JP2022006788A - mechanical seal - Google Patents

Abstract

To provide a mechanical seal capable of supplying fluid to be sealed while sealing the fluid to be sealed.SOLUTION: In a mechanical seal 1 that seals fluid to be sealed by forming a seal part connected in a circumferential direction between sliding surfaces 10a, 20a of a pair of sealing members 10, 20 with relative rotation, one sealing member 20 is provided with a one-way flow path 24 that communicates between the sliding surfaces 10a, 20a and a space to be sealed X in which the fluid to be sealed on the outer diameter side of the sliding surface 20a exists, and the other sealing member 10 is provided with the other flow path 14 that communicates between the sliding surfaces 10a, 20a and an external space Y of the sealing member 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mechanical seal that seals a fluid between two members with relative rotation.

A general mechanical seal includes a static sealing ring fixed to a housing and a rotating sealing ring fixed to a rotating shaft and rotating together with the rotating shaft, and by sliding these sliding surfaces relative to each other, a sliding surface is provided. The sealing portion formed between them and connected in the circumferential direction prevents leakage from the inner diameter side to the outer diameter side or from the outer diameter side to the inner diameter side of the sliding surface.

For example, in the mechanical seal of Patent Document 1, the rotary sealing ring is pressed and urged toward the static sealing ring by a spring, and even if the sliding surfaces are worn, the sliding surfaces slide in close contact with each other. It is possible to maintain the sealing property.

Japanese Unexamined Patent Publication No. 2-12975 (Page 2, Fig. 1)

In the mechanical seal of Patent Document 1, a fluid film is formed by a fluid to be sealed that flows into a minute gap between sliding surfaces that slide relative to each other, thereby achieving both lubricity and sealing property. When the amount of the sealed fluid flowing between the surfaces is small, the fluid film is not sufficiently formed, the lubricity is deteriorated, frictional heat is likely to be generated, and the contamination is accumulated between the sliding surfaces, so that the fluid slides. There was a problem that the surface was easily worn. Further, since the sealed fluid is housed in the space where the mechanical seal is arranged, it is difficult to access the sealed fluid.

An object of the present invention is to provide a mechanical seal capable of supplying a sealed fluid while sealing the sealed fluid.

In order to solve the above problems, the mechanical seal of the present invention is used.
In a mechanical seal that seals the fluid to be sealed by forming a sealing portion connected in the circumferential direction between the sliding surfaces of a pair of sealing members with relative rotation.
On the other hand, the sealing member is provided with a one-way flow path that communicates between the sealed space in which the sealed fluid on either the inner diameter side or the outer diameter side of the sliding surface exists and the sliding surface.
The other sealing member is provided with the other flow path that communicates between the external space of the sealing member and the sliding surface.
According to this, the sliding surface side opening of one flow path and the sliding surface side opening of the other flow path overlap each other with the relative rotation of the sealing member, so that the sealed space and the external space are separated by each flow path. Since the fluid can be communicated with each other, the sealed fluid can be supplied between the sealed space and the external space through the sliding surfaces while sealing the sealed fluid by the sealing portion. Therefore, a fluid film formed by the sealed fluid is easily formed between the sliding surfaces, the lubricity is improved, and access to the sealed fluid is facilitated.

The other sealing member may be a static sealing ring.
According to this, since the other flow path does not rotate relative to each other, the sealed fluid can be stably supplied between the external space and the other flow path.

The sealed fluid may be pressurized by the pressurizing means.
According to this, the flowability of the sealed fluid in each flow path is good.

On the other hand, the sealing member is a rotary sealing ring.
The rotary sealing ring may be urged toward the stationary sealing ring by an urging means.
According to this, since the rotary sealing ring is pressed against the static sealing ring by the urging means, the axial movement of the static sealing ring is prevented, and the sealed fluid is more stable between the external space and the other flow path. Can be supplied.

Both flow paths may be provided so that the sealed fluid is always supplied between the sealed space and the external space.
According to this, the sealed fluid can be continuously supplied between the sealed space and the external space through both flow paths.

The one flow path may be a notch.
According to this, it is possible to construct a large flow path cross-sectional area of the one-sided flow path that opens in the sealed space.

It is sectional drawing which shows an example of the rotating apparatus to which a mechanical seal is applied in an Example of this invention. It is a figure which shows the sliding surface of the rotary sealing ring in an Example. For convenience of explanation, dots are added to the notches provided on the sliding surface. It is a figure which shows the sliding surface of the static sealing ring in an Example. It is an enlarged sectional view which shows the mechanical seal in an Example. It is a figure which shows the modification 1 of the sliding surface of a rotary sealing ring. For convenience of explanation, dots are added to the notches provided on the sliding surface. It is an enlarged sectional view which shows the modification 2 of the mechanical seal in the Example 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 embodiment will be described with reference to FIGS. 1 to 4. In this embodiment, the inner diameter side of the rotary sealing ring and the static sealing ring constituting the mechanical seal will be described as the atmospheric side (low pressure side) as the leakage side, and the outer diameter side will be described as the sealed fluid side (high pressure side). .. Further, the sealed fluid is pressurized by a pressurizing means such as a pump (not shown), and the pressure is higher than that on the atmospheric side.

The mechanical seal 1 shown in FIG. 1 is an inside type that seals the sealed liquid that is about to leak from the outer diameter side to the inner diameter side of the sliding surfaces 10a and 20a, and is fixed to the rotating shaft 2. An annular rotary sealing ring 20 as one of the sealing members provided so as to be rotatable and axially movable together with the rotary shaft 2 via the sleeve 3 and a non-rotating state fixed to the housing 4 of the rotating device. It is mainly composed of an annular static sealing ring 10 as the other sealing member provided.

The rotary sealing ring 20 is axially urged toward the static sealing ring 10 by a coil spring 6 as an urging means, so that the sliding surface 10a of the static sealing ring 10 and the sliding surface of the rotary sealing ring 20 20a and 20a slide closely with each other. The coil spring 6 has one end in the axial direction in contact with the metal retainer 21 holding the rotary sealing ring 20, and the other end in the axial direction is accommodated and arranged in the accommodating hole of the sleeve 3. Further, the retainer 21 can rotate together with the rotating shaft 2 by inserting a detent pin 30 extending in the axial direction from the sleeve 3 into a recess (not shown) formed on the back surface.

The static sealing ring 10 and the rotary sealing ring 20 are typically formed of SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but the sliding material is not limited to this. It can be applied as long as it is used as a sliding material for mechanical seals. The SiC includes a sintered body containing boron, aluminum, carbon and the like as a sintering aid, and materials composed of two or more types of phases having different components and compositions, for example, SiC and SiC in which graphite particles are dispersed. There are reaction sintered SiC, SiC-TiC, SiC-TiN and the like made of Si, and as carbon, resin molded carbon, sintered carbon and the like can be used, including carbon in which carbon and graphite are mixed. In addition to the above sliding materials, metal materials, resin materials, surface modification materials (coating materials), composite materials and the like can also be applied. Furthermore, when a highly corrosive fluid is used as the sealed fluid, a highly corrosive material such as a nickel-based superalloy can also be applied.

As shown in FIG. 1, the rotary sealing ring 20 is formed in a substantially L-shaped cross-sectional view, and an O-ring 22 is inserted into a stepped and annular recess 20b formed on the inner diameter side of the back surface, and a sleeve. The O-ring 22 is inserted around the outer periphery of the third portion so as to be movable in the axial direction. The O-ring 22 functions as a secondary seal, and the sealing property between the rotary sealing ring 20 and the sleeve 3 is ensured.

Further, the rotary sealing ring 20 becomes rotatable together with the rotary shaft 2 by inserting the detent pin 23 extending axially from the retainer 21 into the slit-shaped recess 20c formed on the outer diameter side of the back surface. There is.

As shown in FIGS. 1 and 2, the rotary sealing ring 20 has a space on the outer diameter side from the sliding surface 20a to the outer peripheral surface 20d, that is, the sealed space X in which the sealed fluid exists and the sliding surface 10a. An annular notch 24 is provided as a flow path while communicating with the space between 20a.

Specifically, the notch 24 is formed in an annular shape and slides on the annular peripheral wall surface 24a extending in the axial direction so as to be orthogonal to the flat sliding surface 20a and extending along the inner circumference of the sliding surface 20a. It is composed of a flat bottom surface 24b extending in parallel with the surface 20a. Further, the notch may be formed in a wavy shape or an uneven shape in the axial direction as long as it is connected in an annular shape in the circumferential direction.

Further, the notch 24 extends to a position axially overlapping the entire through hole 14 of the static sealing ring 10 (see FIGS. 1 and 3, in particular, the notch 24 shown by a chain line in FIG. 3). The notch 24 may extend to a position where it vertically overlaps with at least a part of the through hole 14 of the static sealing ring 10.

It is preferable that the notch 24 is formed in an axial dimension so as not to generate dynamic pressure between the sliding surfaces 10a and 20a.

As shown in FIG. 1, the static sealing ring 10 is formed in an L-shaped cross-sectional view, and is an O-ring 11 inserted into an annular recess 40b formed in an end face 40a of a seal cover 40 constituting a housing 4 on the back surface. Is abutted axially to the end surface 40a of the seal cover 40 with the cover 40 interposed therebetween, and the O-ring 12 is inserted between the inner circumference of the static sealing ring 10 and the outer periphery of the seal cover 40. It is held by being done. The O-rings 11 and 12 function as secondary seals, and the sealing property between the static sealing ring 10 and the seal cover 40 is ensured. An O-ring may be arranged between the inner circumference of the housing 4 and the outer circumference of the static sealing ring 10.

Further, the static sealing ring 10 is fixed in a non-rotating state by inserting a detent pin 13 extending axially from the seal cover 40 into the recess 10b formed on the outer diameter side of the back surface.

As shown in FIGS. 1 and 3, the static sealing ring 10 has a through hole 14 as a other flow path that penetrates in the axial direction and communicates between the external space Y of the sealing member and the sliding surfaces 10a and 20a. Multiple equal parts are arranged in the circumferential direction. The number of through holes 14 provided in the static sealing ring 10 may be one. Further, the cross-sectional shape of the through hole 14 may be a shape other than a circle.

Specifically, the through hole 14 is formed in a circular shape having a center substantially in the radial center of the sliding surface 10a. Further, the through holes 14 are arranged at 10 equal parts in the circumferential direction of the sliding surface 10a. The through hole 14 is provided so as to match the number and arrangement of the plurality of fluid supply ports 41 as the external space Y of the sealing member that opens in the end surface 40a of the seal cover 40.

That is, as shown in FIG. 1, the through hole 14 of the static sealing ring 10 and the fluid supply port 41 of the seal cover 40 communicate with each other by being arranged linearly in the axial direction.

Next, the sealing function and the fluid supply function of the mechanical seal 1 will be described with reference to FIG.

As shown in FIG. 4, the sealed fluid flows into the notch 24 of the rotary sealing ring 20 from the sealed space X on the outer diameter side through the sealed space side opening 24e of the notch 24. Further, the sealed fluid enters the minute gap between the sliding surfaces 10a and 20a from the outer diameter side to the inner diameter side due to the pressure. Since the sealed fluid flows into the notch 24, the sealed fluid easily enters from the inside of the notch 24 to the land portions 10e and 20e on the inner diameter side between the sliding surfaces 10a and 20a. Further, the land portion 20e of the rotary sealing ring 20 is formed wider in the radial direction than the land portion 10e of the static sealing ring 10, and more specifically, between the sliding surfaces 10a and 20a due to the facing portions of the land portions 10e and 20e. A seal portion S connected to the seal portion S without interruption in the circumferential direction is formed.

When the sliding surface 20a of the rotary sealing ring 20 slides relative to the sliding surface 10a of the static sealing ring 10 due to the rotation of the rotating shaft 2, the sealed fluid that has entered between the sliding surfaces 10a and 20a slides relative to the sliding surface 10a of the static sealing ring 10 due to its viscosity. It follows the sliding surface 20a of the rotary sealing ring 20. As a result, a fluid film is formed in the circumferential direction on the land portions 10e and 20e on the inner diameter side between the sliding surfaces 10a and 20a, and the sealed fluid flows from the sealed space X of the sliding surfaces 10a and 20a to the atmosphere side. It can be sealed so that it does not leak.

Further, the sliding surface side opening 24f of the notch 24 of the rotary sealing ring 20 and the sliding surface side opening 14f of the plurality of through holes 14 of the static sealing ring 10 are overlapped with each other and are held in the notch 24. The sealed fluid is supplied into the through hole 14.

The sealed fluid supplied into the through hole 14 of the static sealing ring 10 is supplied from the outer space side opening 14e of the through hole 14 to the fluid supply port 41 of the seal cover 40 as the outer space Y. The sealed fluid supplied to the fluid supply port 41 of the seal cover 40 is supplied to a supply destination (not shown) through a flow path formed inside the seal cover 40.

As described above, the mechanical seal 1 forms a seal portion S connected in the circumferential direction by the land portions 10e and 20e between the sliding surfaces 10a and 20a of the rotary sealing ring 20 accompanied by the relative rotation and the static sealing ring 10. The rotary sealing ring 20 is provided with a notch 24 that communicates between the sealed space X on the outer diameter side of the sliding surface 10a and the sliding surfaces 10a and 20a, and the static sealing ring 10 is provided as an external space Y. A through hole 14 is provided so as to communicate between the fluid supply port 41 of the seal cover 40 and the sliding surfaces 10a and 20a. According to this, the notch 24 is formed by overlapping the sliding surface side opening 24f of the notch 24 and the sliding surface side opening 14f of the through hole 14 with the relative rotation of the rotary sealing ring 20 and the static sealing ring 10. Since the sealed space X and the external space Y can always communicate with each other through the through hole 14, the sealed space X and the sealed space X pass between the sliding surfaces 10a and 20a while the sealed fluid is sealed by the sealing portion S. The sealed fluid can be supplied to and from the external space Y.

Further, a fluid film formed by the sealed fluid is likely to be formed between the sliding surfaces 10a and 20a, and the lubricity is improved.

In addition, access to the sealed fluid is facilitated, and it is easy to collect and inspect the sealed fluid in the vicinity of the rotary sealing ring 20 and replace the sealed fluid.

Further, since the fluid to be sealed can be directly supplied between the sliding surfaces 10a and 20a on which the static sealing ring 10 and the rotary sealing ring 20 slide relative to each other, the cooling effect on the sliding portion is high. Further, in the statically sealed ring 10, the cooling efficiency is higher because the fluid to be sealed passes through the through hole 14 and the inside of the statically sealed ring 10. Further, since the through holes 14 are evenly arranged in the circumferential direction, the static sealing ring 10 can be cooled evenly.

Further, the through hole 14 which is the other flow path communicating between the fluid supply port 41 of the seal cover 40 as the external space Y and the sliding surfaces 10a and 20a is provided in the static sealing ring 10. As a result, since the through hole 14 does not rotate relative to each other, the sealed fluid can be stably supplied between the fluid supply port 41 of the seal cover 40 and the through hole 14 of the static sealing ring 10.

Further, since the sealed fluid is pressurized by a pressurizing means (not shown), the sealed fluid has good flowability through the notch 24 of the rotary sealing ring 20 and the through hole 14 of the static sealing ring 10.

Further, on the back surface of the static sealing ring 10, the through hole 14 of the static sealing ring 10 and the fluid supply port 41 of the seal cover 40 are communicated with each other, and the back surface of the static sealing ring 10 and the end surface 40a of the seal cover 40 are communicated with each other. An O-ring 11 is arranged between them. As a result, leakage of the sealed fluid from the outer space side opening 14e of the through hole 14 of the static sealing ring 10 to the outside of the sealing cover 40 is prevented between the back surface of the static sealing ring 10 and the end surface 40a of the sealing cover 40. Will be done.

Further, since the static sealing ring 10 is provided with a plurality of through holes 14, it is possible to improve the supply efficiency of the fluid to be sealed.

Further, since the through hole 14 of the static sealing ring 10 is a through hole penetrating in the axial direction, it is easy to process the static sealing ring 10 to form the other flow path, and when the mechanical seal 1 is attached. Since the seal cover 40 communicates linearly with the fluid supply port 41 in the axial direction, it is easy to align the members with each other.

Further, the rotary sealing ring 20 is axially urged toward the static sealing ring 10 by a coil spring 6 as an urging means. As a result, the rotary sealing ring 20 is pressed against the static sealing ring 10 by the coil spring 6, so that the static sealing ring 10 is prevented from moving in the axial direction, and the fluid supply port 41 of the seal cover 40 and the through hole 14 of the static sealing ring 10 are prevented. The sealed fluid can be supplied more stably with and from. Further, since the load in the axial direction can be applied to the O-ring 11, the sealing property on the back surface side of the static sealing ring 10 can be improved.

Further, the notch 24 of the rotary sealing ring 20 always communicates with a plurality of through holes 14 provided in the static sealing ring 10. That is, since the notch 24 and the through hole 14 are provided between the sealed space X and the external space Y so that the sealed fluid is always supplied, there is a gap between the sealed space X and the external space Y. The sealed fluid can be continuously supplied through the notch 24 and the through hole 14. Therefore, the supply flow rate of the sealed fluid can be stabilized.

Further, by making the one flow path provided in the rotary sealing ring 20 a notch 24, it is easy to process for forming the one flow path in the rotary sealing ring 20, and the cross-sectional area of the flow path of the one flow path is increased. It can be secured to a large extent, and the fluid to be sealed can be efficiently supplied.

Further, by making the one flow path provided in the rotary sealing ring 20 a notch 24, the pressure of the sealed fluid supplied in the notch 24 attempts to axially separate the sliding surfaces 10a and 20a. The influence of the force to do becomes large. Therefore, the load of the coil spring 6 is larger than the pressure difference between the inner diameter side and the outer diameter side of the sliding surfaces 10a and 20a and the pressure of the sealed fluid supplied between the sliding surfaces 10a and 20a. Is set to. As a result, the load of the coil spring 6 reliably prevents the sliding surfaces 10a and 20a from opening in the axial direction due to the supply of the sealed fluid.

Although examples of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these examples, and any changes or additions that do not deviate from the gist of the present invention are included in the present invention. Will be.

For example, in the above embodiment, the mechanical seal 1 has been described as being mainly composed of an annular rotary sealing ring 20 and a static sealing ring 10 as sealing members, but the present invention is not limited to this, and the sealing member of the mechanical seal is not limited to this. As long as it rotates relative to each other, for example, one sealing member may be a rotary sealing ring, and the other sealing member may be composed of an end face of a housing.

Further, in the above embodiment, the mechanical seal 1 has been described as an inside type, but is configured as an outside type that seals the sealed liquid that tends to leak from the inner diameter side to the outer diameter side of the sliding surface. You may. In this case, it goes without saying that the flow path that communicates between the sealed space and the sliding surface is provided so as to open on the inner diameter side of the sliding surface.

Further, in the above embodiment, the embodiment in which the annular notch 24 of the rotary sealing ring 20 always communicates with the through hole 14 of the static sealing ring 10 has been described, but the present invention is not limited to this, and is shown in, for example, Modification 1 of FIG. A notch 24'having a predetermined forming range is provided in the circumferential direction of the sliding surface of the rotary sealing ring 20', and the notch 24' penetrates at least one of the stationary sealing ring 10 depending on the timing of rotation. By matching the phase with the hole 14, the sealed space X and the external space Y may be in a state of intermittent communication. According to this, the sealed fluid can be intermittently supplied while sealing the sealed fluid between the sliding surfaces 10a and 20a'.

Further, in the first modification, as shown in FIG. 5, an example in which a notch 24'as a one-way flow path is formed in the rotary sealing ring 20'has been described, but the modification 2 shown in FIG. 6 has been described. Like the mechanical seal 101, the one-sided flow path formed in the rotary sealing ring 120 may be a through hole 124 having an L-shaped cross section having openings on the sealed space X and the static sealing ring 10 side, respectively.

Further, in the embodiment and the modification, the rotary sealing ring is provided with a one-way flow path for communicating between the sealed space X and the sliding surface, and the static sealing ring is provided with the other flow for communicating between the external space Y and the sliding surface. The mode in which the path is provided has been described, but the present invention is not limited to this, and the statically sealed ring is provided with one flow path for communicating between the sealed space and the sliding surface, and the rotating sealed ring is provided with the other for communicating between the external space and the sliding surface. A flow path may be provided.

Further, the through hole provided in the static sealing ring is not limited to the one penetrating in the axial direction, and may be an L-shaped through hole that opens in the sliding surface and the outer peripheral surface of the static sealing ring, respectively.

Further, the other flow path of the static sealing ring may be a notch.

Further, in the above embodiment, the aspect in which the external space Y is the fluid supply port 41 of the seal cover 40 constituting the housing 4 has been described, but the present invention is not limited to this, and the external space is, for example, a space formed in the housing. It may be an opening such as a pipe extending from a supply destination.

Further, in the above embodiment, as shown in FIG. 4, a mode in which the sealed fluid is supplied from the sealed space X to the outer space Y through the rotary sealing ring 20 and the static sealing ring 10 has been described, but the present invention is limited to this. Instead, for example, the sealed fluid may be supplied from the outer space Y to the sealed space X through the static sealing ring 10 and the rotary sealing ring 20.

Further, the mechanical seal may be applied to various rotating machines such as a compressor and a stirrer. Further, depending on the rotating machine to which the mechanical seal is applied, for example, after supplying the sealed fluid from the sealed space X to the external space Y, the sealed fluid is returned to the original sealed space X again by using a pump or the like. Thereby, it may be configured to circulate the sealed fluid.

Further, in the above embodiment, the embodiment in which one set of mechanical seals is used has been described, but the present invention is not limited to this, and two or more sets of mechanical seals may be used depending on the rotating machine to be applied, for example, the sealed space may be used. When two or more places are formed in the axial direction, two or more sets of mechanical seals may be provided in the axial direction.

Further, when two or more sealed spaces are formed in the radial direction, two or more sets of mechanical seals may be provided in the radial direction. In this case, the static sealing ring may be composed of one member.

Further, in the above embodiment, the rotary sealing ring 20 has been described as being urged in the axial direction by the urging force of the coil spring 6, but the present invention is not limited to this, and the urging force is applied by the bellows as the urging means. It may be a thing.

Further, in the above embodiment, the static sealing ring 10 has been described as being fixed in a non-rotating state, but the present invention is not limited to this, and if the sealing member rotates relative to each other, both sealing members have different rotation speeds. It may be a rotating one.

1 Mechanical seal 2 Rotating shaft 3 Sleeve 4 Housing 6 Coil spring (urging means)
10 Static sealing ring (the other sealing member)
10a Sliding surface 10e Land portion 11 O-ring 14 Through hole (other flow path)
14e Exterior space side opening 14f Sliding surface side opening 15 Through hole 20 Rotating sealing ring (one sealing member)
20a Sliding surface 20e Land portion 21 Retainer 24 Notch (one flow path)
24e Sealed space side opening 24f Sliding surface side opening 40 Seal cover 41 Fluid supply port (external space of sealing member)
101 Mechanical seal 120 Rotating sealing ring (one sealing member)
124 Through hole (one flow path)
X Sealed space Y External space S Sealed part

Claims (6)

In a mechanical seal that seals the fluid to be sealed by forming a sealing portion connected in the circumferential direction between the sliding surfaces of a pair of sealing members with relative rotation.
On the other hand, the sealing member is provided with a one-way flow path that communicates between the sealed space in which the sealed fluid on either the inner diameter side or the outer diameter side of the sliding surface exists and the sliding surface.
The other sealing member is a mechanical seal provided with the other flow path that communicates between the external space of the sealing member and the sliding surface. The mechanical seal according to claim 1, wherein the other sealing member is a static sealing ring. The mechanical seal according to claim 1 or 2, wherein the sealed fluid is pressurized by a pressurizing means. On the other hand, the sealing member is a rotary sealing ring.
The mechanical seal according to any one of claims 1 to 3, wherein the rotary sealing ring is urged toward the stationary sealing ring by an urging means. The mechanical seal according to any one of claims 1 to 4, wherein both flow paths are provided so that the sealed fluid is always supplied between the sealed space and the external space. The mechanical seal according to any one of claims 1 to 5, wherein the one-way flow path is a notch.

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