JP2010112496A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device effectively preventing muddy water or the like in the outside from reaching a lip seal without increasing sliding torque of a lip. <P>SOLUTION: The sealing device includes the lip seal 11 attached to a housing 1 and slidably brought into close contact with a shaft, an inner cover 21 disposed on the shaft outside he lip seal, and an outer cover 31 disposed on the housing outside the lip seal. A first umbrella part having a cylindrical inner peripheral surface is disposed on the outer cover toward one axial direction, a cylindrical second umbrella part is disposed on the inner cover toward the other axial direction, and a cylindrical third umbrella part is disposed on the lip seal or the outer cover toward one axial direction, and the second umbrella part is arranged in an inner peripheral side of the first umbrella part in a non-contact way, and the third umbrella part is arranged in an inner peripheral side of the second umbrella part in a non-contact way, and thereby, the muddy water and the dust in the outside can be prevented from reaching the lip seal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing device (oil seal) according to a sealing technique. The sealing device of the present invention is used, for example, in the field of automobiles or in the field of general general-purpose machines.

  For example, in a sealing device used under conditions exposed to muddy water / dust (hereinafter also referred to as “muddy water”) such as a vehicle drive system, conventionally, as shown in FIG. By arranging the cover 102, it is devised that muddy water or the like outside the machine B hardly reaches the lip seal 101 (see Patent Document 1).

  However, since the cover 102 has a single shielding structure attached to the shaft 103, when muddy water or the like enters the gap 104 between the cover 102 and the lip seal 101, the muddy water or the like no longer reaches the lip seal 101. I can't prevent it.

  In the illustrated conventional example, a side lip 105 is provided on the lip seal 101, and the side lip 105 is slidably brought into close contact with the end surface of the cover 102 so that muddy water or the like does not reach the dust lip 106. Since the side lip 105 is a kind of end face seal, it cannot be used when the axial thrust such as an extension is as large as several tens of millimeters.

  Further, it is conceivable to increase the mud water resistance by increasing the number of dust strips 106, but in this case, there is a disadvantage that the sliding torque increases.

Japanese Utility Model Publication No. 5-54871

  SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a sealing device that can effectively prevent muddy water outside the machine from reaching the lip seal without increasing the sliding torque of the lip. .

  In order to achieve the above object, a sealing device according to claim 1 of the present invention includes a lip seal that is mounted on a housing and that is slidably in close contact with a shaft, and an inner cover that is provided on the shaft outside the lip seal. And an outer cover provided on the housing outside the machine of the lip seal, and a first umbrella portion having a cylindrical inner peripheral surface is provided on the outer cover in one axial direction, and the inner cover A cylindrical second umbrella portion is provided toward the other axial direction, and a cylindrical third umbrella portion is provided on the lip seal or the outer cover toward one axial direction, and an inner circumference of the first umbrella portion is provided. The second umbrella part is arranged in a non-contact manner on the side and the third umbrella part is arranged in a non-contact manner on the inner peripheral side of the second umbrella part, so that muddy water and dust outside the machine are attached to the lip seal. Features a structure that is difficult to reach Is shall.

  The sealing device according to claim 2 of the present invention is the sealing device according to claim 1 described above, wherein at least one of the first to third umbrella portions is integrally provided with an outward flange portion at the tip thereof. Is provided.

  Further, the sealing device according to claim 3 of the present invention is the sealing device according to claim 1, wherein at least one of the first to third umbrella portions is gradually expanded toward the tip. The taper shape is provided.

  Furthermore, the sealing device according to claim 4 of the present invention is the sealing device according to claim 1, wherein the inner cover includes a fitting tube portion fitted to the shaft, a rising portion in the radial direction, and a second portion. An umbrella portion is integrally formed, and at least one of the fitting tube portion and the first to third umbrella portions is integrally provided with an outward fold portion at the tip thereof. To do.

  In the sealing device of the present invention having the above-described configuration, an inner cover provided on the shaft and an outer cover provided on the housing are arranged on the outer side of the lip seal, whereby a double shield is provided on the outer side of the lip seal. The structure is set. Further, a first umbrella portion having a cylindrical inner peripheral surface is provided on the outer cover in one axial direction, and a cylindrical second umbrella portion is provided on the inner cover in the other axial direction, and a lip seal or A cylindrical third umbrella part is provided on the outer cover in one axial direction, and a second umbrella part is disposed in a non-contact manner on the inner peripheral side of the first umbrella part and on the inner peripheral side of the second umbrella part. The third umbrella tube portion is arranged in a non-contact manner, thereby setting a maze structure that makes it difficult for muddy water or the like outside the machine to reach the lip seal. That is, a labyrinth seal is formed between the first umbrella portion and the inner circumferential second umbrella portion. First, the labyrinth seal makes it difficult for muddy water or the like to enter. The muddy water that has passed through the labyrinth seal tends to drip on the shaft from the tip of the second umbrella portion, but since the third umbrella portion is arranged on the inner peripheral side of the second umbrella portion, It hangs down on this third umbrella part instead of above, and after it hangs down, it flows along the outer peripheral surface of the third umbrella part in the circumferential direction and falls downward. Therefore, muddy water or the like can be effectively suppressed from dripping on the shaft and approaching the lip seal.

  In addition, in at least one of the first to third umbrella portions, when an outward flange portion is integrally provided at the tip thereof, this flange portion acts as a damming portion. Is less likely to sag.

  In addition, the first to third umbrella parts basically have a cylindrical shape that is straight in the axial direction, but at least one of the first to third umbrella parts has a taper that gradually increases in diameter toward the tip. Providing the shape makes it easier for muddy water or the like to flow away from the tip portion, so that it is difficult for the muddy water or the like to drip from the tip portion of the umbrella portion.

  In addition, when at least one of the first to third umbrella parts is provided with an outwardly extending barb at the tip, the barb acts as a damming part. Is less likely to sag. This also applies to the fitting cylinder part when the inner cover integrally includes the fitting cylinder part fitted to the shaft, the rising part in the radial direction, and the second umbrella part.

  The present invention has the following effects.

  That is, in the sealing device of the present invention, as described above, since the inner cover and the outer cover are disposed on the outside of the lip seal, a double shielding structure is set. A first umbrella portion having a cylindrical inner peripheral surface is provided on the outer cover in one axial direction, and a cylindrical second umbrella portion is provided on the inner cover in the other axial direction. A cylindrical third umbrella portion is provided in one axial direction, a second umbrella portion is disposed in a non-contact manner on the inner circumferential side of the first umbrella portion, and a third umbrella portion is disposed on the inner circumferential side of the second umbrella portion. Since the umbrella cylindrical portion is arranged in a non-contact manner, a maze structure is set in which muddy water or the like outside the machine hardly reaches the lip seal. Further, since the first to third umbrella parts are not in contact with each other, the sliding torque does not increase. Therefore, according to the present invention, it is possible to provide a sealing device that can effectively prevent muddy water or the like outside the machine from reaching the lip seal without increasing the sliding torque of the lip as intended. .

  In addition, when the outer flange part is provided at the tip of the umbrella part, the tapered part is provided with a taper shape, or the outer part of the umbrella part is provided with an outward burrowing part, muddy water is increasingly ripened. It becomes difficult to get close to the seal. Therefore, the sealing performance by the sealing device of the present invention can be further improved.

  Next, embodiments of the present invention will be described with reference to the drawings.

First embodiment ...
FIG. 1 shows a half-cut section in a mounted state of a sealing device (oil seal) according to a first embodiment of the present invention. The sealing device according to the embodiment seals the sealing fluid such as the lubricating oil in the machine A so that it does not leak into the machine B, and seals the muddy water etc. outside the machine B from entering the machine A. The configuration is as follows.

  That is, first, a lip seal 11 is provided which is attached to the opening of the shaft hole of the housing 1 and is slidably brought into close contact with the peripheral surface of the shaft (rotating shaft) 2. Is mounted on the shaft 2, and an outer cover 31 is also mounted on the outside of the lip seal 11 and mounted on the housing 1. Since the housing 1 has a cylindrical part around the opening of the shaft hole, the lip seal 11 is attached to the inner peripheral side of the cylindrical part and the outer cover 31 is attached to the outer peripheral side of the cylindrical part. ing.

  The lip seal 11 has a metal ring (first metal ring) 12 fitted to the inner peripheral surface of the shaft hole opening of the housing 1, and a rubber-like elastic body 13 is attached to the metal ring 12 ( By the rubber-like elastic body 13, the outer peripheral seal portion 14, the main lip 15, and the dust lip 16 that seal with the housing 1 are integrally formed. The main lip 15 faces the inside of the machine and mainly seals a sealing fluid such as lubricating oil. The dust lip 16 is arranged on the outside of the main lip 15 and faces the outside of the machine to mainly seal muddy water. However, the inner cover 21 and the outer A cover 31 is attached.

  The outer cover 31 is made of a rigid body such as metal or hard resin (for example, a sheet metal press product), is formed into an annular shape, and is fitted with a fitting cylinder portion 32 that is fitted to the outer peripheral surface (stepped portion) of the housing 1. It integrally has a rising portion (expanded diameter portion) 33 and a cylindrical first umbrella portion 34 that extends long toward one side in the axial direction (left side in the figure, the outside of the machine). The first umbrella portion 34 is formed in an axially straight cylindrical shape over the entire length thereof.

  The inner cover 21 is also made of a rigid body such as a metal or a hard resin (for example, a sheet metal press product), is formed into an annular shape, and is fitted into the outer peripheral surface (stepped portion) of the shaft 2 and a radial direction. And a cylindrical second umbrella portion 24 that extends long toward the other side in the axial direction (right side in the drawing, the inside of the machine). The second umbrella portion 24 is formed in a taper shape (conical surface shape) in which the proximal end portion 24a gradually increases in diameter toward the distal end (right end, open end in the figure), and the distal end portion 24b is arranged in the axial direction. Although it is formed in a straight cylindrical shape, it may be a cylindrical shape that is straight in the axial direction over the entire length like the first umbrella portion 34.

  Further, the second umbrella portion 24 is arranged in a state where it does not contact the inner peripheral side of the first umbrella portion 34 (non-contact state), and therefore, an annular minute gap 25 between the umbrella portions 24, 34. The labyrinth seal 26 which is a non-contact type seal is set using the gap 25.

  In addition, the cylindrical third umbrella portion 44 is arranged on the inner peripheral side of the second umbrella portion 24 so as not to contact (non-contact state), and the third umbrella portion 44 is fitted to the lip seal 11. The second metal ring 41 is formed. The second metal ring 41 includes a fitting cylinder part 42 fitted to the inner peripheral side of the first metal ring 12, a radial rising part 43, and a cylindrical third umbrella extending long in one axial direction. The third umbrella portion 44 is integrally provided with an outward flange portion 45 (also referred to as a flange-shaped damming portion) that is formed integrally with the tip of the third umbrella portion 44. The third umbrella portion 44 is disposed on the inner peripheral side of the distal end of the second umbrella portion 24 and the distal end of the second umbrella portion 24 is disposed on the outer peripheral side of the third umbrella portion 44, and both overlap in the axial direction. Are arranged. The outward direction refers to a radially outward direction, but may be an obliquely outward direction.

  Since the inner cover 21 and the outer cover 31 are arranged on the outer side of the lip seal 11 in the sealing device having the above configuration, a double shielding structure is set, and an intrusion passage for muddy water or the like is complicated. In addition, a cylindrical first umbrella portion 34 is provided on the outer cover 31 in one axial direction, and a cylindrical second umbrella portion 24 is provided on the inner cover 21 in the other axial direction. A cylindrical third umbrella portion 44 is provided in one axial direction, the second umbrella portion 24 is disposed in a non-contact manner on the inner peripheral side of the first umbrella portion 34, and the inner peripheral side of the second umbrella portion 24 In addition, since the third umbrella portion 44 is arranged in a non-contact manner, a structure in which muddy water or the like outside the machine B hardly reaches the lip seal 11 is set. That is, the first umbrella part 34 and the second umbrella part 24 on the inner peripheral side form a labyrinth seal 26 between the two umbrella parts 24, 34, and first make it difficult for muddy water or the like to enter here. The muddy water and the like adhering to the outer peripheral surface of the second umbrella portion 24 flows along the outer peripheral surface in the circumferential direction and falls downward. However, some of the muddy water and the like fall on the shaft from the tip of the second umbrella portion 24. Try to sag. However, since the third umbrella portion 44 is disposed on the inner peripheral side of the tip of the second umbrella portion 24, mud water or the like hangs on the third umbrella portion 44, not on the shaft, and then drops on the third umbrella portion 44. It flows along the outer peripheral surface of the umbrella part 44 in the circumferential direction and falls downward. Therefore, muddy water or the like can be effectively suppressed from dripping on the shaft and approaching the lip seal 11.

  Further, since the outward flange portion 45 is integrally provided at the tip of the third umbrella portion 44, this is used as a damming portion, so that muddy water or the like does not easily drip from the tip of the third umbrella portion 44 onto the shaft. ing. Therefore, the muddy water can be prevented from approaching the lip seal 11 also by this.

  It is conceivable that the sealing device according to the first embodiment is added or changed in configuration as follows.

Second embodiment ...
As shown in FIG. 2, the cylindrical second umbrella portion 24 in the inner cover 21 is gradually extended from the base end (left end in the drawing) to the tip (right end, open end in the drawing) over the entire axial length. It is formed in a taper shape in a direction to expand the diameter, that is, a taper shape in which the outer peripheral surface and the inner peripheral surface of the second umbrella portion 24 are gradually expanded from the base end to the tip end over the entire axial length. To form. In this way, as shown by the arrow C, muddy water or the like adhering to the outer peripheral surface of the second umbrella portion 24 easily flows out to the outside of the machine due to gravity (flowing from the larger outer diameter to the smaller one). go). Further, when muddy water or the like that reaches the inner space D of the inner cover 21 adheres to the inner peripheral surface of the second umbrella portion 24 by centrifugal force when the shaft rotates, as shown by the arrow E, the outside of the machine is The muddy water or the like that reaches the tip (which flows from the smaller outer diameter to the larger one) hangs down on the third umbrella portion 44 and easily flows out to the (inner space F of the outer cover 31). Can be expected to flow in the circumferential direction and fall downward). In addition, if at least one part is made into the taper shape of the said direction in the axial direction full length of the 2nd umbrella part 24, the said effect can be obtained in the site | part.

Third embodiment ...
As shown in FIG. 3, the second umbrella portion 24 of the inner cover 21 is formed in a tapered shape so that the diameter gradually increases from the proximal end to the distal end over the entire axial length as in the second embodiment. In addition, in addition, the second metal ring 41 having the third umbrella portion 44 is integrated with the first metal ring 12 of the lip seal 11. In other words, the metal ring 12 formed by combining the two members 41 and 41 has a main body portion fitted to the housing 1, a radial rising portion 43, a third umbrella portion 44, and an outward flange portion 45. In this way, the number of parts and the number of assembly steps of the sealing device can be reduced as compared with the first embodiment.

Fourth embodiment ...
As shown in FIG. 4, the shape of the housing 1 is enlarged, and an enlarged portion (housing enlarged portion) 3 of the housing 1 is used as an outer cover, thereby forming a first umbrella portion. The housing expansion portion 3 has a cylindrical inner peripheral surface 4 corresponding to the inner peripheral surface of the first umbrella portion 34 in the first embodiment. The second umbrella portion 24 of the cover 21 is arranged in a non-contact manner. Therefore, in this case, a minute gap 25 is formed between the housing expansion portion 3 and the second umbrella portion 24 of the inner cover 21, and a labyrinth seal 26 that is a non-contact type seal is set using the gap 25. Yes. In this way, since some parts (outer cover 31) are formed with the housing 1, the number of parts and assembly man-hours of the sealing device can be reduced as compared with the first embodiment.

Fifth Example ...
As shown in FIG. 5, the rising portion 27 is integrally formed from the tip of the second umbrella portion 24 of the inner cover 21 outward in the radial direction, and the fourth from the outer peripheral end of the rising portion 27 toward the one axial direction. The umbrella part 28 is integrally formed, and the fourth umbrella part 28 is arranged in a non-contact manner on the inner peripheral side of the first umbrella part 34 of the outer cover 31 so that the micro gap 25 and the labyrinth seal are provided between the umbrella parts 28, 34. 26 is set. The second umbrella portion 24 is formed in a taper shape that gradually increases in diameter from the base end (left end in the drawing) to the tip end (right end in the drawing) over the entire length in the axial direction. This is also formed in a taper shape that gradually increases in diameter from the base end (right end in the drawing) to the tip end (left end, open end in the drawing) over the entire axial length. In this way, when muddy water or the like that reaches the inner space D of the inner cover 21 adheres to the inner peripheral surface of the second umbrella portion 24 due to the centrifugal force when the shaft rotates, as shown by the arrow E, the centrifugal force Therefore, it is easy to flow out to the outside of the machine (inner space F of the outer cover 31). The muddy water or the like that reaches the tip of the second umbrella portion 24 hangs down on the third umbrella portion 44, flows along the outer circumferential surface of the third umbrella portion 44, flows in the circumferential direction, and falls downward. As shown by the arrow G, it is discharged to the outside along the outer peripheral surface of the fourth umbrella portion 28 by centrifugal force. Therefore, according to the said Example, muddy water etc. can be discharged | emitted effectively using the centrifugal force which generate | occur | produces at the time of shaft rotation.

Sixth Example ...
FIG. 6 shows a cross section of the sealing device (oil seal) according to the sixth embodiment of the present invention in a mounted state. The sealing device according to the embodiment seals the sealing fluid such as the lubricating oil in the machine A so that it does not leak into the machine B, and seals the muddy water etc. outside the machine B from entering the machine A. The configuration is as follows.

  That is, first, a lip seal 11 is provided which is attached to the opening of the shaft hole of the housing 1 and is slidably brought into close contact with the peripheral surface of the shaft (rotating shaft) 2. Is mounted on the shaft 2, and an outer cover 31 is also mounted on the outside of the lip seal 11 and mounted on the housing 1. Since the housing 1 has a cylindrical part around the opening of the shaft hole, the lip seal 11 is attached to the inner peripheral side of the cylindrical part and the outer cover 31 is attached to the outer peripheral side of the cylindrical part. ing.

  The lip seal 11 has a metal ring (first metal ring) 12 fitted to the inner peripheral surface of the shaft hole opening of the housing 1, and a rubber-like elastic body 13 is attached to the metal ring 12 ( By the rubber-like elastic body 13, the outer peripheral seal portion 14, the main lip 15, and the dust lip 16 that seal with the housing 1 are integrally formed. The main lip 15 faces the inside of the machine and mainly seals a sealing fluid such as lubricating oil. The dust lip 16 is arranged on the outside of the main lip 15 and faces the outside of the machine to mainly seal muddy water. However, the inner cover 21 and the outer A cover 31 is attached.

  The outer cover 31 is made of a rigid body such as metal or hard resin (for example, a sheet metal press product), is formed into an annular shape, and is fitted with a fitting cylinder portion 32 that is fitted to the outer peripheral surface (stepped portion) of the housing 1. A rising portion (expanded diameter portion) 33 and a cylindrical first umbrella portion 34 that extends long toward one side in the axial direction (right side in the drawing, the outside of the machine) are integrally provided. The first umbrella portion 34 is formed in a tapered shape (conical surface shape) that gradually increases in diameter from the base end (left end in the drawing) to the tip end (right end and open end in the drawing) over the entire length in the axial direction. In addition, an outwardly facing barb portion (also referred to as barb-shaped damming portion) 35 is integrally provided at the tip thereof.

  The inner cover 21 is also made of a rigid body such as a metal or a hard resin (for example, a sheet metal press product), is formed into an annular shape, and is fitted into the outer peripheral surface (stepped portion) of the shaft 2 and a radial direction. And a cylindrical second umbrella portion 24 extending long toward the other side in the axial direction (left side in the drawing, the inside of the machine). The second umbrella portion 24 is also formed in a taper shape that gradually increases in diameter from the base end (right end in the figure) to the tip end (left end, open end in the figure) over the entire axial length thereof, and An outwardly facing barb portion (also referred to as barb-shaped damming portion) 29 is integrally provided at the tip. Also, an outwardly facing barb portion (also referred to as barb-shaped damming portion) 30 is integrally provided at the tip of the fitting tube portion 22.

Further, the second umbrella portion 24 is arranged in a state where it does not contact the inner peripheral side of the first umbrella portion 34 (non-contact state), and therefore, an annular minute gap 25 is formed between the umbrella portions 24, 34. The labyrinth seal 26 which is formed and is a non-contact type seal is set using the gap 25.

  Further, the third umbrella portion 44 is arranged in a state where the third umbrella portion 44 is not in contact with the inner peripheral side of the second umbrella portion 24 (non-contact state), and the third umbrella portion 44 is fitted to the lip seal 11. A metal ring 41 is formed. The second metal ring 41 includes a fitting cylinder part 42 fitted to the inner peripheral side of the first metal ring 12, a radial rising part 43, and a cylindrical third umbrella extending long in one axial direction. The third umbrella portion 44 is also gradually extended from its base end (left end in the figure) to the tip end (right end and open end in the figure) over its entire length in the axial direction. An outwardly facing barb portion (also referred to as barb-like damming portion) 46 is integrally formed at the tip of the taper. The third umbrella portion 44 is disposed on the inner peripheral side of the distal end of the second umbrella portion 24 and the distal end of the second umbrella portion 24 is disposed on the outer peripheral side of the third umbrella portion 44, and both overlap in the axial direction. Are arranged.

  Since the inner cover 21 and the outer cover 31 are arranged on the outer side of the lip seal 11 in the sealing device having the above configuration, a double shielding structure is set, and an intrusion passage for muddy water or the like is complicated. In addition, a cylindrical first umbrella portion 34 is provided on the outer cover 31 in one axial direction, and a cylindrical second umbrella portion 24 is provided on the inner cover 21 in the other axial direction. A cylindrical third umbrella portion 44 is provided toward one axial direction, and the second umbrella portion 24 is disposed in a non-contact manner on the inner peripheral side of the first umbrella portion 34 and the inner peripheral side of the second umbrella portion 24 In addition, since the third umbrella portion 44 is arranged in a non-contact manner, a structure in which muddy water or the like outside the machine B hardly reaches the lip seal 11 is set. That is, the first umbrella part 34 and the second umbrella part 24 on the inner peripheral side form a labyrinth seal 26 between the two umbrella parts 24, 34, and first make it difficult for muddy water or the like to enter here. The muddy water and the like adhering to the outer peripheral surface of the second umbrella portion 24 flows along the outer peripheral surface in the circumferential direction and falls downward. However, some of the muddy water and the like fall on the shaft from the tip of the second umbrella portion 24. Try to sag. However, since the third umbrella portion 44 is disposed on the inner peripheral side of the tip of the second umbrella portion 24, mud water or the like hangs on the third umbrella portion 44, not on the shaft, and then drops on the third umbrella portion 44. It flows along the outer peripheral surface of the umbrella part 44 in the circumferential direction and falls downward. Therefore, muddy water or the like can be effectively suppressed from dripping on the shaft and approaching the lip seal 11.

  In addition, each of the first to third umbrella portions 24, 34, and 44 is formed in a tapered shape that gradually increases in diameter from the base end to the tip end over the entire axial length. , 34, and 44, the muddy water and the like adhering to the outer peripheral surfaces of the umbrella portions 24, 34, and 44 are made to flow easily in a direction away from the tips of the umbrella portions 24, 34, and 44 (flowing from the larger outer diameter to the smaller one). Therefore, it is difficult for the umbrella portions 24, 34, 44 to hang down from the tip of the umbrella portions 24, 34, 44, so that muddy water or the like can be prevented from approaching the lip seal 11. Each umbrella part 24, 34, 44 formed in the taper shape also has a function of discharging muddy water or the like adhering to the inner peripheral surface by the action of centrifugal force during shaft rotation.

  Further, since the outwardly extending barbs 29, 30, 35, and 46 are integrally provided at the tips of the umbrella portions 24, 34, and 44 and the tips of the fitting tube portion 22 in the inner cover 21, respectively. Muddy water is difficult to drip. Therefore, the muddy water can be prevented from approaching the lip seal 11 also by this.

  In addition, as shown in part by dotted lines in FIG. 6, the axial lengths of the umbrella portions 24, 34, 44 and the axial length of the fitting tube portion 22 in the inner cover 21 can be adjusted and changed as appropriate. It is.

  It is conceivable that the sealing device according to the sixth embodiment is added or changed as follows.

Seventh Example ...
In the sixth embodiment, the third umbrella portion 44 is formed by the second metal ring 41 fitted to the lip seal 11, but instead, as shown in FIG. The outer cover 31 is molded. That is, as shown in FIG. 7, the reduced diameter portion 36 is integrally formed from the tip of the fitting cylinder portion 32 of the outer cover 31 inward in the radial direction, and from the inner peripheral end of the reduced diameter portion 36 to one axial direction. A cylindrical third umbrella portion 44 is integrally formed. The third umbrella portion 44 is formed in a taper shape that gradually increases in diameter from the base end (left end in the drawing) to the tip end (right end and open end in the drawing) over the entire length in the axial direction.

Eighth Example ...
Similarly, in the sixth embodiment, the third umbrella portion 44 is formed by the second metal ring 41 fitted to the lip seal 11, but instead, as shown in FIG. 44 is formed on the rubber-like elastic body 13 of the lip seal 11. That is, as shown in FIG. 8, a cylindrical third umbrella portion 44 is integrally formed on the rubber-like elastic body 13 of the lip seal 11 toward one side in the axial direction. The third umbrella portion 44 is formed in a taper shape that gradually increases in diameter from the base end (left end in the drawing) to the tip end (right end and open end in the drawing) over the entire length in the axial direction.

Ninth Example ...
As shown in FIG. 9, the rising portion 27 is integrally formed from the tip of the second umbrella portion 24 of the inner cover 21 outward in the radial direction, and the fourth from the outer peripheral end of the rising portion 27 toward the one axial direction. The umbrella portion 28 is integrally molded, and a rubber-like elastic body 51 is attached to the fourth umbrella portion 28, and the rubber-like elastic body 51 is arranged in a non-contact manner on the inner peripheral side of the first umbrella portion 34 of the outer cover 31. Then, the minute gap 25 and the labyrinth seal 26 are set between the two 34 and 51. The rubber-like elastic body 51 is formed in a cylindrical shape and has an outer peripheral surface parallel to the inner peripheral surface of the first umbrella portion 34.

  An annular small lip 52 is integrally formed at the other end in the axial direction of the rubber-like elastic body 51. The small lip 52 has an initial gap with respect to the inner peripheral surface of the first umbrella portion 34 or has an initial interference margin set to zero, and spreads by a centrifugal force due to shaft rotation to expand the inner peripheral surface of the first umbrella portion 34. It is configured to be in close contact with muddy water to prevent intrusion. The small lip 52 has a lip bent shape having a lip length (for example, an arc shape in cross section) so that the small lip 52 can be easily expanded by centrifugal force. Since a gap is generated when the shaft is stopped, drainage is ensured.

Tenth embodiment
As shown in FIG. 10, in addition to the configuration of the ninth embodiment, the other end in the axial direction of the rubber-like elastic body 51 is directed to the inner peripheral side of the annular small lip 52 toward the other in the axial direction. The fifth umbrella portion 53 is integrally formed. As the number of umbrella portions increases, the flow paths inside the covers 21 and 31 become more complicated, so that muddy water or the like outside the machine B hardly reaches the lip seal 11.

Sectional drawing of the sealing device which concerns on 1st Example of this invention. Sectional drawing of the sealing device which concerns on 2nd Example of this invention. Sectional drawing of the sealing device which concerns on 3rd Example of this invention. Sectional drawing of the sealing device which concerns on 4th Example of this invention. Sectional drawing of the sealing device which concerns on 5th Example of this invention. Sectional drawing of the sealing device which concerns on 6th Example of this invention. Sectional drawing of the sealing device which concerns on 7th Example of this invention. Sectional drawing of the sealing device which concerns on 8th Example of this invention. Sectional drawing of the sealing device which concerns on 9th Example of this invention Sectional drawing of the sealing device which concerns on 10th Example of this invention. Sectional drawing of the sealing device which concerns on a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 axis | shaft 3 Housing expansion part 4 Inner peripheral surface 11 Lip seal 12, 41 Metal ring 13, 51 Rubber-like elastic body 14 Outer seal part 15 Main lip 16 Dustrip 21 Inner cover 22, 32, 42 Fitting cylinder part 23 , 27, 33, 43 Rising portion 24 Second umbrella portion 25 Small gap 26 Labyrinth seal 28 Fourth umbrella portion 29, 30, 35, 46 Barbed portion 31 Outer cover 34 First umbrella portion 36 Reduced diameter portion 44 Third umbrella portion 45 Flange 52 Small Lip 53 Fifth Umbrella A A Inside B B Outside

Claims (4)

A lip seal mounted on the housing and slidably in close contact with the shaft; an inner cover provided on the shaft outside the lip seal; and an outer cover provided on the housing outside the lip seal. Have
A first umbrella portion having a cylindrical inner peripheral surface is provided on the outer cover toward one axial direction, and a cylindrical second umbrella portion is provided on the inner cover toward the other axial direction, and the lip seal Alternatively, a cylindrical third umbrella portion is provided on the outer cover in one axial direction, the second umbrella portion is disposed in a non-contact manner on the inner peripheral side of the first umbrella portion, and the second umbrella portion A sealing device, wherein the third umbrella portion is arranged in a non-contact manner on the inner peripheral side so that a structure in which muddy water / dust outside the machine does not reach the lip seal is set. The sealing device according to claim 1.
A sealing device, wherein at least one of the first to third umbrella portions is integrally provided with an outward flange portion at a tip thereof. The sealing device according to claim 1.
A sealing device characterized in that at least one of the first to third umbrella portions is provided with a taper shape in which the diameter gradually increases toward the tip thereof. The sealing device according to claim 1.
The inner cover integrally includes a fitting cylinder portion fitted to the shaft, a radial rising portion, and a second umbrella portion,
A sealing device, wherein at least one of the fitting tube portion and the first to third umbrella portions is integrally provided with an outwardly facing barb portion at a tip thereof.

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