JP7373375B2 - sealing device - Google Patents

Description

The present invention relates to a sealing device that seals an annular gap between two relatively rotating members.

2. Description of the Related Art Various devices such as transportation equipment such as cars and robots are equipped with a sealing device that seals an annular gap between two relatively rotating members. Such a sealing device is generally inspected for leakage through periodic inspections such as manual visual inspection. Therefore, if a device equipped with a sealing device continues to be used for a long time even after the sealing device has deteriorated and leakage has occurred, the device itself will deteriorate or break down. For example, when used in wetlands or tropical rainforest areas, there is a lot of dust, exposure to muddy water, and other harsh environments. In recent years, automobiles and the like in particular have been increasingly used in such harsh environments, and it has become difficult to deal with them through periodic inspections alone. Therefore, there is a need for measures to extend the lifespan of devices equipped with sealing devices.

JP2017-89668A Japanese Patent Application Publication No. 9-112701

An object of the present invention is to provide a sealing device that can detect leakage of a fluid to be sealed without manual intervention.

The present invention employs the following means to solve the above problems.

That is, the sealing device of the present invention:
In a sealing device that seals an annular gap between two relatively rotating members,
a reinforcing ring; an elastic seal integrally provided with the reinforcing ring and having a seal lip that slides on one of the two members; a piezoelectric element that vibrates together with the reinforcing ring; a transmitter that transmits an electrical signal;
A leakage detection device comprising: a receiver that receives a signal transmitted from the transmitter; and a detection unit that detects leakage of the fluid to be sealed based on the voltage waveform received by the receiver;
A sealing device comprising:
As a seal lip in the elastic body seal, a main lip that suppresses leakage of the fluid to be sealed and a dust lip that suppresses entry of foreign matter into the fluid to be sealed,
The piezoelectric element is provided at a position between the main lip and the dust lip .
Further, other sealing devices of the present invention include:
In a sealing device that seals an annular gap between two relatively rotating members,
a reinforcing ring; an elastic seal integrally provided with the reinforcing ring and having a seal lip that slides on one of the two members; a piezoelectric element that vibrates together with the reinforcing ring; a transmitter that transmits an electrical signal;
A leakage detection device comprising: a receiver that receives a signal transmitted from the transmitter; and a detection unit that detects leakage of the fluid to be sealed based on the voltage waveform received by the receiver;
A sealing device comprising:
The piezoelectric element is characterized in that it is attached to the reinforcing ring in a cantilevered state.

According to the present invention, the leakage of the fluid to be sealed can be detected by the detection section of the leakage detection device.

If a configuration is adopted in which the piezoelectric element is attached to the reinforcing ring in a cantilevered state, the cantilevered portion will be more likely to vibrate and the sensitivity can be increased, so that the detection accuracy of the leakage detection device can be improved. can be increased.

Further, at least a part of the cantilever portion of the piezoelectric element is preferably disposed at a position where the leaked fluid to be sealed enters a region where the leaked fluid to be sealed accumulates when the piezoelectric element vibrates.

As a result, the leaked fluid to be sealed adheres to the cantilever portion, and the vibration period of the cantilever portion becomes longer, allowing the detection unit to detect a leak.

Furthermore, it is preferable that an absorption structure portion having a structure for absorbing the fluid to be sealed is provided in the cantilever portion.

As a result, when a leak occurs, the absorption structure absorbs the fluid to be sealed, which more reliably increases the weight. Therefore, the detection accuracy of the leak detection device can be improved.

Note that each of the above configurations may be employed in combination as much as possible.

As described above, according to the present invention, leakage of the fluid to be sealed can be detected without manual intervention.

FIG. 1 is a front view of a sealing device main body according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a sealing device main body according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a sealing structure according to an embodiment of the present invention. FIG. 4 is an explanatory diagram of leak detection operation of the sealing device according to the embodiment of the present invention. FIG. 5 is an explanatory diagram of a leak detection method for a sealing device according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Below, with reference to drawings, the form for implementing this invention is illustratively described in detail based on an Example. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this example are not intended to limit the scope of this invention to only those, unless otherwise specified. .

(Example)
A sealing device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a front view of a sealing device main body according to an embodiment of the present invention. In addition, in FIG. 1, a perspective view of a part of the structure is shown by dotted lines. FIG. 2 is a schematic sectional view of a sealing device main body according to an embodiment of the present invention, and corresponds to the AA sectional view in FIG. FIG. 3 is a schematic cross-sectional view of a sealing structure according to an embodiment of the present invention. Note that the sectional view of the sealing device main body in FIG. 3 corresponds to the AA sectional view in FIG. FIG. 4 is an explanatory diagram of leak detection operation of the sealing device according to the embodiment of the present invention. Note that the sealing device main body in FIG. 4 is shown in a partially enlarged cross-sectional view. FIG. 5 is an explanatory diagram of a leak detection method for a sealing device according to an embodiment of the present invention.

<Sealing device>
In particular, with reference to FIG. 3, the overall configuration of the sealing device according to this embodiment will be described. The sealing device 10 according to this embodiment is used to seal an annular gap between two relatively rotating members. In this embodiment, a sealing device 10 is provided to seal an annular gap between a rotating shaft 500 and a housing 600 having a shaft hole 610 into which the rotating shaft 500 is inserted. The sealing device 10 according to the present embodiment includes a sealing device main body 100 disposed in an annular gap between a rotating shaft 500 and a shaft hole 610 of a housing 600, and a leak detection device provided at a position away from the sealing device main body 100. 200. The leak detection device 200 may be installed in the device in which the sealing device main body 100 is provided, or it may be provided in a different position from the device. For example, when used in transportation equipment such as a car, both the sealing device main body 100 and the leak detection device 200 may be included in the transportation equipment. Furthermore, when used in a robot installed in a factory, the leak detection device 200 may be installed at a different location from the robot.

<Sealing device body>
In particular, with reference to FIGS. 1 and 2, the configuration of the sealing device main body 100 according to this embodiment will be described. The sealing device main body 100 includes a reinforcing ring 110 made of a highly rigid material such as metal, and an elastic seal 120 integrally provided with the reinforcing ring 110. The reinforcing ring 110 includes a cylindrical portion 111 and an inward flange portion 112 provided at one end of the cylindrical portion 111. As the material of the elastic seal 120, an elastomer material such as a rubber material can be used. The elastic seal 120 also includes an outer seal portion 121 that is fitted and fixed to the inner circumferential surface of the shaft hole 610 of the housing 600 and a seal lip that slides on the rotating shaft 500. The seal lip according to this embodiment includes a main lip 122 that suppresses leakage of the fluid O to be sealed, and a dust lip 123 that suppresses entry of foreign matter into the fluid to be sealed. A garter spring 130 is attached to the outer peripheral side of the main lip 122 to press the tip of the main lip 122 against the rotating shaft 500.

In the sealing device main body 100 configured as described above, when the rotating shaft 500 rotates, it remains stationary with respect to the housing 600, and the rotating shaft 500 and the seal lip (the main lip 122 and the dust lip 123 ). Thereby, the annular gap between the two members (between the rotating shaft 500 and the housing 600) is sealed.

The sealing device main body 100 according to the present embodiment includes a piezoelectric element 140 that vibrates together with the reinforcing ring 110, a transmitter 150 that transmits an electrical signal from the piezoelectric element 140, and an electrical connection between the piezoelectric element 140 and the transmitter 150. The wiring 160 is connected to the wiring 160.

The piezoelectric element 140 is attached to the reinforcing ring 110 in a cantilevered manner. More specifically, the piezoelectric element 140 has a support 141 fixed to the tip of the inward flange 112 of the reinforcing ring 110, and a direction parallel to the center axis (rotation center axis of the rotating shaft 500) from the tip of the support 141. A cantilever portion 142 (cantilever portion) is provided so as to extend from one side to the other. As a result, the reinforcing ring 110 vibrates as the rotating shaft 500 rotates, and the cantilever section 142 vibrates so that its tip swings greatly. Further, in this embodiment, an absorption structure section 143 having a structure for absorbing the fluid to be sealed is provided at the tip of the cantilever section 142. As a specific example of this absorption structure section 143, it can be constructed by attaching a member made of a material having a function of absorbing liquid leakage to the tip of the cantilever section 142. Materials that absorb leakage may include, for example, nonwoven fabrics, diatomaceous earth, and foam materials. An annular member is manufactured using such a material, and the annular member is attached to the tip of the cantilever portion 142 using an appropriate method such as adhesion, tightening, or press fitting, thereby creating an absorbent structure. A section 143 can be provided.

Further, at least a portion of the cantilever portion 142 of the piezoelectric element 140 is arranged at a position where, when vibrating, it enters a region where leaked fluid to be sealed accumulates. More specifically, the piezoelectric element 140 is provided at a position vertically lower than the rotating shaft 500 when the sealing device main body 100 is installed. In addition, in FIG. 1, when the sealing device main body 100 is installed in a device (device such as a transportation device or a robot), the upper part in the figure corresponds to the upper part in the vertical direction, and the lower part in the figure corresponds to the lower part in the vertical direction. Equivalent to. As shown in FIG. 1, the piezoelectric element 140 is provided in the annular reinforcing ring 100 at a position that is vertically downward when installed in the device. Note that, as shown in the figure, in order to improve detection accuracy, it is desirable to provide a plurality of piezoelectric elements 140 at intervals in the circumferential direction. Furthermore, the piezoelectric element 140 is provided at a position between the main lip 122 and the dust lip 123. With these configurations, at least a portion of the cantilever section 142 can enter a region where leaked fluid to be sealed accumulates while vibrating.

<Leak detection device>
In particular, with reference to FIGS. 3 and 4, the leak detection device 200 will be described. The leak detection device 200 includes a receiver 220 having an antenna 210 that receives a signal transmitted from the transmitter 150, and a detection unit 230 that detects leakage of the fluid to be sealed based on the voltage waveform received by the receiver 220. ing. Note that the detection unit 230 can be configured by a computer having a processor, a storage device such as a memory, I/O, and the like. In this case, the function of the detection unit 230 is realized by a processor executing a program stored in a storage device.

<Leak detection operation (leak detection method)>
In particular, with reference to FIGS. 4 and 5, the operation (detection method) of detecting leakage of the fluid to be sealed will be described. The sealing device main body 100 in FIG. 4 shows an enlarged cross-sectional view of the vicinity of the piezoelectric element 140 in the sealing structure. Further, FIG. 4(a) shows a state in which no leakage occurs, and FIG. 4(b) shows a state in which leakage occurs. FIG. 5 shows a voltage waveform (a graph of changes in voltage value with respect to elapsed time) of the piezoelectric element 140 (more specifically, the cantilever portion 142). Further, FIG. 5(a) shows a state in which no leakage occurs, and FIG. 5(b) shows a state in which leakage occurs. According to the sealing device 10 configured as described above, the cantilever portion 142 of the piezoelectric element 140 vibrates as the rotating shaft 500 rotates, and a wave-shaped voltage is generated. As a result, the voltage waveform generated by the piezoelectric element 140 is transmitted from the transmitter 150 and received by the receiver 220 . This information is sent to the detection unit 230, and if a leak occurs, the detection unit 230 detects it. This will be explained in more detail below.

As shown in FIG. 4, in the sealed structure according to this embodiment, a lubricant G such as grease is applied near the sliding part in order to improve the sliding property between the rotating shaft 500 and the main lip 122. There is. However, if the sealing function deteriorates due to sliding wear of the main lip 122 over time, the fluid O (for example, oil) to be sealed will leak out. The leaked sealing target fluid O accumulates in a region between the main lip 122 and the dust lip 123 and below the rotating shaft 500 in the vertical direction (see FIG. 4(b)).

As described above, at least a portion of the cantilever portion 142 of the piezoelectric element 140 is arranged at a position where, when vibrating, it enters a region where leaked sealing target fluid accumulates. Therefore, when the amount of leakage exceeds a certain amount, a portion of the cantilever portion 142 of the piezoelectric element 140 enters the portion where the leaked fluid to be sealed is collected. More specifically, a portion of the absorbent structure 143 enters the portion. As a result, the fluid to be sealed is absorbed by the absorption structure section 143, and the weight of the piezoelectric element 140 near the tip of the cantilever section 142 increases. Therefore, the voltage waveform sent from the piezoelectric element 140 changes.

Here, the natural frequency ω of the vibrating member is expressed as ω=√(K/M). Note that K is a spring constant and M is mass. Therefore, the heavier the mass M of the vibrating member, the smaller the natural frequency ω and the longer the vibration period. Therefore, assuming that the period of the voltage waveform of the piezoelectric element 140 in a state where no leakage occurs is T1 (see FIG. 5(a)), a predetermined amount of leakage occurs, and the weight near the tip of the cantilever portion 142 increases. If the period of the voltage waveform of the piezoelectric element 140 at this time is T2 (see FIG. 5(b)), then T2>T1. Therefore, TX satisfying TX>T1 is set in advance as a threshold value, and when the period of the voltage waveform of the piezoelectric element 140 exceeds TX, the detection unit 230 determines that a leak has occurred. The portion 230 can detect the occurrence of a leak.

Note that when a leak is detected by the detection unit 230, for example, a device may be provided to notify the user of the device (device such as transportation equipment or robot) to which the sealing device 10 is applied to the occurrence of a leak. suitable. For example, by lighting a lamp to notify the user of the occurrence of a leak, sounding a buzzer to notify the occurrence of a leak, or displaying a message to notify the user of the occurrence of a leak, the user is prompted to replace the sealing device 10 or the sealing device main body 100. can be encouraged. Furthermore, when a leak is detected by the detection unit 230, it is also preferable to control the operation of the device to which the sealing device 10 is applied to be stopped urgently or gradually. As described above, the process to be performed when a leak is detected by the detection unit 230 may be appropriately set according to the characteristics of various devices to which the sealing device 10 is applied.

<Excellent points of the sealing device according to this embodiment>
According to the sealing device 10 according to the present embodiment, the leakage of the fluid O to be sealed can be detected by the detection unit 230 of the leakage detection device 200. Thereby, leakage of the fluid O to be sealed can be detected without manual intervention.

At least a portion of the cantilever section 142 in the piezoelectric element 140 according to this embodiment is arranged at a position where it enters a region where leaked sealing target fluid O accumulates when vibrating. Therefore, the leaked fluid O to be sealed adheres to the cantilever portion 142 and the vibration period becomes longer, allowing the detection portion 230 to detect a leak. In the case of this embodiment, since the piezoelectric element 140 is provided at a position between the main lip 122 and the dust lip 123, at least a portion of the cantilever portion 142 can It enters the area where the leaked fluid O to be sealed accumulates.

Moreover, the piezoelectric element 140 according to this embodiment is attached to the reinforcing ring 110 in a cantilevered state. Thereby, the cantilever portion 142 can be easily vibrated and the sensitivity can be increased, so that the detection accuracy by the leak detection device 200 can be increased.

Furthermore, in this embodiment, an absorption structure section 143 having a structure for absorbing the fluid O to be sealed is provided on the cantilever section 142. As a result, when a leak occurs, the absorption structure 143 absorbs the fluid to be sealed, thereby more reliably increasing the weight. Therefore, the detection accuracy by the leak detection device 200 can be improved.

(others)
In the sealing device main body 100 according to the embodiment described above, the elastic seal 120 has two seal lips, the main lip 122 and the dust lip 123. However, the configuration of the elastic seal in the sealing device main body in the present invention is not limited to the above configuration. It is also applicable to types with only one seal lip and types with three or more seal lips.

Furthermore, the above embodiments have been described on the premise that various devices are used so that the center axis of rotation of the rotating shaft 500 is in the horizontal direction. However, in the present invention, the usage conditions to which the sealing device is applied are not particularly limited. In short, if the leaked fluid to be sealed adheres to at least a portion of the vibrating portion of the piezoelectric element in the usage state in which the sealing device is applied, leakage of the fluid to be sealed can be detected.

10 Sealing device 100 Sealing device main body 110 Reinforcement ring 111 Cylindrical portion 112 Inward flange portion 120 Elastic seal 121 Outer seal portion 122 Main lip 123 Dust lip 130 Garter spring 140 Piezoelectric element 141 Support portion 142 Cantilever portion (cantilever beam part)
143 Absorption structure section 150 Transmitter 160 Wiring 200 Detection device 210 Antenna 220 Receiver 230 Detection section 500 Rotating shaft 600 Housing 610 Shaft hole G Lubricant O Fluid to be sealed

Claims (4)

In a sealing device that seals an annular gap between two relatively rotating members,
a reinforcing ring; an elastic seal integrally provided with the reinforcing ring and having a seal lip that slides on one of the two members; a piezoelectric element that vibrates together with the reinforcing ring; a transmitter that transmits an electrical signal;
A leakage detection device comprising: a receiver that receives a signal transmitted from the transmitter; and a detection unit that detects leakage of the fluid to be sealed based on the voltage waveform received by the receiver;
A sealing device comprising:
As a seal lip in the elastic body seal, a main lip that suppresses leakage of the fluid to be sealed and a dust lip that suppresses entry of foreign matter into the fluid to be sealed,
A sealing device characterized in that the piezoelectric element is provided at a position between the main lip and the dust lip . In a sealing device that seals an annular gap between two relatively rotating members,
a reinforcing ring; an elastic seal integrally provided with the reinforcing ring and having a seal lip that slides on one of the two members; a piezoelectric element that vibrates together with the reinforcing ring; a transmitter that transmits an electrical signal;
A leakage detection device comprising: a receiver that receives a signal transmitted from the transmitter; and a detection unit that detects leakage of the fluid to be sealed based on the voltage waveform received by the receiver;
A sealing device comprising:
A sealing device characterized in that the piezoelectric element is attached to the reinforcing ring in a cantilevered manner. 3. At least a part of the cantilever portion of the piezoelectric element is disposed at a position where the leaked fluid to be sealed enters a region where the leaked fluid to be sealed accumulates when the piezoelectric element vibrates. Sealing device. 4. The sealing device according to claim 3 , wherein an absorption structure portion having a structure for absorbing the fluid to be sealed is provided in the cantilever portion.

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