JP2001116151A - Oil seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil seal capable of maintaining the sealing property of a dust lip stable over a long period without affecting a seal lip. SOLUTION: A portion of the lip end 27a of the dust lip 27 is caused to abut against a rotating shaft 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal which is a type of a sealing device used for preventing leakage of a sealed fluid, and more particularly to an oil seal which can prevent dust and the like from entering from the atmosphere.

[0002]

2. Description of the Related Art Generally, an oil seal is used to prevent leakage of lubricating oil from a bearing portion of a rotating shaft. As one of the oil seals, there is an oil seal including a seal lip located on the sealing side for preventing leakage of lubricating oil as a sealing fluid, and a dust lip for preventing dust and the like from entering from the atmosphere side. Are known.

[0003] Regarding such a conventional oil seal,
An oil seal used for a crankshaft of an automobile engine will be described with reference to FIG.

[0004] As shown in FIG.
Is mounted between a crankshaft 2 as a rotating shaft and a cylinder block 3 as a housing. The oil seal 1 is formed by integrally baking a seal main body 5 made of a rubber-like elastic body on an annular reinforcing ring 4 having a substantially L-shaped cross section.

An annular seal lip 6 is formed on the seal body 5 so as to gradually decrease in diameter from the inner peripheral portion of the reinforcing ring 4 toward a sealing side OS where a sealing fluid such as lubricating oil is located. An annular dust lip 7 is formed so as to gradually reduce the diameter from the inner peripheral portion of the reinforcing ring 4 toward the atmosphere side AS.

The seal lip 6 has an appropriate interference with the crankshaft 2 and has a lip tip 6a that comes into contact with the crankshaft 2. The seal lip 6 has an oil surface 9 having a predetermined oil surface angle expanded from the lip end 6a toward the sealing side OS and a predetermined seal angle expanded from the lip end 6a toward the atmosphere side AS. And a desired area on the side of the lip tip 6a of the seal surface 10 is brought into contact with the surface of the crankshaft 2 with an appropriate interference in the mounted state. A garter spring 11 for maintaining a radial tension between the seal lip 6 and the crankshaft 2 is disposed on a radially outer rear surface of the lip tip 6 a of the seal lip 6.

Incidentally, in recent oil seals 1,
In the mounted state, the pumping function of constantly positioning a sealing fluid such as lubricating oil, which tends to leak from the sealing side OS toward the atmosphere side AS, on the sealing surface 10 abutting on the crankshaft 2 is more effectively exerted. A plurality of screws 12 (simplified by straight lines in FIG. 8) projecting in a substantially triangular mountain shape are used in many cases.

[0008] The other dust lip 7 has a non-contact lip tip 7a slightly separated from the crankshaft 2 in the mounted state. This is because when the lip tip 7a of the dust lip 7 is provided with an interference so as to come into contact with the surface of the crankshaft 2 rotating at a high speed, the seal lip 6 The negative pressure is applied between the seal lip 6 and the dust lip 7 due to the pumping action described above, which promotes abrasion of the seal lip 6 and increases heat generation, which may cause a reduction in durability. .

[0009]

However, in the above-described conventional oil seal, a labyrinth seal formed by a gap between the lip tip 7a of the dust lip 7 and the crankshaft 2 causes external dust or the like located in the AS on the atmosphere side to be removed. Is formed so as to prevent the dust from entering the seal lip 6, but the sealing of the dust lip 7 is stable over a long period of time due to the insufficient clearance of the dust entering from the outside due to the gap. However, there is a problem that the property cannot be maintained.

Therefore, there is a demand for an oil seal capable of maintaining a stable dust lip seal for a long period of time without affecting the seal lip.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an oil seal capable of maintaining a stable dust lip seal for a long period of time without affecting the seal lip. With the goal.

[0012]

According to a first aspect of the present invention, there is provided an oil seal having the following features. It is in the point. And, by adopting such a configuration, the dust lip of the dust lip has a contact portion that comes into contact with the rotating shaft at the tip of the lip to improve sealing performance, and a non-contact portion that does not come into contact with the rotating shaft at the tip of the lip. The air permeability between the seal lip and the atmosphere is provided. Therefore, it is possible to maintain a stable dust lip sealing property for a long time without affecting the sealing lip.

According to a second aspect of the present invention, the oil seal according to the first aspect is characterized in that the dust lip has the same angle between the portions each having a different length toward the rotation axis and each rotation axis in the circumferential direction. Is formed by arranging them along. By adopting such a configuration, a contact portion that abuts on the rotating shaft and a non-contact portion that does not abut on the rotating shaft can be easily formed at the tip of the lip of the dust lip. . Therefore, the oil seal according to claim 1 can be easily realized.

According to a third aspect of the present invention, there is provided an oil seal according to the second aspect, wherein the portions having different lengths are two types of a long portion having a long length and a short portion having a short length. And the long portions and the short portions are alternately arranged along the circumferential direction. By adopting such a configuration, the long portion can easily form a contact portion that abuts on the rotating shaft at the lip tip of the dust lip, and the short portion can be formed of the dust lip. A non-contact portion that does not come into contact with the rotating shaft can be easily formed at the tip of the lip, and the contact portion and the non-contact portion can be easily formed in a well-balanced manner. Therefore, the oil seal according to claim 1 can be realized more reliably and easily.

According to a fourth aspect of the present invention, the oil seal according to the first aspect is characterized in that, in the first aspect, the portions of the dust lip which are formed at different angles with respect to the rotating shaft have the same length toward the respective rotating shafts, and have the same length in the circumferential direction. Is formed by arranging them along. By adopting such a configuration, a contact portion that abuts on the rotating shaft and a non-contact portion that does not abut on the rotating shaft can be easily formed at the tip of the lip of the dust lip. . Therefore, the oil seal according to claim 1 can be easily realized.

According to a fifth aspect of the present invention, there is provided an oil seal according to the fourth aspect, wherein a portion having a different angle has a small angle formed between at least a large angle portion formed with a rotating shaft and a rotating shaft. It has two types, a small angle part and
The point is that the large angle portions and the small angle portions are alternately arranged along the circumferential direction. And, by adopting such a configuration, the large angle portion is located at the tip of the lip of the dust lip.
The contact portion that abuts on the rotating shaft can be easily formed, and the small angle portion can easily form a non-contact portion that does not abut on the rotating shaft at the tip of the lip of the dust lip. At the same time, the contact portion and the non-contact portion can be easily formed with good balance. Therefore, the oil seal according to claim 1 can be realized more reliably and easily.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings. The same or corresponding components as those of the above-described conventional device are denoted by the same reference numerals in the drawings, and description thereof is omitted.

FIGS. 1 to 4 show a first embodiment of an oil seal according to the present invention. FIG. 1 is a longitudinal half sectional view of a main part, and FIG. FIG. 3 is an enlarged development view shown from the center of the shaft, FIG. 3 is a partially enlarged cross-sectional view showing the vicinity of a lip tip of the elongated portion of the dust lip of FIG.
FIG. 4 is a partially enlarged cross-sectional view showing the vicinity of the lip tip of the rectangular portion of the dust lip of FIG.

The oil seal according to the present embodiment is used for a crankshaft of an automobile engine.

As shown in FIG. 1, the oil seal 21 of this embodiment is mounted between a crankshaft 22 as a rotating shaft and a cylinder block 23 as a housing. The oil seal 21 is formed by integrally baking a seal main body 25 made of a rubber-like elastic body on an annular reinforcing ring 24 having a substantially L-shaped cross section made of metal or the like.

An annular seal lip 26 is formed on the seal body 25 so as to gradually decrease in diameter from the inner peripheral portion of the reinforcing ring 24 toward the sealing side OS where the lubricant is located.
A substantially annular dust lip 27 is formed so as to gradually decrease in diameter from the inner peripheral portion of the reinforcing ring 24 toward the atmosphere side AS.

One seal lip 26 has an appropriate interference with the crankshaft 22 and has a lip tip 26a that comes into contact with the crankshaft 22. The seal lip 26 has a lip tip 26 as in the prior art.
a, a sealing surface 30 having a predetermined oil angle and extending from the lip tip 26a toward the atmosphere AS, and a sealing surface 30 having a predetermined sealing angle and extending from the lip tip 26a toward the atmosphere side AS. A desired area of the seal surface 30 on the side of the lip tip 26a is brought into contact with the surface of the crankshaft 22 with an appropriate interference in the mounted state.
The seal lip 26 and the crankshaft 2 are disposed on the radially outer back surface of the lip tip 26a of the seal lip 26.
A garter spring 31 for holding a radial tension between the garter springs 31 is provided. A plurality of screws 3 having a substantially triangular cross section are provided on the sealing surface 30.
2 (simplified by a straight line in FIG. 1), and these screws 32 are used to move the sealing side OS from the atmosphere side A to the atmosphere side A.
It is possible to more effectively exert a pumping action of always positioning a sealing fluid such as lubricating oil that leaks toward S on the sealing side OS.

The other dust lip 27 has a configuration in which a part of the lip tip 27a of the dust lip 27 abuts on the crankshaft 22 in the mounted state.

That is, the dust lip 27 of the present embodiment is used.
Is configured such that portions having different lengths toward the crankshaft 22 are disposed along the circumferential direction at the same angle θ (FIGS. 3 and 4) between the crankshaft 22 and each of the portions.

More specifically, the dust lip 27 of the present embodiment has a long portion 27A having a long length and a short portion 27B having a short length, and as shown in FIG.
Long portions 27A and short portions 27B are alternately arranged along the circumferential direction. As shown in FIG. 2, the lip tip 27a of the dust lip 27 is formed in a plane wave shape so as to be continuous at the long portion 27A and the short portion 27B. Furthermore, the lip tip 27 in the elongated portion 27A
As shown in FIG. 3, a is formed so as to come into contact with the surface of the crankshaft 22 with an appropriate interference in the mounted state, and the lip tip 27 of the short portion 27B is formed.
As shown in FIG. 4, a is formed so as to be in a non-contact state slightly separated from the surface of the crankshaft 22 in the mounted state.

The lip tip 2 of the elongated portion 27A
The interference between the crankshaft 7a and the crankshaft 22 and the gap between the lip tip 27a and the crankshaft 22 in the short portion 27B are different from each other.
It can be easily set by controlling the length toward 2. The values of the interference and the gap may be determined as required according to the design concept or the like.

In this embodiment, the elongated portion 27
A and the lip tip 27a of the dust lip 27 in the short portion 27B are formed so as to be continuous in the circumferential direction, but the lip tip 27a of the dust lip 27 in the long portion 27A and the short portion 27 is discontinuous. For example, a configuration having a step like a comb tooth may be used. In this case, as the portions having different lengths, the lip tip 27a has an elongated portion 27 having a tightening margin with respect to the crankshaft 22.
A, and not only a portion where the lip tip 27a is a short portion 27B separated from the surface of the crankshaft 22 but also a portion where the lip tip 27a is in contact with the surface of the crankshaft 22 or not. May be provided.

Next, the operation of this embodiment having the above-described configuration will be described.

According to the oil seal 21 of the present embodiment,
The sealing property can be improved by the lip tip 27a of the dust lip 27 which is a contact portion which comes into contact with the surface of the crankshaft 22 of the elongated portion 27A with a tight interference. In addition, the lip tip 27a of the dust lip 27, which is a non-contact portion of the rectangular portion 27B that does not come into contact with the surface of the crankshaft 22, allows air to pass between the seal lip 26 and the atmosphere side AS.

Therefore, the oil seal 2 of the present embodiment
According to 1, it is possible to maintain a stable sealing property of the dust lip 27 for a long time without affecting the seal lip 26.

Further, according to the oil seal 21 of the present embodiment, by forming the long portion 27A and the short portion 27 having the same angle θ with the crankshaft 22, the lip tip 27a of the dust lip 27 is formed. , A contact portion abutting against the crankshaft 22 and the crankshaft 2
A non-contact portion that does not come into contact with 2 can be easily formed.

Further, the long portion 27A can easily form a contact portion that abuts against the crankshaft 22 at the lip tip 27a of the dust lip 27, and the short portion 27B can Lip tip 27a
In addition, a non-contact portion that does not contact the crankshaft 22 can be easily formed, and the contact portion and the non-contact portion can be easily formed in a well-balanced manner.

FIGS. 5 to 7 show a second embodiment of the oil seal according to the present invention.

In the oil seal 21A of this embodiment, the length of the dust lip 37 toward the crankshaft 22 is the same (constant), and the lip tip of the dust lip 37 is formed by providing a portion having a different angle from the crankshaft 22. 3
7a is a part of which is brought into contact with the crankshaft 22.

That is, the dust lip 37 of the present embodiment is used.
Are formed by arranging portions having different angles with the crankshaft 22 along the circumferential direction with the same length toward the respective crankshafts 22.

More specifically, as shown in FIG. 5, the dust lip 37 of the present embodiment has a large angle portion 37A.
And small angle portions 37B, and large angle portions 37A and small angle portions 37B are alternately arranged along the circumferential direction. And the lip tip 37a of the dust lip 37 is
The large angle portion 37A and the small angle portion 37B are formed in a front wavy shape so as to be continuous. Furthermore, large angle part 3
As shown in FIG. 6, the lip tip 37a in 7A
The angle θ1 formed between the crankshaft 22 and the crankshaft 22 is formed to be large, and is formed so as to come into contact with the surface of the crankshaft 22 with an appropriate tightening margin in a mounted state. Also, the lip tip 37a in the small angle portion 37B
As shown in FIG. 7, the angle θ2 between the crankshaft 22 and the crankshaft 22 is formed small (θ1> θ2), and is formed so as to be in a non-contact state slightly separated from the surface of the crankshaft 22 in the mounted state. ing.

It should be noted that the interference of the lip tip 37a at the large angle portion 37A with the crankshaft 22 and
The gap between the lip tip 37a and the crankshaft 22 in the small angle portion 37B can be easily set by controlling the angle or the length. The values of the interference and the gap may be determined as required according to the design concept or the like.

In this embodiment, the large angle portion 3
The lip tip 37a of the dust lip 37 in the 7A and the small angle portion 37B is formed to be continuous in the circumferential direction, but the lip tip 37a of the dust lip 37 in the large angle portion 37A and the small angle portion 37 is discontinuous. For example, the crankshaft 22 may have a shape in which the axial position of the crankshaft 22 has a step. In this case, the portions having different angles include a portion where the lip tip 37a is a large angle portion 37A having a tightening margin with respect to the crankshaft 22, and a small angle portion 37B where the lip tip 37a is separated from the surface of the crankshaft 22. It is also possible to adopt a configuration in which not only a portion that becomes the above-mentioned portion but also a portion where a boundary between the lip tip 37a and the surface of the crankshaft 22 is determined.

The other structure is the same as that of the oil seal 21 of the first embodiment described above.

According to the oil seal 21A of this embodiment having such a configuration, the same effects as those of the oil seal of the above-described first embodiment can be obtained.

That is, the sealing property can be improved by the lip tip 37a of the dust lip 37, which is the contact portion that comes into contact with the surface of the crankshaft 22 of the large angle portion 37A with a tight interference, and the crankshaft 22 of the small angle portion 37B can be improved. The lip tip 37a of the dust lip 37, which is a non-contact portion that does not come into contact with the surface, can provide air permeability between the seal lip 26 and the atmosphere side AS.

Accordingly, the oil seal 2 of the present embodiment
According to 1A, it is possible to maintain a stable sealing property of the dust lip 37 for a long time without affecting the seal lip 26.

According to the oil seal 21A of the present embodiment, the large angle portion 37A and the small angle portion 37 having the same length toward the crankshaft 22 are formed, so that the lip tip 37a of the dust lip 37 has A contact portion that contacts the crankshaft 22 and a non-contact portion that does not contact the crankshaft 22 can be easily formed.

Further, the large angle portion 37A is attached to the lip tip 37a of the dust lip 37 by the crankshaft 22.
The contact part which abuts against can be easily formed,
The small angle portion 37B is provided with a lip tip 37 of the dust lip 37.
a, a non-contact portion that does not contact the crankshaft 22 can be easily formed, and the contact portion and the non-contact portion can be easily formed in a well-balanced manner.

The present invention is not limited to the above embodiments, but can be variously modified as required. For example, the configuration may be such that no screw is provided on the sealing surface.

[0046]

As described above, according to the oil seal of the first aspect of the present invention, the dust lip has an improved sealing property at the contact portion which comes into contact with the rotating shaft at the tip of the lip, and the dust at the tip of the lip. The non-contact portion not in contact with the rotating shaft has extremely excellent effects such as providing air permeability between the seal lip and the atmosphere. Therefore, there is an extremely excellent effect that the dust lip can be stably maintained for a long period of time without affecting the seal lip.

Further, according to the oil seal of the present invention according to the second aspect, the tip of the lip of the dust lip is in contact with the rotating shaft formed by the long portion and the rotating shaft formed by the short portion. An extremely excellent effect is obtained such that a non-contact portion that does not abut can be easily formed. Therefore, an extremely excellent effect is achieved such that the oil seal according to claim 1 can be easily realized.

According to the third aspect of the present invention, the elongated portion is provided at the tip of the lip of the dust lip.
The contact portion that abuts against the rotating shaft can be easily formed, and the short portion can easily form a non-contact portion that does not abut against the rotating shaft at the tip of the lip of the dust lip. At the same time, the contact portion and the non-contact portion have extremely excellent effects such as being able to be easily formed in a well-balanced manner. Therefore, the oil seal according to claim 1 can be realized more reliably and easily.

Further, according to the oil seal of the present invention according to claim 4, the tip of the dust lip is brought into contact with the rotating shaft formed by the large angle portion and the rotating shaft formed by the small angle portion. An extremely excellent effect is obtained such that a non-contact portion that does not abut can be easily formed. Therefore, an extremely excellent effect is achieved such that the oil seal according to claim 1 can be easily realized.

According to the oil seal of the fifth aspect of the present invention, the large angle portion can easily form a contact portion at the tip of the lip of the dust lip which comes into contact with the rotating shaft. The angle part is at the tip of the lip of the dust lip,
It is possible to easily form a non-contact portion that does not come into contact with the rotation shaft, and it is possible to form a contact portion and a non-contact portion in a well-balanced and easy manner. Therefore, the oil seal according to claim 1 can be realized more reliably and easily.

[Brief description of the drawings]

FIG. 1 is a longitudinal half sectional view showing a first embodiment of an oil seal according to the present invention.

FIG. 2 is an enlarged development view showing the lip tip of the dust lip of FIG. 1 viewed from the center of the rotation axis.

FIG. 3 is a partially enlarged cross-sectional view showing the vicinity of a lip tip of an elongated portion of the dust lip of FIG. 1;

FIG. 4 is a view similar to FIG. 3 showing the vicinity of the lip tip of the rectangular portion showing the vicinity of the lip tip of FIG. 1;

FIG. 5 is a partial longitudinal half sectional view of a main part showing a second embodiment of the oil seal according to the present invention.

6 is a partially enlarged cross-sectional view showing the vicinity of a lip tip of a large angle portion of the dust lip of FIG.

7 is a view similar to FIG. 6, showing the vicinity of the lip tip of the small angle portion of the dust lip of FIG. 5;

FIG. 8 is a longitudinal half sectional view showing a main part of a conventional oil seal.

[Explanation of symbols]

 21, 21A Oil seal 22 Crankshaft (as a rotating shaft) 23 Cylinder block (as a housing) 25 Seal body 26 Seal lip 27, 37 Dust lip 27A Long part 27B Short part 27a, 37a (Dust lip) Tip 37A Large angle section 37B Small angle section AS Atmospheric side OS Sealed side θ, θ1, θ2 (between rotation axis) Angle

Claims (5)

[Claims] 1. An oil seal having a seal lip mounted between a rotating shaft and a housing and having a dust lip, wherein a part of a lip tip of the dust lip is brought into contact with the rotating shaft. Oil seal. 2. The dust lip is formed by arranging portions having different lengths toward the rotation axis along the circumferential direction at the same angle with respect to each rotation axis. The oil seal according to claim 1, wherein 3. The portion having different lengths has at least two types of a long portion having a long length and a short portion having a short length, and the long portion and the short portion have different lengths. 3. The oil seal according to claim 2, wherein the oil seals are alternately arranged along a circumferential direction. 4. The dust lip according to claim 1, wherein the dust lip is formed by arranging portions having different angles with respect to the rotation axis along the circumferential direction at the same length toward the respective rotation axes. The oil seal according to claim 1, wherein: 5. The part having different angles has at least two types of a large angle part having a large angle with the rotation axis and a small angle part having a small angle with the rotation axis, and The oil seal according to claim 4, wherein the large angle portions and the small angle portions are alternately arranged along the circumferential direction.