JP5674571B2 - mechanical seal - Google Patents

Description

  The present invention relates to a rotary shaft of a pump used for transporting a liquid containing a large amount of sludge or slurry, a shaft of a sink roll installed in a plating tank, a gravel collecting pump for a river, a mud pressure pump, etc. The present invention relates to a mechanical seal for sealing a rotating shaft (hereinafter referred to as “rotating shaft”) of a civil engineering machine.

  The sink roll is a rotating body for winding and reversing the long metal plate in the plating tank in order to continuously plate the long metal plate such as a rolled steel plate. What is disclosed in Document 1 is known. In Patent Document 1, as shown in FIG. 3, a plating tank for continuously immersing a steel plate (1) in a plating bath (2) containing aluminum as a main component to form a plating layer on the surface. In the figure, there is shown a structure in which the steel plate (1) moved downward from above is wound around a sink roll, reversed, and moved upward.

  The shaft of the sink roll, that is, the mechanical seal for the sink roll shaft, is a sink that usually extends through the side wall of the plating tank because the components are not immersed in the plating solution, ease of installation, and good maintainability. It is equipped in the extending part of the roll shaft and is disclosed in Patent Document 2 and Patent Document 3. And as shown in Patent Document 3, the mechanical seal is immersed in the plating solution as a means for pressing and urging the stationary sealing ring to be supported on the side wall of the plating tank in the axial direction. A bellows made of an elastic material such as rubber is used so as not to be affected.

  The mechanical seal shown in Patent Document 3 (see FIG. 1 and the like) is a stationary sealing ring (3) in a state of surrounding an extended shaft portion that protrudes from the plating tank side wall (12) in the sink roll shaft (1). ) And a side wall (12), an elastic material bellows (not shown) is provided. The bellows (not marked) has a base end portion arranged so as to be inserted into the side wall (12), a tip end portion for holding the stationary sealing ring (3) and a one-step bellows portion, As an elastic mechanism for constructing a seal portion by pressing the stationary sealing ring (3) against the rotating sealing ring (4), and as a cylindrical structure covering between the stationary sealing ring (3) and the side wall (12) Configured to work.

  In the mechanical seal having such a structure, the plating solution (2) normally enters the space between the sink roll shaft (1) and the bellows (not marked). Therefore, the bellows (not shown) having a support function of the stationary sealing ring (3) and a pressing biasing function that presses against the rotary sealing ring (4) in the axial direction to generate a seal portion is made of an elastic material. The structure is not affected by the plating solution (2). However, it has been found that depending on the situation of use, a trouble may occur that the leakage exceeds the allowable amount at an early stage.

  When the mechanical seal having the bellows is applied to the horizontal sink roll shaft, there is a tendency that solids or dust easily accumulate inside the bellows, particularly in the lower portion of the bellows portion having a bag shape. When solid matter or the like accumulates in the inner lower portion of the bellows portion, the deterioration of stretchability in the axial direction at that portion is promoted, and the function as the above-described elastic mechanism is likely to deteriorate. In this case, a sufficient pressing force of the stationary sealing ring to the rotating sealing ring cannot be obtained, and there is a possibility that the amount of leakage from the seal portion increases early. In addition, the deterioration of the bellows material (rubber, etc.) itself may be synergistic with the deterioration over time in which a sufficient pressing force of the stationary sealing ring cannot be obtained, thereby increasing the amount of leakage.

JP 2008-13799 A JP-A-6-81180 Japanese Utility Model Publication No. 4-106352

  The object of the present invention is that the elastic mechanism for pressing and sealing the stationary sealing ring functions sufficiently for a long time while following the structure using the bellows functioning as the elastic mechanism and the cylindrical structure as described above. Therefore, the present invention is to provide a mechanical seal that can be improved and can be highly functional with improved durability.

According to the first aspect of the present invention, there is provided a rotary sealing ring 5 that is externally fitted to an extending shaft portion 1A that extends outside the machine on a rotary shaft 1 of the machine and rotates integrally therewith, and movement of the rotary shaft 1 in the direction of the axis P. And the stationary sealing ring 6 supported by the fixed part 2 of the machine so that the rotation about the axis P is impossible, and the stationary sealing ring 6 is pressed against the rotary sealing ring 5 in the axis P direction. An elastic mechanism 7 for forming the seal portion S, and the elastic mechanism 7 is stretched over the stationary sealing ring 6 and the fixed portion 2 in a state of surrounding the extending shaft portion 1A. In a mechanical seal configured with a bellows made of
In the bellows 7, the base end portion 7A on the fixed portion side from the bellows portion 7C and the tip end portion 7B on the stationary sealing ring side are elastically attached in a direction away from each other in the direction of the axis P of the rotary shaft 1. The exterior elastic mechanism 20 is provided in a state straddling the base end portion 7A and the tip end portion 7B through the radially outer portion of the bellows portion 7C .
In order to cover the annular bulging portion 7V bulging outward from the diameter associated with the bellows shape in the inner space of the bellows 7, the base end portion 7A and the distal end portion 7B may be covered. A cylindrical adapter 9 having a ridge ring portion 9b that is supported in a liquid-tight manner and is slidably contacted with one of the other inner peripheral surfaces i in the direction of the axis P is provided. It is a feature.

  According to a second aspect of the present invention, in the mechanical seal according to the first aspect, the exterior elastic mechanism 20 is externally mounted on the base end side annular plate 14 that is externally mounted on the base end portion 7A and the distal end portion 7B. The front-end-side annular plate 17 and the compression-type spring means b disposed between the annular plates 14 and 17 are characterized by being configured.

  The invention according to claim 3 is the mechanical seal according to claim 2, wherein the compression spring means b includes a plurality of coil springs 19 arranged around the axis P. It is a feature.

  The invention according to claim 4 is the mechanical seal according to claim 3, wherein the coil spring 19 is screwed to either the base end side annular plate 14 or the tip end side annular plate 17. It is equipped with the state which is loosely fitted in.

  The invention according to claim 5 is the mechanical seal according to any one of claims 1 to 4, wherein the base end side annular plate 14 is formed at a boundary between the base end portion 7A and the bellows portion 7C. And a configuration in which the front end-side annular plate 17 is fitted and installed in a concave groove 16 formed at the boundary between the front end portion 7B and the bellows portion 7C. Among these, at least one of the configurations is employed.

  According to the first aspect of the present invention, the exterior elastic mechanism elastically urges the bellows in the direction in which the base end portion and the distal end portion, which are arranged with the bellows portion interposed therebetween, are separated. Therefore, even if solid matter or dust accumulates in the lower part of the bellows part and the deterioration of the elasticity of the bellows is promoted or the material such as rubber deteriorates, the elasticity of the bellows declines. The stationary sealing ring can maintain a state where it is sufficiently pressed against the rotating sealing ring. Therefore, since the sealing portion exhibits a sufficient sealing function over a long period of time, it is possible to avoid the inconvenience that the leakage amount increases early. In addition, since the exterior elastic mechanism is arranged through the outside of the bellows portion, that is, without touching the sealing target such as a plating solution, there is no fear of being attacked by the sealing target and there is no risk of deterioration in durability. Convenient. As a result, while following the structure using the bellows functioning as an elastic mechanism and a cylindrical structure, it can be improved so that the elastic mechanism for pressing and sealing the stationary sealing ring can function sufficiently for a longer period of time, It is possible to provide a mechanical seal capable of improving functionality with improved durability.

  According to the invention of claim 2, the exterior elastic mechanism includes a proximal end side annular plate sheathed at the proximal end portion, a distal end side annular plate sheathed at the distal end portion, and a compression mold disposed between these annular plates. There is an advantage that the above-described effect according to the invention of claim 1 can be obtained in a rational state with a simple and good productivity provided with a general structural member.

  According to the invention of claim 3, the compression spring means can be configured by a plurality of coil springs in a preferable state in which the elastic biasing force acts evenly in the circumferential direction while suppressing the radial dimension.

  According to the invention of claim 4, the coil spring can be smoothly expanded and contracted by being guided by the support shaft, and the support shaft to be screwed can be assembled and removed. It has the added advantage of being excellent and easy to store and handle.

  According to the fifth aspect of the present invention, the concave circumferential groove provided between the base end portion or the distal end portion and the bellows portion can smoothly perform elastic displacement of the bellows portion. Since it can also be used as a means for attaching the annular plate on the end side or the tip side, there is an advantage that further rationalization is possible by sharing the functional structure.

Overall view showing a mechanical seal according to the present invention The expanded sectional view which shows the principal part of the mechanical seal of FIG.

  Embodiments of a mechanical seal according to the present invention will be described below with reference to the drawings.

[Example 1]
As shown in FIGS. 1 and 2, the mechanical seal M according to the first embodiment includes a rotating sealing ring 5, a stationary sealing ring 6, a bellows 7, and the like, and a side wall (an example of a fixed portion) of a plating tank (an example of a machine) T. Example) It is configured to straddle a mounting wall 3 that is liquid-tightly attached to the outside of 2 by bolting and a rotating shaft (sink roll shaft) 1. A retainer 4 made of a synthetic resin (for example, chlorosulfonated polyethylene) is externally fitted and locked to the extending shaft portion 1A extending from the side wall 2 of the rotating shaft 1 to the outside using a fastening band 11, and the retainer. A rotary sealing ring 5 is fitted and supported at the end of the side wall 4.

  The rotary sealing ring 5 fitted in the extending shaft portion 1A of the rotating shaft 1 having the axis P is made of Sic as an example and rotates integrally with the extending shaft portion 1A. Reference numeral 12 denotes a tightening band for fixing the rotary sealing ring 5 to the retainer 4, and reference numeral 8 denotes a metal backup ring plate for reinforcing the retainer 4. An example of the material of the stationary sealing ring 6 is ceramic. Reference numeral 21 denotes a stopper ring that reinforces the state in which the retainer 4 is locked to the extending shaft portion 1A, and e is a plating solution as an example of a fluid to be sealed.

  The bellows 7 includes a base end portion 7A that is an end portion on the fixed portion that is locked and fixed to the mounting wall 3, a distal end portion 7B that is a stationary sealing ring side that holds and holds the stationary sealing ring 6, and these base end portions. It is a bellows tube made of an elastic material (example: chlorosulfonated polyethylene) having a single bellows portion 7C connecting 7A and the tip portion 7B. Other materials for the bellows 7 can be rubber materials such as NBR, fluororubber, and EPDM. The bellows 7 also serves as an elastic mechanism that presses and urges the stationary sealing ring 6 against the rotary sealing ring 5 in the direction of the axis P to form a contact-type seal portion S. The inside of the bellows portion 7C is an annular bulge portion 7V that bulges outward in the diameter associated with the bellows shape in the internal space of the bellows 7 (the space portion between the bellows 7 and the extending shaft portion 1A).

  A side circumferential groove 10 that is widened in the direction of the axis P is formed outside the diameter of the insertion hole 3 a of the rotating shaft 1 in the mounting wall 3, and a base end portion 7 </ b> A having a tapered cross section of the bellows 7. Is inserted into the side circumferential groove 10 from the side. And the base end side annular plate (example: made of a stainless steel plate) 14 fitted in the concave circumferential groove 13 at the boundary between the base end portion 7A and the bellows portion 7C of the bellows 7 is arranged on the circumference about the axis P. Then, the plurality of bolts and nuts 25 that are screwed to the mounting wall 3 are pressed against the mounting wall 3 side, whereby the distal end portion of the base end portion 7A is pressed against the side circumferential groove 10 so that both the 7A and 3 are liquid-tight. It is made to join. In the present embodiment, the mounting wall 3 may be regarded as a part of the side wall 2 (that is, a fixed portion).

  A stationary sealing ring 6 is fitted on the inner peripheral surface of the distal end portion 7B (directly fitted and supported), and a fastening band 15 is mounted on the outer peripheral surface. At the boundary between the distal end portion 7B and the bellows portion 7C, a concave circumferential groove 16 is formed in which the distal end side annular plate 17 is fitted and packaged. For example, coil springs 19 are fitted to a plurality of bolts 18 that are screwed to the outer peripheral side of the distal end side annular plate 17 made of stainless steel plate, and the distal end side annular plate 17 and the proximal end side annular plate 14 are connected. Constitutes an exterior elastic mechanism 20 that elastically biases the base end portion 7A and the tip end portion 7B in directions away from each other in the direction of the axis P. The base end side annular plate 14 through which the bolt / nut 25 is inserted is formed to have a larger diameter than the tip end side annular plate 17.

  Specifically, as shown in FIG. 2, the exterior elastic mechanism 20 includes a proximal-side annular plate 14 sheathed on the proximal end 7A, a distal-side annular plate 17 sheathed on the distal end 7B, and both the annular plates. And a compression spring means b disposed between 14 and 17. In the first embodiment, the compression spring means b has a plurality of coil springs 19 arranged around the axis P. These coil springs 19 are equipped in a state of being loosely fitted to bolts 18 which are examples of support shafts screwed to the distal end side annular plate 17. In such a configuration, the base-side annular plate 14 serves as a structure for pressing the front end portion of the base end portion 7A against the side circumferential groove 10 with the bolt / nut 25 and constitutes the exterior elastic mechanism 20. It is a member that functions as a structure for the purpose.

  The exterior elastic mechanism 20 can assist and strengthen the function of pressing and urging the stationary sealing ring 6 against the rotary sealing ring 5 by the bellows 7, that is, the function of generating the seal portion S. For example, as a reinforcement for pushing the stationary sealing ring 6 more strongly, and even when the bellows 7 is deteriorated and its elastic function is lowered, a sufficient elastic urging force, that is, the function of the seal portion S is maintained and the necessary and sufficient seal is maintained. It can be made to function as an auxiliary for demonstrating performance. Other materials for the base end side annular plate 14 and the tip end side annular plate 17 are preferably those having corrosion resistance equal to or higher than that of the stainless steel plate in consideration of leakage of the in-machine liquid (plating solution). It is reasonable that both plates 14 and 17 are made of the same material.

  In the structure without the exterior elastic mechanism 20, the bellows 7 has a function of preventing leakage of the plating solution e from between the stationary sealing ring 6 and the mounting wall 3, and the stationary sealing ring 6 as a rotary sealing ring 5. It is required to have two roles of a pressing bias function. On the other hand, in the structure having the exterior elastic mechanism 20, the bellows 7 can share the function of preventing liquid leakage, and the exterior elastic mechanism 20 can share the function of pressing and urging. Therefore, it is possible to delay the deterioration of the bellows 7 and increase the durability, or even when the bellows 7 are deteriorated, the pressure urging function is maintained and the seal part S can continue to exhibit a good sealing performance. It is done. The material of the coil spring 19 is silicon manganese steel, chrome vanadium steel, chrome molybdenum steel, or stainless steel, but may be other.

  As shown in FIGS. 1 and 2, the bellows 7 is supported in a liquid-tight manner on the distal end portion 7B on the stationary sealing ring side of the bellows portion 7C so as to cover the annular bulge portion 7V from the inside of the diameter. In addition, a cylindrical adapter 9 that is slidably contacted with the inner peripheral surface 22 (i) of the base end portion 7A that is the fixed portion side of the bellows portion 7C in the bellows 7 so as to be relatively movable in the direction of the axis P is provided. Yes. The adapter 9 is made of, for example, PTFE (fluororesin) containing glass fiber or stainless steel, and a fitting support portion 9c fitted in the stationary sealing ring 6 and an outer peripheral flange fitted and supported in a circumferential groove m described later. It has 9a, a convex ring part 9b, and a main body cylinder part 9d, and is equipped with the extended shaft part 1A in a loosely fitted state.

  A circumferential notch 7k for forming a circumferential groove m having an end surface 6a on the side wall 2 side in the axial center P direction of the stationary sealing ring 6 as a groove side wall is formed at the distal end portion 7B. The outer peripheral flange 9a is fitted in m. And the protruding item | line ring part 9b which protrudes on a diameter outer side is formed in the side wall 2 side edge part in the adapter 9, and the outer periphery of the protruding item | line ring part 9b is axis | shaft in the inner peripheral surface 22 (inner peripheral surface i) of 7 A of base end parts. As a structure that is slidably contacted with each other in the direction of the center P, a cylindrical narrow space r having a back-end shape is formed between the inner peripheral surface 23 of the tip 7B (the inner peripheral surface i of the bellows 7) and the adapter 9 in the radial direction. Has been. That is, the base end portion 7 </ b> A on the fixed portion side of the bellows 7 and the stationary sealing ring are to be covered from the radially inner side with respect to the annular bulging portion 7 </ b> V that bulges outwardly in the inner space of the bellows 7. Equipped with a cylindrical adapter 9 that is liquid-tightly supported by any one of the front end portions 7B and that is slidably contacted with any one of the inner peripheral surfaces i in the direction of the axis P. Has been.

  With such a configuration, the contact-type seal portion 24 is formed by sliding contact between the protruding ring portion 9b of the adapter 9 that is liquid-tightly supported by the distal end portion 7B of the bellows 7 and the inner peripheral surface 22 of the proximal end portion 7A. ing. Therefore, even if the plating solution e in the plating tank T reaches the bellows 7 site, foreign matters such as metal pieces, dust, mud, and gravel mixed in the plating solution e are sealed by the contact-type seal portion 24, and the bellows It does not reach the annular bulging portion 7V that is the internal space of the portion 7C. And since it is the contact-type seal | sticker part 24, even if it provides the adapter 9, the bellows 7 can move without a problem following the shake | fluctuation and movement of the rotating shaft 1. FIG. Further, if the adapter 9 is made of a fluororesin, it is excellent in temperature resistance and chemical resistance, and sufficient durability is exhibited even under use conditions immersed in a plating solution.

  Further, as shown in FIG. 2, since a cylindrical narrow space r is formed between the inner peripheral surface i of the bellows 7 and the adapter 9 in the radial direction, if foreign matter enters beyond the contact type seal portion 24. Even if there are cases, they can be stored in the cylindrical narrow space r so as not to reach the annular bulging portion 7V. As a result, the inconvenience that the metal piece accumulates in the lower part of the annular bulging portion 7V and pierces the bellows 7 from the inside, and cracks, cracks or early leakage due to them is avoided, and sufficient durability as expected. A certain mechanical seal M can be realized.

  There are three locations: an inner peripheral surface that internally fits and supports the stationary sealing ring 6 in the bellows 7, a large inner circumferential surface that internally supports and supports the rotary sealing ring 5 in the retainer 4, and a small inner peripheral surface that is externally fitted to the rotary shaft 1. A plurality of circumferential grooves 7a, 4a, 4b are formed at equal intervals in the axis P direction. Existence of these circumferential grooves 7a, large circumferential grooves 4a, small circumferential grooves 4b, and providing appropriate gaps in the direction of the axis P between the neighboring circumferential grooves 7a, 4a, 4b to ensure a certain contact area. Thus, the contact surface pressure with the mating counterpart can be increased without difficulty, and the holding force can be increased as compared with a simple fitting structure. The effect of the circumferential grooves 7a, 4a, 4b (improving the sealing performance by increasing the contact pressure) is also applied to the stopper ring 21.

[Another Example]
The bolt 18 can be configured to be screwed to the proximal end side annular plate 14. The compression spring means b can be constituted by, for example, a single large spring provided between the annular plates 14 and 17 with a diameter surrounding the bellows portion 7C.

DESCRIPTION OF SYMBOLS 1 Rotating shaft 1A Extension shaft part 2 Fixed part 5 Rotating sealing ring 6 Static sealing ring 7 Elastic mechanism, bellows 7A Base end part 7B Tip part 7C Bellows part 13 Concave groove 14 Proximal annular plate 16 Concave groove 17 Tip Side annular plate 18 Support shaft 19 Coil spring 20 Exterior elastic mechanism P Shaft center S Seal part b Compression spring means

Claims (5)

A rotary sealing ring that is externally fitted to an extending shaft portion of the rotating shaft of the machine that is extended to the outside of the machine and rotates together with the rotating shaft. The rotating shaft can be moved in the axial direction, and the rotation about the shaft cannot be performed. A stationary sealing ring supported by a fixed part of the machine, and an elastic mechanism for pressing the stationary sealing ring against the rotary sealing ring in the axial direction to form a sealing part, and the elastic mechanism includes the extension A mechanical seal configured to have a bellows made of an elastic material spanning the stationary sealing ring and the fixed portion in a state surrounding the output shaft portion,
An exterior elastic mechanism that elastically urges a base end portion that is closer to the fixed portion than the bellows portion of the bellows and a distal end portion that is closer to the stationary sealing ring in a direction away from each other in the axial direction of the rotation shaft. , Equipped in a state straddling the proximal end portion and the distal end portion through the radially outer portion of the bellows portion ,
A liquid-tight support is provided on either the base end portion or the tip end portion so as to cover the annular bulge portion that bulges outward from the diameter associated with the bellows shape in the inner space of the bellows. And a mechanical adapter equipped with a cylindrical adapter having a ridge ring portion that is slidably contacted with one of the other inner peripheral surfaces in the axial direction .   The exterior elastic mechanism includes a proximal end side annular plate that is sheathed on the proximal end portion, a distal end side annular plate that is sheathed on the distal end portion, and a compression spring means that is disposed between these annular plates. The mechanical seal according to claim 1 configured as described above.   The mechanical seal according to claim 2, wherein the compression spring means includes a plurality of coil springs arranged around the axis.   4. The mechanical seal according to claim 3, wherein the coil spring is mounted in a state of being loosely fitted to a support shaft that is screwed to either the base end side annular plate or the distal end side annular plate.   The base-end-side annular plate is fitted into a recessed circumferential groove formed at the boundary between the base-end portion and the bellows portion, and the tip-end-side annular plate includes the tip-end portion and the bellows portion. The mechanical seal as described in any one of Claims 1-4 with which at least any one structure of the structure fitted by the recessed groove formed in the boundary of this and carried out is employ | adopted.

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