JP7200826B2 - Air seal member and air seal method - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act From November 28th to 30th, 2018, at the exhibition "International Powder Industry Exhibition Tokyo 2018" at Tokyo Big Sight, we demonstrated the sealing performance of air sealing materials and air sealing methods. From November 28th to 30th, 2018, at the exhibition "International Powder Industry Exhibition Tokyo 2018" at Tokyo Big Sight, about the evaluation test of the sealing performance related to the air sealing member and the air sealing method Distributing pamphlets

TECHNICAL FIELD The present invention relates to an air sealing member and an air sealing method, and more specifically to a technique for sealing a surface of a member to be sealed using gas.

2. Description of the Related Art Conventionally, in pulverizers and stirrers, a seal member is used to seal a rotating shaft in order to prevent powder from entering a bearing portion from around the rotating shaft. As such a seal member, an oil seal used in contact with a rotating shaft is known (see, for example, Patent Document 1). Also, an air seal that uses gas such as air without contacting the rotating shaft is known (see Patent Document 2, for example).

JP 2015-62463 A JP 2012-189211 A

As in the technique described in Patent Document 1, according to the structure in which the rotating shaft, which is the member to be sealed, and the sealing member are in contact with each other, wear of the sealing member generates wear powder, and the wear powder seizes the rotating shaft. Also, problems such as contamination of abrasion powder into the interior of the crusher have occurred.

Further, according to the technique described in Patent Document 2, since the configuration is such that pressurized air is discharged to both sides in the axial direction, an air flow is generated in the direction opposite to the direction in which the seal is required. For this reason, only a part of the gas used for air sealing exhibits a sealing function, and there has been a demand for an improvement in sealing performance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. To provide an air sealing member and an air sealing method capable of improving sealing performance by gas by suppressing an air flow in the opposite direction.

In order to solve the above problems, the present invention has constructed the following air seal member.

(1) A body having a first surface and a second surface, the first surface having an air supply hole through which gas is injected, and the second surface having a An exhaust hole is opened to communicate with the air supply hole and eject the gas injected from the air supply hole, and the exhaust hole is formed in a gap formed between the surface to be sealed of the member to be sealed and the second surface. The air seal member seals the gap by ejecting gas from the air seal member, and a narrowed portion is formed in a flow path extending from the air supply hole to the exhaust hole to reduce the flow path cross-sectional area of the gas. , the air supply hole, the narrowed portion, and the exhaust hole are formed so that their centers are arranged on the same axis, and the air supply hole, the narrowed portion, and the exhaust hole extend along the surface to be sealed. an air seal member that inclines in one of the above directions to eject gas in the one direction.

(2) The air seal member according to (1), wherein the length of the exhaust hole is formed to be shorter than the length of the narrowed portion in the gas flow path direction.

(3) The air seal member according to (1) or (2), wherein a plurality of sets of corresponding exhaust holes and air supply holes are formed, and at least two of the air supply holes communicate with each other.

(4) The member to be sealed is a shaft member, the body portion is formed in a cylindrical shape surrounding the radially outer side of the shaft member, and the one direction is one of the axial directions of the shaft member, ( The air seal member according to any one of 1) to (3).

(5) The air seal member according to any one of (1) to (4), wherein the gap is formed to be 0.2 mm or more and 1.0 mm or less.

Moreover, the present invention has configured the following air sealing method in order to solve the aforementioned problems.

(6) A main body having a first surface and a second surface, the first surface having an air supply hole through which gas is injected, and the second surface having a An air seal member having an exhaust hole that communicates with the air supply hole and ejects the gas injected from the air supply hole, and a gap formed between the surface to be sealed of the member to be sealed and the second surface. (2) an air sealing method for sealing the gap by ejecting gas from the exhaust hole, wherein a flow path extending from the air supply hole to the exhaust hole is provided with a throttle for reducing a flow path cross-sectional area of the gas; The air supply hole, the narrowed portion, and the exhaust hole are formed so that their centers are arranged on the same axis, and the air supply hole, the narrowed portion, and the exhaust hole are covered with the cover. An air sealing method in which gas is ejected in one direction by inclining in one of the directions along the sealing surface.

(7) The air sealing method according to (6), wherein the gap is 0.2 mm or more and 1.0 mm or less.

(8) The air sealing method according to (6) or (7), wherein the gas is air.

(9) The air sealing method according to any one of (6) to (8), wherein the flow velocity of the gas passing through the exhaust holes is 40 m/sec or more.

According to the air sealing member and the air sealing method according to the present invention, the generation of abrasion powder is prevented by non-contact sealing with respect to the member to be sealed, and the air flow in the direction opposite to the sealing direction is suppressed. By doing so, it is possible to improve the gas sealing performance.

The perspective view which showed the air-seal member which concerns on this embodiment. (a) is a cross-sectional view showing an air seal member, and (b) is an enlarged view of an exhaust hole portion in FIG. 2(a). The perspective view which showed the analysis model of an Example. The side view which showed the analysis model of an Example. FIG. 10 is a perspective view showing analysis results of an example; The top view which showed the analysis result of an Example. The side view which showed the analysis model of a comparative example. The perspective view which showed the analysis result of the comparative example. The top view which showed the analysis result of a comparative example. Sectional drawing which showed the method of a seal performance evaluation test.

First, a schematic configuration of an air seal member 1 according to the present invention will be described with reference to FIGS. 1 and 2. FIG. As shown in FIGS. 1 and 2, the air seal member 1 according to the present embodiment is a short cylindrical member made of resin. Although it is possible to use other materials such as metals such as aluminum and stainless steel as the air seal member 1, resin is most suitable from the viewpoint of rust prevention and seizure prevention.

Resins employed as materials for the air seal member 1 include polyphenylene sulfide (PPS), polyetherimide (PEI), polyetheretherketone (PEEK), polyimide (PI), polyacetal (POM), polyamide (PA) and Phenol resin, polypropylene, polyethylene, and the like can be used, but PPS is most suitable because of its excellent processing precision in cutting.

As shown in FIGS. 1 and 2, the air seal member 1 has a cylindrical body portion 2 . The body portion 2 has an outer peripheral surface 2a as a first surface and an inner peripheral surface 2b as a second surface. At both axial end portions of the main body portion 2, flange portions 3, 3 projecting in the outer diameter direction are formed.

The air seal member 1 is formed with eight flow paths 10, 10, . Specifically, an air supply hole 11 into which gas is injected from an external air supply device is opened in the outer peripheral surface 2a. Further, an exhaust hole 12 is formed in the inner peripheral surface 2b to communicate with the air supply hole 11 inside the main body 2 and through which the gas injected from the air supply hole 11 is ejected.

On the outer peripheral surface 2a, between the flange portions 3, 3 is configured as a communication passage 4 that communicates with the air supply holes 11, 11, . . . . This communication path 4 allows a plurality of air supply holes 11 and exhaust holes 12 to be provided even when there is only one air supply device and only one gas supply destination. As a result, the air flowing through the gap C can be evenly and uniformly distributed, and a uniform sealing effect can be obtained. Further, it is possible to share a supply route for supplying gas to the air supply holes 11, 11, . . . . It should be noted that it is also possible to form the communicating passage 4 inside the main body portion 2 . Moreover, the communication path 4 may be configured to communicate with at least two air supply holes 11 .

In the air seal member 1 according to this embodiment, the channel 10 extending from the air supply hole 11 to the exhaust hole 12 is formed with a constricted portion 13 that reduces the cross-sectional area of the gas channel. That is, as shown in FIG. 2B, the flow path 10 is composed of an air supply hole 11, a constricted portion 13, and an exhaust hole 12, and the exhaust hole 12 is narrower than the air supply hole 11 (flow path cross-sectional area is small).

A shaft member A, which is a member to be sealed in this embodiment, is inserted through the inside of the air seal member 1 . In this embodiment, the outer surface Pa of the shaft member A is used as the surface to be sealed. In this embodiment, as shown in FIG. 2(b), a gap C is formed between the outer surface Pa of the shaft member A and the inner peripheral surface 2b of the air seal member 1. As shown in FIG. In the air seal member 1 , the gap C is sealed by blowing gas into the gap C from the exhaust holes 12 .

In the air seal member 1 according to this embodiment, as shown in FIG. (one direction) (toward the sealing direction as it approaches the inner peripheral surface 2b). As a result, the gas is ejected from the exhaust hole 12 in the sealing direction (see FIG. 5).

Next, a CAE (computer aided engineering) analysis conducted by the applicant of the present application on the sealing method of the air seal member 1 will be described with reference to FIGS. 3 to 6. FIG. The analysis described in this specification was performed using “LS-DYNA (registered trademark)”, which is CAE software manufactured by Livermore Software Technology Corporation (a US company).

For this analysis, the applicant prepared an analysis model Me in which the gas flow path formed by the air seal member 1 was divided into eight parts in the radial direction, as shown in FIGS. Specifically, the analysis model Me models the flow path 10 formed in the air seal member 1 and the gap C between the air seal member 1 and the shaft member A.

In the analysis model Me, a channel model 10m that models the channel 10 of the air seal member 1 is constructed. As shown in FIG. 4, the flow path model 10m is composed of an air supply hole model 11m, a throttle part model 13m, and an exhaust hole model 12m corresponding to the air supply hole 11, the throttle part 13, and the exhaust hole 12, respectively.

Since the analytical model Me is obtained by dividing the air seal member 1 and the shaft member A into eight, the symmetrical boundary planes P1 to P5 shown in FIG. A sliding wall boundary condition with Also, the outflow ports E1 to E4 shown in FIG. 3 are open boundary surfaces. Especially in this embodiment, the side on which the outlets E1 and E2 are formed in the sealing direction is the first outlet, and the side on which the outlets E3 and E4 are formed in the opposite direction is the second outlet. The other surface was the surface of the air seal member 1 or the shaft member A, and a solid wall boundary condition was applied in which the flow velocity at the boundary surface was zero.

In the analysis model Me of this analysis, the radius of the shaft member A (φ/2 shown in FIG. 3) was set to 42 mm. Moreover, the inner diameter of the air seal member 1 was set to 85 mm. That is, the gap C between the inner peripheral surface 2b of the air seal member 1 and the outer surface Pa of the shaft member A was set to 0.5 mm. The axial length L of the air seal member 1 was set to 42 mm.

Air having a mass density of 1.18415 kg/m ³ and a viscosity coefficient of 1.85508×10 ⁻⁵ Pa·sec was used as the gas. Air under these conditions is introduced from the inlet E0 at a rate of 0.625 L/min as indicated by the arrow Ai in FIG. Analyzed. The diameter of the exhaust hole model 12m was set to 0.5 mm so that the flow velocity of the circulating gas was 50 m/sec.

FIG. 5 shows the streamline Af, which is the path along which the gas discharged from the exhaust hole model 12m flows after hitting the discharge portion As on the outer surface Pa of the shaft member A. FIG. As shown in FIGS. 5 and 6, according to the analysis model Me in this analysis, the streamline Af spirally rotates around the discharge portion As as indicated by the arrow R, and then flows toward the first outlets E1 and E2. formed only in the sealing direction.

Next, CAE analysis performed by the applicant for comparison with the sealing method in the air seal member 1 will be described with reference to FIGS. 7 to 9. FIG. For this analysis, the applicant created a comparative model Mc in which the gas flow path formed by the air seal member according to the comparative example was divided into eight in the radial direction, as shown in FIG. Specifically, the comparative model Mc reproduces the flow path formed in the air seal member and the gap C between the air seal member and the shaft member A according to the comparative example.

The comparison model Mc is obtained by dividing the air seal member and the shaft member A into eight parts in the same manner as the analysis model Me, and includes boundary conditions such as symmetrical boundary surfaces P11, P13j, and P15, outlets E11, E12, E13, and E14, and Other analysis conditions were configured similarly to the analysis model Me.

In the comparative model Mc, a channel model 110m that reproduces the channel of the air seal member was configured. As shown in FIG. 7, the channel model 110m is formed of channels with a constant diameter.

8 and 9 show a streamline Af, which is a path along which the gas discharged from the flow path model 110m flows after hitting the discharge portion As on the outer surface Pa of the shaft member A. FIG. As shown in FIGS. 8 and 9, according to the comparison model Mc in this analysis, the streamline Af is in the sealing direction on the side of the first outlets E11 and E12 and in the opposite direction on the side of the second outlets E13 and E14. and was formed. Note that the streamline Af displayed so as to surround the discharge portion As in FIG. 9 is not formed in the gap C, but is the gas flow (air flow) before entering the flow path model 110m as shown in FIG. Gas flow on the outside of the seal member).

As described above, in the comparative model Mc, the gas flowed through both the first outflow ports E11 and E12 and the second outflow ports E13 and E14. , the gas could flow only in the sealing direction, which is the side of the first outflow ports E1 and E2. This is because in the present embodiment, the cross-sectional area of the flow passage is reduced by the constricted portion 13, thereby increasing the flow velocity of the gas. That is, by reducing the cross-sectional area of the flow path, the gas is exhausted at a high flow velocity of 50 m/sec. Since the exhaust hole 12 is inclined in the direction along the outer side surface Pa, which is the surface to be sealed, an airflow is generated in the sealing direction. When an airflow in the sealing direction is generated at a high flow velocity, the airflow in the direction opposite to the sealing direction becomes low pressure, is caught in the airflow in the sealing direction, and is sucked up in the sealing direction. This suppresses the generation of air currents in the opposite direction.

That is, in the air seal member 1, the exhaust hole 12 is provided so as to be inclined toward the sealing direction, and the narrowed portion 13 is formed to reduce the flow passage cross-sectional area of the flow passage 10. As shown in FIG. As a result, the flow velocity of the gas discharged from the exhaust hole 12 can be increased, so that the gas can be jetted in the sealing direction. Therefore, in the analytical model Me, the gas could flow only in the sealing direction. In this way, from the viewpoint of increasing the flow velocity of the gas discharged from the exhaust hole 12, it is preferable to set the diameter of the exhaust hole 12 so that the flow velocity of the flowing gas is 40 m/sec or more.

Moreover, from the viewpoint of maintaining the flow velocity of the gas flowing through the exhaust hole 12 to some extent, it is preferable to set the gap C between the outer surface Pa and the inner peripheral surface 2b to 0.2 mm or more. Furthermore, from the viewpoint of enhancing the sealing performance of the air seal member 1, it is preferable to set the gap C to 1.0 mm or less. The narrowed portion 13 is for reducing the flow passage cross-sectional area of the flow passage 10, and does not necessarily have to be inclined with respect to the surface to be sealed as in the present embodiment. may be perpendicular to

Thus, according to the air seal member 1 according to the present embodiment and the air seal method using the air seal member 1, it is possible to suppress the airflow in the direction opposite to the sealing direction. Specifically, the gas at a high flow rate from the exhaust hole 12 flows into the gap C while maintaining the velocity to some extent, the static pressure around the exhaust hole 12 decreases, and the gas enters from the second outlets E13 and E14. As a result, as shown in FIGS. 5 and 6, the gas flow line Af rotates in a vortex and allows the gas to flow only in the sealing direction. That is, since the gas used for air sealing and the gas entering from the second outflow ports E13 and E14 can exhibit a sealing function, the sealing performance of the air seal member 1 can be improved.

In addition, according to the air seal member 1 according to the present embodiment, the air seal member 1 does not come into contact with the shaft member A because the gas is used for sealing. Therefore, the air seal member 1 does not wear out, and problems such as seizure of the shaft member A due to abrasion powder and contamination of the abrasion powder into the interior of the crusher do not occur. In this way, in the air seal member 1, by performing non-contact sealing with respect to the shaft member A, it is possible to prevent the generation of abrasion powder and improve the gas sealing performance.

In this embodiment, the air seal member 1 has a cylindrical shape, but the shape of the air seal member 1 is not limited to the shape of this embodiment. 13 and exhaust holes 12 can be used as long as the shape can form the flow path 10 .

Further, in the present embodiment, the flow path 10 is formed by processing the air seal member 1 after forming it into a cylindrical shape, but the flow path 10 can also be configured in another configuration. For example, it is possible to divide the air seal member 1 into a plurality of members having grooves, and form the grooves as the flow paths 10 when these members are assembled.

In addition, the gas used in this embodiment can be pressurized air, pressurized nitrogen gas, carbon dioxide gas, or the like, as long as it is a fluid and can produce a high pressure. In particular, it is preferable to employ pressurized air for the reasons that it has an appropriate kinematic viscosity, is excellent in cost, and can be used as a compressor for factory ancillary equipment.

Also, the inclination angle of the exhaust hole 12 (the angle formed with the inner peripheral surface 2b) can be set within the range of 0 to less than 90 degrees. The closer the inclination of the exhaust hole 12 is parallel to the axial direction (the closer it is to 0), the more gas can be ejected in the sealing direction.

Moreover, in the air seal member 1, it is preferable to form the length of the exhaust hole 12 shorter than the length of the narrowed portion 13 in the gas flow path direction. As a result, it is possible to reduce the energy loss due to the viscous resistance by shortening the portion where the gas flow speed is high.

Further, in the present embodiment, the shaft member A is the member to be sealed, which is the symmetry of sealing by the air seal member 1 . That is, the body portion 2 is formed in a cylindrical shape surrounding the radially outer side of the shaft member A, and one of the axial directions of the shaft member A is configured as the sealing direction. Specifically, the flow paths 10 are formed side by side in the circumferential direction of the air seal member 1, and the exhaust holes 12 are formed so as to be inclined in the axial direction of the shaft member A. As shown in FIG. Thereby, the air seal member 1 can be used as a seal member for the shaft member A.

Since the air seal member 1 according to this embodiment does not use lubricating oil such as grease, it can be applied to manufacturing equipment for foods and pharmaceuticals. In particular, since the air seal member 1 can be applied to the shaft member A as described above, it is suitable as a seal member for rotating shafts of grinders and stirrers.

Next, with reference to FIG. 10, a sealing performance evaluation test performed on the air seal member 1 according to the present embodiment will be described. As shown in FIG. 10, in this test, a cylindrical shaft member A (made of stainless steel) was inserted inside the air seal member 1, and a powder case 21 and a lid member 22 were arranged above the air seal member 1. do. A powder receiving member 23 is arranged below the shaft member A and the air seal member 1 .

Then, powder Pt, which is an object to be sealed, is placed inside the powder case 21, and the shaft member A is rotated as shown by the arrow Ra in a state in which gas is injected into the flow path 10 of the air seal member 1 as shown by the arrow F. , whether or not the powder Pt can be sealed (whether the powder Pt can be prevented from falling into the powder receiver 23) was evaluated.

In this test, granulated sugar with an average particle size of 0.25 mm was used as powder Pt. Further, the gap between the outer peripheral surface of the shaft member A and the inner peripheral surface of the air seal member 1 was set to 0.3 mm. In addition, the gas supply pressure to the flow path 10 was set to 0.02 MPa, and the flow rate was set to 10 L/min. Further, the shaft member A was rotated at 100 rpm by a rotation driving mechanism such as a motor (not shown) to perform the test.

In this test, the powder Pt did not drop inside the powder receiving member 23 even after 24 hours under the temperature condition of 23.5 degrees. That is, it was confirmed that the air seal member 1 did not cause seal leakage even after 24 hours had passed under the present test conditions.

1 air seal member 2 main body
2a outer peripheral surface (first surface) 2b inner peripheral surface (second surface)
3 flange portion 4 communication passage
10 channel 10 m channel model
11 air supply hole 11m air supply hole model
12 exhaust hole 12m exhaust hole model
13 Squeezed part 13m Squeezed part model
21 powder case 22 lid member
23 powder receiving member Pt powder
110m channel model A shaft member
Af Streamline Ai Arrow
Ao Arrow As Discharge part
C Clearance E0 Inlet
E1 First outlet E2 First outlet
E3 second outlet E4 second outlet
E11 first outlet E12 first outlet
E13 second outlet E14 second outlet
Me Analysis model Mc Comparison model
L Member length Pa Outer surface
P Symmetrical Boundary R Arrow
F Air flow direction Ra Rotation direction

Claims (9)

having a body portion with a first surface and a second surface;
The first surface has an air supply hole through which gas is injected,
The second surface has an exhaust hole that communicates with the air supply hole inside the main body and ejects the gas injected from the air supply hole,
An air seal member that seals the gap formed between the surface to be sealed and the second surface of the member to be sealed by ejecting gas from the exhaust hole into the gap,
A narrowed portion that reduces the cross-sectional area of the gas flow path is formed in the flow path from the air supply hole to the exhaust hole,
The air supply hole, the narrowed portion, and the exhaust hole are formed so that their centers are arranged on the same axis,
An air sealing member, wherein gas is jetted in one direction by tilting the air supply hole, the narrowed portion, and the exhaust hole in one direction out of directions along the surface to be sealed. 2. The air seal member according to claim 1, wherein a length of said exhaust hole is shorter than a length of said constricted portion in a gas flow path direction. A plurality of sets of the corresponding exhaust holes and the air supply holes are formed,
3. The air seal member according to claim 1, wherein at least two of said air supply holes communicate with each other. The member to be sealed is a shaft member,
The body portion is formed in a tubular shape surrounding the radially outer side of the shaft member,
The air seal member according to any one of claims 1 to 3, wherein the one direction is one of the axial directions of the shaft member. 5. The air seal member according to any one of claims 1 to 4, wherein said gap is formed to be 0.2 mm or more and 1.0 mm or less. A main body having a first surface and a second surface, the first surface having an air supply hole through which gas is injected, and the second surface having the air supply hole inside the main body. An air seal member having an exhaust hole through which gas injected from the air supply hole is ejected is opened, and the gap formed between the sealed surface and the second surface of the member to be sealed is filled with the An air sealing method for sealing the gap by ejecting gas from an exhaust hole,
A narrowed portion that reduces the cross-sectional area of the gas flow path is formed in the flow path from the air supply hole to the exhaust hole,
The air supply hole, the narrowed portion, and the exhaust hole are formed so that their centers are arranged on the same axis,
An air sealing method, wherein the gas is ejected in one direction by inclining the air supply hole, the narrowed portion, and the exhaust hole in one of directions along the surface to be sealed. 7. The air sealing method according to claim 6, wherein said gap is 0.2 mm or more and 1.0 mm or less. The air sealing method according to claim 6 or 7, wherein the gas is air. The air sealing method according to any one of claims 6 to 8, wherein the flow velocity of said gas passing through said exhaust hole is 40 m/sec or more.

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