JP6424116B2 - Seal structure - Google Patents

Description

  The present invention relates to a seal structure.

Conventionally, for example, in a refrigerant compressor, a rotary shaft seal for sealing a refrigerant such as chlorofluorocarbon and a fluid such as refrigerating machine oil is shown in FIG.
This rotary shaft seal is interposed between the casing (housing) 40 and the rotary shaft 41 of the refrigerant compressor, and allows the fluid (refrigerant and refrigerating machine oil) stored in the fluid storage chamber 42 side to flow to the low pressure side 43. A seal unit body is provided in which a rubber member 45 having a seal lip portion 44 that is in sliding contact with the rotating shaft 41 is integrated with a metal outer case 46. Inside the seal unit body, a seal element 47 made of fluorine resin or the like and a metal inner case 48 are assembled by holding and fixing by crimping (bending) the low pressure side end of the outer case 46 (Patent Literature). 1).

JP 2004-332866 A

In the rotary shaft seal as shown in FIGS. 7 and 8, the sealing fluid corresponding surface 46 a of the inner flange portion of the outer case 46 is covered with the axial center orthogonal wall portion 49 of the rubber member 45. In addition, a plurality of recesses 50 are formed. The recess 50 is a trace of a metal fitting holding small protrusion (not shown) that holds the outer case 46 when the rubber member 45 is press-molded or injection-molded in the molding die. At the bottom of such a conventional recess 50, a thin bottom wall rubber portion 50A having a constant thickness T remains.
Then, the refrigerant easily diffuses and penetrates into the rubber, and the refrigerant that has penetrated into the rubber member 45 expands with a rapid temperature rise or pressure fluctuation, thereby generating a crack Y as shown by a broken line in FIG. Such a phenomenon called a blister causes a crack Y in the rubber. In FIG. 8, the refrigerant that has permeated the adhesion interface between the sealing fluid corresponding surface 46 a of the inner flange portion of the outer case 46 and the axially orthogonal wall portion 49 of the rubber member 45 suddenly expands and is indicated by two broken lines. Cracks Y and Y are generated, and accordingly, the elastic pressure contact force of the seal lip portion 44 (shown in FIGS. 7 and 8) with respect to the rotating shaft 41 becomes uneven in the circumferential direction, and its posture in the circumferential direction Becomes uneven and unstable. Accordingly, the sealing performance is suddenly lowered.

  Therefore, an object of the present invention is to provide a seal structure that suppresses the occurrence of such blisters with a simple shape and configuration.

A seal structure according to the present invention includes a seal unit body in which a rubber portion having a seal lip portion is integrated with a metal fitting having at least a circumferential surface portion and an axial center orthogonal surface portion, and includes a rotary shaft seal for a refrigerant compressor. In the seal structure used for sealing the refrigerant , a plurality of through holes are formed around the axial center orthogonal wall portion of the rubber portion covering the sealing refrigerant corresponding surface of the axial center orthogonal surface portion of the metal fitting. Further, in the inner part of the through hole, the metal surface of the metal fitting corresponding to the sealed refrigerant is exposed, and the seal lip part is exposed from the inner diameter end side of the axial center orthogonal wall part. The radial length from the inner peripheral edge of each of the through holes to the outer peripheral edge of the seal lip portion is set to a minute dimension of 0.5 mm to 1.5 mm. expansion gas refrigerant generated inside the rubber portion from One in which was formed so as to release.

Also, the total area of the plurality of the through-hole is, radial width is one that is set at 5% to 80% of the area of the annular zone area equal to the through-hole.

  According to the seal structure of the present invention, it is possible to escape the expanded bubbles (generated in the rubber) to the outside at the base of the seal lip portion with a simple shape and configuration, and to suppress blisters. Therefore, the sealing lip portion can be kept in sliding contact with the rotating shaft in a stable posture while maintaining a perfect circle, and the sealing performance can be maintained.

It is the cross-sectional side view which showed one Embodiment of this invention. It is a principal part expanded sectional side view explaining the effect | action of this invention. It is a front view of a seal structure (rotating shaft seal). It is a front view of another seal structure (rotary shaft seal). It is a front view of another seal structure (rotary shaft seal). It is a front view of another seal structure (rotary shaft seal). It is a cross-sectional side view which shows the conventional rotating shaft seal. It is a principal part expanded sectional side view explaining the conventional problem.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
As shown in FIG. 1, the sealing structure of the present invention is intended to be used as a rotation shaft seal for refrigerant compressors, interposed between the refrigerant compressor casing (housing) 10 and the rotary shaft 11 Then, a refrigerant (low boiling point fluid) such as chlorofluorocarbon gas on the fluid (refrigerant) storage chamber 12 side is sealed.

  In the seal structure of the present invention, a rubber part 5 having a seal lip part 6 and a cylindrical metal fitting (outer case) 4 are integrated, and the seal unit body is formed by the rubber part 5 and the metal fitting (outer case) 4. 1 is configured. Inside the seal unit body 1, a fluororesin seal element 14 and a metal inner case 15 are disposed, and the seal element 14 and the inner case 15 are caulked at the low pressure side end of the metal fitting (outer case) 4. It is held and fixed by (bending) processing.

Bracket (outer case) 4, in a state assembled to the rotary shaft 11, the circumferential surface portion 2 disposed in the axial center L ₀ and the same axis shape of the rotation shaft 11, the axis L ₀ of the rotary shaft 11 And an axial center orthogonal surface portion (inner collar portion) 3 formed by bending the end portion on the fluid storage chamber 12 side of the circumferential surface portion 2 along a surface orthogonal to the surface.
A stepped portion 19 and a concave circumferential groove 18 are formed on the inner peripheral surface of the hole portion of the casing (housing) 10 of the refrigerant compressor, and the axial center orthogonal surface portion (inner collar portion) 3 is a part of the rubber portion 5 (axial center). The seal structure (rotary shaft seal) is connected to the low pressure side 13 by a retaining ring 20 that faces the stepped portion 19 through the orthogonal wall portion 7) and is fitted in the concave circumferential groove 18. It is installed to prevent movement to

The rubber portion 5 includes a U-shaped covering portion 17 that covers the axial center orthogonal surface portion 3 of the metal fitting 4, a seal lip portion 6 that extends toward the fluid storage chamber 12 and comes into sliding contact with the rotating shaft 11, and An outer peripheral covering portion 21 that covers the outer peripheral surface of the circumferential surface portion 2 of the metal fitting 4 is provided.
The U-shaped covering portion 17 covers the sealing fluid corresponding surface 3 a of the axial center orthogonal surface portion 3 (on the side of the refrigerant storage chamber 12) and the low pressure side 13 that covers the inner surface of the axial center orthogonal surface portion 3. And the connecting wall portion 16 for connecting the axial center orthogonal wall portion 7 and the covering wall portion 9 on the inner diameter side. The seal lip portion 6 is connected to the refrigerant storage chamber 12 from the inner diameter side of the axial center orthogonal wall portion 7 to the connecting wall portion 16.
It is formed by stretching. The axial center orthogonal wall portion 7 is connected to the outer peripheral covering portion 21 on the outer diameter side. A plurality of outer peripheral ridges 22 are formed on the outer peripheral covering portion 21, and the fluid storage chamber 12 and the low pressure side 13 are sealed outside the circumferential surface portion 2.

As shown in FIGS. 1 and 3, a plurality of through holes 8 are formed in the axial center orthogonal wall portion 7 of the rubber portion 5.
The rubber thickness of the axial center orthogonal wall portion 7 in the through hole 8 is 0 (zero), and the seal fluid corresponding surface 3a of the axial center orthogonal surface portion 3 of the metal fitting 4 is exposed in the inner part of the through hole 8. ing. As shown in FIG. 3, when viewed from the axial direction, the through-holes 8 are formed in a rectangular shape, and are regularly arranged at equal pitches in the circumferential direction.
The rubber portion 5 is formed by press molding or injection molding in a molding die, and is bonded and integrated with the metal fitting (outer case) 4 by vulcanization baking. At the time of press molding of the rubber part 5 or the like, in order to correct the position of the metal fitting 4, a plurality of places on the metal fitting 4 are pressed by the metal fitting holding pin (protrusion) in the mold. A plurality of through holes 8 are formed in the axial center orthogonal wall portion 7 of the rubber portion 5 by the traces.
As described above, the configuration in which the sealed refrigerant corresponding surface 3a (the metal surface thereof) is “exposed” at the back of the through hole 8 is a feature of the present invention. Is not limited to the case where the rubber thickness is 0 (zero) and the bottom wall rubber portion is not present at all, and even if the primary treatment film (varnish film or the like) is attached to the metal surface, or , Even if an ultrathin rubber film having a thickness of less than 10 μm remains, it is defined as being included in the concept.
Therefore, as described above, “a plurality of through-holes 8 are arranged in the circumferential direction in the axial orthogonal wall portion 7 of the rubber portion 5 covering the sealing fluid corresponding surface 3 a of the axial orthogonal surface portion 3 of the metal fitting 4. The configuration “provided” means that a plurality of metal exposed portions F are arranged in the circumferential direction on the axially orthogonal wall portion 7 of the rubber portion 5 that covers the sealed fluid corresponding surface 3a of the axially orthogonal surface portion 3 of the metal fitting 4. In other words. In both press molding and injection molding, the protrusion dimension of the metal fitting restraining pin (protrusion) in the mold that forms the rubber part 5 is set slightly longer than the conventional protrusion dimension, and is orthogonal to the axis. This can be easily implemented simply by press molding / injection molding while strongly pressing the sealing fluid corresponding surface 3a of the surface portion 3 with the tip surface of the pin (projection). The through-hole 8 may be formed by other means such as cutting / cutting.

The use method (action) of the above-described seal structure of the present invention will be described.
As shown in FIG. 1, the sealing structure of the present invention is mounted between the rotary shaft 11 and the casing 10, such as a refrigerant compressor, the sealing lip 6 of the rubber portion 5 is in sliding contact with the rotary shaft 11, the refrigerant The low-boiling point fluid (refrigerant) is sealed from the storage chamber 12 to the low-pressure side 13 so as not to leak. In the refrigerant storage chamber 12, the pressure is increased or decreased while maintaining a pressure higher than that of the low pressure side 13, and the low boiling point fluid (refrigerant) stored in the refrigerant storage chamber 12 penetrates into the rubber part 5. .

As shown in FIG. 2, when there is a rapid temperature rise or when the refrigerant storage chamber 12 side is suddenly depressurized, it penetrates into the inside of the rubber part 5 and the shaft orthogonally intersecting surface part 3 of the metal fitting 4 and the shaft of the rubber part 5. The low boiling point fluid (refrigerant) accumulated at the adhesion interface with the orthogonal heart wall 7 expands rapidly due to the temperature rise and pressure fluctuation, and an expanded bubble g is generated. When the expansion bubble g tries to expand further, the refrigerant (expansion bubble g) quickly escapes to the through hole 8 and is discharged from the through hole 8 to the outside ( refrigerant storage chamber 12), as indicated by an arrow. That is, the occurrence of cracks (occurrence of blisters) inside the axially orthogonal wall part 7 of the rubber part 5 is suppressed, and the occurrence of blisters at the base end part (root) of the seal lip part 6 is prevented.

2 and 3, the radial length L from the inner peripheral edge 8a of the through hole 8 to the outer peripheral edge 6a of the seal lip 6 is set to 0.5 mm to 1.5 mm. .
If the length dimension L is less than 0.5 mm, the rigidity of the rubber part 5 that holds the posture of the seal lip part 6 may be insufficient. If the length dimension L exceeds 1.5 mm, the rubber part 5 It is difficult for the expansion bubble g generated inside the through hole 8 to escape.

Further, the total area S ₁ of the plurality of through holes 8 is set to 5% to 80% of the area S ₀ of the annular band region 39 in which the radial width dimension W ₀ is equal to the through holes 8. Preferably, it is 10% to 80%, and more desirably 20% to 75%.
When the total area S ₁ of the through-hole 8 to the area S ₀ of the annular band region 39 is less than the lower limit value, there is a possibility that can not suppress the occurrence of blisters in the interior of the rubber section 5, if the upper limit value, When the rubber part 5 is press-molded or injection-molded, the fluidity of the rubber material is deteriorated and molding becomes difficult.

  The present invention can be modified in design, and for example, as shown in FIG. 4, the through holes 8 may be formed in a parallelogram. Moreover, the through-hole 8 may be trapezoidal as shown in FIG. 5, or the through-hole 8 may be formed in an oval shape as shown in FIG. Further, the shape of the seal lip portion 6 is not limited to a bent piece shape (“height” shape) as in the illustrated embodiment, and may have a shape having a plurality of ridges that are in sliding contact with the rotating shaft 11. Alternatively, it is also possible (as a configuration in which the seal element 14 is omitted) to have a shape having a rubber expansion head having various cross-sectional shapes at the radial inner end edge of the axial center orthogonal surface portion 3 of the metal fitting 4 (not shown). . Further, the seal structure is preferably a structure without the seal element 14 or the inner case 15 (not shown).

As described above, the seal structure according to the present invention is a seal unit body in which the rubber portion 5 having the seal lip portion 6 is integrated with the metal fitting 4 having at least the circumferential surface portion 2 and the axial center orthogonal surface portion 3. 1, a plurality of through-holes 8 are arranged in the circumferential direction in the axial center orthogonal wall portion 7 of the rubber portion 5 covering the sealing fluid corresponding surface 3 a of the axial center orthogonal surface portion 3 of the metal fitting 4. Since the expansion bubble g of the refrigerant generated inside the rubber part 5 is escaped from the through hole 8, the crack Y (see FIG. 8) from the inside of the rubber part 5 can be prevented. Thereby, the attitude | position of the seal lip | rip part 6 can be stably hold | maintained at a perfect circle, and the leak of a fluid can be prevented over a long period of time. In addition, in the manufacturing process, it can be implemented at low cost by a slight change / adjustment of the pin (protrusion) or the like and a slight increase in the pressing force.

  In addition, since it is used as a rotary shaft seal for a refrigerant compressor, the excellent sealing structure of the present invention against a low boiling point refrigerant whose volume rapidly changes greatly due to temperature rise or pressure fluctuation is Demonstrates great power and contributes practically.

  Further, the seal lip portion 6 extends from the inner diameter end side of the axial center orthogonal wall portion 7 to the fluid storage chamber 12 side, and the radial length from the inner peripheral edge 8a of each through hole 8 to the outer peripheral edge 6a of the seal lip portion 6 is increased. Since the length L is set to 0.5 mm to 1.5 mm, the rigidity of the rubber part 5 that maintains the posture of the seal lip part 6 can be secured, and the expanded bubble g generated inside the rubber part 5 Can be quickly released from the through-hole 8. Therefore, generation | occurrence | production of a blister can be suppressed, ensuring the stability of the seal lip | rip part 6 of the rubber part 5. FIG.

Further, since the total area S ₁ of the plurality of through holes 8 is set to 5% to 80% of the area S ₀ of the annular band region 39 in which the radial width dimension W ₀ is equal to the through holes 8, the rubber portion 5 The expansion bubble g generated inside can be quickly discharged to the outside and cracking can be prevented. And it can shape | mold easily in the case of press molding or injection molding of the rubber part 5. FIG.

DESCRIPTION OF SYMBOLS 1 Seal unit body 2 Circumferential surface part 3 Axis center orthogonal surface part 3a Sealing fluid (refrigerant) corresponding surface 4 Metal fitting (outer case)
5 Rubber part 6 Seal lip part 6a Outer peripheral edge 7 Axis center orthogonal wall part 8 Through hole 8a Inner peripheral edge 12 Refrigerant (fluid) storage chamber 39 Annular belt area g Expanded bubble L Radial direction length dimension W ₀ Radial direction width dimension S ₁ Total area S ₀ area

Claims (2)

A seal unit body (1) formed by integrating a rubber part (5) having a seal lip part (6) into a metal fitting (4) having at least a circumferential surface part (2) and an axial center orthogonal surface part (3). In a seal structure used for sealing a refrigerant as a rotary shaft seal for a refrigerant compressor ,
A plurality of through-holes (8) are formed around the axially orthogonal wall part (7) of the rubber part (5) covering the sealed refrigerant corresponding surface (3a) of the axially orthogonal surface part (3) of the metal fitting (4). Further, the metal surface of the sealing refrigerant corresponding surface (3a) of the metal fitting (4) is exposed at the back of the through hole (8),
And the said seal lip | rip part (6) is extended from the inner diameter end side of the said axial center orthogonal wall part (7) to the refrigerant | coolant storage chamber (12) side, and from the inner periphery (8a) of each said through-hole (8). The radial direction length dimension (L) to the outer peripheral edge (6a) of the seal lip portion (6) is set to a minute dimension of 0.5 mm to 1.5 mm,
Seal structure which is characterized by being configured so as to release the expansion bubble (g) of the refrigerant generated inside the rubber portion from the through-hole (8) (5). The total area (S ₁ ) of the plurality of through holes (8) is 5% to the area (S ₀ ) of the annular band region (39) in which the radial width dimension (W ₀ ) is equal to the through holes (8) The seal structure according to claim 1, which is set to 80% .

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