JP7350448B2 - mechanical seal - Google Patents

Description

The present invention relates to mechanical seals.

Mechanical seals are used to prevent leakage of sealed fluids. A mechanical seal includes a pair of sealing rings whose sliding surfaces slide against each other as they rotate relative to each other. In such mechanical seals, in recent years, it has been desired to reduce the energy lost due to sliding, and mechanical seals that improve the lubricity between sliding surfaces have been developed.

For example, the mechanical seal shown in Patent Document 1 includes a first sealing ring that rotates together with a rotating shaft and a second sealing ring that is fixed to a housing, and slides on the sliding surfaces of these sealing rings. This prevents the sealed fluid sealed in the space on the outer diameter side from leaking into the space on the inner diameter side. Further, on the outer diameter side of the second sealing ring, a plurality of first strain control recesses formed as notches in the inner diameter direction are arranged in the circumferential direction, and the sliding surface of the second sealing ring On the opposite side, a plurality of second strain control recesses formed as counterbore holes in the axial direction are arranged in the circumferential direction. When the pressure of the fluid to be sealed acts on the second sealing ring, the second sealing ring is deformed using the first strain control recess and the second strain control recess as base points to generate distortion. Irregularities are formed on the sliding surface of the sealing ring.

Japanese Patent Application Publication No. 2009-79634 (Page 7, Figure 3)

According to the mechanical seal disclosed in Patent Document 1, when the first sealing ring and the second sealing ring rotate relative to each other, the convex portion formed on the sliding surface of the second sealing ring moves against the sliding surface of the first sealing ring. It functions as a substantial sliding surface that slides on the sliding surface, and the fluid to be sealed is introduced into the recess formed in the sliding surface of the second sealing ring and discharged between the sliding surfaces. Dynamic pressure is generated, the sliding surfaces are separated by the dynamic pressure, and the fluid to be sealed is interposed between the sliding surfaces, thereby improving lubricity and achieving low friction. However, in the mechanical seal of Patent Document 1, when the pressure of the fluid to be sealed acts on the second sealing ring, the mechanical seal is deformed with the first strain control recess and the second strain control recess as base points. Since the second sealing ring is deformed so as to be distributed over the entirety thereof, sufficient irregularities may not be formed on the sliding surface, and there is a possibility that high lubricity may not be obtained.

The present invention has been made in view of these problems, and provides a mechanical seal that can obtain high lubricity by reliably forming unevenness on the sliding surface that can sufficiently hold the fluid to be sealed. The purpose is to provide

In order to solve the above problems, the mechanical seal of the present invention has the following features:
A mechanical seal having a pair of sealing rings having sliding surfaces that slide relative to each other and sealing a fluid to be sealed,
A plurality of grooves extending from the back side to the sliding surface side are formed in the circumferential direction on one sealing ring,
The groove portion is formed so that the circumferential width on the sliding surface side is smaller than the circumferential width on the back surface side.
According to this, the width in the circumferential direction on the back side of the groove is large, and a large deformation allowance for the back side part of one sealing ring is ensured, so that one sealing ring is applied to the pressure of the fluid to be sealed in the inner radial direction. When the grooves are in contact with each other, the diameters of the back side portions facing each other in the circumferential direction with the groove in between are reduced so that they are closer to each other than the sliding surface side portions, and the circumferential width of the sliding surface side of the grooves is smaller than that of the back side. Since it is smaller than the side, the internal stress caused by the diameter reduction can be effectively transmitted to the sliding surface side, and the sliding surface can be locally bulged to a large extent to reliably form irregularities on the sliding surface.

The groove portion may be formed such that the width in the circumferential direction gradually decreases from the back surface side toward the sliding surface side.
According to this, it is possible to ensure strength by reducing the spatial volume of the groove as much as possible while ensuring a deformation margin for one sealing ring.

The groove portion may be opened on a side opposite to the sealed fluid in the radial direction.
According to this, since the groove portion is opened on the side opposite to the fluid to be sealed in the radial direction, the sliding surface side of one sealing ring tends to bulge out.

The groove portion may have a portion where the width in the circumferential direction is constant in the radial direction.
According to this, the groove portion can be formed with good workability.

On the other sealing ring side of the one sealing ring, a nose portion may be provided in an annular shape extending in the circumferential direction and protruding stepwise in the axial direction and having the sliding surface.
According to this, the strength of one of the sealing rings is improved by the nose portion, so that the sliding surface side of the groove in one of the sealing rings can be formed thin. Further, since the nose portion receives the pressure of the fluid to be sealed, one of the sealing rings tends to contract in diameter.

The one sealing ring may be integrally formed.
According to this, one sealing ring is integrally formed, and the strength per unit volume of one sealing ring is constant, so that the portion of one sealing ring on the side of the other sealing ring can be reliably deformed. and easy to process.

1 is a side sectional view showing an example of a mechanical seal in Example 1 of the present invention. FIG. FIG. 3 is a diagram of the sliding surface of the stationary sealing ring viewed from the axial direction. FIG. 3 is a view of the back surface of the stationary sealing ring viewed from the axial direction. (a) is a sectional view taken along line AA in FIG. 3, and (b) is a view taken along arrow B in FIG. FIG. 3 is a side cross-sectional view showing the stationary seal ring attached to the housing and the seal cover. (a) is a schematic diagram showing a pressure receiving part where the pressure of the fluid to be sealed acts on the static sealing ring, and (b) is a schematic diagram showing the state in which the diameter of the static sealing ring is reduced from the state of (a) due to the pressure of the fluid to be sealed. It is a diagram. FIG. 3 is a schematic diagram showing the amount of bulge of the thin plate portion of the stationary sealing ring. 7 is a view taken along arrow C in FIG. 6. FIG. It is a figure which shows the stationary sealing ring in Example 2 of this invention. It is a figure which shows the stationary sealing ring in Example 3 of this invention. It is a figure which shows the stationary sealing ring in Example 4 of this invention.

EMBODIMENT OF THE INVENTION The form for implementing the mechanical seal based on this invention is demonstrated below based on an Example.

A sliding component according to Example 1 will be described with reference to FIGS. 1 to 8. In this embodiment, the outer diameter side of the sealing ring constituting the mechanical seal will be described as the sealed liquid side (high pressure side), and the inner diameter side will be explained as the leak side, which is the atmosphere side (low pressure side). Furthermore, the sliding surface side of the stationary sealing ring will be described as the front side.

A mechanical seal 1 for general industrial machinery shown in FIG. 1 seals a sealed liquid F that tends to leak from the outer diameter side of mutually opposing sliding surfaces 11 and 21 toward the inner diameter side (that is, toward the atmosphere A side). It is an inside type seal cover 5 fixed to a housing 4 constituting an attached device, and a stationary seal ring 10 as one of the annular seal rings provided in a state where rotation is regulated. , and a rotary sealing ring 20 as the other annular sealing ring provided on the rotating shaft 3 via a fixed sleeve 2 so as to be rotatable integrally with the rotating shaft 3. The rotary seal ring 20 is attached to the stationary sleeve 2 so as to be movable in the axial direction, and the rotary seal ring 20 is biased in the axial direction toward the stationary seal ring 10 by a spring (not shown). By rotating along with the rotating shaft 3, the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 closely slide against each other. As will be described later, the sliding surface 11 of the stationary sealing ring 10 is the end surface of the nose portion 12 that is formed to protrude in the axial direction from the end surface 10a on the rotating sealing ring 20 side (hereinafter also referred to as the front side). The sliding surface 11 is a flat surface extending perpendicularly to the axial direction over its entire surface in a natural state before pressure is applied by a sealed liquid F to be described later. Further, the sliding surface 21 of the rotary sealing ring 20 is a flat surface extending perpendicularly to the axial direction over the entire surface.

The stationary sealing ring 10 and the rotating sealing ring 20 are typically formed of a combination of SiC (i.e., hard materials) or a combination of SiC (i.e., hard material) and carbon (i.e., soft material), but are not limited to this. Any material that is used as a sliding material for mechanical seals can be used. Note that SiC includes sintered bodies using boron, aluminum, carbon, etc. as sintering aids, as well as materials consisting of two or more phases with different components and compositions, such as SiC in which graphite particles are dispersed, and SiC. There are reactive sintered SiC, SiC-TiC, SiC-TiN, etc. made of Si, and as carbon, carbon that is a mixture of carbonaceous and graphite, resin-molded carbon, sintered carbon, etc. can be used. In addition to the above-mentioned sliding materials, metal materials, resin materials, surface-modified materials (for example, coating materials), composite materials, etc. can also be used.

As shown in FIGS. 2 and 3, the stationary seal ring 10 is formed in a short cylindrical shape that is annular when viewed in the axial direction. The nose portion 12 is formed in an annular shape, and a portion of the nose portion 12 in the radial direction protrudes toward the ring 20 side. Further, on the back side of the sliding surface 11 of the stationary sealing ring 10 (that is, the side opposite to the rotating sealing ring 20), there is a notch groove 13 as a groove portion that opens on the back side and the inner diameter side and extends in the axial direction. A plurality of them are formed equally spaced in the direction. In this embodiment, eight cutout grooves 13 are formed in the circumferential direction, but the number of cutout grooves 13 is not limited to this embodiment.

In other words, the stationary sealing ring 10 includes a plurality of thick plate portions 14 as thick portions, which are spaced apart from each other, between a plurality of notch grooves 13 which are spaced apart from each other in the circumferential direction. A thin plate part 15 that is thinner in the axial direction than the thick plate part 14 and a high pressure side part of the adjacent thick plate parts 14 extending in the axial direction from the thin plate part 15 are connected. , and a side plate portion 16 that is thinner in the radial direction than the thick plate portion 14. Further, a stepped portion 16a that forms a step in the radial direction is formed on the thin plate portion 15 side of the side plate portion 16, and a reduced diameter portion 5a (FIG. 1 ) are engaged in the axial direction to prevent the stationary sealing ring 10 from coming off. Note that the front surface of the thick plate portion 14 on the rotary seal ring 20 side and the front surface of the thin plate portion 15 on the rotary seal ring 20 side are formed flush with each other, and the end surface 10a of the stationary seal ring 10 is It consists of Further, the outer circumferential surface of the thick plate portion 14 and the outer circumferential surface of the side plate portion 16 are formed flush with each other, and constitute the outer circumferential surface of the stationary sealing ring 10. The stepped portion 16a and the reduced diameter portion 5a may be omitted if the stationary sealing ring 10 is prevented from coming off by other means. In that case, the stationary sealing ring 10 may have a uniform circumferential surface, or It may have an uneven shape.

As shown in FIGS. 3 and 4, the notch groove 13 has a rectangular shape when viewed from the rear, and an isosceles triangular shape when viewed from the inner diameter direction. Specifically, the side surfaces 14a of the pair of thick plate portions 14 that are spaced apart in the circumferential direction with the notch groove 13 in between are such that the back side sides 14b are separated by a distance of L1 in the circumferential direction, and the sliding surface The notched grooves 13 extend in the axial direction so as to gradually taper toward the 11 side, and intersect at a position slightly on the back side of the end surface 10a of the stationary sealing ring 10 to form the tip portion 13a of the notched groove 13. This tip 13a extends in the radial direction perpendicular to the axis of the stationary sealing ring 10. Moreover, the side 14b on the back side of the side surface 14a of the pair of thick plate parts 14 extends parallel to the tip part 13a extending in the radial direction when viewed from the back side. That is, in the notch groove 13, the circumferential dimension of the cross section perpendicular to the axial direction is constant over the radial direction, in other words, the circumferential width is constant over the radial direction. Further, the circumferential dimension L1 of the end 13c on the back side of the notched groove 13 on the radially opposite side to the sealed liquid F (see FIG. 5), in other words, the arcuate line connecting the inner diameter ends of the pair of sides 14b is: The distance L2 in the circumferential direction between the end portions 14c of adjacent notch grooves 13 on the radially opposite side and on the rear side from the sealed liquid F (see FIG. 5), in other words, the inner diameter side and the rear side end of the thick plate portion 14 It is shorter than the dimension L2 of the circular arc wire extending in the circumferential direction of the section (L1<L2). Note that the shape of the notch groove 13 is formed to be plane symmetrical with respect to a plane S (hereinafter simply referred to as reference plane S) that extends radially from the center of the stationary sealing ring 10 so as to pass through the circumferential center of the notch groove 13. As a result, as will be described later, when the stationary sealing ring 10 receives pressure from the sealed liquid F, deformation occurs symmetrically about the reference plane S, and the thin plate portion 15 that defines the notch groove 13 deforms. The deformation stress is concentrated at the center in the circumferential direction, and the direction of deformation is toward the sliding surface 11, so the deformation stress is transmitted to the sliding surface 11, and the swelling of the sliding surface 11, which will be described later, is efficient. Occurs often.

The axial thickness L4 of the thin plate portion 15 is shorter than the axial thickness L5 of the thick plate portion 14 (L4<L5).

The thickness L6 of the side plate portion 16 is shorter than the radial thickness L7 of the thick plate portion 14 (L6<L7).

Further, as particularly shown in FIG. 4(a), the nose portion 12 is arranged closer to the inner diameter side of the end surface 10a of the stationary sealing ring 10. That is, the inner diameter end of the nose portion 12 is arranged on the inner diameter side than the inner diameter end of the side plate portion 16. More specifically, the inner diameter end 11a of the sliding surface 11 of the stationary sealing ring 10 is arranged on the inner diameter side of the outer diameter end 13b of the notched groove 13, which is the inner diameter end of the side plate portion 16. In this embodiment, the nose portion 12 does not overlap the side plate portion 16 in the axial direction, but at least the inner diameter end of the nose portion 12 (that is, the end opposite to the sealed liquid F) is illustrated. ) is arranged on the inner diameter side than the outer diameter end of the notch groove 13, the outer diameter end of the nose portion 12 may partially overlap the side plate portion 16 in the axial direction.

Next, the form of the stationary sealing ring 10 when the mechanical seal 1 is used will be explained based on FIGS. 5 to 8.

As shown in FIG. 5, when the stationary sealing ring 10 is attached to the housing 4 and the seal cover 5, an annular groove 4a is formed on the front surface of the housing 4, and a groove 4a is arranged in the groove 4a. An endless secondary seal 6, for example, an O-ring, is provided uniformly in the circumferential direction (that is, has the same shape in the circumferential direction), and is provided on the outer side of the back side of the stationary sealing ring 10 (that is, the side opposite to the rotating sealing ring 20). The sealed liquid F enters between the stationary seal ring 10 on the outer diameter side of the secondary seal 6 and the seal cover 5, and the sealed liquid F enters between the stationary seal ring 10 on the outer diameter side of the secondary seal 6 and the seal cover 5, and Intrusion into the notch groove 13 (ie, the atmosphere A side) is prevented. That is, the outer circumferential surface of the stationary sealing ring 10, specifically the outer circumferential surfaces of the thick plate part 14, thin plate part 15, side plate part 16, and nose part 12, absorb the pressure of the sealed liquid F from the outer diameter toward the inner diameter. It is configured as a pressure receiving section 17 that receives the pressure. That is, the secondary seal 6 may be disposed around the stationary sealing ring 10 closer to the liquid to be sealed F than the notch groove 13 and the liquid to be sealed F will not flow into the notch groove 13 . Note that the force from the liquid to be sealed F acts on the front surface of the thin plate section 15 (that is, the end surface 10a) and the front surface of the stepped section 16a in the axial direction toward the rear side in addition to the pressure receiving section 17. It acts dominantly on the outer circumferential surface, particularly on the outer circumferential surface of the thick plate portion 14, causing the stationary sealing ring 10 to contract in diameter as will be described later. In addition, the inner circumferential surface of the stationary sealing ring 10, specifically, the inner circumferential surfaces of the thick plate portion 14, thin plate portion 15, side plate portion 16, and nose portion 12, are placed on the atmosphere A side having a lower pressure than the liquid F to be sealed. facing.

As shown in FIGS. 6(a) and 6(b), when the pressure receiving part 17 of the stationary sealing ring 10 receives the pressure of the liquid to be sealed, the strength is reduced compared to other parts because of the notch groove 13. The weaker portion of the stationary sealing ring 10 on the back side in the axial direction becomes smaller in diameter due to the pressure. Specifically, as particularly shown in FIG. 6(b), when the pressure-receiving portion 17 of the stationary sealing ring 10 receives the pressure of the sealed liquid F, the notch groove 13 is formed on the sliding surface 11 when viewed from the inner diameter direction. It has an isosceles triangular shape that tapers toward the side, ensuring a large deformation margin for the back side portion, and the back side portions and inner diameter side portions of adjacent thick plate portions 14 are connected to each other. Since it is a free end so to speak, the tip 13a of the notch groove 13 is used as a bending point and the back side and inner diameter side parts of the thick plate part 14 are pressed so that they approach each other in the circumferential direction. As a result, the stationary sealing ring 10 is reduced in diameter. At this time, the thin plate part 15 and the nose part 12 have an endless annular shape without the notch groove 13 and have high structural strength, so that the closer they are to the sliding surface 11 in the axial direction, the less deformation occurs. Therefore, the diameter of the portion on the back side of the stationary sealing ring 10 is greatly reduced, and the portion on the sliding surface 11 side is reduced in diameter. The internal stress generated by this pressing is transmitted so as to concentrate on the thin plate part 15, which is thinner than the thick plate part 14, and causes the thin plate part 15 to bulge in the axial direction toward the rotary sealing ring 20. (See Figures 7 and 8). Here, since the side plate portion 16 has an isosceles triangular shape when viewed in the radial direction, the portion on the back side is larger in the circumferential direction, and the portion on the outer diameter side is tapered toward the sliding surface 11 side. The thin plate portion 15 is bulged and deformed, and as a result, internal stress tends to concentrate on the thin plate portion 15. Further, when the thin plate portion 15 is bulged toward the rotary sealing ring 20 side, the nose portion 12 is also deformed so as to bulge along the thin plate portion 15 . In addition, in FIGS. 6 and 7, for convenience of explanation, the amount of deformation of the side plate portion 16 and the amount of bulge of the thin plate portion 15 are shown larger than in reality.

Further, as shown in FIG. 6(b), the notch groove 13 has a side plate portion 16 on the outer diameter side and is opened to communicate with the space on the inner diameter side, so that the thin plate portion 15 has a side plate portion 16 on the outer diameter side. The portion on the inner diameter side is more easily deformed than the portion on the side, and the amount of bulge of the thin plate portion 15 toward the rotary sealing ring 20 side is larger at the portion on the inner diameter side. Further, since the nose portion 12 is disposed on the inner diameter side of the end face 10a of the stationary sealing ring 10, it is deformed by the large expansion of the thin plate portion 15. Further, the thin plate portion 15 has a larger amount of bulge toward the rotary sealing ring 20 at the center in the circumferential direction than at both ends in the circumferential direction. More specifically, regarding the bulging aspect of the thin plate portion 15, as shown in FIG. The part (that is, the part most opposite to the fluid to be sealed in the radial direction) bulges out the most, and it bulges outward from the innermost radial part to the periphery. In FIG. 7, the amount of bulge of the thin plate portion 15 is schematically illustrated by halftone dots, and the higher the density of the halftone dot, the larger the amount of bulge in the axial direction. Furthermore, in FIG. 7, illustration of the nose portion 12 is omitted for convenience of explanation.

As shown in FIG. 8, the thin plate portion 15 is bulged toward the rotary sealing ring 20, so that a portion of the sliding surface 11 corresponding to the circumferential center of the thin plate portion 15 is formed as a convex portion 8. Microscopically, the convex portion 8 becomes a portion that comes into contact with the sliding surface 21 of the rotary sealing ring 20, and the portions corresponding to both ends of the thin plate portion 15 in the circumferential direction and the thick plate portion 14 are formed as the recessed portion 7. Microscopically, this is a portion that does not contact the sliding surface 21 of the rotary sealing ring 20. Between the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20, portions that contact each other and portions that are spaced apart in the axial direction occur alternately at equal intervals in the circumferential direction. In this direction, concave portions 7 are regularly formed between convex portions 8 in the circumferential direction. Note that since the sealed liquid F has a higher viscosity than gas, it does not leak from the recess 7 into the low-pressure side space when the mechanical seal 1 is stopped, or the amount that leaks is very small.

When the stationary seal ring 10 and the rotating seal ring 20 rotate relative to each other, since the convex portion 8 is formed at the circumferential end of the recess 7, the liquid F to be sealed that has flowed into the recess 7 is transferred to the rotary seal ring 20. It follows the rotational direction, and the pressure of the sealed liquid F is increased in the recess 7, and the increased pressure flows out from the vicinity of the convex part 8, which is the end of the recess 7, to its surroundings. As a result, the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 are slightly separated, and the sealed liquid F existing between the sliding surfaces 11 and 21 provides good lubrication. It has come to form a state. In particular, when the thick plate portions 14 described above are pressed closer to each other in the circumferential direction, a plurality of bulging convex portions 8 are formed in the thin plate portion 15 spaced apart in the circumferential direction. The sealed liquid F can be easily held in the concave portion 7 formed between the convex portions 8, and dynamic pressure can be generated by the rotation of the rotary sealing ring 20.

As explained above, the notch groove 13 is formed so that the circumferential width on the sliding surface 11 side is smaller than the circumferential width dimension L1 on the back side. In this way, the circumferential width of the notch groove 13 on the back side (that is, the dimension L1) is larger than the circumferential width on the sliding surface 11 side (that is, the tip end 13a side), and the width of the back side of the stationary sealing ring 10 is Since a large amount of deformation allowance is ensured for the parts, when the pressure of the sealed liquid F is applied, the parts on the back side of the pair of thick plate parts 14 that face each other across the notch groove 13 in the circumferential direction move into the sliding surface 11. The diameter of the stationary sealing ring 10 is reduced so that they are closer to each other than the side parts, and the width in the circumferential direction on the sliding surface 11 side of the notched groove 13 is smaller than that on the back side, so that the internal stress caused by the diameter reduction is absorbed by the thin plate part. 15, the sliding surface 11 can be locally bulged out greatly, and unevenness can be reliably formed on the sliding surface 11.

Specifically, when receiving the pressure of the liquid to be sealed F, the diameters of the thick plate portions 14 are reduced so that the back side portions of the thick plate portions 14 approach each other with the tip portion 13a of the notch groove 13 as the bending point.

In addition, since the sliding surface 11 side of the notched groove 13 is tapered, the thick plate portion 14 is arranged near the tip 13a of the notched groove 13, and the strength of the portion of the stationary sealing ring 10 on the sliding surface 11 side is ensured. be done. Further, the tip end 13a of the notch groove 13 is configured such that the side surfaces 14a of the pair of thick plate portions 14 intersect at a position slightly on the back side of the end surface 10a of the stationary sealing ring 10, and the thin plate portion 15 is formed thin. Therefore, the thin plate portion 15 can expand with high responsiveness. Thereby, the recess 7 can be reliably formed between the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20, and the liquid to be sealed F can be held within the recess 7. The dynamic pressure generated in the recess 7 allows the sliding surfaces 11 and 21 to be slightly spaced apart, thereby improving sliding performance.

Furthermore, the notched groove 13 is formed in an isosceles triangular shape whose circumferential width gradually decreases from the back side toward the sliding surface 11 side when viewed from the inner diameter direction, so that The strength of the stationary sealing ring 10 can be ensured by making the space volume of the notch groove 13 as small as possible while ensuring the deformation allowance of the portion.

Further, the side plate portion 16 connects the outer diameter side portions of the adjacent thick plate portions 14, and the notch groove 13, which is the space between the adjacent thick plate portions 14, is the space on the side of the liquid to be sealed F. Since the notched groove 13 and the sealed liquid F do not communicate with each other, a large pressure difference between the notch groove 13 and the sealed liquid F can be ensured, and the expansion of the thin plate portion 15 toward the rotary sealing ring 20 can be performed reliably.

Further, since the cutout groove 13 is opened on the inner diameter side, the end surface 10a of the stationary sealing ring 10 can be expanded with higher responsiveness than in the case where the cutout groove 13 is not opened on the inner diameter side. In particular, the inner diameter side of the end face 10a of the stationary sealing ring 10 can be greatly expanded.

In addition, the notched groove 13 has a cross section perpendicular to the axial direction that is constant over the radial direction, in other words, a width in the circumferential direction is constant over the radial direction. According to this, the notch groove 13 can be formed with better workability than, for example, a notch groove having a complex shape such as a pyramidal or conical shape that opens on the back side.

Further, since the axial thickness L4 of the thin plate portion 15 is thinner than the axial thickness L5 of the thick plate portion 14, the thin plate portion 15 expands with high responsiveness following the diameter reduction of the stationary sealing ring 10. You can make it come out.

Furthermore, since the thickness L6 of the side plate portion 16 is thinner than the radial thickness L7 of the thick plate portion 14, it is possible to deform the side plate portion 16 with high responsiveness in accordance with the diameter reduction of the stationary sealing ring 10. can.

Further, since the dimension L2 of the circumferential inner diameter side portion of the thick plate portion 14, which has higher structural strength than the thin plate portion 15, is longer than the circumferential direction dimension L1 of the notch groove 13, the strength of the stationary sealing ring 10 can be ensured. In addition, since the length of the thin plate portion 15 in the circumferential direction is short, when the stationary sealing ring 10 contracts in diameter, the deformation occurs locally and concentrates, so the amount of bulge toward the rotating sealing ring 20 must be large. I can do it.

Further, in the thin plate part 15, the thick plate part 14 and the thin plate part 15 are equally distributed in the circumferential direction, and can form unevenness evenly on the sliding surface 11, so that the static sealing ring 10 and the rotating The slidability with the sealing ring 20 can be further improved.

Further, on the sliding surface 11 side of the thin plate portion 15 and the thick plate portion 14, a nose portion 12 protruding in the axial direction is provided in an annular shape over the circumferential direction. According to this, the strength of the stationary sealing ring 10 is improved by the nose portion 12, so that the thin plate portion 15 can be formed thin.

Further, the nose portion 12 is disposed closer to the inner diameter side than the side plate portion 16, and the bulge of the thin plate portion 15 in the axial direction can be suitably transmitted to the nose portion 12.

In addition, the static sealing ring 10 has the thick plate part 14, thin plate part 15, side plate part 16, and nose part 12 integrally formed, so compared to a static sealing ring in which each part is made of a different material or member. Thus, the thin plate portion 15 and the side plate portion 16 can be reliably deformed. Moreover, since the notch groove 13 can be formed by cutting out the annular member, the stationary sealing ring 10 can be easily processed.

Next, a mechanical seal according to Example 2 will be described with reference to FIG. 9. Note that explanations of the same and overlapping configurations as those of the previous embodiment will be omitted.

As shown in FIG. 9(a), the stationary sealing ring 100 in Example 2 is formed so that the cutout groove 131 is open to the back side and the inner diameter side. This notched groove 131 has a substantially convex shape when viewed in the radial direction, and includes a first groove portion 131a that is rectangular when viewed from the inner diameter direction and extends in the axial direction from the back side of the stationary sealing ring 100 toward the sliding surface 111 side. A second groove part 131b is rectangular when viewed from the inner diameter direction and extends in the axial direction from the first groove part 131a toward the sliding surface 111 side. It's communicating. Further, the circumferential width dimension L11 of the second groove portion 131b is formed shorter than the circumferential width dimension L10 of the first groove portion 131a (L10<L11), and the first groove portion 131a of the pair of thick plate portions 141 A step portion 141a is formed near the communication portion between the first groove portion 131b and the second groove portion 131b.

As shown in FIG. 9(b), when the stationary sealing ring 100 receives the pressure of the liquid to be sealed F, the back side portions of the thick plate portions 141 approach each other, and accordingly, the step portions 141a become closer to each other. As the thin plate portion 151 approaches, internal stress is transmitted to the thin plate portion 151, and the thin plate portion 151 bulges toward the sliding surface 111 side. As a result, the recesses 70 and the protrusions 80 are formed on the sliding surface 111. As shown in FIG. 9(c), the notched groove 131 is opened on the inner diameter side, so that the notch groove 131 is opened at the circumferential center and the innermost part of the thin plate part 151 (i.e., at the most opposite side from the sealed fluid in the radial direction). point) is the most bulging, and it bulges outward from the innermost point to the periphery.

Next, a mechanical seal according to Example 3 will be described with reference to FIG. 10. Note that explanations of the same and overlapping configurations as those of the previous embodiment will be omitted.

As shown in FIG. 10, the stationary sealing ring 200 in Example 3 has a trapezoidal notch 231 that tapers gradually from the back side toward the sliding surface 211 when viewed from the inner diameter direction. That is, the notch groove 231 has a circumferential width dimension L21 of the portion on the sliding surface 211 side that is smaller than a circumferential width dimension L20 of the portion on the back side (L20<L21). Since the cutout groove 231 in the third embodiment has a width dimension L21 in the circumferential direction on the sliding surface 211 side, the thin plate portion 215 bulges out in the axial direction more than the notch groove 13 in the first embodiment. can be done. Moreover, since the notch groove 231 gradually tapers toward the sliding surface 211, the space volume can be made smaller than that of the notch groove 131 in the second embodiment, and strength can be ensured.

Next, a mechanical seal according to Example 4 will be described with reference to FIG. 11. Note that explanations of the same and overlapping configurations as those of the previous embodiment will be omitted.

As shown in FIG. 11, the stationary sealing ring 300 in Example 4 has a notched groove 331 in a semi-elliptical shape extending from the back side toward the sliding surface 311 when viewed from the inner diameter direction. This notch groove 331 has an arc shape such that the portion on the sliding surface 311 side is tapered compared to the circumferential width dimension L30 of the portion on the back side, so that the stationary sealing ring 300 When receiving pressure, the thin plate portion 351 can reliably bulge toward the sliding surface 311. Moreover, since the shape of the cutout groove 331 is simple, the workability of the cutout groove 331 is good.

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

For example, in the embodiment described above, the side plate portion 16 is formed on the outer diameter side of the thin plate portion 15, but the present invention is not limited to this. For example, the side plate portion may be formed on the inner diameter side of the thin plate portion. Alternatively, they may be formed on both sides of the thin plate portion in the radial direction. In the case of an outside type mechanical seal that seals the sealed fluid that tends to leak from the inner diameter side toward the outer diameter side (i.e., the atmosphere side), the side plate part is formed on the inner diameter side of the thin plate part, and the side plate part is formed on the inner diameter side of the thin plate part. A secondary sealing member is arranged on the back side or the inner diameter side to prevent the sealed fluid from leaking to the atmosphere side, and to prevent the sealed fluid from entering the notch groove. Further, when the side plate portions are formed on both sides of the thin plate portion in the radial direction, the secondary seal member may be disposed on the side plate portion on the side of the fluid to be sealed.

Further, in the above embodiment, the circumferential dimension L1 of the notch groove 13 is shorter than the dimension L2 of the thick plate part 14 on the inner diameter side in the circumferential direction. may be formed longer than the circumferential direction. In this case, the circumferential dimension of the recess formed between the sliding surfaces when the stationary sealing ring is reduced in diameter can be increased.

Further, in the above embodiment, the thick plate portions 14 are arranged equally in the circumferential direction, but the circumferential length and number of the thick plate portions can be freely changed.

Further, in the above embodiment, the notch groove 13 is formed in the stationary sealing ring 10, but the notch groove 13 may be formed in the rotating sealing ring 20, or the notch groove 13 is formed in both. may have been done.

Furthermore, in the above embodiments, the fluid to be sealed is a liquid, but the fluid to be sealed may be a gas, or may be a mist mixture of a liquid and a gas.

Further, in the above embodiment, the secondary seal member is arranged on the back side of the stationary sealing ring, but the secondary sealing member is not limited to this, and may be arranged on the outer diameter side of the stationary sealing ring, for example. . That is, it is sufficient if high pressure is applied to the surface of the side plate portion on the sealed fluid side, for example, the outer peripheral surface of the side plate portion 16 in the first embodiment.

1 Mechanical seal 3 Rotating shaft 6 Secondary seal 7 Recess 10, 10' Stationary sealing ring (one sealing ring)
11, 11' Sliding surface 12 Nose part 13, 13' Notch groove 14, 14' Thick plate part (thick part)
15, 15' Thin plate part 16, 16' Side plate part 17 Pressure receiving part 20 Rotating sealing ring (other sealing ring)
21 Sliding surface 100 Stationary sealing ring 121 Nose portion 131 Notch groove 141 Thick plate portion (thick wall portion)
151 Thin plate part 161 Side plate part 171 Pressure receiving part 200 Stationary sealing ring 231 Notch groove 241 Thick plate part (thick part)
215 Thin plate portions 261, 262 Side plate portion A Atmosphere F Sealed liquid (sealed fluid)

Claims (7)

A mechanical seal having a pair of sealing rings having sliding surfaces that slide relative to each other and sealing a fluid to be sealed,
A plurality of grooves extending from the axial back side to the axial sliding surface side are formed in the circumferential direction on one of the sealing rings,
The groove portion is formed such that the circumferential width on the axial sliding surface side is smaller than the circumferential width on the axial back side , and the circumferential width on the axial back side is smaller. A mechanical seal in which the width of the groove in the axial direction is larger than that of the mechanical seal. The mechanical seal according to claim 1, wherein the groove portion is formed so that a circumferential width thereof gradually decreases from the axial back side toward the axial sliding surface side. 3. The mechanical seal according to claim 2, wherein each of the groove portions has plane symmetry in the circumferential direction with respect to a reference plane extending radially from the center of the one sealing ring. One of the outer diameter side and inner diameter side of the pair of sealing rings is a sealed fluid side, and the other is a leakage side,
The mechanical seal according to any one of claims 1 to 3, wherein the groove portion is opened on a radial leakage side . 5. The mechanical seal according to claim 1, wherein the groove portion has a portion where a circumferential width is constant in a radial direction. Any one of claims 1 to 5, wherein a nose portion protruding stepwise in the axial direction and provided with the sliding surface is provided in an annular shape in the circumferential direction on the side of the other sealing ring of the one sealing ring. Mechanical seals listed in . 7. The mechanical seal according to claim 1, wherein said one sealing ring is integrally formed.

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