JP2022011102A - mechanical seal - Google Patents

Abstract

To provide a mechanical seal which can reliably prevent a rotary sealing ring from following a stationary sealing ring and being removed when a stationary side element is separated from a rotary side element.SOLUTION: A mechanical seal 1 has: a rotary sealing ring 6 which rotates with a sleeve 4 attached to a rotary shaft 2 of a rotary device; and a stationary sealing ring 7 held by a housing 3. The sleeve 4 is formed with a protruding part 40 protruding in an outer diameter direction. The rotary sealing ring 6 contacts with the protruding part 40 to be restricted from moving in an axial direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mechanical seal that seals a rotating shaft.

The mechanical seal is used by being mounted between the housing of the fluid device and the rotating shaft arranged so as to penetrate the housing, and is fixed to the stationary side element configured by the housing or the like. The sliding surface of the ring and the sliding surface of the rotating sealed ring that rotates together with the rotating side element such as the rotating shaft are brought into sliding contact in the circumferential direction to reduce friction generated on the sliding surface and prevent leakage of the sealed fluid. It has a function to prevent it.

As shown in Patent Document 1, a general stationary mechanical seal is a rotation that rotates together with a static sealing ring held by a holding member fixed to a housing and a tubular sleeve externally fixed to a rotating shaft. It is equipped with a sealing ring to improve lubricity by forming a liquid film, which is a sealed fluid, between the sliding surfaces of the static sealing ring and the rotary sealing ring when the sealing rings slide relative to each other. ing. (See Patent Document 1)

Japanese Unexamined Patent Publication No. 2016-125597 (Page 1, Fig. 2)

By the way, since the mechanical seal is a precision instrument, it is necessary to inspect it regularly. To inspect the sliding surface of the mechanical seal, drain the fluid to be sealed from the drain port and then remove the fixing bolts and the like. The stationary element is moved toward the outside of the machine so as to be separated from the rotating element inside the machine.

The sliding surface of the static sealing ring and the sliding surface of the rotary sealing ring are smooth, and a liquid, which is a fluid to be sealed, is interposed between the sliding surfaces. If the stationary element is moved toward the outside of the machine so as to be separated from the rotating element in this state, the rotating sealing ring follows the movement of the stationary sealing ring while the sliding surfaces are attracted to each other. There was something. Further, since the space between the outer circumference of the sleeve and the inner circumference of the stationary side element is narrow, when the stationary side element is moved toward the outside of the machine so as to be separated from the rotating side element, the space is relatively negatively pressured. As a result, it sometimes promoted the follow-up of the rotary sealing ring.

In this way, the rotary sealing ring is moved to the outside of the machine together with the static sealing ring, and the rotary sealing ring falls off from the holding member holding the rotary sealing ring, collides with the outer peripheral surface of the sleeve and the inner peripheral surface of the casing, and is damaged. There was a risk.

The present invention has been made by paying attention to such a problem, and is a mechanical seal that can surely prevent the rotary sealing ring from following and detaching from the stationary sealing ring when the stationary side element is separated from the rotating side element. The purpose is to provide.

In order to solve the above problems, the mechanical seal of the present invention is used.
A mechanical seal having a rotary sealing ring that rotates with a sleeve attached to the rotating shaft of a rotating device and a static sealing ring that is held in a housing.
The sleeve is formed with a protruding portion that protrudes in the outer diameter direction.
The rotary sealing ring is restricted from moving in the axial direction by abutting on the protruding portion.
According to this, when the stationary side element of the mechanical seal is separated from the rotating side element, the rotating sealing ring that tries to follow the stationary sealing ring abuts on the protruding portion formed on the sleeve and moves in the axial direction. Since it is regulated, it is possible to reliably prevent the rotary sealing ring from following and detaching from the stationary sealing ring.

The rotary sealing ring is provided with an inclined surface that is inclined toward the stationary sealing ring, and the protruding portion is provided with an inclined surface that abuts on the inclined surface in an inclined state.
According to this, a part of the impact force is released in the radial direction by the contact between the inclined surfaces of the rotary sealing ring and the protruding portion, so that the impact due to the contact is alleviated.

The rotary sealing ring is held by a holding member from the back surface side via a secondary seal.
The rotary sealing ring is allowed to move in the axial direction to the protruding portion while the sealed state on the back side is maintained by the secondary sealing.
According to this, when the rotary sealing ring moves and comes into contact with the projecting portion, the space on the back side of the rotary sealing ring is sealed by the secondary seal, so that the space on the back surface side is sealed from the outer diameter side chamber into which the fluid to be sealed is introduced. The fluid does not flow into the space, and a sudden change in atmospheric pressure is unlikely to occur in the space.

An elastic member is interposed between the inner peripheral surface of the rotary sealing ring and the outer peripheral surface of the sleeve.
According to this, when the rotary sealing ring moves in the axial direction until it abuts on the protruding portion, it has a cushioning function to prevent the inner peripheral surface of the rotary sealing ring from directly contacting the outer peripheral surface of the sleeve.

The sleeve is formed with an annular groove that is recessed on the inner diameter side.
A communication hole is formed to communicate the inner diameter side chamber between the static sealing ring and the sleeve and the concave groove.
According to this, when the rotary sealing ring moves to the static sealing ring side, the gas is allowed to move into the concave groove by the communication hole, so that the negative pressure generated in the inner diameter side chamber is reduced.

The elastic member is arranged between the inner diameter side chamber and the concave groove.
According to this, the elastic member can exert a cushioning function between the inner peripheral surface of the rotary sealing ring and the outer peripheral surface of the sleeve without obstructing the communication of the gas between the inner diameter side chamber and the concave groove.

It is sectional drawing which shows the structure of the mechanical seal of Example 1 of this invention. It is a partially enlarged sectional view which shows the sleeve, the rest sealing ring, and the rotary sealing ring. It is a schematic diagram which shows the mode that the stationary side element is separated from the rotating side element. (A) is a partially enlarged cross-sectional view showing a statically sealed ring and a rotary sealing ring arranged at a predetermined position, and (b) is an embodiment in which the rotary sealing ring moves following the statically sealed ring side at the time of disassembly. It is a schematic diagram which shows, and (c) is a schematic diagram which shows the mode that the rotary seal ring abuts on a protruding portion, and the static seal ring and the rotary seal ring are separated. It is a partially enlarged sectional view which shows the mechanical seal structure in Example 2 of this invention. (A) is a partially enlarged cross-sectional view showing a statically sealed ring and a rotary sealing ring arranged at a predetermined position, and (b) is an embodiment in which the rotary sealing ring moves following the statically sealed ring side at the time of disassembly. It is a schematic diagram which shows, and (c) is a schematic diagram which shows the mode that the rotary seal ring abuts on a protruding portion, and the static seal ring and the rotary seal ring are separated. It is a partially enlarged sectional view which shows the mechanical seal structure in Example 3 of this invention. It is a partially enlarged sectional view which shows the mechanical seal structure in Example 4 of this invention.

A mode for carrying out the mechanical seal according to the present invention will be described below based on examples.

The mechanical seal according to the first embodiment will be described with reference to FIGS. 1 to 4. Hereinafter, the left side of the paper surface of FIG. 1 will be described as the outside of the machine which is the atmospheric region, and the right side of the paper surface will be described as the inside of the machine which is the sealed fluid region.

As shown in FIG. 1, the mechanical seal 1 of this embodiment is composed of a stationary side element S and a rotating side element R. The stationary side element S includes a flange 10 fixed to the housing 3 by bolts 12 and nuts 13, an annular collar 14 disposed between the flange 10 and the housing 3, and a coil disposed on the collar 14. The spring 15 is held by the compression ring 16 that transmits the pressing force of the coil spring 15 to the back surface side of the stationary ring holding member 70, and the stationary ring holding member 70 that is pressed from the compression ring 16 toward the rotary sealing ring 6. It is mainly composed of the static sealing ring 7 and the closed ring 7.

The rotation side element R is held by a cylindrical sleeve 4 fixed to the rotation shaft 2 by a fixing ring 17, a rotation ring holding member 5 attached to the outer peripheral side of the sleeve 4, and the rotation ring holding member 5. It is mainly composed of a rotary sealing ring 6.

As shown in FIG. 2, the mechanical seal 1 of the present embodiment is outside the sliding portion T formed by the sliding surface F1 included in the rotary sealing ring 6 and the sliding surface F2 included in the static sealing ring 7. It is an inside type and a stationary type that seals the sealed fluid L that is about to leak from the outer diameter side chamber 21 on the diameter side toward the inner diameter side chamber 20 on the inner diameter side of the sliding portion T.

The rotary sealing ring 6 is formed with an annular convex portion 62 that protrudes in the axial direction from the side surface 61, and a sliding surface of the convex portion 62 facing the static sealing ring 7 is formed flat. It is a surface F1.

The rotary sealing ring 6 has a notch 65 formed on the back surface 60 side, and the rotational force of the rotary shaft 2 is transmitted by engaging the pin 50 extending in the axial direction from the rotary ring holding member 5. It is supposed to be done. Further, an O-ring 71 as a secondary seal disposed on the rotary ring holding member 5 is interposed on the back surface 60 of the rotary seal ring 6, and the sealed fluid L of the outer diameter side chamber 21 is interposed in the rotary seal ring 6. It is prevented from wrapping around to the inner peripheral surface 64 side of the rotary sealing ring 6 and leaking to the inner diameter side chamber 20 on the atmosphere side through the back surface 60 of the rotary sealing ring 6.

Further, on the outer side end portion of the inner peripheral surface 64, an annular inclined surface 66 formed so as to be inclined toward the outer diameter side and the side surface 61 side, and an axial direction from the outer side end portion of the inclined surface 66. A peripheral surface 67 is formed so as to be orthogonal to the extending side surface 61.

The sleeve 4 is formed with an annular protruding portion 40 protruding toward the outer diameter side. The protruding portion 40 is divided by an inclined surface 41, a peripheral surface 42, and an inclined surface 43, which will be described later.

The outer peripheral surface 34 of the sleeve 4 has a flat peripheral surface 4A facing the inner peripheral surface 64 of the rotary sealing ring 6 slightly separated from the inner peripheral surface 64 in a state where the mechanical seal 1 is assembled, and the outer peripheral end of the peripheral surface 4A. From the annular inclined surface 41 inclined from the outer diameter side to the outside of the machine, the peripheral surface 42 extending from the outer end of the inclined surface 41 toward the outside of the machine, and the outer end of the peripheral surface 42. Mainly from the inclined surface 43 extending to the inner diameter side and inclined toward the outside of the machine, and the peripheral surface 4B extending from the outer end of the inclined surface 43 and formed on the inner diameter side of the peripheral surface 4A. It is configured.

The inclined surface 41 of the protruding portion 40 of the sleeve 4 and the inclined surface 66 of the rotary sealing ring 6 are arranged so as to be substantially parallel and separated from each other in a state where the mechanical seal 1 is assembled.

Returning to FIG. 1, the inspection of the sliding surface F2 of the static sealing ring 7 of the mechanical seal 1 will be described. After draining the sealed fluid L sealed in the outer diameter side chamber 21 from a drain port (not shown), the nut 13 of the stationary side element S is loosened and the flange 10 is removed from the housing 3. After that, as shown in FIG. 3, the collar 14 is gripped, and the rest ring unit U including the collar 14, the coil spring 15, the compression ring 16, the rest ring holding member 70, and the rest seal ring 7 is moved toward the outside of the machine. Let me. In this way, the static sealing ring 7 is moved to the space outside the machine, and the sliding surface F2 is inspected visually or the like. The detailed procedure for separating the static sealing ring 7 from the rotary sealing ring 6 will be described later.

The sliding surface F2 of the static sealing ring 7 and the sliding surface F1 of the rotary sealing ring 6 are smooth. Further, even after the sealed fluid L is discharged from the drain port, the liquid which is the sealed fluid L is interposed between the sliding surfaces F1 and F2. As will be described later, when the sealing ring on one side moves, the sliding surfaces may be attracted to each other, and the sealing ring on the other side may also move following the sealing ring on one side. In particular, if a liquid is present between the sliding surfaces, the sliding surfaces are likely to be adsorbed to each other.

Further, as shown in FIG. 3, the inner peripheral surface 14A of the collar 14 of the stationary ring unit U and the peripheral surface 4B of the sleeve 4 are close to each other in the radial direction and are close to each other in the radial direction. Since the length in the direction is long, when the stationary ring unit U is moved toward the outside of the machine, a negative pressure is likely to be generated in the inner diameter side chamber 20 (see FIG. 2).

Hereinafter, a detailed procedure for separating the static sealing ring 7 from the rotary sealing ring 6 will be described. FIG. 4A shows a state in which the sealed fluid L is discharged from the drain port in order to disassemble and inspect the mechanical seal 1. When the stationary ring unit U of the stationary side element S is moved toward the outside of the machine, the rotary sealing ring 6 becomes the stationary sealing ring 7 as the stationary ring unit U moves while the sliding surfaces F1 and F2 are attracted to each other. Follow.

When the stationary ring unit U is further moved, the rotary sealing ring 6 comes into contact with the protruding portion 40 of the sleeve 4, as shown in FIG. 4 (b).

Specifically, the inclined surface 66 of the rotary sealing ring 6 abuts on the inclined surface 41 of the protruding portion 40 formed on the sleeve 4, so that the rotary sealing ring 6 is restricted from moving to the outside of the machine. From this, even if the rotary sealing ring 6 follows the stationary sealing ring 7, the rotary sealing ring 6 can be reliably prevented from being separated from the rotary ring holding member 5.

Further, since the inclined surfaces 41 and 66 come into contact with each other, a part of the impact force due to the contact between the rotary sealing ring 6 and the sleeve 4 is released in the radial direction, so that the impact due to the contact is alleviated. It has become. Further, since the inclined surfaces 41 and 66 are parallel to each other, the relaxation action is excellent.

Further, as the rotary sealing ring 6 moves to the outside of the machine, the O-ring 51 slightly extends in the axial direction while being in contact with the back surface 60 of the rotary sealing ring 6, and the inner diameter side of the O-ring 51 and the rotary sealing ring 6 A space 23 is formed between the back surface 60 and the rotary ring holding member 5, and a space 24 is formed between the outer diameter side of the O-ring 51 and the back surface 60 of the rotary sealing ring 6 and the rotary ring holding member 5. .. The space 23 communicates with the inner diameter side chamber 20, and the space 24 communicates with the outer diameter side chamber 21.

The rotary sealing ring 6 is allowed to move in the axial direction to the projecting portion 40 while the sealed state on the back surface 60 side is maintained by the O-ring 51, and the rotary sealing ring 6 moves to the projecting portion 40. When abutting on the inclined surface 41, the space 23 and the space 24 on the back surface 60 side of the rotary sealing ring 6 are sealed by the O-ring 51. As a result, the fluid from the outer diameter side chamber 21 does not flow into the space 23 through the space 24, and the negative pressure of the space 23 increases as the rotary sealing ring 6 is moved to the static sealing ring 7 side. Due to the negative pressure generated in the space 23, a force acts on the rotary sealing ring 6 toward the rotary ring holding member 5, so that the sliding surface F1 and the sliding surface F2 can be easily separated from each other.

When the stationary ring unit U is further moved to the outside of the machine from the state shown in FIG. 4 (b), the regulatory force of the protruding portion 40 exceeds the suction force between the sliding surface F1 and the sliding surface F2, and the sliding surface F2 slides. The suction state between the surfaces F1 and F2 is released, and the sliding surfaces F1 and F2 are separated from each other as shown in FIG. 4C.

Next, the mechanical seal according to the second embodiment will be described with reference to FIG. The same components as those shown in the first embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 5, in the mechanical seal 11 according to the second embodiment, the shape of the sleeve 4 in the first embodiment is changed, and an annular concave groove 46 is formed on the peripheral surface 4A inside the machine, and the concave groove 46 and the groove 46 are formed. A sleeve 44 is used in which the inner diameter side chamber 20 is communicated with the communication hole 45.

The concave groove 46 has a substantially trapezoidal cross section from the outer diameter side to the inner diameter side, and is partitioned by a machine outer side surface 47, a bottom surface 48, and a machine inner side surface 49. The machine outer side surface 47 and the machine inner side surface 49 are inclined so as to expand from the bottom surface 48 toward the outer diameter side, and are formed so that the volume of the concave groove 46 becomes large.

The concave groove 46 and the inner diameter side chamber 20 are communicated with each other by a communication hole 45. Specifically, the communication hole 45 is formed by a hole 45a formed by being inclined from the outer side surface 47 of the machine to the inner diameter side of the sleeve 44 and toward the outside of the machine, and from the inclined surface 43 toward the inner diameter side of the sleeve 44 and toward the inside of the machine. It is configured by connecting with a hole 45b which is inclined and drilled.

Since the communication hole 45 is formed in a substantially V-shape in the axial cross section by the inclined hole 45a and the hole 45b, the volume of the communication hole 45 is large.

FIG. 6A shows a state in which the sealed fluid L is discharged from the drain port in order to disassemble and inspect the mechanical seal 11. When the stationary ring unit U of the stationary side element S is moved toward the outside of the machine, the rotary sealing ring 6 becomes the stationary sealing ring 7 as the stationary ring unit U moves while the sliding surfaces F1 and F2 are attracted to each other. Follow.

As shown in FIG. 6B, when the static sealing ring 7 of the stationary ring unit U is moved to the outside of the machine while the sliding surfaces F1 and F2 are attracted to each other, the rotary sealing ring 6 becomes the stationary sealing ring. Follow 7 and move to the outside of the machine.

In this way, when the stationary ring unit U is moved toward the outside of the machine, the atmosphere in the concave groove 46 moves to the inner diameter side chamber 20 side through the communication hole 45, and the negative pressure generated in the inner diameter side chamber 20 is reduced. It has become.

When the stationary ring unit U is further moved to the outside of the machine from the state where the rotary sealing ring 6 shown in FIG. 6B is restricted from moving by the protruding portion 40 of the sleeve 4, a space 25 is created in the inner diameter side chamber 20. Since they are communicated with each other, negative pressure is unlikely to occur in the inner diameter side chamber 20, the suction state between the sliding surfaces F1 and F2 is smoothly released, and the sliding surfaces F1 and F2 shown in FIG. 6C are separated from each other. It will be in the state of being.

Further, even when the stationary ring unit U of the second embodiment is reassembled after the inspection of the stationary ring unit U, the movement of the atmosphere is allowed in the concave groove 46 and the communication hole 45 formed in the sleeve 44. Therefore, it is prevented that the air in the inner diameter side chamber 20 formed between the housing and the sleeve 44 is compressed to hinder the assembly.

Next, the mechanical seal according to the third embodiment will be described with reference to FIG. 7. The same components as those shown in Examples 1 and 2 are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 7, in the mechanical seal 111 according to the third embodiment, the shape of the sleeve 44 in the second embodiment is changed, and an annular shallow groove 91 is formed between the convex portion 40 and the concave groove 46 in the axial direction. The sleeve 144 is formed and an O-ring 90 as an elastic member is arranged in the shallow groove 91.

Since the O-ring 90 is arranged in the shallow groove 91, when the mechanical seal 111 is disassembled, the rotary seal ring 6 is moved in the axial direction until it abuts on the protruding portion 40. The inner peripheral surface 64 of No. 6 is prevented from directly contacting the outer peripheral surface 144A of the sleeve 144, and has a cushioning function.

Further, since the O-ring 90 is arranged between the inner diameter side chamber 20 and the concave groove 46, the O-ring 90 does not interfere with the communication between the inner diameter side chamber 20 and the concave groove 46.

Next, the mechanical seal according to the fourth embodiment will be described with reference to FIG. The same components as those shown in the first to third embodiments are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 8, the mechanical seal 211 according to the third embodiment has a protrusion having a machine outer side surface 140A in which the shape of the sleeve 4 in the first embodiment is changed and the machine outer end portion of the protrusion portion hangs down in the vertical direction. It is a shape portion 140. Further, an annular shallow groove 146 having a substantially concave shape in the axial cross section is formed inside the machine from the protruding portion 140.

Further, the hole 145a is formed linearly from the outer side surface 140A of the machine toward the inside of the machine in the axial direction, and the hole 145b is formed vertically from the bottom surface of the shallow groove 146, whereby the hole 145a and the hole 145b are formed. Is connected to form a sleeve 244 in which a communication hole 145 is formed.

The shallow groove 146 and the inner diameter side chamber 20 are communicated with each other by the communication hole 145, and the negative pressure in the inner diameter side chamber 20 is reduced by the communication hole 145 and the shallow groove 146.

Although Examples 1 to 4 of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these Examples, and the present invention may be changed or added without departing from the gist of the present invention. Included in the invention.

For example, in the first to fourth embodiments, the rotary sealing ring 6 is held by the rotary ring holding member 5, but the present invention is not limited to this. It may be a mechanical seal that holds the.

Further, in Examples 1 to 4, the inside type mechanical seal has been described as an example, but the present invention is not limited to this, and an outside type mechanical seal may be used.

Further, in the first to fourth embodiments, the mechanical seal in which the static sealing ring is arranged on the outside of the machine has been described as an example, but the present invention is not limited to this, and the mechanical seal in which the static sealing ring is arranged on the inside of the machine is not limited to this. May be.

Further, in the first to fourth embodiments, it has been described as an example that the protruding portion 40 is in contact with the inclined surface 66 of the inner peripheral surface 64 of the rotary sealing ring 6 to restrict the movement in the axial direction. However, the present invention is not limited to this, and the protruding portion 40 may be restricted from moving in the axial direction by abutting on the side surface 61 of the rotary sealing ring 6.

Further, in the first to fourth embodiments, the inclined surface 66 of the inner peripheral surface 64 of the rotary sealing ring 6 abuts on the inclined surface 41 of the protruding portion 40 to restrict the movement in the axial direction, that is, the inclined surface. Although the case where they are in contact with each other has been described as an example, the present invention is not limited to this, as long as the movement of the rotary sealing ring 6 in the axial direction can be restricted, only the protruding portion 40 may be provided with an inclined surface, or the rotary sealing ring 6 may be provided. Only the inner peripheral surface 64 of the above may be provided with an inclined surface, or both the projecting portion 40 and the rotary sealing ring 6 may not have an inclined surface and the radial surfaces may come into contact with each other.

1 Mechanical seal 2 Rotating shaft 3 Housing 4 Sleeve 5 Rotating ring holding member (holding member)
6 Rotating sealed ring 7 Static sealing ring 11 Mechanical seal 14 Color 15 Coil spring 16 Compression ring 20 Inner diameter side chamber 21 Outer diameter side chamber 34 Outer surface 40 Protruding part 41 Inclined surface 43 Inclined surface 44 Sleeve 45 Communication hole 46 Concave groove 51 O-ring (Secondary seal)
70 Resting ring holding member 90 O-ring (elastic member)
111 Mechanical seal 140 Protruding part 144 Sleeve 145 Communication hole 146 Shallow groove 211 Mechanical seal 244 Sleeve F1 Sliding surface F2 Sliding surface L Sealed fluid R Rotating side element S Resting side element U Resting ring unit

Claims (6)

A mechanical seal having a rotary sealing ring that rotates with a sleeve attached to the rotating shaft of a rotating device and a static sealing ring that is held in a housing.
The sleeve is formed with a protruding portion that protrudes in the outer diameter direction.
The rotary sealing ring is a mechanical seal whose axial movement is restricted by abutting on the protruding portion. The mechanical seal according to claim 1, wherein the rotary sealing ring has an inclined surface inclined toward the stationary sealing ring, and the protruding portion has an inclined surface that abuts on the inclined surface in an inclined state. The rotary sealing ring is held by a holding member from the back surface side via a secondary seal.
The mechanical seal according to claim 1 or 2, wherein the rotary sealing ring is allowed to move in the axial direction to the protruding portion while the sealed state on the back side is maintained by the secondary sealing. The mechanical seal according to any one of claims 1 to 3, wherein an elastic member is interposed between the inner peripheral surface of the rotary sealing ring and the outer peripheral surface of the sleeve. The sleeve is formed with an annular groove that is recessed on the inner diameter side.
The mechanical seal according to any one of claims 1 to 4, wherein a communication hole for communicating the inner diameter side chamber between the static sealing ring and the sleeve and the concave groove is formed. The mechanical seal according to claim 5, wherein the elastic member is arranged between the inner diameter side chamber and the concave groove.

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