JP2000337518A - Sealing-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent sealing fluid from leaking along a screw groove at a stationary state in a sealing-up device provided with a screw groove at a sealing part slidably coming into close contact with a partner member by providing a check valve to allow the flow from the atmosphere side to the sealing fluid side and intercept the reverse flow. SOLUTION: In this sealing-up device, an outer circumferential seal part 2 made of a rubber-like elastic material is bakingly bonded to the metallic fitting ring 1, and on the inner circumferential side of the fitting ring, a seal lip made of a resin such a PTFE is held, and a helical screw groove 5 is formed on the seal part 4 slidably and closely contacted with the circumferential face of a shaft as the partner member of slide. In this case, in the respective screw groove 5, check valves 6 allowing flow from the atmosphere side (x) to sealing fluid side (y) at mounting and intercepting the reverse flow from the sealing fluid side (y) to the atmosphere side (x) are provided on one position or a plurality of positions. The check valve 6 is formed into a plate-like valve element 7 fixed on the bottom face 5a of the screw groove 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a sealing device,
More specifically, the present invention relates to a sealing device provided with a thread groove in a seal portion slidably contacting a mating member.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a seal lip 51 made of resin is provided, and a seal portion 52 of the seal lip 51 is slidably in close contact with a peripheral surface of a shaft (not shown).
A sealing device provided with a thread groove 53 is known. The thread groove 53 exerts a pumping action when the shaft rotates, and pushes the sealing fluid in the thread groove 53 back from the atmosphere side to the sealing fluid side. When the shaft is stationary, the sealing fluid leaks along the thread groove 53. Sometimes. Therefore, conventionally, as shown in the figure, a blocking portion 54 is provided in the thread groove 53 to prevent leakage of the sealing fluid when the shaft is stationary. Is provided, in addition to the flow from the sealed fluid side to the atmosphere side, in addition to blocking the flow from the opposite atmosphere side to the sealed fluid side, this causes a decrease in the pumping ability related to the pumping action. Has become.

[0003]

SUMMARY OF THE INVENTION In view of the above, the present invention is directed to a sealing device having a thread groove in a seal portion slidably in close contact with a mating member. It is an object of the present invention to provide a sealing device capable of preventing the occurrence of the above-mentioned problem and exhibiting a sufficient pumping ability at the time of rotation by a thread groove, thereby exhibiting excellent sealing performance.

[0004]

In order to achieve the above object, a sealing device according to a first aspect of the present invention is a sealing device provided with a thread groove in a sealing portion slidably in close contact with a mating member. A check valve is provided in the screw groove to allow a flow from the fluid to the sealed fluid side and to block a flow in the opposite direction.

According to a second aspect of the present invention, there is provided a sealing device according to the first aspect, wherein a check valve is formed by a plate-shaped valve body fixed or integrally formed on the bottom surface of the thread groove. It is a feature.

As in the sealing device according to the first aspect of the present invention having the above-mentioned structure, a check ring is provided in the thread groove to allow the flow from the atmosphere side to the sealed fluid side and to shut off the flow in the opposite direction. When this is done, only the sealing fluid in the thread groove is allowed to flow from the atmosphere side to the sealing fluid side by the check valve action of the check valve, and the flow of the sealing fluid from the sealing fluid side to the atmosphere side in the opposite direction is blocked. Will be. There are various aspects of the structure of the check valve.
As described in (1), it is preferable to form the check valve by a plate-shaped valve element fixed or integrally formed on the bottom surface of the thread groove, because the easiness of manufacture or molding can be ensured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a half section of the sealing device according to the embodiment, and FIG. 2 is an enlarged perspective view of a main part thereof.

As shown in FIG. 1, the sealing device (also referred to as a screw seal or a thread groove seal) according to the embodiment first has a metal mounting ring 1, and the mounting ring 1 is provided with a rubber-like elastic material. A seal lip (also referred to as a resin lip) 3 made of PTFE or the like is held on the inner peripheral side of the mounting ring 1, and the seal lip 3 is slid. One or a plurality of helical screw grooves 5 are formed in a seal portion 4 slidably in close contact with a peripheral surface 10a of a shaft 10 (see FIG. 4) which is a moving partner member. 5 allows the flow (flow in the suction direction) from the atmosphere side x to the sealed fluid side y at the time of mounting, and blocks the flow (flow in the leak direction) from the sealed fluid side y to the atmosphere side x in the opposite direction. Check valve 6 It provided a plurality of locations, as shown enlarged in FIG. 2, the respective check valve 6 is formed by a plate-shaped valve body 7 fixed to the bottom surface 5a of the screw groove 5.

The check valve 6 opens when the shaft 10 rotates,
An opening / closing type stopping point having a function of closing when the shaft 10 stops, and is configured as follows.

That is, first, the check ring 6 is formed as a plate fixed to only the bottom surface 5a of the screw groove 5. Also, as shown in FIG.
Of the thread groove 5 in the depth direction (height) h is larger than the depth d of the thread groove 5 so that the check valve 6 is caught in the circumferential direction with respect to the peripheral surface 10a of the shaft 10 at the time of mounting. (H> d). As shown in FIG. 4, when the shaft 10 is inserted into the inner periphery of the sealing device, the check ring 6 does not go against the flow of the sealing fluid (liquid such as oil) in the suction direction when the shaft 10 rotates. When the shaft 10 falls down ((A) in the figure), it is set so as to be caused by the flow of the sealing fluid in the leak direction when the shaft 10 stops and pressed against the peripheral surface 10a of the shaft 10 ((B) in the figure).

According to the sealing device having the above configuration, as described above, the flow from the atmosphere side x to the sealed fluid side y is allowed, and the flow from the opposite sealed fluid side y to the atmosphere side x is shut off. Since the check ring 6 is provided in the thread groove 5, the check fluid in the screw groove 5 is changed from the atmosphere side x to the seal fluid side y by the check valve action of the check ring 6.
To the sealed fluid side y
To the atmosphere x. Therefore, the directionality of the check ring 6 can effectively prevent the sealing fluid from leaking along the screw groove 5 when the shaft 10 is at rest, and at the same time the screw groove 5 can rotate when the shaft 10 rotates.
Sufficient pump capacity (suction pump capacity).

Further, since the check valve 6 is formed by the plate-shaped valve element 7 fixed to the bottom surface 5a of the thread groove 5, the check valve 6 or the resin seal lip 3 can be manufactured or molded. Easy.

[0014]

The present invention has the following effects.

That is, first, in the sealing device according to the first aspect of the present invention having the above-mentioned structure, in the sealing device provided with a thread groove in the sealing portion slidably in close contact with the mating member, A check valve is provided in the screw groove to allow the flow to the outside and to block the flow in the opposite direction. Therefore, the check valve action by the check valve prevents the sealed fluid in the screw groove from the atmosphere side. Only the flow to the sealed fluid side is allowed, and the flow from the sealed fluid side to the atmosphere side in the opposite direction is blocked. Therefore, due to the directionality of the check ring, it is possible to effectively prevent the sealing fluid from leaking along the screw groove when stationary, and to exert sufficient pumping ability on the screw groove during rotation.

In addition, in the sealing device according to the second aspect of the present invention having the above structure, the check valve is formed by a plate-shaped valve body fixed or integrally formed on the bottom surface of the screw groove. Therefore, the ease of manufacturing or molding the check valve can be ensured.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a sealing device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the sealing device.

FIG. 3 is a sectional view of a main part of the sealing device.

FIGS. 4A and 4B are cross-sectional views showing an operation state of a check valve;

FIG. 5 is a perspective view of a main part of a sealing device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mounting ring 2 Outer peripheral seal part 3 Seal lip 4 Seal part 5 Screw groove 5a Bottom surface 6 Check valve 7 Valve body 10 Shaft (counterpart member) 10a Peripheral surface

Claims (2)

[Claims] 1. A sealing device provided with a thread groove (5) in a sealing portion (4) slidably in close contact with a mating member (10), allowing a flow from the atmosphere side to the sealing fluid side and in the opposite direction. A sealing device, characterized in that a check valve (6) for blocking the flow of air is provided in the thread groove (5). 2. The sealing device according to claim 1, wherein a check valve (6) is formed by a plate-shaped valve element (7) fixed or integrally formed on a bottom surface (5a) of the screw groove (5). And sealing device.