JPH0689851B2 - Sealing device assembly - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device assembly disposed between two movable members so as to seal a space between the movable members and an external environment.

[Conventional technology]

Conventionally, as a sealing device assembly of this type, (US Pat.
No. 4460184) As shown in FIG. 2, an L-shaped metal seal ring C provided with one or a plurality of seal lips 11 and an L-shaped metal seal lip contact ring D facing the seal ring C.
The seal member is used as a seal member in a place where the leakage of the lubricant from the bearing portion or the intrusion of dust, muddy water or the like is prevented by in combination with the above.

However, this sealing device assembly seals against the muddy water which is going to intrude from the outside by the sliding surface of the seal lip 11 which does not directly adhere to the muddy water, but allows a certain amount of muddy water to enter the seal. Therefore, when the bearing is stopped and when the operation is started from the stop, the seal lip 11 has a drawback that it bites the accumulated foreign matter to increase the amount of wear and heat is generated, which adversely affects the sealability.

To solve this (US Patent No. 4516783)
As shown in FIG. 3, sealing lips 12a, 12b, 12c are provided on the first annular element E and the second annular element F of L-shaped cross section which rotate relative to each other, and the sealing lips 12a, 12b, 12c are directed toward the outside and the forward direction. A closure assembly is provided that is configured to be

However, the sealing device assembly has excellent sealing performance from the outside, but the tightening force of the seal lips 12b and 12c depends only on the elastic force due to the lip deformation, and the deformation amount due to wear of the sliding surface of the lip. The sealing performance decreases as the tightening force decreases due to the decrease of the elastic force and deterioration of the elastic body, and the seal lip 12b of the end face seal compensates for the error that occurs at the time of assembly, so the tightening margin of the lip is inevitably excessive, resulting in high torque. However, there were drawbacks such as high heat generation and early wear.

[Problems to be solved by the invention]

The present invention provides a sealing device assembly which eliminates these drawbacks, maintains the sealing property, reduces the rotational torque, prevents the heat aging by suppressing the heat generation of the lip sliding portion, and improves the durability. To do.

[Means for solving problems]

The present invention will be described with reference to the drawings as shown in FIG.
Two mutually movable members, shaft 7 and housing 8.
A first annular element A having a substantially L-shaped cross section and a second annular element B having a substantially U-shaped cross section, which are fixed to each other. The first annular element A and the second annular element are combined so as to be relatively rotatable, A sealing device assembly in which a plurality of seal lips 1.2.3 made of an elastic material such as synthetic rubber are provided on the first annular element A,
The first annular element A is fixed to the shaft 7, and a plurality of sealing lips 1.2.3 are provided on the first annular element A, the plurality of sealing lips are provided on the inner circumference of the inner cylindrical portion of the second annular element. It is characterized in that a first seal lip that slides on the side surface, and a second seal lip and a third seal lip that slide on the inner peripheral side surface of the outer peripheral side cylindrical portion of the second annular element are provided.

[Action]

Since the present invention is characterized by the above-mentioned structure, the plurality of seal lip 1.2.3 are each subjected to a centrifugal force according to the rotation speed during rotation, and each of them has a substantially U-shaped cylindrical portion 4.5 of the second annular element B.
Since it is pressed against the inner peripheral side surface, even if the seal lip sliding surface is worn or the elastic body is deteriorated, the surface pressure of the sliding portion hardly changes, so that stable sealing performance can be obtained for a long time. The surface pressure of the sliding part of the seal lip, which is necessary for the sealing performance, is obtained from the elastic force due to the deformation of the seal lip and the centrifugal force due to the rotation, so that the elastic force (tightening margin) of the seal lip is smaller than that of the conventional sealing device assembly. Since it can be set small, the starting torque can be reduced. This is because the centrifugal force does not work when there is no rotation and only the elastic force of the seal lip, so it is a light slide, the torque at startup is small, the centrifugal force works as the number of rotations increases, and the seal lip is pressed to seal. It works ideally to improve performance.

As shown in FIG. 1, the plurality of seal lips formed on the first annular element A are the same as the first seal lips 1 that slide on the substantially U-shaped inner peripheral side cylindrical portion 4 of the second annular element B. ,
A second seal lip 2 and a third seal lip 3 that slide on the inner peripheral side surface of the outer peripheral side cylindrical portion 5 of the second annular element B,
And it is desirable that the plurality of seal lip 1.2.3 are radial seal lip.

That is, by setting all the lips as radial lips with a small assembly error, the rip tightening margin can be made smaller than that of the end face lips, and can be set to an appropriate value. Therefore, it is possible to reduce the rotation torque, suppress heat generation, and suppress early wear. Furthermore, the first seal lip 1 is most likely to come into contact with external contaminants, but if this is installed so that the seal lip extends in the direction toward the outside, foreign substances from the outside are blocked while the lubricant is supplied, Since the first seal lip 1 has a small diameter, the peripheral speed can be reduced and the wear resistance can be improved.

In addition, external contaminants such as water, earth and sand, and mud that have passed through the first seal lip 1 will enter here by arranging them so that the lip direction of the second seal lip 2 is in the forward direction with the path toward the outside. Is prevented. The third seal lip 3 is a radial seal that faces inward, and serves to prevent leakage of a lubricant such as grease from the inside.

Further, there is a labyrinth effect between the cylindrical portion 6 of the first annular element A and the inner peripheral side cylindrical portion 4 of the second annular element B, which does not easily allow intrusion of water, mud, etc. inward. At the same time, by lowering the bent portion of the inner peripheral side cylindrical portion 4 downward, it is possible to further enhance the effect. The rubber is exposed to the outside to the minimum, and the seal lip is protected from mud, earth and sand, etc. It is shaped to

Furthermore, a lubricant is enclosed in the space 9 surrounded by the first annular element A and the second annular element B, but the volume of the space 9 can be relatively large in terms of its shape, so that the condition is severe externally. Since the lubricant can be supplied to the first seal lip 1 exposed to the air for a long period of time, the durability of the first seal lip 1 can be improved. Then, the flow path of the non-contact portion between the first annular element A and the distal end portion of the inner peripheral side cylindrical portion 4 of the second annular element B, which is the outflow path of the lubricant existing in the gap 9, to the outside direction.
In 10, combined with throttling resistance, unnecessary lubricant flows out from the flow path 10 in the first seal lip direction due to the reaction force caused by the centrifugal force causing the lubricant to flow in the direction of the arrow along the first annular element A. Can be prevented.

〔The invention's effect〕

Since the sealing device assembly of the present invention is provided so that all the seal lip slides outward in the radial direction, it exhibits stable sealing performance for a long period of time, and has a small torque at a low rotation speed and a high rotation speed. Sometimes it has a function to improve the sealing performance, and it has a structure that supplies an appropriate amount of lubricant to the tip of the seal lip and maintains this for a long time.
It is an ideal sealing device assembly that exhibits sealing performance even under harsh conditions.

[Brief description of drawings]

FIG. 1 is a sectional view of the sealing device assembly of the present invention. Second
FIG. 3 and FIG. 3 are sectional views of a conventional sealing device assembly. A ... 1st annular element, B ... 2nd annular element 1 ... 1st seal lip, 2 ... 2nd seal lip, 3
...... Third seal lip, 4 ... Cylinder part, 5 ... Cylinder part,
6 ... Cylindrical part, 7 ... Shaft, 8 ... Housing, 9 ... Void, 10 ... Flow path

Claims (1)

[Claims] 1. A sealing device assembly disposed between two members to seal a space between an inner space between a mutually movable shaft and a housing and an external environment, the cross section being fixed to the shaft. A plurality of sealing lips formed by combining a substantially L-shaped first annular element and a second annular element having a substantially U-shaped cross section fixed to the housing so as to be rotatable relative to each other, and the first annular element being made of an elastic body such as synthetic rubber. A first seal lip that slides on the inner peripheral side surface of the inner peripheral side cylindrical portion of the second annular element, and a second seal that slides on the inner peripheral side surface of the outer peripheral side cylindrical portion of the second annular element. A sealing device assembly comprising a lip and a third seal lip.