JP2002098234A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device with an excellent durability realizing a long life of the device while reducing an invasion of a dust. SOLUTION: A cover 8 slide-contacted with a housing 30 and closing a gap at an atmosphere side A between a sleeve part 2 and an oil seal part 4 is provided. Thereby, a dust such as muddy water invading to the gap at the atmosphere side A between the sleeve part 2 and the oil seal part 4 is reduced and an abrasion degree of a slide-contact part of the device by the dust can be reduced. Therefore, a durability can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device applied to a shaft sealing portion such as a kingpin portion of an agricultural work machine or the like in which dust on the atmosphere side such as muddy water is severe.

[0002]

2. Description of the Related Art Conventionally, as a sealing device used in a place where air-side dust conditions such as muddy water are severe, there are, for example, those shown in FIGS.

A sealing device 101 shown in FIG. 3 seals between a housing 300 and a shaft 400 which are concentrically and relatively rotatably assembled with each other, and is folded radially outward on an atmosphere side A attached to the shaft 400. A sleeve portion 102 as a first seal member having a sleeve inner ring 103 as a sleeve and an oil seal portion 104 as a second seal portion attached to the housing 300 are integrated.

The sleeve portion 102 has a sleeve inner ring 103, and the air side A of the sleeve inner ring 103 is folded back and extends to the side S to be sealed.

The portion of the sleeve inner ring 103 which is attached to the shaft 400 is a cylindrical portion 103A,
The portion that is folded back at the end and extends in the outer diameter direction
B, a portion that is folded back from the bent portion 103B and extends to the sealing target side S is defined as an outer peripheral bent portion 103C.

A rubber-like elastic body is fixed to the inner peripheral surface of the cylindrical portion 103 A of the sleeve inner ring 103, and serves as a fitting portion with the shaft 400.

The oil seal portion 104 has an oil seal inner ring 105 and a seal lip portion 106.

The oil seal inner ring 105 is a cylindrical member which is bent into a substantially U-shaped cross section so as to sandwich the outer bent portion 103C of the sleeve inner ring 103.

The housing 30 of the oil seal inner ring 105
0 are cylindrical portions 105A and 105
A portion that is folded back at the S end of the sealing target side S and extends toward the inner diameter side is a bent portion 105B, and a portion that is folded back from the bent portion 105B and extends to the atmosphere side A is an inner circumferential bent portion 105C.

[0010] At the inner end of the inner peripheral bent portion 105C of the oil seal inner ring 105, the outer peripheral surface of the cylindrical portion 103A and the inner peripheral surface of the outer peripheral bent portion 103C of the inner ring 103 of the sleeve are formed in the bent space of the inner ring 103 of the sleeve. A seal lip portion 106 that slides is provided.

The seal lip portion 106 extends from the inner end of the inner peripheral bent portion 105C of the oil seal inner ring 105 to the side S to be sealed and slides on the outer peripheral surface of the cylindrical portion 103A. A to extend to cylindrical part 1
03A, a two-stage wedge-shaped rubber lip 106B in sliding contact with the outer peripheral surface, and an outer peripheral bent portion 103C extending to the atmosphere side A.
A planar seal 10 having a plurality of projections that are in sliding contact with the inner peripheral surface
6C.

On the outer periphery of the main lip 106A, there is provided a garter spring 107 for applying a tightening force to the outer peripheral surface of the cylindrical portion 103A of the sleeve inner ring 103.

In the sealing device 101 having the above configuration, the flat seal 106C abutting on the inner peripheral surface of the outer bent portion 103C of the inner ring 103 prevents dust such as muddy water from entering from the atmosphere A from entering the inside. In addition, the two-stage rubber lip 106B prevents dust from leaking into the sealing target side S.

The sealing device 201 shown in FIG. 4 has a housing 300 which is mounted concentrically and relatively rotatably.
A sleeve portion 202 having a flange portion 203 turned radially outward on the atmosphere side A attached to the shaft 400, and a housing 300.
An oil seal portion 204 attached to the protection plate 20 provided at a predetermined axial distance from the flange portion 203.
5 are assembled and integrated.

The sleeve portion 202 has a sleeve inner ring 206. The sleeve inner ring 103 has its atmosphere side A turned radially outward to form a radially outward flange portion 203 on the atmosphere side A. .

The oil seal 204 has an oil seal inner ring 207 and a seal lip 208.

The oil seal inner ring 207 is an annular member having a caulking portion 207a for caulking the protection plate 205 on the atmosphere side A and a bent portion 207b having a substantially V-shaped cross section radially inward on the side S to be sealed. is there.

On the inner peripheral side of the bent portion 207b of the oil seal inner ring 207, there is provided a seal lip 208 which is in sliding contact with the outer peripheral surface of the sleeve inner ring 206. Also,
A positioning sliding portion 207c is provided at an end of the bent portion 207b having a substantially V-shaped cross section.

The seal lip 208 comprises a first lip 208A extending to the side S to be sealed and two second lips 208B extending to the atmosphere side A. Also, the first
A garter spring 209 is provided on the outer periphery of the lip 208A for applying a tightening force to the sleeve inner ring 206.

The protection plate 205 has an inner cylindrical portion 205a, an outer cylindrical portion 205b, and a radial portion 205c.
An annular member having a substantially U-shaped cross section and an outer cylindrical portion 205b
Is fitted to the inner peripheral surface of the oil seal inner ring 207 and caulked together with the end of the radial portion 205c at the caulking portion 207a.

On the other hand, the rubber-like elastic body 21 is provided on the inner peripheral surface of the sleeve inner ring 206 and the end surface A on the atmosphere side of the flange portion 203.
0 is fixed. The rubber-like elastic body 210 on the atmosphere side A of the flange 203 is provided with a protective plate 205 and a flange 20.
Third and fourth lips 211, 212 provided between
Is provided.

The third lip 211 extends toward the radial portion 205c of the protection plate 205, is inclined inward in the radial direction, and is formed so as to slide on the end face of the radial portion 205c on the side S to be sealed. The lip 212 extends to the outer cylindrical portion 205b of the protective plate 205 toward the atmosphere side A, and is formed so as to slide on the inner peripheral surface of the outer cylindrical portion 205b.

A dust lip 213 is continuously provided on the rubber-like elastic body 210 near the root of the flange portion 203. The dust lip 213 extends to the atmosphere side A, is inclined radially outward, and is formed so as to be in sliding contact with the inner peripheral surface of the inner cylindrical portion 205a of the protection plate 205.

In the sealing device 201 having the above structure, the dust lip 213 provided on the sleeve portion 202 prevents muddy water and the like from the atmosphere side A from entering the inside, and furthermore, the protection plate 205 and the flange portion Third between 203
The fourth lips 211 and 212 prevent muddy water and the like from leaking into the side S to be sealed.

[0025]

However, the prior art as described above has the following problems.

In the sealing device 101 shown in FIG. 3, the outer circumferential bent portion of the sleeve inner ring 103 moves in the axial direction due to the repetition of the thrust play, and the sleeve portion 102 and the oil seal portion 1 are moved.
Dust such as mud that has entered the gap a between the layers 04 and accumulated and adhered is repeatedly pressed. Since the compressed dust enters the sliding contact portion of the flat seal 106C, the wear of the flat seal 106C is accelerated, and the life is extremely shortened.

The flat seal 106C is configured to extend in the direction in which it is lifted and opened (extends obliquely in the direction of the atmosphere A) with respect to the direction in which the compressed dust enters (the direction of the atmosphere A). As shown in FIG. 3, there is a problem that the service life is apt to be shortened with respect to a king pin portion or the like which is used in a vertical type in which the atmosphere side A where dust accumulation and fixation easily occur is directed upward.

Further, in the sealing device 201 of FIG. 4, the mud accumulates and adheres to the dust lip 213 violently, and the stiffness is small because the dust 213 is worn and the mud adheres (plastic) and is a rubber-like elastic body. Depending on the properties, the followability of the dust lip 213 is reduced, and the sealing property is reduced.

The dust lip 213 is configured to extend in a direction in which it is lifted and opened (extends obliquely in the direction of the atmosphere A) with respect to the direction in which dust enters (the direction of the atmosphere A). In addition, there is a problem that the service life is easily shortened, for example, with respect to a kingpin portion or the like used in a vertical type in which the atmosphere side A where dust accumulation and fixation easily occur is directed upward.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to reduce the intrusion of dust and extend the life of the device. It is to provide a device.

[0031]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, an annular gap between two members which are mounted concentrically and rotatably relative to each other is sealed. In a sealing device provided with a first seal member attached to one of the inner members and a second seal member attached to the other member, an atmosphere side between the first seal member and the second seal member is provided. A cover for closing the gap is provided on the atmosphere side.

Therefore, dust such as muddy water that enters the gap on the atmosphere side between the first seal member and the second seal member is reduced, and the degree of abrasion of the sliding contact portion of the device by the dust can be reduced, and durability can be reduced. Performance can be improved.

In addition, since the sealing device is provided with the above-described structure for the king pin portion or the like used in a vertical type in which the atmosphere side is upward, dust accumulation and fixation are unlikely to occur as in the related art, and the life is extended. It becomes possible.

It is preferable that the cover has an umbrella shape that is inclined from the atmosphere side to the sealed side as going from the inner diameter side to the outer diameter side.

Thus, dust such as muddy water can be scattered in the outer diameter direction at the time of rotation, and the sticking of dust can be prevented.

Preferably, the cover is formed of metal or resin.

As a result, it has abrasion resistance and rigidity comparable to the fixation of muddy water, and the mud sticks to the atmosphere side A as compared with that made of rubber-like elastic material, and the performance is significantly reduced. Can be prevented, and the durability can be improved.

The first seal member has a sleeve whose air side is turned back to the other member side, and the second seal member has the sleeve of the first seal member turned back to the other member side. It is preferable to provide a flat seal that is in surface contact with the other member-side peripheral surface of the bent portion.

Thus, it is possible to suppress the dust from entering the sealing target side due to the planar seal coming into surface contact with the bent portion, and to improve the durability of the sealing target side seal.

[0040] The second seal member has a seal lip portion incorporated in the space where the sleeve is folded and slidingly contacting the sleeve, and the seal lip portion is provided with the first lip portion.
It is preferable that the sleeve of the seal member be provided with an end face lip that is turned back on the atmosphere side and comes into end face contact with the side face to be sealed of the bent portion extending in the radial direction.

With this, even when the dust is pressed by the thrust play, the press-fitting of the end face lip sliding contact portion improves the sealing performance, so that the intrusion of the dust is prevented and the number of the dust is reduced as compared with a general radial seal. The durability can be doubled.

[0042]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) FIG. 1 is a view showing a sealing device according to an embodiment. In FIG. 1, a sealing device 1 is used in a place where dust conditions on the atmosphere side A such as muddy water are severe as in the prior art, and a housing 30 as a two member which is concentrically and relatively rotatably assembled with each other.
To seal between the shafts 40 inserted into the housing 30.

The sealing device 1 includes a sleeve portion 2 as a first sealing member having a sleeve inner ring 3 as a sleeve which is radially outwardly folded toward the atmosphere side A attached to the shaft 40 and a housing 30. An oil seal part 4 as a second seal part to be attached is integrated.

The sleeve portion 2 includes a sleeve inner ring 3 and a cover 8.
The atmosphere side A of the sleeve inner ring 3 is folded back and extends to the side S to be sealed.

The portion of the sleeve inner ring 3 attached to the shaft 40 is folded back at the end A on the atmosphere side of the cylindrical portion 3A, and the portion extending in the outer radial direction is folded back from the bent portion 3B and the bent portion 3B. A portion extending to the sealing target side S in parallel with the portion 3A is defined as an outer bent portion 3C as a bent portion.

The inner peripheral surface of the cylindrical portion 3A and the bent portion 3
A rubber-like elastic body substantially conforming to the shape of the surface is fixed to the end surface B of the rubber member B by baking. Cylindrical part 3A
The rubber-like elastic body on the inner peripheral surface forms a fitting portion with the outer peripheral surface of the shaft 40.

A press fitting allowance 8A is press-fitted into the fitting portion between the sleeve portion 2 and the shaft 40 from the atmosphere side A, and the cover 8 is fixed to the atmosphere side A of the apparatus. The cover 8 is a thin plate having a small thickness, has high rigidity, and is formed of a material such as metal or resin.

The cover 8 has a cylindrical portion 3A of the sleeve inner ring 3.
And extends along the bent portion 3 </ b> B, and further comes into sliding contact with the housing 30 as it is.

The cover 8 has a housing 4 on the side of the shaft 4.
The shape is inclined to the sealing target side S from the 0 side. As a result, dust such as muddy water on the atmosphere side A does not accumulate between the shaft 40 and the cover 8 but scatters to the housing 30 side to prevent the dust from sticking.

The oil seal portion 4 includes an oil seal inner ring 5
And a seal lip portion 6.

The oil seal inner ring 5 is a cylindrical member bent into a substantially U-shaped cross section so as to sandwich the outer bent portion 3C of the sleeve inner ring 3.

The portion of the oil seal inner ring 5 attached to the housing 30 is a cylindrical portion 5A, and the portion of the cylindrical portion 5A that is folded back at the S end to be sealed and extends toward the inner diameter side is a bent portion 5B.
The portion bent from the bent portion 5B and extending to the atmosphere side A is defined as an inner circumferential bent portion 5C.

A rubber-like elastic body is integrally fixed around the oil seal inner ring 5 by baking. The rubber-like elastic body on the outer peripheral surface of the cylindrical portion 5A serves as a fitting portion with the inner peripheral surface of the housing 30.

On the inner peripheral surface of the cylindrical portion 5 A of the oil seal inner ring 5, a flat seal 9 having a plurality of projections formed of this rubber-like elastic body is provided with an outer bent portion 3 of the sleeve inner ring 3.
It comes into sliding contact with the C outer peripheral surface.

The flat seal 9 prevents dust which has not been completely prevented by the cover 8 from entering the interior. In particular, since the flat seal 9 has a plurality of projections, it does not lose the sealing force against thrust shift, vibration, and the like, and exhibits an effect of preventing dust from entering.

The rubber-like elastic body on the atmosphere side A of the flat seal 9 extends to the atmosphere side A and comes into contact with the side S to be sealed of the cover 8.

At the inner end of the inner peripheral bent portion 5C of the oil seal inner ring 5, the outer peripheral surface of the cylindrical portion 3A and the bent portion 3B of the sleeve inner ring 3 are formed in the space where the sleeve inner ring 3 is bent.
A seal lip portion 6 that is in sliding contact with the surface S to be sealed is provided.

The seal lip portion 6 extends from the inner end of the inner peripheral bent portion 5C of the oil seal inner ring 5 to the side S to be sealed and slides on the outer peripheral surface of the cylindrical portion 3A.
A, a rubber lip 6B extending in the axial direction A and sliding in contact with the outer peripheral surface of the cylindrical portion 3A and having a two-stage axial wedge-shaped rubber lip
Similarly to B, the end portion lip 6C extends to the atmosphere side A and slidably contacts the bent portion 3B surface S to be sealed.

The main lip 6A is provided on the side S to be sealed most, and seals the object to be sealed.

On the outer periphery of the main lip 6A, a garter spring 7 for applying a tightening force to the outer peripheral surface of the cylindrical portion 3A of the sleeve inner ring 3 is provided.

The rubber lip 6B is for preventing dust from entering finally, and is provided on the atmosphere side A of the main lip 6A.

The end face lip 6C is provided on the atmosphere side A of the rubber lip 6B, is bent in a rectangular shape in cross section, and once inclines to the inner diameter side and then extends to the outer diameter side. Therefore, it has a strong sealing force against intrusion of dust such as muddy water.

Then, the end face lip 6C is
Thus, the intrusion of dust that cannot be completely prevented can be prevented.

Further, the shape of the end face lip 6C does not significantly affect the sealing force even if it is deformed in the axial direction, so that it can cope well with thrust play.

Then, the outer circumferential bent portion 3C of the sleeve inner ring 3
Is arranged so as to be sandwiched by the oil seal inner ring 5 of the oil seal portion 4, and the sleeve device 2 and the oil seal portion 4 are integrally assembled to form the sealing device 1.

After the oil seal portion 4 is attached to the housing 30 and the sleeve portion 2 is attached to the shaft 40, the press-fit margin 8A of the cover 8 is set between the shaft 40 and the sleeve portion 2 on the atmosphere side. The cover 8 is assembled by being press-fitted from A.

In the sealing device 1 having the above structure, the cover 8 is provided on the atmosphere side A of the device, so that dust such as muddy water that enters between the sleeve portion 2 and the oil seal portion 4 is different from the conventional device. , The degree of wear of the sliding contact portion of the device due to dust can be reduced, and the durability can be improved.

The cover 18 has an umbrella shape which is inclined from the atmosphere side A to the sealed side S as going from the shaft 40 side to the housing 30 side, so that dust such as muddy water can be scattered in the outer diameter direction during rotation. In addition, it is possible to prevent sticking of dust and the like.

Since the cover 8 is formed of a material having high rigidity such as metal or resin, the cover 8 has abrasion resistance and rigidity comparable to the fixation of muddy water. It is possible to prevent the performance from remarkably deteriorating due to the sticking of mud to A, and the durability can be improved.

Since the flat seal 9 slidingly contacting the outer bent portion 3C of the sleeve inner ring 3 is provided on the inner circumferential surface of the cylindrical portion 5A of the oil seal inner ring 5, the flat seal 9 comes into surface contact with the outer bent portion 3C. It is possible to suppress dust from entering the inside of the sealing target side S, and to improve the durability of the other rubber lip 6B, the end face lip 6C, and the like.

Further, the flat seal 9 only needs to prevent the intrusion of dust that could not be prevented by the cover 8, and it is possible to efficiently prevent dust from entering.

Since the end face lip 6C is provided on the seal lip portion 6, even when the dust is pressed by the thrust play,
Since the press-fitting of the sliding contact portion of the end face lip 6C improves the sealing property, intrusion of dust can be prevented, and the durability can be improved several times as compared with a general radial seal.

The end face lip 6C only needs to prevent the intrusion of dust that could not be prevented by the cover 8 and the flat seal 9, so that efficient dust intrusion can be prevented.

As shown in FIG. 1, a sealing device 1 is attached to a kingpin portion or the like used in a vertical type in which the atmosphere side A faces upward.
Is provided with the above-described structure, dust is unlikely to accumulate and stick as in the related art, and the life can be extended.

(Second Embodiment) FIG. 2 is a view showing a sealing device according to a second embodiment. In FIG.
As in the prior art, the sealing device 11 is used in places where dust conditions on the atmosphere side A such as muddy water are severe, and a housing 30 as two members which are concentrically and relatively rotatably assembled with each other and a housing 30 inside the housing 30. This seals between the inserted shafts 40.

The sealing device 11 generally includes a sleeve portion 12 as a first seal member having a flange portion 13 on the atmosphere side A attached to a shaft 40, and an oil seal portion 14 as a second seal portion attached to the housing 30. A protective plate 15 provided at a predetermined axial distance from the flange portion 13 and fitted to the oil seal portion 14; and a cover 18 provided on the atmosphere side A of the protective plate 15; 12 and an oil seal portion 14 are assembled via a protection plate 15, and a cover 18 is fitted to the sleeve portion 12 to be integrated.

The oil seal 14 has an oil seal inner ring 16 and a seal lip 17.

The inner ring 16 of the oil seal includes a caulking portion 16a for caulking and fixing the protection plate 15 to the atmosphere side A of the cylindrical portion 16c.
And a bent portion 16b having a substantially U-shaped cross section on the radially inner peripheral side on the side to be sealed S as a second region of the cylindrical portion 16c.

A rubber-like elastic body 19 is integrally fixed to the inner and outer peripheral surfaces of the bent portion 16b having a substantially U-shaped cross section of the oil seal inner ring 16. Further, the rubber-like elastic body 19 on the outer peripheral surface of the bent portion 16 b having a substantially U-shaped cross section and the outer peripheral surface side of the cylindrical portion 16 c of the oil seal inner ring 16 form a fitting portion with the housing 30.

The section U of the oil seal inner ring 16
A seal lip portion 17 is provided on the inner peripheral side of the U-shaped bent portion 16b so as to slidably contact the outer peripheral surface of the cylindrical portion 20a of the sleeve inner ring 20, and the end of the bent portion 16b having a substantially U-shaped cross section is provided with a sleeve. A positioning sliding portion 21 for positioning when the portion 12 and the oil seal portion 14 are assembled is provided so as to slidably contact the sealing target side S of the flange portion 13.

The seal lip portion 17 has a first lip 17A extending from the inner peripheral side of the bent portion 16b to the side S to be sealed, and a second lip 17B extending to the atmosphere side A. On the outer periphery of the first lip 17A, a garter spring 22 for applying a tightening force to the outer peripheral surface of the cylindrical portion 20a of the sleeve inner ring 20 is provided.

The protection plate 15 is an annular member having a substantially U-shaped cross section opened to the side S to be sealed having an inner cylindrical portion 15a, an outer cylindrical portion 15b, and a radial portion 15c. It is fitted to the inner peripheral surface of the cylindrical portion 16c and is caulked by the caulking portion 16a together with the end of the radial portion 15c.

The sleeve section 12 has a sleeve inner ring 20 and a rubber-like elastic body 23. This sleeve inner ring 20
Has a cylindrical portion 20a and a radially outward flange portion 13 on the atmosphere side A of the cylindrical portion 20a. A rubber-like elastic body 23 having a shape substantially conforming to the shape of these surfaces is fixed to the inner peripheral surface of the cylindrical portion 20a of the sleeve inner ring 20 and the end surface of the flange portion 13 on the atmosphere side A continuously.

The rubber-like elastic body 23 is provided with a third lip 25 and a fourth lip 26 provided between the protection plate 15 and the flange 13.

The third lip 25 extends to the protective plate 15 side,
The positioning sliding portion 21 is formed so as to be inclined inward in the radial direction and slidably contact the end surface of the protective plate 15 on the side S to be sealed, and the positioning sliding portion 21 is fixed to the flange portion 13 so that a predetermined contact pressure is applied to the third lip 25. Is in sliding contact with

The fourth lip 26 extends to the outer cylindrical portion 15b of the protection plate 15 toward the atmosphere side A, and is formed so as to slide on the inner peripheral surface of the outer cylindrical portion 15b.

A dust lip 24 is continuously provided on the rubber-like elastic body 23 near the root of the flange portion 13. The dust lip 24 extends to the atmosphere side A, is inclined outward in the radial direction, and is formed so as to be in sliding contact with the inner peripheral surface of the inner cylindrical portion 15 a of the protection plate 15.

The rubber-like elastic body 23 on the inner peripheral surface of the cylindrical portion 20 a of the inner ring 20 of the sleeve forms a fitting portion with the outer peripheral surface of the shaft 40.

The cover 18 is a thin plate having no thickness, has high rigidity, and is made of metal or resin (for example, PTFE).
Etc.). The inner peripheral side of the cover 18 is slidably and sealingly contacted to the atmosphere side A of the radial portion 15c of the protective plate 15 (or the tip of the caulking portion 16a of the oil seal inner ring 16). The sleeve 12 is fitted. The cover 18 has an umbrella shape, and has a shape inclined from the shaft 40 toward the housing 30 toward the housing 30.

The sleeve portion 12 and the oil seal portion 14 are integrally assembled via a protection plate 15.

That is, the positioning sliding portion 21 for positioning slidably comes into contact with the end surface of the flange portion 13 on the side S to be sealed so as to apply a predetermined contact pressure to the third lip 25. The ends of the first lip 17A and the second lip 17B of the seal lip 17 are slidably and sealingly fitted on the outer peripheral surface of the cylindrical portion 20a in the axial direction (thrust direction).

Then, the outer cylindrical portion 15b of the protection plate 15 is fitted to the inner peripheral surface of the cylindrical portion 16c of the oil seal inner ring 16, and the outer peripheral portion is caulked by the caulking portion 16a.
The inner peripheral side of the cover 18 is fitted and integrated with the sleeve portion 12 so that the outer peripheral side of the cover 18 slidably and sealingly contacts the atmospheric side A of the radial portion 15 c of the protection plate 15. Is assembled.

The sealing device 11 configured as described above is
The cover 18 provided on the atmosphere side A can reduce the intrusion of dust such as muddy water on the atmosphere side A into the inside. Further, the dust lip 24, the third lip 25, and the fourth
The lip 26 prevents muddy water or the like from leaking into the sealed object side S.

The cover 18 has an umbrella shape inclined from the air side A to the sealed side S from the shaft 40 side toward the housing 30 side, so that dust such as muddy water can be scattered in the outer diameter direction during rotation. In addition, it is possible to prevent sticking of dust and the like.

The sleeve portion 12 and the oil seal portion 1
By making it possible to reduce the intrusion of dust such as muddy water during the period 4, the degree of wear of the sliding contact portion of the device due to dust can be reduced, and the durability can be improved.

Further, since the cover 18 is formed of a material having high rigidity such as metal or resin, mud accumulates on the dust lip 24 as in the prior art because of its high abrasion resistance and high rigidity that is not inferior to muddy water. The effect of preventing the phenomenon that the performance is remarkably reduced due to the fixation is remarkably improved as compared with the rubber-like elastic body, and the followability and durability of the dust lip 24 can be improved.

In particular, since the sealing device 1 is provided with the above-described configuration for a kingpin portion or the like used in a vertical type in which the atmosphere side A is upward, dust accumulation and fixation are unlikely to occur as in the related art. Service life can be extended.

[0099]

As described above, according to the present invention, the cover for closing the air gap between the first seal member and the second seal member is provided on the air side, so that the first seal member and the second seal member are provided. Dust such as muddy water that enters the gap on the atmosphere side between the members is reduced, and the degree of abrasion of the sliding contact portion of the device by the dust can be reduced, so that the durability can be improved.

As the cover moves from the inner diameter side to the outer diameter side,
By having an umbrella shape inclined from the atmosphere side to the sealing target side, dust such as muddy water can be scattered in the outer diameter direction at the time of rotation, and dust sticking or the like can be prevented.

Since the cover is made of metal or resin, it has abrasion resistance and rigidity comparable to the fixation of muddy water. As a result, the performance can be prevented from being significantly reduced, and the durability can be improved.

The second seal portion has a flat seal in which the sleeve of the first seal member is brought into surface contact with the peripheral surface on the other member side of the bent portion bent back to the other member side. It is possible to suppress the dust from entering the object to be sealed due to surface contact, and to improve the durability of the seal on the object to be sealed.

The seal lip portion is provided with an end lip which is in contact with the side surface to be sealed of the bent portion in which the sleeve of the first seal member is folded back on the atmosphere side and extends in the radial direction.
Even when the dust is pressed by the thrust backlash, the crimping of the end face lip sliding contact part improves the sealing performance, preventing the intrusion of dust and improving the durability several times compared to the general radial seal. Can be planned.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a sealing device according to a first embodiment.

FIG. 2 is a half sectional view showing a sealing device according to a second embodiment.

FIG. 3 is a half sectional view showing a conventional sealing device.

FIG. 4 is a half sectional view showing a conventional sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing device 2 Sleeve part 3 Sleeve inner ring 3A Cylindrical part 3B Bent part 3C Outer periphery bent part 4 Oil seal part 5 Oil seal inner ring 5A Cylindrical part 5B Bent part 5C Inner peripheral bent part 6 Seal lip part 6A Main lip 6B Rubber lip 6C End lip 7 Garter spring 8 Cover 8A Press-fit allowance 9 Plane seal 11 Sealing device 12 Sleeve portion 13 Flange portion 14 Oil seal portion 15 Protective plate 15a Inner cylindrical portion 15b Outer cylindrical portion 15c Radial portion 16 Oil seal inner ring 16a Caulking portion 16b Bent part 16c Cylindrical part 17 Seal lip part 17A First lip 17B Second lip 18 Cover 19 Rubber-like elastic body 20 Sleeve inner ring 20a Cylindrical part 21 Sliding part 22 Garter spring 23 Rubber-like elastic body 24 Dustrip 25 Third lip 26 4th lip

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsunejiro Senoo 64 Ishizukita-cho, Sakai-shi, Osaka Kubota Sakai Works Co., Ltd. (72) Inventor Masaaki Hama 64 Ishizukita-cho, Sakai-shi, Osaka Kubota Co., Ltd. Inside the Sakai Works (72) Inventor Shota Nagasawa 64 Ishizu-Kitacho, Sakai City, Osaka Prefecture F-term in the Kubota Sakai Works 3J006 AE23 CA03

Claims (5)

[Claims] 1. A seal for sealing an annular gap between two members which are concentrically and relatively rotatably assembled with each other, wherein a first seal member attached to one of the two members and a second member are attached to the other member. A sealing device comprising: a second sealing member mounted; and a cover for closing a gap on the atmosphere side between the first sealing member and the second sealing member on the atmosphere side. 2. The sealing device according to claim 1, wherein the cover has an umbrella shape inclined from the atmosphere side to the sealing target side as going from the inner diameter side to the outer diameter side. 3. The sealing device according to claim 1, wherein the cover is formed of metal or resin. 4. The first seal member has a sleeve whose air side is turned back to the other member side, and the second seal member has the sleeve of the first seal member turned back to the other member side. The sealing device according to claim 1, further comprising a flat seal that comes into surface contact with the other member-side peripheral surface of the bent portion. 5. The seal member according to claim 1, wherein the second seal member has a seal lip portion which is incorporated in a space where the sleeve is folded and slidably contacts the sleeve, and the seal lip portion is formed by the sleeve of the first seal member. 5. The sealing device according to claim 4, further comprising an end face lip that comes into contact with a side face to be sealed of a bent portion that is folded on the atmosphere side and extends in the radial direction.