JP3859801B2 - Pressure-resistant oil seal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure-resistant oil seal used for a reciprocating shaft or a rotating shaft of a portion where fluid pressure inside a machine increases.
[0002]
[Prior art]
FIG. 2 shows an example of a conventional oil seal of this type. The oil seal 1 is formed by integrally forming a seal portion 3 made of a rubber-like elastic material on a metal reinforcement ring 2 having an L-shaped cross section, and is made of resin between the reinforcement ring 2 and the seal lip 4 of the seal portion 3. A backup ring 5 is arranged. When the internal pressure P inside the housing 6 to which the oil seal 1 is attached is higher than the outside atmospheric pressure Q, the seal lip 4 is strongly pressed against the shaft 7 by the internal pressure P, and the seal lip 4 wears abnormally. It may be deformed. On the other hand, when the backup ring 5 is provided, the internal pressure P applied to the seal lip 4 is received by the backup ring 5, so that such a problem does not occur. Further, a mounting portion 3a is provided on the seal portion 3 so as to cover the annular portion 2a of the metal reinforcing ring 2, and the outer diameter thereof is made larger than the inner diameter of the mounting hole 6a of the housing 6 so as to provide a tightening allowance. In this state, the mounting portion 3a is press-fitted, and the flange portion 2b of the reinforcing ring 2 is applied to the seal stopper 6b of the housing 6, so that the internal pressure P acting in the axial direction and the radial direction is received by the entire oil seal 1. It has become.
[0003]
[Problems to be solved by the invention]
In such a pressure-resistant oil seal 1, when a high internal pressure P is applied, the attachment portion 3a of the seal portion 3 extends to the atmospheric pressure Q side, and the fitting force between the attachment portion 3a and the attachment hole 6a of the housing 6 is weakened. In order to prevent this, the end surface 3b on the outer periphery of the mounting portion 3a is extended so as to be received by the seal stopper 6b of the housing 6. For this reason, if a high internal pressure P is repeatedly applied from various directions in this state, the outer peripheral end surface 3b of the attachment portion may be pressed against the seal stopper 6b and peeled off from the reinforcing ring 2. The peeled rubber portion is sandwiched between the flange portion 2b of the reinforcing ring 2 and the seal stopper 6b, and finally falls off from the seal portion 3 and there is a risk of deteriorating the durability of the oil seal.
[0004]
The present invention solves such a conventional problem, and an object thereof is to provide a pressure-resistant oil seal in which the durability of the oil seal is improved.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention separates the end face facing the seal stopper of the housing, which is a mounting counterpart member on the outer periphery of the mounting portion of the seal portion, and a part of the flange portion of the reinforcing ring from the seal stopper of the housing, The remaining portion of the flange portion is brought into contact with the seal stopper. Thereby, since the outer peripheral end face of the attachment portion of the seal portion is not pressure-bonded to the seal stopper due to the internal pressure, the portion is not peeled off or dropped off, and the durability can be improved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of the present invention. The oil seal 11 is formed by integrally forming a seal portion 13 made of a rubber-like elastic material on a metal reinforcement ring 12 having an L-shaped cross section, and is made of resin between the reinforcement ring 12 and the seal lip 14 of the seal portion 13. A backup ring 15 is arranged. The reinforcing ring 12 includes an annular portion 12a that extends in the axial direction, and a flange portion 12b that extends radially inward from the annular portion 12a and has a step portion 12c in the middle. The seal portion 13 has an attachment portion 13a that covers the annular portion 12a of the reinforcing ring 12 and is attached to the housing 16 on the outer peripheral side, and has a seal lip 14 that presses against the shaft 17 on the inner peripheral side.
[0007]
The oil seal 11 press-fits the attachment portion 13 a of the seal portion 13 into the attachment hole 16 a of the housing 16, and causes the flange portion 12 b of the reinforcing ring 12 to abut on the seal stopper 16 b of the housing 16. In this state, the radially outer portion from the end surface 13b of the outer periphery of the mounting portion 13a and the step portion 12c of the flange portion 12b of the reinforcing ring 12 is separated from the seal stopper 16b, and only the radially inner portion from the step portion 12c is sealed. It is in contact with the stopper 16b. Therefore, even if the internal pressure P is applied from various directions, the outer peripheral end surface 13b of the mounting portion of the seal portion 13 is not crimped to the seal stopper 16b, so that the portion is between the seal stopper 16b and the flange portion 12b. Since it is not pinched and peeled off or dropped off, durability can be improved.
[0008]
In the present embodiment, a step portion 12 c is provided in the middle of the flange portion 12 b of the reinforcing ring 12, and the end surface 13 b of the outer periphery of the mounting portion 13 a of the seal portion 13 and a part of the reinforcing ring flange portion 12 b are sealed stopper 16 b of the housing 16. However, the flange portion 12b of the reinforcing ring 12 may be a straight flat surface, and a similar stepped portion toward the reinforcing ring 12 may be provided at the seal stopper 16b portion of the housing 16.
[0009]
【The invention's effect】
As is apparent from the above embodiment, the present invention separates the surface facing the seal stopper of the housing, which is a mounting counterpart member on the outer periphery of the seal portion, and a part of the flange portion of the reinforcing ring away from the seal stopper of the housing. In addition, the remaining portion of the flange portion is brought into contact with the seal stopper. Thereby, since the outer peripheral end face of the attachment portion of the seal portion is not pressure-bonded to the seal stopper due to the internal pressure, the portion is not peeled off or dropped off, and the durability can be improved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of an oil seal showing an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of an oil seal showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Oil seal 12 Reinforcement ring 12a Annular part 12b Flange part 12c Step part 13 Seal part 13a Mounting part 13b End surface 14 of a mounting part outer periphery 14 Seal lip 15 Backup ring 16 Housing 16a Mounting hole 16b Seal stopper 17 Axis

Claims (2)

A reinforcing ring comprising an annular portion extending in the axial direction and a flange portion extending radially inward from the annular portion and contacting the seal stopper of the mating member; and an attachment portion covering the annular portion of the reinforcing ring; In a pressure-resistant oil seal provided with a seal portion made of a rubber-like elastic material having a seal lip on the side, an end surface of the attachment portion of the seal portion facing the seal stopper of the mating member and a flange portion of the reinforcement ring A pressure-resistant oil seal in which a portion is separated from the seal stopper and a remaining portion of the flange portion of the reinforcing ring is brought into contact with the seal stopper. 2. The pressure-resistant oil seal according to claim 1, wherein a step portion is provided in the middle of the flange portion of the reinforcing ring, whereby a part of the end surface of the seal portion mounting portion and the flange portion of the reinforcing ring is separated from the seal stopper.

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