JP2005009584A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of preventing the leakage in a stopped state through a slit of a seal lip in stopping. <P>SOLUTION: A spiral slit 8 is cut on a sliding face slid on a rotating shaft 12 of the seal lip 3, and an annular seal part 7 kept into face-contact with the shaft is mounted over the circumference on a part different from the slit 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealing device such as an oil seal used for a shaft seal portion of various devices, and more particularly to a structure having a slit on a sliding surface of a seal lip.
[0002]
[Prior art]
Conventionally, there is a sealing device 101 having a slit 103 in a seal lip 102 as shown in FIG. 2 (see Patent Document 1).
[0003]
The sealing device 101 shown in FIG. 2 has a spiral slit 103 formed by obliquely cutting in one direction on a sliding surface that slides on the outer peripheral surface of the rotating shaft of the resin seal lip 102. The spiral slit 103 has the ability to follow the shaft eccentricity of the seal lip 102, and the suction performance of pulling back the sealing object (fluid etc.) to the sealing side I by the screw effect (pumping action) of the slit 103 has been obtained. .
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-332501
[Problems to be solved by the invention]
In the sealing device as described above, the object to be sealed is not leaked to the anti-sealing side O due to the suction performance by the screw effect of the slit 103 when the rotary shaft rotates. However, when the rotating shaft is stationary, the suction performance due to the screw effect of the slit 103 disappears, and there is a problem that a stationary leak occurs in which the sealing object leaks to the anti-sealing side O through the slit.
[0006]
The present invention has been made in view of the above prior art, and an object of the present invention is to prevent static leakage through the slit of the seal lip when stationary.
[0007]
[Means for Solving the Problems]
The present invention pays attention to the fact that a slit is formed on the entire sliding surface of the seal lip, so that static leakage occurs, and an annular seal portion that makes surface contact with the sliding surface of the seal lip over the entire circumference in addition to the slit. The idea that can prevent the stationary leakage was obtained.
[0008]
The configuration of the present invention that embodies the above idea is to seal an annular gap between two members that are concentrically and relatively rotatable, and is a seal lip that slidably seals and contacts one of the two members. A spiral slit is cut into a sliding surface that slides on the one member of the seal lip, and an annular seal portion that is in surface contact over a circumference is provided at a portion different from the slit. And
[0009]
In this configuration, since the annular seal portion of the sliding surface is in surface contact over the entire circumference, stationary leakage through the slit is stopped by the annular seal portion, so that stationary leakage due to the slit can be prevented.
[0010]
It is preferable that the annular seal portion is provided on the side opposite to the seal with respect to the slit.
[0011]
In this configuration, the annular seal portion seals the non-sealed side of the slit where static leakage occurs through the slit, so that static leakage due to the slit can be prevented.
[0012]
In this way, the annular seal portion may be provided on the sliding surface on the anti-sealing side of the slit, and may be provided on the root side or the distal end side of the seal lip with respect to the extending direction of the seal lip. Conceivable. In particular, considering that the seal lip is normally extended toward the sealing side, when the tip is extended toward the sealing side, an annular seal portion is formed on the base side of the sealing lip with respect to the slit.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a half sectional view showing a sealing device according to an embodiment. The sealing device 1 in FIG. 1 uses a housing 11 and a rotary shaft 12 inserted through a shaft hole of the housing 11 as two members that are concentrically and relatively rotatable. An annular gap between the two is sealed. And the fluid as a sealing target object of the sealing side I is prevented from leaking to the anti-sealing side O.
[0015]
The sealing device 1 includes a seal body 2 attached to the inner periphery of the shaft hole of the housing 11, and a seal lip 3 extending from the seal body 2 in the direction of the rotary shaft 12 and slidably sealingly contacting the outer peripheral surface of the rotary shaft 12. It is equipped with.
[0016]
The seal body 2 has a reinforcing ring 4 inside, and a rubber-like elastic body 5 is baked around the reinforcing ring 4.
[0017]
The reinforcing ring 4 includes a cylindrical portion 41 extending in the axial direction of the rotary shaft 12 and an inward flange portion 42 facing the inner diameter direction on the anti-sealing side O of the cylindrical portion 41.
[0018]
The rubber-like elastic body 5 baked on the outer peripheral side of the tubular portion 41 forms a fitting portion 6 for fitting the sealing device 1 to the inner periphery of the shaft hole of the housing 11.
[0019]
Further, the rubber-like elastic body 5 baked to the inner diameter of the inward flange portion 42 is formed with a protruding portion 51 with its tip protruding in the inner diameter direction.
[0020]
The seal lip 3 is bonded to the sealing side I end surface of the rubber-like elastic body 5 baked on the inward flange portion 42.
[0021]
The seal lip 3 is made of a resin such as PTFE (polytetrafluoroethylene).
[0022]
The seal lip 3 extends from the seal body 2 to the rotating shaft 12 while being slightly inclined to the sealing side I, and the base side that is in contact with the outer peripheral surface of the rotating shaft 12 forms an annular seal portion 7 that makes surface contact over one circumference. .
[0023]
The seal lip 3 further extends to the sealing side I in the axial direction with the tip end side of the annular seal portion 7 being in contact with the outer peripheral surface of the rotary shaft 12. A spiral slit 8 is cut in one diagonal direction on the entire contact surface (sliding surface) of the seal lip 3 on the tip side of the annular seal portion 7. The slit 8 is carved into a triangular groove having a triangular cross section.
[0024]
That is, on the contact surface (sliding surface) of the seal lip 3 with respect to the rotating shaft 12, the slit 8 is cut on the tip side, and the annular seal portion 7 is formed on the base side different from the slit 8.
[0025]
The sealing device 1 having the above configuration can obtain suction performance by the screw effect of the slit 8 when the rotary shaft 12 rotates, and seals the fluid even if the fluid enters the contact surface where the slit 8 of the seal lip 3 exists. Can be pulled back to side I.
[0026]
On the other hand, when the rotation of the rotary shaft 12 is stopped, the fluid on the sealing side I tends to leak to the anti-sealing side O through the slit 8, but is provided on the anti-sealing side O rather than the slit 8 of the seal lip 3. Since the formed annular seal portion 7 seals the fluid, it is possible to prevent a stationary leak in which the fluid transmitted through the slit 8 leaks to the anti-sealing side O.
[0027]
Thus, the sealing device 1 can satisfactorily prevent the fluid on the sealed side I from leaking to the anti-sealed side O regardless of the rotation and stop of the rotating shaft 12.
[0028]
【The invention's effect】
As described above, the present invention can prevent static leakage through the slit of the seal lip when stationary.
[Brief description of the drawings]
FIG. 1 is a half sectional view showing a sealing device according to an embodiment.
FIG. 2 is a half sectional view showing a conventional sealing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sealing device 2 Seal main body 3 Seal lip 4 Reinforcement ring 5 Rubber-like elastic body 6 Fitting part 7 Annular seal part 8 Slit 11 Housing 12 Rotating shaft 41 Cylindrical part 42 Inward flange part 51 Projection part

Claims (2)

Sealing an annular gap between two members that are concentrically rotatable relative to each other.
A seal lip that slidably seals against one of the two members;
The sealing lip is characterized in that a spiral slit is cut in a sliding surface of the seal lip that slides on the one member, and an annular seal portion that is in surface contact over a circumference is provided in a portion different from the slit. apparatus. The sealing device according to claim 1, wherein the annular seal portion is provided on a side opposite to the slit from the slit.

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