JP2015108445A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device including a function that seals foreign objects so as to prevent the foreign objects at the exterior of a housing from intruding into the housing and a function that releases a pressure in the housing to the exterior of the housing when the pressure exceeds a predetermined value and having a structure which makes the external foreign objects, such as a scale, less likely to be caught by a slide part and prevents wear of the slide part from accelerating.SOLUTION: A sealing device includes: first and second seal lips which slidably contact with a rotary member in a tight manner thereby sealing foreign objects; and a check lip which opens and closes a pressure release passage formed in the sealing device. When a pressure exceeds a predetermined value, the check lip and any one of the first and second seal lips are opened to release the pressure to the exterior of a housing. At that time, the other of the first and second seal lips is kept slidably contacted with the rotary member in the tight manner.

Description

  The present invention relates to a sealing device according to a sealing technique, and more particularly, is mounted between a seal housing and a rotating member inserted through the housing to seal the foreign matter so that foreign matter outside the housing does not enter the housing. The present invention relates to a sealing device for releasing the pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value.

  Conventionally, a sealing device shown in FIG. 6 is known as this type of sealing device, and this sealing device includes a rubber seal lip 51 disposed on the housing inner side A and a resin ( The seal lip 51 and the seal ring 52 are caulked by the mounting ring 57 of the seal lip 51 together with the three metal rings 53, 54 and 55 having a L-shaped cross section and the rubber back ring 56. It is fixed.

  The metal ring 53 on the housing inner A side is formed by integrally forming a cylindrical portion 53b from the outer peripheral end portion of the radial direction portion 53a toward the housing inner A side, and the L-shaped bent portion has a through-hole shape. A communication portion 53c is provided.

  The intermediate metal ring 54 is formed by integrally forming a cylindrical portion 54b from the outer peripheral end of the radial portion 54a toward the housing outer side B, and a radial gap 54c is provided between the intermediate ring 54 and the mounting ring 57. It has been.

  Further, the metal ring 55 on the housing outer side B is formed by integrally forming a cylindrical part 55b from the outer peripheral end of the radial direction part 55a toward the housing inner side A, and the cylindrical part 55b is an intermediate metal ring. 54 and a mounting ring 57, and this cylindrical portion 55b is provided with a notch-shaped communication portion 55c penetrating in the axial direction. This communication portion 53c is the inner peripheral side of the caulking portion 57a at the end of the mounting ring 57 Has reached.

  Therefore, in this sealing device, when the pressure on the housing interior A side exceeds a predetermined value, the seal lip 51 is opened by being pressed by this pressure (separated from the peripheral surface 62a of the rotating member 62), and the housing A pressure release channel is formed that can release pressure from the inside A side to the housing exterior B side through the through hole-like communication portion 53c, the radial gap 54c, and the notch-like communication portion 55c (arrow). C).

  The sealing device having the above configuration is often used in a roll bearing portion of a continuous casting machine, and in this case, exhibits a sealing function that suppresses external foreign matters such as water and scale (sludge) from entering the machine. The sealing device also has a function of discharging oil air (corresponding to the pressure) in order to maintain the lubrication of the bearings in the machine, and therefore, a pressure release channel is provided as described above.

  Since the sealing device includes the resin seal ring 52 with respect to the former sealing function, it is possible to exhibit excellent sealing performance.

  However, since the resin seal ring 52 is a seal part having a rectangular cross section and a cylindrical inner peripheral surface, the cylindrical inner peripheral surface of the resin seal ring 52 and the peripheral surface of the rotating member 62 are provided. If foreign matter such as a scale is caught between 62a and 62a, wear of the resin seal ring 52 is promoted, and there is a concern that the life of the sealing device and the bearing may be affected.

JP-A-9-170663

  In view of the above, the present invention has a function of sealing foreign matter so that foreign matter outside the housing does not enter the housing and a function of releasing pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value. An object of the present invention is to provide a sealing device having a structure in which an external foreign object such as a scale is difficult to bite into the sliding portion, and thus wear of the sliding portion is hardly promoted.

  In order to achieve the above object, a sealing device according to claim 1 of the present invention is a sealing device mounted between a housing and a rotating member inserted through the housing so that foreign matter outside the housing does not enter the housing. A sealing device that seals the foreign matter and releases the pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value. The sealing device seals the foreign matter by slidably contacting the rotating member. And a check lip that opens and closes a pressure release passage formed inside the sealing device, and the check lip and the first and second when the pressure exceeds a predetermined value. When one of the seal lips opens, the pressure is released to the outside of the housing. Other seal lip of the first and second seal lips and maintains a state of close contact with slidably on the rotating member.

  In the sealing device of the present invention having the above configuration, the first and second seal lips are arranged in the axial direction so as to be slidably in contact with the rotating member. Is demonstrated. The seal lip slides on the rotating member at the end of the lip, and has a small sliding area compared to a seal part having a cylindrical cross section and a cylindrical inner peripheral surface, that is, the seal ring, It is relatively difficult to bite foreign matter. Therefore, it is possible to reduce the wear of the sliding portion due to the biting of foreign matter.

  In the sealing device of the present invention, when the pressure inside the housing exceeds a predetermined value, the check lip and any one of the first and second seal lips open to open the pressure to the housing. Since the pressure is released to the outside, a pressure releasing function for releasing the pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value is exhibited. Even if one of the first and second seal lips opens, the other maintains the state in which the other is slidably in contact with the rotating member, so that the sealing function can be continued. Since the check lip is normally closed, even if the pressure inside the housing decreases due to a power failure or the like, it is possible to prevent foreign matter from entering the housing from entering the inside of the housing.

  The sealing device according to claim 2 of the present invention is the sealing device according to claim 1, wherein the first lip member includes a mounting portion attached to the housing and a first seal lip slidably in close contact with the rotating member. A second lip member disposed outside the housing of the first seal lip, and a protective ring disposed further outside the housing of the second lip member, wherein the second lip member is A holding ring fitted into the mounting portion; a second seal lip that is slidably in contact with the rotating member; and a check lip that is in close contact with and away from the protective ring; A communication portion that communicates the space between the first seal lip and the holding ring and the space between the holding ring and the check lip; and the protective ring includes an inner peripheral end portion and a peripheral surface of the rotating member. When the pressure inside the housing exceeds a predetermined value, the first seal lip and the check lip are opened to open the pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value. It is characterized by doing.

  In the sealing device having the above configuration, the first and second seal lips are arranged in the axial direction so as to be slidably in close contact with the rotating member. The basic sealing function is demonstrated. In addition, since a check lip is provided as a third seal lip and this check lip is in close contact with the protective ring, external foreign matter enters the machine via a communication portion provided in the holding ring of the second lip member. Is also suppressed.

  Further, in the sealing device having the above configuration, a pressure release channel is provided for releasing the pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value. The pressure is applied to the outside of the housing from the radial gap formed between the inner peripheral end of the protective ring and the peripheral surface of the rotating member at the end of the flow path through the communicating portion provided in the holding ring of the two lip members. Open. Accordingly, a pressure releasing flow (air flow) is generated in the radial gap, so that an external foreign object enters the sealing device from the radial gap and bites into the sliding portion between the second seal lip and the rotating member. It is possible to suppress the penetration by this flow of pressure release.

  That is, in the prior art of FIG. 6 described above, the end of the pressure release flow path is located in a notch-like communication portion 55c provided in the metal ring 55, and the pressure release flow (air flow, arrow C) is generated here. Therefore, no flow of pressure release occurs in the radial gap 55d formed between the inner peripheral end of the metal ring 55 and the peripheral surface 62a of the rotating member 62. Therefore, regardless of whether the pressure is being released or not, there is always a possibility that an external foreign matter may enter the sealing device from the radial gap 55d. According to the sealing device of the present invention having the above-described configuration, During the pressure release, a pressure release flow is generated in the radial gap, so that it is possible to suppress external foreign matter from entering the sealing device from the radial gap by the pressure release flow.

  Even if the first seal lip on the housing inner side is opened by pressure, the second seal lip on the outer side of the housing maintains a slidable close contact with the rotating member.

  The sealing device according to claim 3 of the present invention is the sealing device according to claim 2, wherein the first seal lip is a seal lip made of a rubber-like elastic body, and the second seal lip is at least The lip end is made of resin so that the resin is a seal lip that is slidably in contact with the peripheral surface of the mating member.

  The basic seal structure composed of the combination of the first seal lip and the second seal lip is made of a rubber material for the first seal lip disposed on the inner side of the housing and the second seal lip disposed on the outer side of the housing. It is preferable that the sliding portion is made of a resin material having excellent wear resistance, and according to this, it is possible to provide a seal structure that exhibits performance equivalent to that of the above-described conventional technology in terms of wear resistance and sealability. Is done.

  The sealing device according to a fourth aspect of the present invention is the sealing device according to the second or third aspect, wherein the protective ring has a diameter dimension gradually decreasing from the housing inner side to the housing outer side. An inclined taper portion is provided, the check lip is in intimate contact with the inner peripheral surface of the taper portion, and the check lip is disposed on the outer peripheral side of the second seal lip.

  If a check lip is provided as a third seal lip in addition to the basic seal structure composed of the combination of the first seal lip and the second seal lip, the axial length of the seal device is increased and the seal device is Although there is a concern about an increase in size, it is possible to suppress an increase in the axial length of the sealing device by arranging the check lip on the outer peripheral side of the second seal lip. For this purpose, the protective ring is provided with a tapered portion inclined in a direction in which the diameter dimension gradually decreases from the inside of the housing to the outside of the housing, and the check lip is brought into close contact with the inner peripheral surface of the tapered portion. Therefore, it is preferable to arrange the check lip on the outer peripheral side of the second seal lip. According to this, even if three lips are provided, the space in the axial direction is only two lips. Further, the lip end of the check lip can be arranged on the inner side of the seal housing from the lip end of the second seal lip.

  The sealing device according to claim 5 of the present invention is the sealing device according to claim 1, wherein the first lip member includes a mounting portion attached to the housing and a first seal lip slidably in close contact with the rotating member. And a second lip member disposed on the housing inner side of the first seal lip, and the second lip member is slidable on the rotating member and the holding ring fitted in the mounting portion. A second seal lip that is in close contact with the first lip member, and a communication portion is provided between the first and second lip members to communicate the interior of the housing and the space between the first and second seal lips. The member is provided with a check lip that opens and closes the communication portion by coming into close contact with the second lip member and presses against the pressure when the pressure inside the housing exceeds a predetermined value. It is the check lip and said first sealing lip is characterized by opening the pressure to the outside of the housing by opening respectively.

  In the sealing device having the above configuration, the first and second seal lips are arranged in the axial direction so as to be slidably in close contact with the rotating member. The basic sealing function is demonstrated.

  In the sealing device having the above-described configuration, when the pressure inside the housing exceeds a predetermined value, the pressure is pressed by this pressure, and the check lip and the first seal lip are opened, whereby the first and second lip members are opened. The pressure is released to the outside of the housing via a communication portion provided therebetween. Therefore, the pressure release function is exhibited. Even if the first seal lip on the outside of the housing is opened by pressure, the second seal lip on the inside of the housing maintains a slidable close contact with the rotating member.

  Furthermore, the sealing device according to claim 6 of the present invention is the sealing device according to any one of claims 1 to 5, wherein the sealing device is used in a bearing portion of an oil-air-out lubrication system in a steel continuous casting machine. It is used.

  Since the sealing device of the present invention exerts an action of releasing the pressure when the pressure inside the housing exceeds a predetermined value, it is suitable for use in an oil-air-out lubrication type bearing portion in a steel continuous casting machine. ing. Therefore, in this case, the effects of the present invention can be realized in this technical field.

  According to the present invention, in a sealing device having a function of sealing foreign matter so that foreign matter outside the housing does not enter the housing and a function of releasing the pressure to the outside of the housing when the pressure inside the housing exceeds a predetermined value. It is possible to provide a sealing device having a structure in which an external foreign object is less likely to bite into the sliding portion and wear of the sliding portion is hardly promoted. Even if either one of the first and second seal lips opens, the other maintains the slidably close contact with the rotating member, so that the sealing function can be continued. Since the check lip is always closed, foreign matter outside the housing can be prevented from entering the housing even if the pressure inside the housing is reduced due to a power failure or the like.

Sectional drawing of the principal part of the sealing device which concerns on 1st Example of this invention. Explanatory drawing which shows the path | route of the pressure release flow path in the sealing device Sectional drawing of the principal part of the sealing device which concerns on 2nd Example of this invention. Sectional drawing of the principal part of the sealing device which concerns on 3rd Example of this invention. Explanatory drawing which shows the path | route of the pressure release flow path in the sealing device Sectional drawing of the principal part of the sealing device which concerns on a prior art example

  Next, embodiments of the present invention will be described with reference to the drawings.

First embodiment
1 and 2 show a sealing device 1 according to a first embodiment of the present invention. The sealing device 1 is mounted between a seal housing 61 (FIG. 2) and a rotating member 62 inserted through the housing 61 so as to be able to open a store, and foreign matter (water, scale, etc.) outside the housing (outside the machine) B (In-machine) A sealing device having a function of sealing foreign matter so as not to enter A, and a function of releasing the pressure to the housing exterior B when the pressure inside the housing A exceeds a predetermined value. The sealing device 1 is a sealing device used for a bearing portion of an oil-air-out lubrication system in a steel continuous casting machine. In this case, the rotating member 62 is a roll shaft and a bearing mechanism is provided inside the housing A. The lubricating oil is supplied to the bearing mechanism at high pressure in an oil-air state.

  The sealing device 1 according to this embodiment includes a first lip member 11 including a first seal lip 19 slidably in close contact with a mounting portion 12 attached to an inner peripheral surface 61 a of a housing 61 and a peripheral surface 62 a of a rotating member 62. And a second lip member 21 disposed on the housing exterior B side of the first seal lip 11, and a protective ring 31 disposed on the housing exterior B side of the second lip member 21. , 21 and 31 constitute a sealing device 1.

  The first lip member 11 has a cylindrical mounting portion 12 fitted to the inner peripheral surface 61a of the housing 61, and radially inward at one end of the mounting portion 12 (an end portion on the housing interior A side). A radial portion 13 is provided, and a lip end 19a is provided at the inner peripheral end of the radial portion 13 toward the outside B of the housing, and the lip end 19a slides on the peripheral surface 62a of the rotating member 62. A first sealing lip 19 is provided that is intimately close. The first lip member 11 is obtained by attaching (vulcanizing and bonding) a rubber-like elastic body 15 to a metal reinforcing ring 14 having an L-shaped cross section. A first seal lip 19 is integrally formed with the portion 16, the inner peripheral rubber portion 17, the end face rubber portion 18, and the like.

  The second lip member 21 has a metal holding ring 22 fitted to the inner peripheral surface of the mounting portion 12 of the first lip member 11, and a rubber-like elastic body 23 at the inner peripheral end of the holding ring 22. The second seal lip 24 is provided with the lip end 24a toward the outside B of the housing by the rubber-like elastic body 23 and slidably comes into contact with the peripheral surface 62a of the rotating member 62 with the lip end 24a. Similarly, a check lip 26 that is provided with a lip end 26a toward the outside B of the housing and is in close contact with the protective ring 31 with the lip end 26a is integrally formed. The holding ring 22 is formed by integrally forming a radial portion 22b toward one end of a cylindrical portion 22a fitted to the inner peripheral surface of the mounting portion 12 inward in the radial direction. A rubber-like elastic body 23 is attached to the inner peripheral end. The second seal lip 24 has at least the surface portion of the lip end 24 a made of a resin (PTFE or the like) 25 (a resin material is attached to a rubber-like elastic body). It is a resin sliding type seal lip that is slidably in close contact with the surface 62a.

  The protective ring 31 is made of a single metal ring. That is, the protective ring 31 is formed by integrally forming a radial portion 31b radially inward at one end of the cylindrical portion 31a fitted to the inner peripheral surface of the mounting portion 12, and this radial portion 31b. In the middle of the radial direction, an annular taper portion 31c is provided which is inclined in a direction in which the diameter gradually decreases from the housing inner side A to the housing outer side B. The inner circumferential surface of the tapered portion 31c is checked. The lip 26 is in close contact with each other. Since the protective ring 31 is thus provided with the tapered portion 31c, the inner peripheral end portion of the radial portion 31b is disposed on the inner peripheral side of the other end (end portion on the housing exterior B side) of the cylindrical portion 31a. Alternatively, the inner peripheral end portion of the radial portion 31b may be disposed on the housing exterior B side with respect to the other end of the cylindrical portion 31a. It is arranged on the outer peripheral side.

  The inner diameter dimension of the protection ring 31 is set slightly larger than the outer diameter dimension of the rotating member 62, so that a radial gap 31 d is formed between the inner peripheral end of the protection ring 31 and the peripheral surface 62 of the rotating member 62. Is set.

  In addition, a communication portion 22c that connects the first sealing lip 19 and the space 41 between the holding ring 22 and the space 42 between the holding ring 22 and the check lip 26 to the holding ring 22 of the second lip member 21 has a shaft. It is provided as a hole that penetrates in the direction.

  In addition, when the pressure inside the housing A exceeds a predetermined value, the sealing device 1 is pressed by this pressure to open the first seal lip 19 and the check lip 26 (the peripheral surface 62a of the rotating member 62). Alternatively, the pressure release flow path 43 (FIG. 2) is used to release the pressure to the outside B of the housing via the communication portion 22c and the radial gap 31d by being separated from the inner peripheral surface of the tapered portion 31c of the protective ring 31. Is provided.

  The second seal lip 24 is at least a surface portion of the lip end 24a made of the resin 25 and is not easily deformed, and the tightening allowance for the rotating member 62 is set large. The lip end 24 a remains in contact with the peripheral surface 62 a of the rotating member 62 even if the operation is applied.

  In the sealing device 1 having the above-described configuration, the first seal lip 19 and the second seal lip 24 are arranged in the axial direction and are slidably in close contact with the peripheral surface 62a of the rotating member 62. 24 provide a sealing function against external foreign matter. The seal lips 19, 24 slide on the peripheral surface 62 a of the rotating member 62 at the lip ends 19 a, 24 a, and have seal parts (seal rings) having a rectangular cross section and a cylindrical inner peripheral surface. Since the sliding area is small in comparison, it is difficult for foreign matter to bite into the sliding portion. Therefore, it is possible to reduce wear of the sliding portion due to the biting of foreign matter.

  Further, in the sealing device 1 having the above structure, when the pressure inside the housing A exceeds a predetermined value, the first seal lip 19 and the check lip 26 are opened to release the pressure to the housing outside B. As a result, a pressure releasing function for releasing the pressure to the outside B of the housing when the pressure inside the housing A exceeds a predetermined value is exhibited. Even when the first seal lip 19 is opened, the second seal lip 24 maintains a state in which the second seal lip 24 is slidably in contact with the peripheral surface 62a of the rotating member 62, so that the sealing function can be continued. Since it is not necessary to consider the pressure release function as the second seal lip 24, it is possible to adopt a design (increased tightening margin, increased rigidity, etc.) exclusively for enhancing the seal function against external foreign matter, and therefore the seal lip 24 It is possible to further promote the extension of the service life. Since the check lip 26 is always closed, even if the pressure inside the housing A is reduced due to a power failure or the like, it is possible to suppress the entry of external foreign matter into the housing inside A.

  Further, in the sealing device 1 configured as described above, a pressure release channel 43 is provided for releasing the pressure to the housing exterior B when the pressure inside the housing A exceeds a predetermined value. Is formed between the inner peripheral end of the protective ring 31 and the peripheral surface 62a of the rotating member 62 at the end of the flow path 43 through the communication portion 22c provided in the holding ring 22 of the second lip member 21. The pressure is released from the directional gap 31d toward the outside B of the housing. Accordingly, a pressure releasing flow (air flow) is generated in the radial gap 31d (arrow C), and an external foreign substance enters the sealing device 1 from the radial gap 31d and enters the second seal lip 24 and the rotating member 62. Since it is possible to suppress biting into the sliding portion between them, a structure in which external foreign matter such as a scale hardly enters the sealing device 1 and wear of the sliding portion of the sealing device 1 is not easily promoted. A sealing device can be provided.

  Further, since the first seal lip 19 made of the rubber-like elastic body 15 and the second sliding lip 24 of the resin sliding type in which the lip end 24a is made of the resin 25 are combined, the wear resistance and the seal are improved. It is possible to provide a seal structure that exhibits performance comparable to that of the conventional technology. In addition, even if the rotating member 62 such as a roll is bent and the mounting eccentricity is increased, the second seal lip 24 having the resin 25 on the lip end 24a follows, and therefore, between the rotating member 62 and the second seal lip 24. A gap is not generated, and thus an excellent sealing function can be exhibited.

  In addition, since the check lip 26 is disposed on the outer peripheral side of the second seal lip 24 while having three lips, the axial length of the sealing device 1 is increased, and the sealing device 1 is increased in size. No seal structure can be provided.

Second embodiment ...
In the first embodiment, the tapered portion 31 c is provided in the radial direction of the radial portion 31 b in the protective ring 31, but this tapered portion 31 c is provided at the inner peripheral end of the radial portion 31 b in the protective ring 31. May be provided. In FIG. 3 shown as the second embodiment, the tapered portion 31 c is provided to reach the inner peripheral end portion of the radial direction portion 31 b in the protective ring 31. A relatively large radial gap 31 d is set between the inner peripheral end of the protective ring 31 and the peripheral surface 62 of the rotating member 62.

Third embodiment
4 and 5 show a sealing device 101 according to a third embodiment of the present invention. The sealing device 101 is mounted between a seal housing 61 (FIG. 5) and a rotating member 62 rotatably inserted in the housing 61, and seals foreign matter so that foreign matter outside the housing B does not enter the inside A of the housing. The sealing device has a function and a function of releasing the pressure to the housing exterior B when the pressure inside the housing A exceeds a predetermined value. The sealing device 101 is a sealing device used for an oil-air-out lubrication type bearing in a steel continuous casting machine. In this case, the rotating member 62 is a roll shaft and a bearing mechanism is provided inside the housing A. The lubricating oil is supplied to the bearing mechanism at high pressure in an oil-air state.

  The sealing device 101 according to this embodiment includes a first lip member 111 including a first seal lip 119 slidably in close contact with the mounting portion 12 attached to the inner peripheral surface 61 a of the housing 61 and the peripheral surface 62 a of the rotating member 62. And a second lip member 131 disposed on the housing inside A side of the first seal lip 119, and the sealing device 1 is configured by a combination of these parts 111 and 131.

  The first lip member 111 has a cylindrical mounting portion 112 fitted to the inner peripheral surface 61 a of the housing 61, and radially inward at one end of the mounting portion 112 (an end portion on the housing exterior B side). A radial portion 113 is provided, and a lip end 119a is provided at the inner peripheral end of the radial portion 113 toward the housing outer B side, and the lip end 119a slides on the peripheral surface 62a of the rotating member 62. A first seal lip 119 is provided that is intimately close. The first lip member 111 is obtained by attaching (vulcanizing and bonding) a rubber-like elastic body 115 to a metal-made reinforcing ring 114 having an L-shaped cross section. The outer peripheral rubber portion 116 attached to the outer peripheral surface of the cylindrical portion 114a of 114, the inner peripheral rubber portion 117 attached to the inner peripheral surface of the cylindrical portion 114a of the reinforcing ring 114, and the radial portion 114b of the reinforcing ring 114 A first seal lip 119 is integrally formed with an end face rubber portion 118 and the like attached to the end face in the axial direction. The check lip 121 will be described later.

  The second lip member 131 has a cylindrical mounting portion 132 that is fitted to the inner peripheral surface of the inner peripheral rubber portion 117 and is the inner peripheral surface of the mounting portion 112 of the first lip member 111. A radial portion 133 is provided at one end of 132 inward in the radial direction. A lip end 136a is provided at the inner peripheral end of the radial portion 133 toward the housing outer B side, and the lip end 136a is rotated. A second seal lip 136 that is slidably in close contact with the peripheral surface 62a of the member 62 is provided. The second lip member 131 is formed by attaching a rubber-like elastic body 135 to a metal holding ring 134 having an L-shaped cross section, and the second seal lip 136 is formed by the rubber-like elastic body 135. ing.

  A communication portion 141 is provided between the first lip member 111 and the second lip member 131 to communicate the housing interior A with the space 143 between the first seal lip 119 and the second seal lip 136. In addition, a check lip 121 that opens and closes the communication portion 141 by being in close contact with and away from the second lip member 131 is provided.

  The communication portion 141 is an inner peripheral surface of the mounting portion 112 of the first lip member 111 and is provided on the inner peripheral rubber portion 117, or a plurality of grooves 120 extending in the axial direction on the circumference, and the groove 120. It is composed of a combination with an annular axial gap 142 set between the radial direction portion 113 of the first lip member 111 and the radial direction portion 133 of the second lip member 131 so as to open and close the communication portion 141. Thus, the first lip member 111 is provided with a check lip 121.

  The check lip 121 is formed integrally with the end surface rubber portion 118 by the rubber-like elastic body 115 in the first lip member 111, the lip end 121a is formed inward in the radial direction, and the lip end 121a is formed in the second lip member. 131 is in contact with the radial portion 134b of the retaining ring 134 so as to be able to contact and separate. Accordingly, when a predetermined amount of pressure is applied from the outside in the radial direction, the check lip 121 is opened to allow the pressure to pass inward in the radial direction. With these configurations, when the pressure inside the housing A exceeds a predetermined value, the check lip 121 and the first seal lip 119 are opened when the pressure inside the housing A exceeds a predetermined value. 141, and a pressure release passage 144 (FIG. 5) for releasing the pressure to the outside B of the housing via a gap (not shown) between the first seal lip 119 and the rotating member 61.

  In the sealing device 101 having the above configuration, the first seal lip 119 and the second seal lip 136 are arranged in the axial direction and slidably come into contact with the peripheral surface 62a of the rotating member 62. , 136 provides a sealing function against external foreign matter. The seal lips 119, 136 slide on the peripheral surface 62a of the rotating member 62 at the lip ends 119a, 136a, and have a cylindrical part and a seal part (seal ring) having a cylindrical inner peripheral surface. Since the sliding area is small in comparison, it is difficult for foreign matter to bite into the sliding portion. Therefore, it is possible to reduce wear of the sliding portion due to the biting of foreign matter.

  Further, in the sealing device 101 having the above-described configuration, the pressure is released to the outside B of the housing by opening the check lip 121 and the first seal lip 119 when the pressure inside the housing A exceeds a predetermined value. As a result, a pressure releasing function for releasing the pressure to the outside B of the housing when the pressure inside the housing A exceeds a predetermined value is exhibited. Even when the first seal lip 119 is opened, the second seal lip 136 maintains the slidably close contact with the peripheral surface 62a of the rotating member 62, so that the sealing function can be continued. Since it is not necessary to consider the pressure release function as the second seal lip 136, it is possible to adopt a design (such as increased fastening allowance or increased rigidity) exclusively for enhancing the seal function against external foreign matter. It is possible to further promote the extension of the service life. Since the check lip 121 is always closed, even if the pressure inside the housing A is lowered due to a power failure or the like, it is possible to suppress the entry of external foreign matter into the housing inside A.

DESCRIPTION OF SYMBOLS 1,101 Sealing device 11,111 1st lip member 12,112,132 Attachment part 13,22b, 31b, 113,133 Radial direction part 14,114 Reinforcement ring 15,23,115,135 Rubber-like elastic body 16,116 Outer peripheral rubber part 17, 117 Inner peripheral rubber part 18, 118 End rubber part 19, 119 First seal lip 19a, 24a, 26a, 119a, 121a, 136a Lip end 21, 131 Second lip member 22, 134 Retaining ring 22a, 31a Tubular portion 22c, 141 communication portion 24, 136 Second seal lip 25 Resin 26, 121 Check lip 31 Protective ring 31c Tapered portion 31d Small gap 41, 42, 143 Space 43, 144 Pressure release flow path 61 Housing 61a Inner circumference Surface 62 Rotating member 62a Circumferential surface 120 Groove 142 Axial clearance A Housing inside B Housing outside

Claims (6)

A sealing device mounted between a housing and a rotating member inserted through the housing, wherein the foreign matter is sealed so that the foreign matter outside the housing does not enter the housing, and the pressure inside the housing exceeds a predetermined value. A sealing device for releasing the pressure to the outside of the housing,
A first and a second seal lip that seals the foreign matter by slidably contacting the rotating member; and a check lip that opens and closes a pressure release passage formed inside the sealing device;
When the pressure exceeds a predetermined value, the check lip and any one of the first and second seal lips are opened to release the pressure to the outside of the housing. 2. The sealing device according to claim 1, wherein the other seal lip of the first and second seal lips is slidably kept in close contact with the rotating member. The sealing device according to claim 1.
A first lip member having a first seal lip that is slidably in close contact with the mounting portion and the rotating member, and a second lip member disposed on the outside of the housing of the first seal lip; A protective ring disposed on the housing outer side of the second lip member,
The second lip member has a holding ring fitted to the mounting portion, a second seal lip that is slidably in contact with the rotating member, and a check lip that is in close contact with and away from the protective ring. And
The holding ring has a communication portion that communicates the space between the first seal lip and the holding ring and the space between the holding ring and the check lip,
The protective ring forms a radial gap between its inner peripheral end and the peripheral surface of the rotating member;
When the pressure inside the housing exceeds a predetermined value, the pressure device is pressed by the pressure to open the first seal lip and the check lip, thereby releasing the pressure to the outside of the housing. . The sealing device according to claim 2.
The first seal lip is a seal lip made of a rubber-like elastic body,
The sealing device according to claim 1, wherein at least a lip end of the second seal lip is made of a resin so that the resin is slidably in contact with a peripheral surface of the mating member. The sealing device according to claim 2 or 3,
The protective ring includes a tapered portion inclined in a direction in which the diameter gradually decreases from the inside of the housing to the outside of the housing, and the check lip is in close contact with the inner peripheral surface of the tapered portion. Is arranged on the outer peripheral side of the second seal lip. The sealing device according to claim 1.
A first lip member having a mounting portion attached to the housing and a first seal lip that is slidably in contact with the rotating member; and a second lip member disposed on the inner side of the housing of the first seal lip. And
The second lip member has a holding ring fitted to the mounting portion, and a second seal lip that is slidably in close contact with the rotating member,
A communication portion is provided between the first and second lip members to communicate the interior of the housing and the space between the first and second seal lips;
The first lip member is provided with a check lip that opens and closes the communication portion by being in close contact with and away from the second lip member,
When the pressure inside the housing exceeds a predetermined value, the pressure is pressed by the pressure, and the check lip and the first seal lip are opened to release the pressure to the outside of the housing. . The sealing device according to any one of claims 1 to 5,
The said sealing apparatus is used for the bearing part of the oil air out lubrication system in a steel continuous casting machine.

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