the hatching of the elastic ring 40 is omitted. As shown in FIG. 2, the two electrodes 42 are arranged at intervals in the circumferential direction of the elastic ring 40. Since the elastic ring 40 rotates together with the rotating shaft 2 in normal times, the relative angular positions of the two electrodes 42 with respect to the rotating shaft 2 do not change.

As shown in FIG. 2, a current is supplied to the electrode 42 by the battery 44. As long as the electrode 42 is in contact with the conductive material portion of the rotating shaft 2, the current from the battery 44 continues to flow through the circuit having the two electrodes 42 and the rotating shaft 2.

The electrode 42 may be made of a hard conductive material, such as copper. However, preferably, the electrode 42 is formed from an elastomer containing powder of a conductive material. By forming the electrode 42 from a material similar to other parts of the inner peripheral surface of the elastic ring 40, the pressure acting between the elastic ring 40 and the dust strip 22 is made substantially uniform over the circumferential direction. In any case, the inner surface of the electrode 42 smoothly connects to the inner peripheral surface of the elastic ring 40.

A measuring instrument 46 for measuring the state of electrical conduction between the electrodes 42 is arranged on the elastic ring 40. In this embodiment, the measuring instrument 46 is an ammeter, but may be an ohmmeter or an impedance meter.

Further, a wireless transmitter 48 for transmitting a signal indicating the measurement result of the measuring instrument 46 is arranged on the elastic ring 40. The wireless transmitter 48 may be an IC tag using the principle of RFID, or may be another type of wireless transmitter. The radio transmitter 48 repeatedly (for example, periodically) or continuously transmits a signal indicating the measurement result of the measuring device 46. The signal indicating the measurement result of the measuring instrument 46 may be in a form that can be recognized by a human being or a form that can be recognized by a machine.

In this embodiment, the measuring instrument 46 and the wireless transmitter 48 are embedded in the elastic ring 40, but the measuring instrument 46 and / or the wireless transmitter 48 is located in the elastic ring 40 so as not to contact the dust strip 22, for example, the elastic ring. It may be arranged and fixed to the end face of 40.

On the other hand, the outer peripheral surface of the rotating shaft 2 has a conductive region made of a conductive material and a non-conductive region made of a non-conductive material, and the conductive region and the non-conductive region are arranged in the circumferential direction of the rotating shaft 2. The region inside the outer peripheral surface of the rotating shaft 2 is formed of a conductive material. Specifically, a non-conductive section 50, which is a thin plate made of a non-conductive material, is embedded in a part of the outer peripheral surface of the rotating shaft 2 which is entirely made of a conductive material. The non-conductive section 50 corresponds to the non-conductive region. The other portion of the outer peripheral surface of the rotating shaft 2 corresponds to the conductive region. In this embodiment, two non-conductive sections 50 are provided.

The non-conductive section 50 is formed of a hard resin material having a small coefficient of friction, such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE). The outer peripheral surface of the non-conductive section 50 is flush with other parts of the rotating shaft 2.

In the above configuration, if the two electrodes 42 arranged on the inner peripheral surface of the elastic ring 40 are in contact with the conductive region of the rotating shaft 2, the resistance or impedance between the electrodes 42 is low, and between the electrodes 42. The current flowing through is large. On the other hand, if one or both of the two electrodes 42 are in contact with the non-conductive region (non-conductive section 50) of the rotating shaft 2, the resistance or impedance between the electrodes 42 is high, and the current flowing between the electrodes 42 is high. small.

In this embodiment, in a normal state in which the liquid to be sealed does not enter between the elastic ring 40 and the rotating shaft 2, as shown in FIG. 2, the two electrodes 42 of the sealing device 1 are on the outer peripheral surface of the rotating shaft 2. It is in contact with a conductive region (a region other than the non-conductive section 50).

Since the rotating shaft 2 is tightly fitted to the elastic ring 40, as shown in the enlarged view of FIG. 3, the elastic ring 40 rotates together with the rotating shaft 2 together with the electrode 42 in normal times. Frictional force F ₁ between the elastic ring 40 and the rotary shaft 2 can be expressed by the following equation.

F ₁ = μ ₁ N ₁ = 2πμ ₁ T
Here, μ ₁ is the coefficient of friction between the elastic ring 40 and the rotating shaft 2, and N ₁ is the binding force of the elastic ring 40 to the rotating shaft 2. T is the tension of the elastic ring 40.

The tip of the dust strip 22 is pressed against the outer peripheral surface of the elastic ring 40. _{The frictional force F 2} between the elastic ring 40 and the dust strip 22 can be expressed by the following equation.

F ₂ = μ ₂ N ₂
Here, μ ₂ is the coefficient of friction between the elastic ring 40 and the dust strip 22, and N ₂ is the binding force of the dust strip 22 to the elastic ring 40.

_{As shown in FIG. 3, F 2} <F ₁ in normal times, that is, in a state where the sealed liquid does not enter between the elastic ring 40 and the rotating shaft 2. In this state, the elastic ring 40 rotates at an _{angular velocity R 2} equal to the angular _{velocity R 1 of the rotating shaft 2.} That is, the relative angular positions of the elastic ring 40 and the rotating shaft 2 are invariant, and the current from the battery 44 continues to flow through the circuit having the two electrodes 42 and the rotating shaft 2, and as shown in FIG. A constant current value is measured. The resistance or impedance between the electrodes 42 is low, and the current flowing between the electrodes 42 is large.

On the other hand, as shown in FIG. 4, when the sealed liquid (for example, oil) has entered between the inner peripheral surface of the elastic ring 40 and the outer peripheral surface of the rotating shaft 2 (there is a leak of the sealed liquid), F ₂ > become _{F 1.} In FIG. 4, the arrow OF indicates the flow of the sealed liquid. In this state, the elastic ring 40 rotates at an angular velocity R _{2 smaller than the angular velocity R 1} of the rotating shaft 2. That is, the relative angular positions of the elastic ring 40 and the rotating shaft 2 change, and the electrode 42 contacts the conductive region on the outer peripheral surface of the rotating shaft 2 or the non-conductive section 50. Therefore, as shown in FIG. 5, the current flowing between the electrodes 42 periodically increases or decreases. Here, the amount of the sealed liquid that penetrates between the elastic ring 40 and the rotating shaft 2 is very small, and the elastic ring 40 and the rotating shaft 2 are not completely separated by the sealed liquid, but the surface of the electrode 42. It is assumed that the minute convex portion of the rotary shaft 2 comes into contact with the minute convex portion on the outer peripheral surface of the rotating shaft 2.

By analyzing the measurement result of the measuring instrument 46 that measures the state of electrical conduction between the elastic ring 40 between the dust strip 22 and the rotating shaft 2 and the rotating shaft 2, it is detected whether or not there is a leak of the sealed liquid. It is possible.

When an extremely large amount of sealed liquid enters between the inner peripheral surface of the elastic ring 40 and the outer peripheral surface of the rotating shaft 2, if the sealed liquid is insulating, the current flowing between the electrodes 42 is cut off. If the liquid to be sealed is conductive, the current flowing between the electrodes 42 becomes a substantially constant low value. However, before that, since the current flowing between the electrodes 42 increases or decreases, leakage of the sealed liquid can be detected at an early stage.

The measuring instrument 46 measures the state of electrical conduction between the electrodes 42, and the wireless transmitter 48 transmits a signal indicating the measurement result of the measuring instrument 46. A signal indicating the measurement result of the measuring device 46 is received by an external receiving device (not shown), and it is possible to recognize the sealed state between the elastic ring 40 and the rotating shaft 2 by analyzing the measurement result. .. Since the transmitter 48 is a wireless transmitter arranged on the elastic ring 40, it does not take time and effort to deploy the cable.

FIG. 6 is a cross-sectional view taken along the line II-II of FIG. 1 as in FIG. 2, but shows a cross-sectional view of the elastic ring and the rotating shaft of the sealed structure according to the modified example. In this modification, in a normal state in which the liquid to be sealed does not enter between the elastic ring 40 and the rotating shaft 2, as shown in FIG. 6, the two electrodes 42 of the sealing device 1 are on the outer peripheral surface of the rotating shaft 2. It is in contact with the non-conductive region (non-conductive section 50).

In this modification, in the normal state, the relative angular positions of the elastic ring 40 and the rotating shaft 2 are unchanged, the resistance or impedance between the electrodes 42 is high, and as shown in FIG. 7, the current flowing between the electrodes 42 Is small (eg zero). On the other hand, when the sealed liquid enters between the elastic ring 40 and the rotating shaft 2 (when the sealed liquid leaks), the relative angular positions of the elastic ring 40 and the rotating shaft 2 change, and the electrode 42 changes. As shown in FIG. 7, the current flowing between the electrodes 42 periodically increases or decreases in contact with the conductive region or the non-conductive region on the outer peripheral surface of the rotating shaft 2. Here, the amount of the sealed liquid that penetrates between the elastic ring 40 and the rotating shaft 2 is very small, and the elastic ring 40 and the rotating shaft 2 are not completely separated by the sealed liquid, but the surface of the electrode 42. It is assumed that the minute convex portion of the rotary shaft 2 comes into contact with the minute convex portion on the outer peripheral surface of the rotating shaft 2.

By analyzing the measurement result of the measuring instrument 46 that measures the state of electrical conduction between the elastic ring 40 between the dust strip 22 and the rotating shaft 2 and the rotating shaft 2, it is detected whether or not there is a leak of the sealed liquid. It is possible.

When an extremely large amount of sealed liquid enters between the inner peripheral surface of the elastic ring 40 and the outer peripheral surface of the rotating shaft 2, if the sealed liquid is insulating, the current flowing between the electrodes 42 is cut off. If the liquid to be sealed is conductive, the current flowing between the electrodes 42 becomes a substantially constant low value. However, before that, since the current flowing between the electrodes 42 increases or decreases, leakage of the sealed liquid can be detected at an early stage.

FIG. 8 is a cross-sectional view of a sealed structure according to another modified example. In this modification, the dust strip 22 is not provided, and the elastic ring 40 is arranged between the inclined surface of the main lip 20 on the atmosphere side and the rotating shaft 2. The rotating shaft 2 is tightly fitted to the elastic ring 40. Further, two electrodes 42 are arranged on the elastic ring 40, and the two electrodes 42 are arranged in the circumferential direction of the elastic ring 40. Also in this case, as in the above embodiment and the modified example, the leakage of the sealed liquid from the main lip 20 is prevented by measuring the electric conduction state between the elastic ring 40 and the rotating shaft 2 with the measuring instrument 46. Can be recognized accurately.

Further, in the structure of FIG. 1, an elastic ring 40 is arranged between the tip of the dust strip 22 and the rotating shaft 2, and an elastic ring 40 is arranged between the inclined surface of the main lip 20 on the atmosphere side and the rotating shaft 2. You may. An elastic ring 40 may be arranged between the tip of the dust strip 21 and the rotating shaft 2. In either case, two electrodes 42 may be arranged on the elastic ring 40, and the two electrodes 42 may be arranged in the circumferential direction of the elastic ring 40.

Although the present invention has been illustrated and described above with reference to preferred embodiments of the present invention, those skilled in the art can change the form and details without departing from the scope of the invention described in the claims. It will be understood that there is. Such changes, modifications and modifications should be within the scope of the present invention.

For example, in the above embodiment, the housing (outer member) 4 is stationary, while the rotation axis (inner member) 2 rotates around the central axis Ax. However, the present invention can also be applied to a structure in which the inner member is stationary and the outer member is rotated. The present invention can also be applied to a structure in which the inner member and the outer member rotate, and the inner member and the outer member rotate relative to each other.

The sealing device 1 according to the embodiment is a single sealing member, but the basic structure of the sealing device is not limited to the embodiment, and the present invention can be applied to a sealing device in which a plurality of sealing members are combined. is there. Further, the shape of the lip that presses the elastic ring against the inner member is not limited to the embodiment.

In the embodiment, two non-conductive sections 50 are provided, and the angular spacing between the two non-conductive sections 50 is equal to the angular spacing between the two electrodes 42. However, the number of non-conductive sections 50 may be 1 or 3 or more.

In the embodiment, the number of electrodes 42 arranged on the elastic ring 40 is two, but the number of electrodes may be three or more.

The above embodiments and modifications may be combined as long as there is no contradiction.

Aspects of the invention are also described in the numbered clauses below.

Clause 1. A sealing device that is disposed between a relatively rotating inner member and an outer member and seals a gap between the inner member and the outer member, wherein the inner member is at least partially made of a conductive material. Formed,
A mounting portion attached to the outer member and
An annular lip that is arranged radially inside the mounting portion and extends toward the inner member.
An elastic ring made of an elastic material arranged between the lip and the inner member and to which the inner member is tightly fitted.
At least two electrodes arranged on the inner peripheral surface of the elastic ring,
A measuring instrument arranged on the elastic ring and measuring the state of electrical conduction between the electrodes,
A sealing device arranged on the elastic ring and comprising a wireless transmitter that repeatedly or continuously transmits a signal indicating a measurement result of the measuring instrument.

Clause 2. The sealing device described in Clause 1 and
With the inner member
Having the outer member
The outer peripheral surface of the inner member has a conductive region made of a conductive material and a non-conductive region made of a non-conductive material, and the conductive region and the non-conductive region are arranged in the circumferential direction of the inner member.
A sealing structure characterized in that the inner region of the outer peripheral surface of the inner member is formed of a conductive material.

According to this clause, if at least two electrodes arranged on the inner peripheral surface of the elastic ring are in contact with the conductive region of the inner member, the resistance or impedance between the electrodes is low and the current flowing between the electrodes is large. If one or both of the at least two electrodes are in contact with the non-conductive region of the inner member, the resistance or impedance between the electrodes is high and the current flowing between the electrodes is low. When the liquid to be sealed does not enter between the elastic ring and the inner member, the relative angular position between the elastic ring and the inner member is invariant, and the current flowing between the electrodes is constant. On the other hand, when the sealed liquid enters between the elastic ring and the inner member (when the sealed liquid leaks), the relative angular position between the elastic ring and the inner member changes, and the current flowing between the electrodes changes. Increase or decrease (for example, periodically). Therefore, it is possible to detect whether or not there is a leak of the sealed liquid by analyzing the measurement result of the measuring instrument.

Clause 3. The feature is that at least two electrodes of the sealing device are brought into contact with the conductive region on the outer peripheral surface of the inner member in a normal state in which the liquid to be sealed does not enter between the elastic ring and the inner member. The sealed structure described in Clause 2.

According to this clause, in the normal state, the relative angular position of the elastic ring and the inner member is invariant, the resistance or impedance between the electrodes is low, and the current flowing between the electrodes is large. When the liquid to be sealed enters between the elastic ring and the inner member (when the liquid to be sealed leaks), the relative angular position between the elastic ring and the inner member changes, and the electrode is conductive on the outer peripheral surface of the inner member. The current flowing between the electrodes increases or decreases (eg, periodically) in contact with the region or in contact with the non-conductive region.

Clause 4. In a normal state in which the liquid to be sealed does not enter between the elastic ring and the inner member, one or both of the at least two electrodes of the sealing device are brought into contact with the non-conductive region on the outer peripheral surface of the inner member. The sealed structure according to Clause 2, characterized in that it is.

According to this clause, in the normal state, the relative angular position of the elastic ring and the inner member is invariant, the resistance or impedance between the electrodes is high, and the current flowing between the electrodes is small. When the liquid to be sealed enters between the elastic ring and the inner member (when the liquid to be sealed leaks), the relative angular position between the elastic ring and the inner member changes, and the electrode is conductive on the outer peripheral surface of the inner member. The current flowing between the electrodes increases or decreases (eg, periodically) in contact with the region or in contact with the non-conductive region.

1 Sealing device 2 Rotating shaft (inner member)
4 Housing (outer member)
16 Outer cylindrical part (mounting part)
20 Main lip Main lip (seal lip)
21,22 Dustrip 40 Elastic ring 42 Electrode 44 Battery 46 Measuring instrument 48 Radio transmitter 50 Non-conductive intercept (non-conductive region)

Claims (2)

A sealing device that is disposed between a relatively rotating inner member and an outer member and seals a gap between the inner member and the outer member, wherein the inner member is at least partially made of a conductive material. Formed,
A mounting portion attached to the outer member and
An annular lip that is arranged radially inside the mounting portion and extends toward the inner member.
An elastic ring made of an elastic material arranged between the lip and the inner member and to which the inner member is tightly fitted.
At least two electrodes arranged on the inner peripheral surface of the elastic ring,
A measuring instrument arranged on the elastic ring and measuring the state of electrical conduction between the electrodes,
A sealing device arranged on the elastic ring and comprising a wireless transmitter that repeatedly or continuously transmits a signal indicating a measurement result of the measuring instrument. The sealing device according to claim 1 and
With the inner member
Having the outer member
The outer peripheral surface of the inner member has a conductive region made of a conductive material and a non-conductive region made of a non-conductive material, and the conductive region and the non-conductive region are arranged in the circumferential direction of the inner member.
A sealing structure characterized in that the inner region of the outer peripheral surface of the inner member is formed of a conductive material.

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