JP4597116B2 - Mechanical seal, shaft seal device, and seal ring for them - Google Patents

Description

  The present invention relates to a seal ring composed of a plurality of segments and an annular spring, a mechanical seal configured using the seal ring, and a shaft seal device configured using a plurality of pairs of mechanical seals.

  The mechanical seal using the segment seals the space between the inner circumferential surface of the seal and the outer circumferential surface of the rotary shaft by an outer annular spring, and presses and urges the seal ring in the axial direction so that the side circumference of the seal ring is It seals between a surface and the side wall of a housing, and it is comprised so that the space between the outer peripheral surface of a rotating shaft and a housing side wall can be sealed by it. As such a mechanical seal, what was indicated in patent documents 1 and patent documents 2 is known.

  In other words, a mechanical seal using a plurality of segments is described as follows: “A plurality of seal rings formed by winding an annular spring around a plurality of sealing segments arranged in the circumferential direction of a rotating shaft are connected to each other by their segment connecting portions. It is defined as a mechanical seal that is arranged side by side in the axial direction in a state where the direction is equal to 50, and is provided with elastic means that presses the plurality of seal rings in the axial direction and presses them against the side peripheral wall of the housing. '' it can.

  In such a mechanical seal, the annular spring is fitted and fitted in a recessed groove formed in the outer peripheral portion of each segment, and the outer diameter side portion of the annular spring, specifically, the left and right sides with respect to the annular spring , And three sides on the outer peripheral side are exposed. In the mechanical seal, a slight leak of the seal target occurs. However, for example, when the seal target has a relatively high viscosity such as rubber or synthetic resin, a problem occurs depending on the leaked seal target. Sometimes.

In other words, the seal object that leaks and accumulates in the annular space of the housing, which is the part that houses the mechanical seal, gradually cools down when the annular spring that is sheathed across each segment is pushed axially or when the machine stops. If the object to be sealed becomes a bad influence on the annular spring during the next machine operation, the annular spring may drop off early, the segment may be deformed or damaged, or the sealing function may be impaired due to them. I was awake.
JP 2005-201314 A Japanese Patent Laid-Open No. 7-19840

  The object of the present invention is that even when a sealing object (particularly a highly viscous sealing object) leaks and accumulates in the housing space of the mechanical seal in the housing, the annular spring may come off from the segment early. , Improved mechanical seal, shaft seal device, and seal ring used in them, capable of avoiding damage to segments and deterioration of sealability due to them, and exhibiting good sealability over a long period of time Is to provide

According to the first aspect of the present invention, in the mechanical seal, a plurality of seal rings 5 formed by winding an annular spring 7 around a plurality of sealing segments 6 arranged in the circumferential direction of the rotary shaft 1 are connected to each other by segments. The portion 15 is arranged side by side in the axial direction with the circumferential direction being 51, and provided with elastic means d that presses the plurality of seal rings 5, 5 in the axial direction and presses against the side wall 3h of the housing 3. The segment 6 is provided with a cover portion 10 that covers the annular spring 7 positioned on the outer peripheral side of the segment 6 on one side and the outer peripheral side in the axial direction, and the annular spring is formed by the plurality of cover portions 10 integrally formed with the segment 6. Ri formed substantially entire circumference is covered spring 7, a pair of seal rings 5, 5 adjacent in the axial direction of the plurality of sealing rings 5 and 5, opposite to the one side in the axial direction of each other The other side each other is is characterized in that are arranged to face.

The invention according to claim 2 is the seal ring used for the mechanical seal M according to claim 1, and is wound around the plurality of sealing segments 6 arranged in the circumferential direction and the plurality of sealing segments 6. Each segment 6 is integrally formed with a cover portion 10 that covers one side and the outer peripheral side of the annular spring 7 positioned on the outer peripheral side thereof in the axial direction. It is characterized by being formed .

According to a third aspect of the present invention, in the seal ring according to the second aspect, the end portions of the cover portion 10 are brought into contact with each other by arranging the segments 6 and 6 to face each other in the axial direction. In the axial direction, the other side is configured to be closed with each other .

  According to the first aspect of the present invention, the portion where the annular spring is exposed by the cover portion provided in the segment, that is, one of the left and right sides of the three sides of the left and right sides and the outer peripheral side with respect to the annular spring, Since the outer side and the outer side are covered, compared to the conventional one where the left and right sides and the three sides of the outer side are exposed, the leakage target is likely to be an annular spring. Can be reduced. As a result, it is reduced that the annular spring comes off from the segment at an early stage or the segment is damaged due to the sealing object that has leaked in, and that the sealing performance deteriorates due to them, and a good sealing performance is obtained over a long period of time. An improved mechanical seal that can be demonstrated can be provided.

According to invention of Claim 1, the following effects are acquired. That is, in the single segment, either the left or right side with respect to the annular spring is open, but by arranging the segments in parallel so as to face each other in the axial direction, either left or right opened Since these sides are closed with respect to each other, it is possible to realize a configuration in which all the three sides are closed. In other words, the structure according to the invention of claim 1 or 2 can be strengthened without any complication as a structure for devising the arrangement of adjacent segments, and the sealing object that has leaked in can be strengthened. It is possible to completely prevent the annular spring from coming off the segment at an early stage, damaging the segment, and the deterioration of the sealing performance due to them, and exhibiting a good sealing performance over a long period of time. Can be improved and a mechanical seal can be provided.

According to the invention of claim 2, it is possible to provide a seal ring capable of obtaining the effect of the invention of claim 1, and according to the invention of claim 3, the effect of the invention of claim 2 is enhanced. A more preferable seal ring that can be provided can be provided .

  Embodiments of a mechanical seal, a shaft seal device, and a seal ring according to the present invention will be described below with reference to the drawings. 1 is a sectional view of a shaft seal device, FIG. 2 is an enlarged sectional view of a mechanical seal portion, FIG. 3 is a side view of the seal ring, FIG. 4 is a sectional view of the seal ring of FIG. FIG. 6 is a perspective view showing a segment connecting portion.

[Example 1]
1 and 2 show a shaft seal device A and a mechanical seal M which are equipped in a molding machine or the like. In FIG. 1, 1 is a rotating shaft having an axis P, 2 is a cylindrical shaft that is externally fitted to the rotating shaft 1 so as to rotate integrally therewith, 3 is a housing composed of first to fifth housing portions 3A to 3E, and M is facing. A pair of mechanical seals 4 and 4 are purge gas supply paths formed in the second housing portion 3B. In FIG. 1, the right side portion of the first housing portion 3A is the atmosphere side, and the left side portion of the fifth housing portion 3E is the aircraft inner side. In the present embodiment, the cylindrical shaft 2 with which the segment 6 is slidably contacted may be substantially viewed as the rotating shaft 1.

  As shown in FIGS. 1 to 4, each mechanical seal M is a seal formed by winding an annular spring 7 around three (for example) seal segments 6 arranged in the circumferential direction of the rotary shaft 1. Two of the rings 5 (one example) are arranged side by side in the axial direction with the segment connecting portions 8 being 51 in the circumferential direction, and the two seal rings 5 and 5 are pressed in the axial direction. A plurality of winding springs (an example of elastic means) 9 that press against the side wall of the housing 3, specifically, the side wall 3h of the first housing part 3A and the side wall 3h of the third housing part 3C are provided. A ring plate 2b for forming the labyrinth portion r is attached to the end of the cylinder shaft 2 on the machine inner side by welding or the like.

  That is, the first mechanical seal M accommodated in the annular space 20 formed across the first housing portion 3A and the second housing portion 3B is formed between the outer peripheral surface 2a of the cylindrical shaft 2 and the first housing portion 3A. The space between the side wall 3h is sealed. And the 2nd mechanical seal M accommodated in the annular space part 20 formed ranging over the 2nd housing part 3B and the 3rd housing part 3C is the outer peripheral surface 2a of the cylindrical shaft 2, and the 3rd housing part 3C. The space between the side wall 3h is sealed. The housing 3 is made of a fluororesin such as PTFE, other resins, or a metal material.

  The detailed structure of the mechanical seal M will be described using the second mechanical seal M. First, as shown in FIGS. 2 to 6, the segment 6 includes an inner peripheral surface 6 a, a first side peripheral wall 6 b for sliding contact, and a cover portion integrally formed following the outer end of the first side peripheral wall 6 b. 10, a second side peripheral wall 6 d on the side of the circular opening 6 c for inserting the annular spring 7, and an outer peripheral groove 6 e for covering the annular spring 7, which is made of a synthetic resin (fluororesin etc.) and has an arc shape It is comprised by the member of. The cover portion 10 covers the one side and the outer peripheral side in the axial direction of the annular spring 7 located on the outer peripheral side of the segment 6, and is in the outer diameter direction in a state where it is lowered from the first side peripheral wall 6 b by one step in the thickness direction. And a peripheral wall 10a that is integrally formed so as to be positioned on one side in the axial direction of the annular spring 7, and a peripheral wall 10b that is integrally formed continuously from the outer peripheral end of the side peripheral wall 10a.

  One end portion in the circumferential direction of the segment 6 has a first cut surface 11 on the inner peripheral surface side inclined in a direction extending in the circumferential direction toward the outer diameter side, and an inner periphery on the second side peripheral wall 6d side. It is comprised in the 1st end part t1 which has the recessed part 12 formed so that the side part may be cut off by half of thickness. In addition, the other end includes a second cut surface 13 on the outer peripheral surface side that is inclined in a direction extending in the circumferential direction toward the inner diameter side, and a narrow tip end protrusion 14 that can be fitted into the recessed portion 12. It is comprised in the 2nd end part t2 which has. That is, as shown in FIG. 4, the first and second end portions t <b> 1 and t <b> 2 are fitted and engaged with each other, and a slight relative movement along the outer peripheral surface 2 a of the cylindrical shaft 2 is enabled. The segment connecting portion 15 formed by the first and second end portions t1 and t2 is configured so that the width dimension of the segment connecting portion 15 is exactly the same as the width dimension of the segment 6 in the state of being fitted and engaged. . As a result, a sealing action is possible by pressing the inner peripheral surface 6a of the segment 6 against the outer peripheral surface 2a of the cylindrical shaft 2 by the tightening biasing force in the diameter reducing direction by the annular spring 7. .

  The pair of seal rings 5, 5 are arranged so that the segment connecting portions 15, 15 are arranged side by side in the axial direction in a state where the segment connecting portions 15, 15 are in the circumferential direction (an alternating state) (see FIG. 2, each segment 6 of the seal ring 5) located on the right side is provided with a stepping rod-like projecting pin 16 made of synthetic resin. An engagement hole 17 into which the locking pin 16 can be loosely fitted is formed at a corresponding position of each segment 6 of the other seal ring 5 (the seal ring 5 located on the left side in FIG. 2). Here, for convenience, the segment 6 with the locking pin 16 is defined as a segment 6A with a pin, the seal ring 5 using this is defined as a male seal ring 5A, the segment 6 with the engagement hole 17 is defined as a segment 6B with a hole, The seal ring 5 using this is defined as a female seal ring 5B. The annular spring 7 is configured by hooking and connecting both ends of a multi-turn coil spring formed by twisting a metal wire.

  When the locking pin 16 is made of metal, as shown in FIG. 7, a pin having a diameter smaller than that of the locking pin shown in FIG. It is configured by driving into a non-through hole 6z. In this way, even if the sliding surface is worn, the metal locking pin 16 can be prevented from appearing on the first side peripheral wall 6b for sliding contact.

  Now, the pair of seal rings 5A and 5B is configured by winding the annular spring 7 with three segments 6A and 6B having the above-described structure arranged in the circumferential direction, and the segments 5A and 5B are axially arranged. The end portions of the cover portions 10, 10, specifically the side ends of the outer peripheral wall 10 b come into contact with each other so that the other side in the axial direction of the annular spring 7 These are configured to close each other as a lid. That is, the pair of seal rings 5A and 5B adjacent in the axial direction among the plurality of seal rings 5 are arranged so that the other side (side where the arc opening 6c is formed) faces each other in the axial direction. It has been. As a result, the annular springs 7 and 7 are configured so that they are hardly exposed to the annular space 20 (there is only a possibility that a very small gap is formed in the three segment connecting portions 15. , See FIG.

  The pair of mechanical seals M, M are arranged with the annular partition portion 3b of the second housing portion 3B interposed therebetween, and the holes 18 that open in both sides of the annular partition portion 3b and extend in the axial direction are even in the circumferential direction. A plurality of positions are formed for each angle, and the winding springs 9 for the mechanical seals M and M are accommodated in the holes 18. Between the winding spring 9 and the seal ring 5, that is, between the first mechanical seal M and the female seal ring 5B, and between the second mechanical seal M and the male seal ring 5A, fluororesin such as PTFE or the like A stopper ring 19 made of the above material is interposed. Each stopper ring 19 is accommodated in the annular space 20 so as to be movable in the axial direction and not relatively rotatable by using a knock pin 21 struck by the annular partition portion 3b. The inner diameters of both the stopper ring 19 and the annular partition portion 3b are set to values that form a clear gap in the radial direction from the cylindrical shaft 2. Reference numeral 22 denotes a snap ring for pre-attaching the stopper ring 19 to the second housing portion 3B in a state of being prevented from coming off.

  In FIG. 1 and FIG. 2, only the winding spring 9 for the second mechanical seal M is illustrated for the convenience of drawing. Further, only the knock pin 21 for the first mechanical seal M is drawn for the same reason. In the first mechanical seal M, the winding spring 9 pushes the female seal ring 5B through the stopper ring 19, whereby the first side peripheral wall 6b (of the pinned segment 6A) of the male seal ring 5A is moved to the first housing part. 3A side wall 3h is press-contacted. Further, in the second mechanical seal M, the winding spring 9 pushes the male seal ring 5A through the stopper ring 19, and thereby the first side peripheral wall 6b (of the holed segment 6B) of the female seal ring 5B is third. It is press-contacted to the side wall 3h of the housing part 3B.

  The aforementioned supply path 4 has an inlet portion 4A connected to a gas supply path of a purge gas supply means (not shown), and an outlet portion 4B of the second housing portion 3B (annular partition portion 3b) in the radial direction. It penetrates and opens in a gap portion with the cylinder shaft 2. Although illustration is omitted, in the annular partition portion 3b, the supply path 4 is formed in a portion between the hole 18 for accommodating the coil spring 9 and the adjacent hole 18 arranged alternately in the circumferential direction. ing. That is, the purge gas is configured to be supplied to the annular space portions 20 and 20 through the gaps between the supply path 4 and the mechanical seals M and M, and the pressure of the purge gas causes each mechanical seal M portion to In other words, the annular space portions 20 and 20 are configured so as to be able to regulate in a high dimension that the sealing target such as rubber or synthetic resin or the atmosphere (or the atmosphere with dust) leaks.

  Since the mechanical seal M and the shaft seal device A according to the present invention are configured as described above, even if the object to be sealed leaks from the inside of the machine into the second annular space 20 for accommodating the second mechanical seal M due to supply of purge gas. Since the annular springs 7 and 7 are almost completely covered by the respective cover portions 10 and 10 and the arc opening 6c due to the opposing arrangement thereof, the sealing target hardly reaches the annular spring 7. Become. In addition, due to the positive pressure due to the supply of purge gas, leakage of the object to be sealed from the inside of the machine is suppressed.

  As a result, even if an object to be sealed with a highly viscous material such as rubber or synthetic resin leaks into the annular space 20, it does not reach the annular spring 7. The conventional problems such as the ring spring 7 coming off from the segment 6 at an early stage or being damaged due to the pushing out of the direction or the object to be cooled and solidified due to the machine stop being adversely affected during the next operation, etc. are avoided, and the sealing performance is thereby deteriorated. Improved mechanical seal M, shaft seal device A, and seal ring 5 for them can be realized.

[Another Example]
(1) The number of seal rings 5 constituting the mechanical seal M may be three or more. For example, in the case of using three seal rings, if the side peripheral wall 10a in the segment of the center seal ring in the axial direction is flush with the second side peripheral wall 6b, any arc opening 6c is closed. Convenient. (2) The cover unit 10 may be configured separately from the segment 6 made of, for example, a sheet metal material, and mounted on the segment 6 using attachment means. (3) In the shaft seal device of the first embodiment, a pair of mechanical seals M and M are used, but a structure using one set or three or more sets of mechanical seals M may be used.

  (4) A mechanical seal M with a single seal ring 5 is also possible. In this case, if the stopper ring 19 is configured to press the side peripheral wall 6b on the arc opening 6c side of the segment 6, the arc opening 6c is formed. The stopper ring 19 can be closed, which is convenient. (5) The number of segments 6 may be two or four or more. (6) The position of the end portion on the large diameter side of the locking pin 16 is set to a position that falls within the thickness range of the segment 6 as indicated by the phantom line in FIG. 2, and the locking pin 16 is connected to the side wall 3 h of the housing 3. It is convenient if the structure never touches.

Sectional drawing which shows the structure of a mechanical seal and a shaft seal device (Example 1) Enlarged sectional view showing the structure of the mechanical seal part Side view of the mechanical seal of FIG. Sectional view of the mechanical seal of FIG. The perspective view of the principal part which shows the structure of a segment connection part Side view of segment Sectional drawing of the principal part which shows another structure of a locking pin

DESCRIPTION OF SYMBOLS 1 Rotating shaft 3 Housing 3b Annular partition part 3h Side wall 4 Supply path 5 Seal ring 6 Segment 7 Annular spring 9 Winding spring 10 Cover part 10a Side peripheral wall 10b Outer peripheral wall 15 Segment connection part 18 Hole part 19 Stopper ring 20 In the annular space part 23 Peripheral surface A Shaft seal device M Mechanical seal d Elastic means

Claims (3)

A plurality of seal rings, in which a plurality of sealing segments arranged in the circumferential direction of the rotating shaft are wound around an annular spring, are arranged side by side in the axial direction, with each segment connecting part being 51 in the circumferential direction. And providing elastic means for pressing the plurality of seal rings in the axial direction against the side wall of the housing, and the annular spring positioned on the outer peripheral side of the segment on the outer side of the segment in the axial direction. is equipped with a cover portion for covering said a plurality of cover portions which are integrally formed on the segment Ri formed substantially entire circumference is covered of said annular spring, a pair of adjacent in the axial direction of the plurality of seal ring seals A mechanical seal in which rings are arranged so that the other side, which is opposite to the one side in the axial direction, faces each other . A seal ring used for the mechanical seal according to claim 1, comprising a plurality of sealing segments arranged in the circumferential direction and an annular spring wound around the plurality of sealing segments. In addition, each segment is integrally formed with a cover portion that covers one side and the outer peripheral side in the axial direction of the annular spring located on the outer peripheral side of each segment. 3. The structure according to claim 2, wherein the segments are opposed to each other in the axial direction so that the ends of the cover portion come into contact with each other and close the other side in the axial direction of the annular spring. Seal ring.

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