JP2021092257A - mechanical seal - Google Patents

Abstract

To provide a mechanical seal capable of achieving high lubricity by reliably forming irregularity enough to hold sealed fluid between a pair of sealing rings.SOLUTION: A mechanical seal 1 includes a pair of sealing rings 10, 20 which slide with each other, for sealing sealed fluid F, one sealing ring 10 having a plurality of cutout grooves 13 arranged on the opposite side to the sealed fluid F in the radial direction while separating from each other in the peripheral direction and opening at least to the back side. Between each of the cutout grooves 13 and a space on the sealed fluid F side, an annular secondary seal member 6 is arranged. The cutout grooves 13 each have an axial size L3 larger than a peripheral size L1 of the end on the radial opposite side to the sealed fluid F.SELECTED DRAWING: Figure 6

Description

The present invention relates to a mechanical seal.

In order to prevent leakage of the fluid to be sealed, a mechanical seal having a pair of sealing rings that rotate relative to each other and slide on the sliding surfaces is used. In such mechanical seals, it has been desired in recent years to reduce the energy lost due to sliding, and mechanical seals for improving lubricity between sliding surfaces have been developed.

For example, the mechanical seal shown in Patent Document 1 includes a first sealing ring that rotates with a rotation shaft and a second sealing ring that is fixed to a housing, and slides the sliding surfaces of these sealing rings with each other. This prevents the sealed fluid sealed in the outer diameter side space from leaking into the inner diameter side space. 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 also as a sliding surface in 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 with the first strain control recess and the second strain control recess as base points to cause strain, thereby causing the second strain. The sliding surface of the sealing ring of the above is formed with irregularities.

Japanese Unexamined Patent Publication No. 2009-79634 (Page 7, Fig. 3)

According to the mechanical seal of Patent Document 1, when the first sealing ring and the second sealing ring are relatively rotated, the convex portion formed on the sliding surface of the second sealing ring slides on the first sealing ring. It functions as a substantial sliding surface that slides on the surface, and by introducing the sealed fluid into the recess formed in the sliding surface of the second sealing ring and discharging it between the sliding surfaces, the sliding surfaces are separated from each other. By generating dynamic pressure, the sliding surfaces are separated from each other by the dynamic pressure, and a sealed fluid is interposed between the sliding surfaces, lubricity is improved and friction is reduced. 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 distorted so as to be dispersed as a whole, there is a possibility that sufficient unevenness is not formed on the sliding surface and high lubricity cannot be obtained.

The present invention has been made by paying attention to such a problem, and high lubricity can be obtained by surely forming irregularities capable of sufficiently holding a sealed fluid between a pair of sealing rings. The purpose is to provide a mechanical seal that can be used.

In order to solve the above problems, the mechanical seal of the present invention is used.
A mechanical seal that has a pair of sealing rings that slide relative to each other and seals the fluid to be sealed.
One sealing ring is provided with a plurality of notched grooves that are radially separated from the sealed fluid in the radial direction and open at least on the back surface side, and the notched grooves and the sealed fluid side are arranged. An annular secondary seal member is arranged between the space and the space.
The notch groove has an axial dimension larger than the circumferential dimension of the end portion radially opposite to the sealed fluid.
According to this, since it has a notch groove, one of the sealing rings is deformed so as to reduce or increase the diameter on the side opposite to the sealed fluid due to the pressure of the sealed fluid, and the notch groove is axial. Since the dimension is larger than the circumferential dimension of the end opposite to the sealed fluid in the radial direction, the internal stress generated by the deformation is transmitted to the other sealing ring side in one sealing ring, and the other in one sealing ring. The portion on the sealing ring side of the above can be locally greatly bulged to surely form irregularities between the pair of sealing rings.

Each of the cutout grooves may be plane-symmetrical in the circumferential direction with reference to a reference plane extending radially from the center of the one sealing ring.
According to this, when one of the sealing rings receives the pressure of the fluid to be sealed, the deformation occurs symmetrically in the circumferential direction of the notch groove with the reference plane as the center. The moving surface can be greatly expanded.

The circumferential dimension of the end portion of the thick portion formed between the adjacent notch grooves on the side opposite to the sealed fluid is radially opposite to the sealed fluid of the notch groove. It may be longer than the circumferential dimension of the end of.
According to this, the circumferential dimension of the end portion radially opposite to the sealed fluid of the notch groove is longer than the circumferential dimension of the end portion radially opposite to the sealed fluid of the thick portion. Therefore, it is possible to increase the amount of bulging in the axial direction of the portion of one sealing ring on the other sealing ring side while ensuring the strength of one sealing ring.

On the other sealing ring side of the one sealing ring, a nose portion having a sliding surface that projects in a stepwise manner in the axial direction and slides with the other sealing ring is provided in an annular shape in the circumferential direction. May be good.
According to this, since the strength of one sealing ring is improved by the nose portion, one sealing ring is less likely to be damaged.

The end portion of the sliding surface opposite to the sealed fluid may be arranged on the side opposite to the sealed fluid from the end portion of the notch groove on the sealed fluid side.
According to this, the axial bulge of the portion of one sealing ring on the other sealing ring side can be suitably transmitted to the sliding surface.

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

It is a side sectional view which shows an example of the mechanical seal in Example 1 of this invention. It is the figure which looked at the sliding surface of the static sealing ring from the axial direction. It is the figure which looked at the back surface of the static sealing ring from the axial direction. (A) is a cross-sectional view taken along the line AA of FIG. 3, and FIG. 3B is a view taken along the arrow B of FIG. It is a side sectional view which shows the state which the static sealing ring is attached to a housing and a seal cover. (A) is a schematic view showing a pressure receiving portion on which the pressure of the sealed fluid acts on the statically sealed ring, and (b) is a schematic diagram showing a state in which the statically sealed ring is reduced in diameter due to the pressure of the sealed fluid from the state of (a). It is a figure. It is the schematic which shows the bulging amount of the thin plate part of a static sealing ring. It is a C arrow view of FIG. (A) to (c) are diagrams for explaining an example of the form of a statically sealed ring having a notch groove whose circumferential dimension is larger than the axial dimension. It is a figure which shows the static sealing ring in Example 2 of this invention. It is a figure which shows the static sealing ring in Example 3 of this invention.

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

The sliding parts according to the first embodiment will be described with reference to FIGS. 1 to 9. 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 described as the atmospheric side (low pressure side) as the leakage side. Furthermore, the sliding surface side of the static sealing ring will be described as the front side.

The mechanical seal 1 for general industrial machinery shown in FIG. 1 seals the sealed liquid F that tends to leak from the outer diameter side to the inner diameter side (that is, the atmosphere A side) of the sliding surfaces 11 and 21 facing each other. A static sealing ring 10 as one of the annular sealing rings provided on the seal cover 5 fixed to the housing 4 constituting the attached device in a state where rotation is restricted. It is mainly composed of a rotary sealing ring 20 as another sealing ring of an annular shape provided on the rotating shaft 3 in a state of being integrally rotatable with the rotating shaft 3 via a fixing sleeve 2. The rotary sealing ring 20 is attached to the fixing sleeve 2 in a state where it can be moved in the axial direction, and the rotary sealing ring 20 is axially urged toward the static sealing ring 10 by a spring (not shown). By rotating along with the rotating shaft 3, the sliding surface 11 of the static sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 slide closely with each other. As will be described later, the sliding surface 11 of the static sealing ring 10 is formed so as to project axially from the end surface 10a on the rotary sealing ring 20 side (hereinafter, also referred to as the front side). The sliding surface 11 is a flat surface orthogonal to the axial direction over the entire surface in a natural state before the pressure of the sealed liquid F, which will be described later, is applied. The sliding surface 21 of the rotary sealing ring 20 is a flat surface orthogonal to the axial direction over the entire surface.

The static sealing ring 10 and the rotary sealing ring 20 are typically formed of SiC (that is, a hard material) or a combination of SiC (that is, a hard material) and carbon (that is, a soft material), but are not limited to this. The moving material can be applied as long as it is used as a sliding material for mechanical sealing. The SiC includes a sintered body using 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 (for example, coating materials), composite materials and the like can also be applied.

As shown in FIGS. 2 and 3, the static sealing ring 10 is formed in a short tubular shape forming an annular shape in the axial direction, and is rotationally sealed on the front end surface 10a of the static sealing ring 10. A nose portion 12 having a part protruding in the radial direction is formed in an annular shape on the ring 20 side. Further, on the back surface side of the sliding surface 11 of the static sealing ring 10 (that is, the side opposite to the rotary sealing ring 20), a plurality of notch grooves 13 opening on the back surface side and the inner diameter side and extending in the axial direction are plurality of in the circumferential direction. It is formed evenly. In this embodiment, eight notch grooves 13 are formed in the circumferential direction, but the number of notch grooves 13 is not limited to this embodiment.

In other words, in the static sealing ring 10, a thick plate portion 14 as a wall thickness portion and a plurality of thick plate portions are arranged apart from each other between the notch grooves 13 arranged apart from each other in the circumferential direction. The front side portions of the 14s are connected, and the thin plate portion 15 which is thinner in the axial direction than the thick plate portion 14 and the high-pressure side portion of the adjacent thick plate portions 14 extending in the axial direction from the thin plate portion 15 are connected. , A side plate portion 16 that is thinner in the radial direction than the thick plate portion 14 is formed. Further, a step portion 16a forming a step in the radial direction is formed on the thin plate portion 15 side of the side plate portion 16, and the diameter-reduced portion 5a reduced in diameter on the step portion 16a and the front surface portion of the seal cover 5 (FIG. 1). The static sealing ring 10 is prevented from coming off by engaging with (see.) In the axial direction. The front surface of the thick plate portion 14 on the rotary sealing ring 20 side and the front surface of the thin plate portion 15 on the rotary sealing ring 20 side are formed flush with each other, and the end surface 10a of the static sealing ring 10 is formed flush with each other. It is configured. Further, the outer peripheral surface of the thick plate portion 14 and the outer peripheral surface of the side plate portion 16 are formed flush with each other, forming the outer peripheral surface of the static sealing ring 10. The stepped portion 16a and the diameter-reduced portion 5a may be omitted as long as the static sealing ring 10 is prevented from coming off by other means. In that case, the static sealing ring 10 may have a uniform peripheral surface, or the other. It may have an uneven shape of.

As shown in FIGS. 3 and 4, the notch groove 13 has a rectangular shape when viewed from the rear or the inner diameter direction. Specifically, the notch groove 13 is formed by a pair of surfaces 13c extending in parallel facing each other in the circumferential direction and a surface 13b extending so as to connect a portion orthogonal to these surfaces 13c on the outer diameter side of the surface 13c (that is, a notch). It is composed of an outer diameter surface 13b) of the groove 13 and a surface extending so as to connect each surface 13c and a portion on the front end side of the surface 13b at right angles (that is, the back surface of the thin plate portion 15). Dimension L1 in the circumferential direction of the end portion 13a on the side opposite to the sealed liquid F (see FIG. 5) of the notch groove 13 and on the back surface side, in other words, on the inner diameter side of the thick plate portion 14 adjacent to the notch groove 13. The arc line connecting the back end portions is the radial separation dimension L2 of the end portion 14a on the back side opposite to the sealed liquid F (see FIG. 5) between the adjacent notch grooves 13, in other words, the thickness. It is shorter than the dimension L2 of the arc line extending in the circumferential direction of the inner diameter side and the back surface side end portion of the plate portion 14 (L1 <L2). Further, the axial dimension L3 of the notch groove 13 is longer than half of the axial length of the thick plate portion 14 and longer than the circumferential dimension L1 of the notch groove 13 (L1 <L3). The shape of the notch groove 13 is a surface S extending radially from the center of the static sealing ring 10 so as to pass through the central portion in the circumferential direction of the notch groove 13 (hereinafter, simply referred to as a reference surface S. It suffices to be formed plane-symmetrically with reference to (see)), whereby when the statically sealed ring 10 is subjected to the pressure of the sealed liquid F, the deformation is symmetrical with respect to the reference plane S, as described later. The deformation stress is concentrated in the central portion in the circumferential direction of the thin plate portion 15 that divides the notch groove 13, and the deformation direction is toward the sliding surface 11, so that the deformation stress is transmitted to the sliding surface 11. Therefore, the sliding surface 11, which will be described later, bulges efficiently.

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

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

Further, as shown in FIG. 4A in particular, the nose portion 12 is arranged so as to be closer to the inner diameter side of the end surface 10a of the static sealing ring 10. That is, the inner diameter end of the nose portion 12 is arranged on the inner diameter side of the inner diameter end of the side plate portion 16. More specifically, the inner diameter end 11a of the sliding surface 11 of the static sealing ring 10 is arranged on the inner diameter side of the outer diameter surface 13b of the notch groove 13 which is the inner diameter end of the side plate portion 16. In this embodiment, the nose portion 12 does not overlap with 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 portion opposite to the sealed liquid F). ) Is arranged on the inner diameter side of the notch groove 13 on the inner diameter side, the outer diameter end of the nose portion 12 may partially overlap with the side plate portion 16 in the axial direction.

Next, the form of the static sealing ring 10 when the mechanical seal 1 is used will be described with reference to FIGS. 5 to 8.

As shown in FIG. 5, when the static sealing ring 10 is attached to the housing 4 and the seal cover 5, a concave groove 4a is formed in an annular shape on the front surface of the housing 4 and arranged in the concave groove 4a. An endless secondary seal 6, for example, an O-ring, is provided uniformly in the circumferential direction (that is, has a similar shape in the circumferential direction), and is provided on the back side of the static sealing ring 10 (that is, the side opposite to the rotating sealing ring 20). The liquid F to be sealed is pressed against the end face on the diameter side, penetrates between the static sealing ring 10 on the outer diameter side of the secondary seal 6 and the seal cover 5, and is on the inner diameter side of the secondary seal 6. Invasion into the notch groove 13 (that is, the atmosphere A side) is prevented. That is, the outer peripheral surface of the static sealing ring 10, specifically, the outer peripheral surface of the thick plate portion 14, the thin plate portion 15, the side plate portion 16, and the nose portion 12 applies the pressure of the sealed liquid F from the outer diameter to the inner diameter. It is configured as a pressure receiving unit 17. That is, the secondary seal 6 may be arranged around the static sealing ring 10 on the side of the sealed liquid F with respect to the notch groove 13 so that the sealed liquid F does not flow into the notch groove 13. The force of the liquid to be sealed F acts axially on the front surface (that is, the end surface 10a) of the thin plate portion 15 and the front surface of the step portion 16a in addition to the pressure receiving portion 17 toward the back surface side. It acts predominantly on the outer peripheral surface, particularly the outer peripheral surface of the thick plate portion 14, and the diameter of the static sealing ring 10 is reduced as described later. Further, the inner peripheral surface of the static sealing ring 10, specifically, the inner peripheral surface of the thick plate portion 14, the thin plate portion 15, the side plate portion 16, and the nose portion 12 is on the atmosphere A side having a lower pressure than the sealed liquid F. Facing.

As shown in FIGS. 6A and 6B, when the pressure receiving portion 17 of the static sealing ring 10 receives the pressure of the sealed liquid F, there is a notch groove 13, so that the strength is higher than that of other portions. The portion of the weak static sealing ring 10 on the back side in the axial direction is reduced in diameter by pressure. Specifically, as shown in FIG. 6B, when the pressure receiving portion 17 of the static sealing ring 10 receives the pressure of the sealed liquid F, the portion on the back surface side and the inner diameter side of the adjacent thick plate portions 14 Since these parts are not connected to each other, so to speak, they are free ends, the parts on the back surface side and the inner diameter side of the plank portion 14 are pressed so as to approach each other in the circumferential direction, and the static sealing ring 10 is reduced in diameter. To do. Further, since the thin plate portion 15 and the nose portion 12 have no notch groove 13 and are endlessly annular and have high structural strength, they are less likely to be deformed as they are closer to the sliding surface 11 in the axial direction. Therefore, the portion of the static sealing ring 10 on the back surface side is greatly reduced in diameter, and the portion on the sliding surface 11 side is reduced in diameter. As a result, as shown in the right figure of FIG. 6B, the thin plate portion 15 thinner than the thick plate portion 14 can be axially bulged toward the rotary sealing ring 20 due to the internal stress generated by this pressing. It has become like. Further, when the thin plate portion 15 is bulged toward the rotary sealing ring 20, the nose portion 12 is also deformed so as to bulge along the thin plate portion 15. In FIG. 6, for convenience of explanation, the amount of deformation of the side plate portion 16 and the amount of swelling of the thin plate portion 15 are shown larger than they actually are.

Further, as shown in FIG. 6B, the cutout groove 13 has a side plate portion 16 on the outer diameter side and is opened so as to communicate with the space on the inner diameter side, so that the thin plate portion 15 has an outer diameter. The inner diameter side portion is more easily deformed than the side portion, and the amount of swelling of the thin plate portion 15 toward the rotary sealing ring 20 side is larger in the inner diameter side portion. Further, since the nose portion 12 is arranged on the inner diameter side of the end surface 10a of the static sealing ring 10, it is deformed by receiving a large bulge of the thin plate portion 15. Further, the thin plate portion 15 has a larger amount of swelling toward the rotary sealing ring 20 at the central portion in the circumferential direction than at both ends in the circumferential direction. More specifically, regarding the bulging mode of the thin plate portion 15, as shown in FIG. 7, which is a view of the thin plate portion 15 viewed from the rotary sealing ring 20 side in the axial direction, the thin plate portion 15 is located at the center in the circumferential direction and the innermost diameter. The portion (that is, the portion on the opposite side of the sealed fluid in the radial direction) is the most bulging, and the portion bulging from the innermost diameter portion to the periphery in a divergent manner. In FIG. 7, the amount of swelling of the thin plate portion 15 is schematically shown by halftone dots, and it is shown that the higher the density of the halftone dots, the larger the amount of swelling in the axial direction. Furthermore, in FIG. 7, the nose portion 12 is not shown for convenience of explanation.

As shown in FIG. 8, the thin plate portion 15 is bulged toward the rotary sealing ring 20, so that the portion of the sliding surface 11 corresponding to the circumferential central portion of the thin plate portion 15 is formed as a convex portion 8. Microscopically, the convex portion 8 is a portion that comes into contact with the sliding surface 21 of the rotary sealing ring 20, and the portions corresponding to both ends in the circumferential direction of the thin plate portion 15 and the thick plate portion 14 are formed as recesses 7. Microscopically, it is a portion that does not come into contact with the sliding surface 21 of the rotary sealing ring 20. Between the sliding surface 11 of the static sealing ring 10 and the sliding surface 21 of the rotary sealing ring 20, portions that are in contact with each other and portions that are separated in the axial direction are alternately generated in the circumferential direction at equal intervals, that is, the circumference. In the direction, the concave portions 7 are regularly formed between the convex portions 8 in the circumferential direction. Since the sealed liquid F has a higher viscosity than the gas, it does not leak from the recess 7 into the space on the low pressure side when the mechanical seal 1 is stopped, or the amount of leakage is very small.

When the static sealing ring 10 and the rotary sealing ring 20 rotate relative to each other, the convex portion 8 is formed at the circumferential end of the concave portion 7, so that the sealed liquid F flowing into the concave portion 7 is the rotary sealing ring 20. Following the movement in the rotational direction, the pressure of the sealed liquid F is increased in the concave portion 7, and the sealed liquid F with increased pressure flows out from the vicinity of the convex portion 8 which is the end of the concave portion 7 to the periphery thereof. As a result, the sliding surface 11 of the static sealing ring 10 and the sliding surface 21 of the rotary sealing ring 20 are slightly separated from each other, and the sealed liquid F existing between the sliding surfaces 11 and 21 provides good lubrication. It is supposed to be in a state. In particular, when the thick plate portions 14 are pressed so as to approach each other in the circumferential direction, a plurality of bulging convex portions 8 are formed on the thin plate portion 15 so as to be separated from each other in the circumferential direction. The liquid F to be sealed can be easily held in the recesses 7 formed between the convex portions 8, and dynamic pressure can be generated by the rotation of the rotary sealing ring 20.

As described above, the thin plate portion 15 and the side plate portion 16 are formed thinner than the thick plate portion 14, and the space between the adjacent thick plate portions 14, that is, the notch groove 13 has the axial dimension L3. Is larger than the circumferential dimension L1, so when the thick plate portion 14 and the side plate portion 16 receive the pressure of the sealed liquid F in the inner diameter direction, the thick plate portions 14 can be brought close to each other and the thick plate portion 14 can be brought close to each other. The internal stress generated by the proximity of each other can be effectively transmitted to the thin plate portion 15, and the sliding surface 11 can be locally greatly bulged to surely form irregularities on the sliding surface 11.

Specifically, when the axial dimension L30 of the notch groove 13'is smaller than the circumferential dimension L10 as in the static sealing ring 10'shown in FIG. 9, the thin plate portion 15' has a gentle curvature. The convex portion 8'that bulges in the axial direction and is formed between the sliding surfaces 11'and 21 can be formed large in the circumferential direction, while the concave portion is made relatively small in the circumferential direction to form the sealed liquid F. The amount of leakage into the space on the atmosphere A side can be minimized. However, when the thick plate portion 14'and the side plate portion 16'are subjected to the pressure of the sealed liquid F in the inner diameter direction, if the circumferential and axial regions of the thin plate portion 15'and the side plate portion 16'are too large, they stand still. Since the strength of the sealing ring 10'is weak, there is a risk of damage.

On the other hand, in this embodiment, the notch groove 13 has an axial dimension L3 larger than a circumferential dimension L1. Therefore, the larger L3 is, the more the notch groove 13 can be formed close to the sliding surface 11 to facilitate the bulging of the thin plate portion 15, and the smaller L1 is, the more the static sealing ring 10 is cut out. The occupied volume of the notch groove 13 is small, and the strength of the static sealing ring 10 can be maintained. Further, since the secondary seal 6 is pressed against the end surface of the static sealing ring 10 on the back surface side (that is, the side opposite to the rotary sealing ring 20), a large pressure receiving area can be obtained, and the static sealing ring 10 has a reduced diameter. Easy to make. As a result, the recess 7 can be reliably formed between the sliding surface 11 of the static sealing ring 10 and the sliding surface 21 of the rotary sealing ring 20, and the sealed liquid F can be held in the recess 7. Due to the dynamic pressure generated in the recess 7, the sliding surfaces 11 and 21 can be slightly separated from each other to improve the slidability.

Further, the side plate portion 16 connects the portions on the outer diameter side 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 sealed liquid F side. Therefore, a large pressure difference between the notch groove 13 and the liquid F to be sealed can be secured, and the thin plate portion 15 can be reliably bulged toward the rotary sealing ring 20 side.

Further, since the axial thickness dimension L4 of the thin plate portion 15 is thinner than the axial thickness dimension L5 of the thick plate portion 14, the thin plate portion 15 swells with high responsiveness following the reduced diameter of the static sealing ring 10. You can get it out.

Further, since the thickness dimension L6 of the side plate portion 16 is thinner than the thickness dimension L7 in the radial direction of the thick plate portion 14, the side plate portion 16 can be deformed with high responsiveness following the reduced diameter of the static sealing ring 10. it can.

Further, since the dimension L2 of the portion on the inner diameter side in the circumferential direction of the thick plate portion 14 having higher structural strength than the thin plate portion 15 is longer than the dimension L1 of the portion on the inner diameter side in the circumferential direction of the notch groove 13, the static sealing ring 10 Since the strength can be secured and the length of the thin plate portion 15 in the circumferential direction is short, the portion deformed when the static sealing ring 10 is reduced in diameter becomes local and concentrated, so that the amount of swelling to the rotary sealing ring 20 Can be taken large.

Further, in the thin plate portion 15, the thick plate portion 14 and the thin plate portion 15 are evenly arranged in the circumferential direction and can be evenly arranged on the sliding surface 11 to form irregularities. 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 projecting in the axial direction is provided in an annular shape in the circumferential direction. According to this, since the strength of the static sealing ring 10 is improved by the nose portion 12, the thin plate portion 15 can be formed thin.

Further, the nose portion 12 is arranged closer to the inner diameter side than the side plate portion 16, so that the axial bulge of the thin plate portion 15 can be suitably transmitted to the nose portion 12.

Further, since the static sealing ring 10 is integrally formed with the thick plate portion 14, the thin plate portion 15, the side plate portion 16, and the nose portion 12, it is compared with the static sealing ring in which each portion is formed of a different material or a different member. Therefore, the thin plate portion 15 and the side plate portion 16 can be reliably deformed. Further, since the notch groove 13 may be formed in the annular member, the static sealing ring 10 can be easily processed.

Next, the mechanical seal according to the second embodiment will be described with reference to FIG. It should be noted that the description of the same configuration as that of the above embodiment and the overlapping configuration will be omitted.

As shown in FIG. 10, the static sealing ring 100 in the second embodiment is formed so that the notch groove 131 opens in the space on the back surface side and the outer diameter side. That is, the side plate portion 161 is formed so as to extend from the thin plate portion 151 in the axial direction and connect the portions on the inner diameter side of the adjacent thick plate portions 141. Further, when the static sealing ring 100 is attached to the housing 4 and the seal cover 5, the secondary seal 6 arranged in the concave groove 4a'formed in the housing 4 is on the back side of the static sealing ring 100. The liquid F to be sealed is pressed against the end surface on the inner diameter side, and is arranged in the space on the inner diameter side of the sliding surface 111. That is, the inner peripheral surface of the static sealing ring 100, specifically, the inner peripheral surface of the thick plate portion 141, the thin plate portion 151, the side plate portion 161 and the nose portion 121 of the sealed liquid F from the inner diameter to the outer diameter. It is a pressure receiving unit 171 that receives pressure.

As shown in FIGS. 10B and 10C, when the pressure receiving portion 171 of the static sealing ring 100 receives the pressure of the liquid F to be sealed, the static sealing ring 100 is deformed to the outer diameter side, and each thick plate portion. The 141 moves in the outer radial direction so as to move away from each other, whereby the thin plate portion 151 thinner than the thick plate portion 141 can be contracted to the back surface side.

Next, the mechanical seal according to the third embodiment will be described with reference to FIG. It should be noted that the description of the same configuration as that of the above embodiment and the overlapping configuration will be omitted.

As shown in FIG. 11, the static sealing ring 200 in the third embodiment is formed so that the notch groove 231 opens into the space on the back surface side. That is, the side plate portion 261 is formed so as to extend axially from the outer diameter side portion of the thin plate portion 251 and connect the outer diameter side portions of the adjacent thick plate portions 241 to each other, and the side plate portion 262 is the thin plate portion. It is formed so as to extend axially from the inner diameter side portion of 251 and connect the inner diameter side portions of adjacent thick plate portions 241 to each other.

Since the static sealing ring 200 is provided with side plate portions 261,262 on the inner diameter side and the outer diameter side of the thin plate portion 251, it shrinks when the pressure of the sealed liquid F is applied as compared with the embodiment of the first embodiment. Although it is difficult to measure the diameter, since the structural strength is secured, it is possible to prevent damage to the static sealing ring 200.

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 within the scope of the gist of the present invention are included in the present invention. Is done.

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

Further, in the above embodiment, the embodiment in which the thick plate portions 14 are evenly arranged in the circumferential direction is illustrated, but the length and quantity of the thick plate portions in the circumferential direction can be freely changed.

Further, in the above embodiment, the embodiment in which the notch groove 13 is formed in the static sealing ring 10 is illustrated, but the notch groove 13 may be formed in the rotary sealing ring 20, or the notch groove 13 is formed in both of them. It may have been.

Further, in the above embodiment, the form in which the sealed fluid is a liquid has been illustrated, but the sealed fluid may be a gas or a mist in which a liquid and a gas are mixed.

Further, in the above embodiment, the form in which the secondary seal member is arranged on the back surface side of the static sealing ring has been illustrated, but the present invention is not limited to this, and for example, the secondary sealing member may be arranged on the outer diameter side of the static sealing ring. .. That is, a high pressure may be applied to the surface of the side plate portion on the sealed fluid side, for example, in the first embodiment, the outer peripheral surface of the side plate portion 16.

1 Mechanical seal 3 Rotating shaft 6 Secondary seal 7 Recess 8 Convex part 10, 10'Static 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 Rotational sealing ring (the other sealing ring)
21 Sliding surface 100 Static sealing ring 121 Nose part 131 Notch groove 141 Thick plate part (thick part)
151 Thin plate part 161 Side plate part 171 Pressure receiving part 200 Static sealing ring 231 Notch groove 241 Thick plate part (thick part)
251 Thin plate part 261,262 Side plate part A Atmosphere F Sealed liquid (sealed fluid)

Claims (6)

A mechanical seal that has a pair of sealing rings that slide relative to each other and seals the fluid to be sealed.
One sealing ring is provided with a plurality of notched grooves that are radially separated from the sealed fluid in the radial direction and open at least on the back surface side, and the notched grooves and the sealed fluid side are arranged. An annular secondary seal member is arranged between the space and the space.
The notch groove is a mechanical seal whose axial dimension is larger than the circumferential dimension of the end portion radially opposite to the sealed fluid. The mechanical seal according to claim 1, wherein each of the cutout grooves is plane-symmetrical in the circumferential direction with respect to a reference plane extending radially from the center of the one sealing ring. The circumferential dimension of the end portion of the thick portion formed between the adjacent notch grooves on the opposite side of the sealed fluid from the sealed fluid has a diameter different from that of the sealed fluid in the circumferential direction of the notch groove. The mechanical seal according to claim 1 or 2, which is longer than the dimension of the end opposite to the direction. On the other sealing ring side of the one sealing ring, a nose portion having a sliding surface that projects in a stepwise manner in the axial direction and slides with the other sealing ring is provided in an annular shape in the circumferential direction. The mechanical seal according to any one of claims 1 to 3. The end portion of the sliding surface on the side opposite to the sealed fluid in the radial direction is arranged on the side opposite to the sealed fluid in the radial direction with respect to the radial end portion on the sealed fluid side in the notch groove. Item 4. The mechanical seal according to Item 4. The mechanical seal according to any one of claims 1 to 5, wherein the one sealing ring is integrally formed.

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