JP4609636B2 - Sealing device - Google Patents

Description

  The present invention relates to a sealing device, and more particularly to a sealing device for an oil seal provided with a sub lip for the purpose of preventing air from being blown into a fluid at a negative pressure on the sealed fluid side.

  Conventionally, for example, a sealing device 101 shown in FIG. 3 is known. The sealing device 101 includes a metal ring 102 having an L-shaped cross section and a seal body 103 made of a rubber-like elastic body that is vulcanized and bonded so as to cover the metal ring 102. The seal body 103 includes a fixed sealing portion 104 positioned on the outer peripheral side of the metal ring 102, a main lip 105 on the inner peripheral side of the metal ring 102, and a dust lip 106 positioned on the atmosphere side A from the main lip. A lip portion 107 is formed, and a recess 109 for mounting a garter spring 108 is formed on the outer peripheral side opposite to the edge of the main lip 105.

  The sealing device 101 is disposed between a housing 111 positioned on the outer peripheral side of the metal ring 102 and a shaft 112 that is on the inner peripheral side of the metal ring 102 and is concentric with the housing 111. The metal ring 102 is fitted through the fixed sealing portion 104, and the main lip portion 105 and the dust lip 106 are attached to the shaft 112 so as to slide.

  In the sealing device 101, the atmosphere side A has an action for preventing the dust on the atmosphere side A from being mixed into the fluid to be sealed and preventing the dust from adhering to the main lip 105 and wearing it at an early stage. The main lip 105 mainly performs the function of preventing the fluid to be sealed from flowing out to the atmosphere side A. The garter spring 108 attached to the recess 109 formed on the opposite side of the edge of the main lip 105 is tightened radially inward so that the main lip 105 follows the movement of the shaft 112 in the radial direction. It has become.

  However, the main lip 105 of the sealing device 101 prevents the fluid to be sealed from flowing out and allows the fluid existing in the annular space 113 formed between the main lip 105 and the dust lip 106 to be sealed on the side B to be sealed. As a countermeasure against this problem, Japanese Utility Model Publication No. 62-12933 discloses a groove on the circumferential surface of the dust lip 106 as a countermeasure against the problem that the annular space 113 becomes negative pressure and wear of the main lip 105 is promoted. Alternatively, it has been proposed to form a protruding portion, but when the sealing target side B has a negative pressure, a sufficient measure cannot be taken.

  Further, Japanese Utility Model Laid-Open No. 61-179458 and Utility Model Registration No. 2526784 disclose a device in which an auxiliary lip is provided on the side B to be sealed from the main lip 105, both of which are problems when the shaft 112 is inserted. In order to solve the problem, there has been no proposal for a problem relating to the orientation of the auxiliary lip tip, in the case where the sealing target side B is under negative pressure.

  That is, the sealing device 101 cannot effectively cope with the differential pressure from the atmosphere side when the sealed fluid side B has a negative pressure, and the action from the atmosphere side A directly acts on the main lip 105. The main lip 105 is lifted in the direction of the arrow α which is the housing side 111. For this reason, a gap is generated between the main lip 105 and the shaft 112 so that air enters the sealed fluid side B, and the fluid to be sealed and the air filled in the sealed fluid side B are mixed with the pump performance. However, no countermeasure has been proposed for this problem.

Japanese Utility Model Publication No. 62-12933 Japanese Utility Model Publication No. 61-179458 Utility Model Registration No. 2526784

  The present invention has been made in view of the above-described problems, and its purpose is to reduce the pump performance without air being mixed into the fluid to be sealed even when negative pressure is generated on the sealed fluid side. It is an object to provide a sealing device for an oil seal that can be prevented.

To achieve the above object, a sealing device according to claim 1 of the present invention is a sealing device in sealed fluid closely slidably on the peripheral surface of the main lip shaft so as not to leak to atmosphere side, said main lip A sub lip is provided on the sealing fluid side of the main lip, the lip tip of the sub lip faces the atmosphere side opposite to the lip tip of the main lip, and the sealing fluid side slope is slidable on the peripheral surface of the shaft And a plurality of protrusions are provided on the sealing fluid side slope of the sub lip that is the sliding surface, and the protrusion is sealed against the pressure of the space between the main lip and the sub lip. When the pressure difference from the pressure on the fluid side becomes large, the sub lip is bent greatly, and the contact area with the shaft on the sliding surface is expanded, the protrusion comes into contact with the shaft, so that Pressure It is characterized in that forms a starve communication passage.

  The present invention has the following effects.

That is, the sealing device of the present invention provided with the structure mentioned above, if the sealed fluid side of the negative pressure, since the sub-lip is attached to the sealed fluid side Ri Lord liter flop, the influence of the pressure difference between the atmosphere side by the sub lip it is prevented, and since the sub-lip is inclined toward the main lip side, is contacted strongly to the axis of the sub-lip and it is possible to prevent the inflow of the sealed fluid side of the air, thereby to the fluid which is sealed It is possible to prevent the mixing of air and prevent the pump performance from deteriorating.

Furthermore, since the sub-lip is protruding on a surface of the slide and the shaft are formed, the pressure difference increases between the pressure and the pressure of the sealed fluid side of the space between the main lip and the auxiliary lip with suction action of the main lip, sub-lip is largely bent, when the contact area between the shaft and the sliding surfaces has expanded, the projections communication passage is formed around the protrusion in contact with the shaft, the pressure differential is relieved, Saburi' flop Contact and main ripple It is possible to prevent the wear of the head from being accelerated.

  Preferred embodiments of the present invention will be described below with reference to the drawings. However, the scope of the present invention is not intended to be limited to the contents described in this embodiment unless otherwise specified.

  FIG. 1 shows a cross section of a main part of a sealing device 1 according to an embodiment of the present invention, which is configured as follows.

  The sealing device 1 includes a metal ring 2 having an L-shaped cross section, a seal body 3 made of a rubber-like elastic body bonded by vulcanization adhesion so as to cover the metal ring 2, and a seal body on the metal ring 2. A sub-metal ring 11 fitted through the part 3 and a sub-lip 12 made of a rubber-like elastic body bonded to the sub-metal ring 11 by vulcanization. The seal main body 3 is located on the outer peripheral side of the metal ring 2 and is in close contact with the housing. A seal lip portion 7 having a dust lip 6 inclined toward the atmosphere side A, and a garter spring 8 is mounted on the outer peripheral side opposite to the edge of the main lip 5. A recess 9 is formed. A cylindrical portion 11A of the secondary metal ring 11 is fitted to the cylindrical portion of the metal ring 2 via the seal main body 3, and a shaft and a sliding member are provided at the inner peripheral side end of the flange portion 11B of the secondary metal ring 11. A sub lip 12 having a plurality of projections 14 on a sliding surface 13 which is a moving surface and having a tip inclined toward the main lip 5 side is vulcanized and bonded.

  The intervals at which the protrusions 14 are provided on the sliding surface 13 do not have to be equal, and may be provided so that the two protrusions are close to each other so as to form a pair and a communication path is formed therebetween. The shape, size, height, and the like of the protrusion 14 are not particularly limited, and may be set within the scope of the object of the present invention.

  FIG. 2 shows an example of a mounting state of the sealing device 1 according to the embodiment, in which the left side is the atmosphere side A and the right side is a sealed fluid side B in which a liquid such as oil to be sealed is sealed. It is.

  As shown in FIG. 2, the sealing device 1 having the above-described configuration is disposed between a housing 22 and a shaft 21 concentric with the housing 22, and is fixed and sealed by vulcanization bonding to the outer peripheral side of the metal ring 2. 4, the metal ring 2 is fitted to the inner peripheral side of the housing 22, and the main lip 5 and the dust lip 6 positioned at the tip of the seal lip portion 7 vulcanized and bonded to the inner peripheral side of the metal ring 2 are The sub lip 12 which is mounted so as to slide with the shaft 21 and is vulcanized and bonded to the inner peripheral side end of the flange portion 11B of the sub metal ring 11 is slid with the shaft 21 with the tip directed toward the main lip side 5. It is mounted to move.

  Therefore, when the sealed fluid side B has a negative pressure, even if the main lip 5 is lifted to the housing 22 side due to the differential pressure with respect to the atmosphere side A, the action of the negative pressure is prevented by the sub lip 12, and the sub lip 12 is Since it is inclined toward the side, the sub lip 12 is brought into strong contact with the shaft 21 side by the action of negative pressure, so that the inflow of air into the fluid to be sealed can be prevented.

  Further, since the protrusion 14 is formed on the sliding surface 13 of the sub lip 12, pressure is accumulated in the space C between the main lip 5 and the sub lip 12 by the suction action of the main lip 5, and the pressure in the space C and the sealing fluid side When the pressure difference from the pressure of B increases and the sub lip 12 bends greatly and the area of the sliding surface 13 in contact with the shaft 21 increases, the projection 14 contacts the shaft 21 and a communication path is formed around the projection 14. Since the pressure difference is relaxed, it is possible to prevent the sub lip 12 and the main lip 5 from being accelerated. In particular, when the projections 14 are arranged in pairs, a passage is ensured between the projections, so that it is possible to achieve further effects.

  Further, a plurality of protrusions may be provided on the sliding surface of the dust lip 6 in the same manner as described above. This makes it possible to prevent the space D formed between the main lip 5 and the dust lip 6 from becoming a negative pressure.

  Further, in this embodiment, the sub lip 12 vulcanized and bonded to the sub metal ring 11 is fitted to the metal ring 2 through the seal body 3, but the sub lip 12 is integrally molded with the seal body 3 and vulcanized. It may be what you did.

Partial sectional view of a sealing device according to the present invention Sectional drawing which shows the mounting state of the sealing device Sectional drawing which shows the mounting state of the sealing device concerning a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Metal ring 3 Seal main-body part 4 Fixed sealing part 5 Main lip 6 Dustrip 7 Seal lip part 8 Garter spring 9 Recess 11 Sub metal ring 11A Cylindrical part 11B Flange part 12 Sub lip 13 Sliding surface 14 Protrusion 21 Shaft 22 Housing A Atmosphere side B Sealed fluid side C, D space

Claims (1)

In the sealing device in which the main lip is slidably in contact with the peripheral surface of the shaft so that the sealing fluid does not leak to the atmosphere side,
A sub lip is provided on the sealing fluid side of the main lip;
The sub lip is a sliding surface whose lip tip faces the atmosphere side opposite to the lip tip of the main lip, and whose sealing fluid side slope is slidably in close contact with the peripheral surface of the shaft,
A plurality of protrusions are provided on the circumference of the sealing fluid side inclined surface of the sub lip which is the sliding surface,
When the protrusion has a large pressure difference between the pressure in the space between the main lip and the sub lip and the pressure on the sealing fluid side, the sub lip is greatly bent and the contact area with the shaft on the sliding surface is increased. In addition, the sealing device is characterized in that when the projection comes into contact with the shaft, a pressure relief passage is formed around the projection .

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