JP6924060B2 - mechanical seal - Google Patents

Description

The present invention relates to a mechanical seal used as a shaft sealing means for industrial equipment such as a stirrer.

As a mechanical seal used as a shaft sealing means for a stirrer or the like, the contact portion between the static sealing ring provided on the seal case and the rotating sealing ring provided on the rotating shaft rotates relative to each other, so that the outer periphery of the contact portion is rotated. It is known that the side fluid region and the inner peripheral side fluid region are configured to shield and seal.

Therefore, in such a mechanical seal, frictional heat is generated by the relative rotation of the contact portions of both sealing rings, and the frictional heat becomes excessive, so that the contact portion is seized, abnormal wear or distortion. There is a risk of causing troubles such as the occurrence of.

Therefore, in the conventional mechanical seal, as disclosed in Patent Document 1, a cooling fluid is supplied from the outside to the contact portion of both sealing rings to cool the contact portion.

WO2006 / 022378

However, since the mechanical seal disclosed in Patent Document 1 requires a supply source and supply equipment for a cooling fluid, equipment costs and installation construction costs are incurred, and maintenance costs such as running costs are also high.

An object of the present invention is to provide a mechanical seal capable of efficiently cooling the contact portion of both sealing rings without requiring such a cooling fluid supply source or supply equipment. ..

In the present invention, in order to achieve the above object, the rotary sealing ring provided on the rotating shaft has a main body portion and a sealed end face forming portion having a diameter smaller than that of the main body portion and projecting from the tip surface of the main body portion. The contact portion between the sealed end face forming portion of the rotary sealing ring and the static sealing ring provided on the seal case rotates relative to each other, so that the outer peripheral side fluid region and the inner peripheral side region of the contact portion are separated from each other. It is configured to shield and seal, and the main body of the rotary sealing ring has a cooling passage that penetrates from an inlet portion that opens on the outer peripheral surface to an outlet portion that opens in the vicinity of the sealed end surface forming portion on the tip surface thereof. We propose a mechanical seal in which is formed.

In such a mechanical seal, the main body of the rotary sealing ring is provided with a cylindrical cover body that is close to the static sealing ring and surrounds the outer peripheral region of the sealing end face forming portion, or the seal case is provided with a cylindrical cover body. , It is preferable to provide a cylindrical cover body that is close to the main body of the rotary sealing ring and surrounds the outer peripheral region of the sealing end face forming portion. Further, it is preferable that an annular recess is formed on the tip surface of the static sealing ring so as to face the outlet portion of the cooling passage and in the outer peripheral region of the contact portion.

According to the mechanical seal of the present invention, the fluid in the fluid region on the outer peripheral side of the contact portion of both sealing rings is discharged from the outlet portion of the cooling passage toward the contact portion as the rotary sealing ring rotates. The discharged fluid can effectively cool the contact portion without the need for a cooling fluid supply source or supply equipment. In particular, by providing the cover body in the main body or the seal case of the rotary sealing ring and / or forming the annular recess in the tip surface of the static sealing ring, the discharged fluid can be discharged into the cover body or in the cover body or by forming the annular recess. Since it is actively circulated in the annular recess, heat exchange between the contact portion of both sealing rings and the discharged fluid is sufficiently performed, and the contact portion is cooled more effectively.

It is sectional drawing which shows an example of the mechanical seal which concerns on this invention. It is a detailed view which shows the main part of FIG. 1 in an enlarged manner. It is sectional drawing of the main part along the line AA of FIG. It is sectional drawing of the main part corresponding to FIG. 2 which shows the modification of the mechanical seal which concerns on this invention. It is sectional drawing of the main part corresponding to FIG. 2 which shows the other modification of the mechanical seal which concerns on this invention. It is sectional drawing of the main part corresponding to FIG. 2 which shows the further modification example of the mechanical seal which concerns on this invention. It is sectional drawing of the main part corresponding to FIG. 2 which shows the further modification example of the mechanical seal which concerns on this invention. It is sectional drawing of the main part corresponding to FIG. 2 which shows the further modification example of the mechanical seal which concerns on this invention.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of a mechanical seal according to the present invention, FIG. 2 is a detailed view showing an enlarged main part of FIG. 1, and FIG. 3 is a main part along the line AA of FIG. It is a cross-sectional view of.

The mechanical seal shown in FIG. 1 is used as a shaft sealing means for a rotating device such as a stirrer, and is provided on the annular seal case 2 attached to the shaft sealing portion housing 1 of the rotating device and the seal case 2. The static sealing ring 3 is arranged between the static sealing ring 3 and the spring retainer 5 fixed to the rotating shaft 4 of the rotating device which penetrates the seal case 2 concentrically, and the static sealing ring 3 and the spring retainer 5. The rotary sealing ring 6 provided so as to be movable in the axial direction in 4 and the rotary sealing ring 6 loaded between the spring retainer 5 and the rotary sealing ring 6 are pressed against the static sealing ring 3 and brought into contact with the rotary sealing ring 3 in the axial direction. It is provided with a spring member 7 attached to the surface.

The mechanical seal rotates relative to each other while the static sealing ring 3 and the rotating sealing ring 6 are in contact with each other, so that the inner peripheral side fluid region H of the sealing end faces 3b and 6a as the contact portion of both sealing rings 3 and 6 and the outer periphery thereof. It is configured to shield and seal the side fluid region L. In this example, the mechanical seal is an outside type mechanical seal in which the fluid region H on the inner peripheral side of the sealed end faces 3b, 6a of both sealing rings 3 and 6 is the in-flight region and the fluid region L on the outer peripheral side thereof is the atmospheric region. Has been done.

As shown in FIG. 1, the rotary sealing ring 6 is an appropriate sealing ring material selected according to sealing conditions such as the properties of the fluid in the inner peripheral side fluid region H (hereinafter, also referred to as a sealed fluid), and will be described later. It is made of a material softer than the static sealing ring 3 (for example, carbon or the like). The rotary sealing ring 6 includes an annular main body portion 9, an annular sealed end surface forming portion 10 that is concentric with the main body portion 9 and protrudes in the axial direction from the tip surface 9b of the main body portion 9, and a base of the main body portion 9. It is composed of an annular holding portion 11 which is concentrically connected to the main body portion 9 on the end surface. The rotary sealing ring 6 is held so as to be movable in the axial direction with respect to the rotary shaft 4 with an O-ring 12 interposed between the holding portion 11 and the rotary shaft 4.

The sealed end face forming portion 10 of the rotary sealing ring 6 has an outer diameter smaller than the outer diameter of the main body portion 9 and an inner diameter thereof formed to be the same as the inner diameter of the main body portion 9 or larger than the inner diameter of the main body portion 9. Is the part of. The sealed end surface 6a formed at the tip of the sealed end surface forming portion 10 is formed of an annular smooth flat surface whose entire surface is orthogonal to the axial direction.

The outer diameter of the holding portion 11 of the rotary sealing ring 6 is set to be the same as the outer diameter of the main body portion 9 or smaller than the outer diameter of the main body portion 9, and the inner diameter thereof is set to be larger than the inner diameter of the main body portion 9. It is an annular part. A holding ring 13 having a substantially L-shaped cross section is fitted to the holding portion 11.

The holding ring 13 is an integral structure including a cylindrical portion 13a that fits on the outer peripheral surface of the holding portion 11 of the rotary sealing ring 6 and an annular plate portion 13b that contacts the base end portion of the holding portion 11. .. The holding ring 13 prevents relative rotation with respect to the rotary sealing ring 6 by engaging the drive pin 14a attached to the annular plate portion 13b with the engaging hole 11a formed at the base end portion of the holding portion 11. Has been done.

As shown in FIG. 1, the static sealing ring 3 is an annular body made of a material harder than the rotary sealing ring 6 such as ceramics such as silicon carbide and cemented carbide, and is located on the inner peripheral side of the seal case 2. It is fitted and fixed via O-rings 8 and 8. The outer diameter of the tip surface 3a of the static sealing ring 3 is formed to be larger than the outer diameter of the sealed end surface 6a of the rotary sealing ring 6, and the inner diameter thereof is formed to be smaller than the inner diameter of the sealed end surface 6a. The tip surface 3a of the static sealing ring 3 is formed of an annular smooth plane orthogonal to the axial direction. The sealed end surface 6a of the rotary sealing ring 6 is in contact with the tip surface 3a, and a sealed end surface 3b having the same inner and outer diameters as the sealed end surface 6a is formed.

The spring retainer 5 is inserted between the annular portion 5a fixed to the rotary shaft 4 by the set screw 15 and the holding portion 11 of the rotary sealing ring 6 and the rotary shaft 4 protruding from the inner peripheral side thereof. It is a cylindrical integral structure composed of a cylindrical portion 5b. The O-ring 12 is loaded in an annular space surrounded by a holding portion 11 of the rotary sealing ring 6, a main body 9 of the rotary shaft 4 and the rotary sealing ring 6, and a cylindrical portion 5b of the spring retainer 5. An insertion hole 5c through which a drive pin 14b attached to the holding ring 13 is inserted is formed in the annular portion 5a of the spring retainer 5. By inserting the drive pin 14b into the insertion hole 5c, the rotary sealing ring 6 is prevented from rotating relative to the rotating shaft 4 in a state where the rotary sealing ring 6 is allowed to move in the axial direction within a predetermined range.

The spring member 7 is a plurality of coil springs (only one is shown in FIG. 1) loaded between the annular portion 5a of the spring retainer 5 and the annular plate portion 13b of the holding ring 13, and the holding ring 13 The rotary sealing ring 6 is urged to be pressed against the static sealing ring 3 via the above, and the sealing end surface 6a of the rotary sealing ring 6 is brought into contact with the sealed end surface 3b of the static sealing ring 3.

Thus, the main body 9 of the rotary sealing ring 6 is formed with an inlet portion 16a that opens on the outer peripheral surface 9a, and opens from the inlet portion 16a to the vicinity of the sealed end surface forming portion 10 on the tip surface 9b thereof. A plurality of cooling passages 16 penetrating the outlet portion 16b are formed at equal intervals in the circumferential direction of the main body portion 9.

In each cooling passage 16, as shown in FIG. 2, the fluid F in the outer peripheral side fluid region L flows into the cooling passage 16 from the inlet portion 16a as the rotary sealing ring 6 rotates, and exits in the cooling passage 16. After moving toward the portion 16b, the fluid is discharged from the outlet portion 16b toward the sealed end faces 3b, 6a of both sealing rings 3, 6. In this example, the cooling passage 16 is a through hole having a circular cross section formed linearly so as to form an inclination angle shown in FIGS. 2 and 3. A circular inlet portion 16a and an outlet portion 16b are formed.

That is, as shown in FIG. 2, each cooling passage 16 is formed so that the outlet portion 16b has an inclination angle that deviates by a predetermined angle α in the inner peripheral direction of the rotary sealing ring 6 with respect to the inlet portion 16a. As shown in the above, the surface of the rotary sealing ring 6 that passes through the center line, and the inlet portion 16a is the rotation direction of the rotary sealing ring 6 (rotational direction of the rotary shaft 4) R with respect to the surface X that passes through the outlet portion 16b. It is formed so as to have an inclination angle that deviates by a predetermined angle β. Here, α is preferably 5 ° or more and 45 ° or less. Further, β is preferably 10 ° or more and 75 ° or less, and more preferably 40 ° or more and 75 ° or less.

In the mechanical seal configured as described above, the fluid (for example, air or water) F in the fluid region L on the outer peripheral side is taken into the cooling passage 16 from the inlet portion 16a by rotating the rotary sealing ring 6. Then, the fluid is discharged from the outlet portion 16b toward the sealed end faces 3b, 6a of both sealing rings 3, 6. Then, the sealed end faces 3b and 6a are heat-exchanged and cooled by contact with the fluid (hereinafter, also referred to as discharge fluid F) F discharged from the outlet portion 16b of the cooling passage 16. As a result, troubles such as seizure due to frictional heat on the sealed end faces 3b and 6a, abnormal wear, and distortion are prevented.

Hereinafter, other embodiments will be described. Cooling of the sealed end faces 3b, 6a of both sealing rings 3, 6 by the discharge fluid F from the outlet portion 16b of the cooling passage 16 is more effective by devising, for example, as shown in FIGS. 4 to 8. It can be carried out.

That is, as shown in FIG. 4, it is the tip surface 3a of the static sealing ring 6, and the sealing rings 3 and 6 are sealed on the outer peripheral side of the sealing end surface 3b so as to face the outlet portion 16b of the cooling passage 16. An annular recess 17 is formed so as to surround the outer peripheral regions of the end faces 3b and 6a. By forming such an annular recess 17, the discharge fluid F from the outlet portion 16b of the cooling passage 16 can be discharged from the sealed end faces 3b, 6a of both sealing rings 3, 6 as shown in FIG. It enters the inside and becomes a circulating flow toward the rotary sealing ring 6, and the contact time between the discharge fluid F and the sealing end faces 3b and 6a increases. As a result, heat exchange between the sealed end faces 3b and 6a and the discharge fluid F is performed more satisfactorily, and the sealed end faces 3b and 6a are cooled more effectively by the discharge fluid F.

The annular recess 17 has an inner peripheral surface 17a whose diameter gradually increases toward the opening (rotary sealing ring 6 side) of the recess 17, and an outer peripheral surface 17b whose diameter gradually increases toward the opening of the annular recess 17. And the connecting surface connecting the inner peripheral surface 17a and the outer peripheral surface 17b, so that the discharge fluid F flows more smoothly in the annular recess 17.

Further, as shown in FIG. 5, the main body 9 of the rotary sealing ring 6 has a cylindrical cover that surrounds the outer peripheral region of the sealed end face forming portion 10 of the rotary sealing ring 6 in a state close to the static sealing ring 3. The body 18 is provided. In this example, the cylindrical portion 13a of the holding ring 13 is extended to the vicinity of the tip surface 3a of the static sealing ring 3, and the extended portion is integrally formed with the cover body 18. The cover body 18 is formed with a through port 18a connecting the inlet portion 16a of each cooling passage 16 and the fluid region L on the outer peripheral side. The through port 18a is an opening that takes in the fluid in the fluid region L on the outer peripheral side and flows it toward the cooling passage 16.

By providing such a cover body 18, the discharge fluid F from the outlet portion 16b of the cooling passage 16 can be brought into the cover body 18 and the static sealing ring 3 from the sealing end faces 3b and 6a of both sealing rings 3 and 6. It actively flows into the gap 18b, and the discharged fluid F is circulated by repeating this flow. From this, the discharge fluid F and the sealed end faces 3b, 6a are sufficiently brought into contact with each other, and the sealed end faces 3b, 6a are cooled more effectively. The cover body 18 is not an extension of the cylindrical portion 13a of the holding ring 13, but may be attached to the main body portion 9 of the rotary sealing ring 6 as a separate body. In this case, the cover body 18 can have a halved structure in which two semi-cylindrical members are formed into a cylindrical shape and attached to the main body 9 of the rotary sealing ring 6.

Further, as shown in FIG. 6, the seal case 2 has a cylindrical cover body that surrounds the outer peripheral region of the sealed end face forming portion 10 of the rotary sealing ring 6 in a state of being close to the main body 9 of the rotary sealing ring 6. 19 is attached via fixing means. By providing such a cover body 19, the discharge fluid F from the outlet portion 16b of the cooling passage 16 can be discharged from the sealed end faces 3b of both sealing rings 3 and 6 as in the case where the cover body 18 is provided. The discharge fluid F is circulated from 6a to the gap 19a between the cover body 19 and the main body 9 of the rotary sealing ring 6 by repeating this flow. From this, the discharge fluid F and the sealed end faces 3b, 6a are sufficiently brought into contact with each other, and the sealed end faces 3b, 6a are cooled more effectively. The cover body 19 can have a halved structure in which two semi-cylindrical members are formed into a cylindrical shape and attached to the main body 9 of the rotary sealing ring 6.

Further, in the one shown in FIG. 7 or 8, the annular recess 17 and the cover body 18 or the cover body 19 are combined, and both sealing rings 3 and 6 by the discharge fluid F from the outlet portion 16b of the cooling passage 16 Cooling of the sealed end faces 3b and 6a of the above is performed more effectively.

That is, in the one shown in FIG. 7, both the sealing rings 3 are formed from the outlet portion 16b by the cover body 18 protruding from the main body portion 9 of the rotary sealing ring 6 and the annular recess 17 formed on the tip surface 3a of the static sealing ring 3. The flow of the discharge fluid F toward the sealed end faces 3b, 6a of, 6 is performed more strongly, and the cooling of the sealed end faces 3b, 6a by the discharge fluid F is performed extremely effectively.

Further, in the one shown in FIG. 8, the cover body 19 protruding from the seal case 2 and the annular recess 17 formed on the tip surface 3a of the static sealing ring 3 from the outlet portion 16b to the sealing end faces of both sealing rings 3 and 6. The flow of the discharge fluid F toward 3b and 6a is performed more strongly, and the sealing end faces 3b and 6a are cooled by the discharge fluid F extremely effectively.

The configuration of the present invention is not limited to the above-described embodiments, and can be appropriately improved or modified without departing from the basic principles of the present invention.

For example, in each of the above embodiments, the present invention is applied to an outside type mechanical seal in which the outer peripheral fluid region L is an unsealed fluid region, and the fluid in the unsealed fluid region is applied to the sealed end faces of both sealed rings 3 and 6. Although it was used as the discharge fluid F which is the cooling fluid of 3b and 6a, the present invention is applied to an inside type mechanical seal in which the outer peripheral fluid region of the sealed end surface 3b and 6a is the sealed fluid region (internal region). It is also possible to use the sealed fluid (process fluid) as the discharge fluid F, which is the cooling fluid of the sealed end faces 3b, 6a, regardless of whether it is a gas or a liquid. Further, each cooling passage 16 is not limited to the above-mentioned linear shape. For example, an opening is formed from the outer peripheral surface 9a of the main body 9 toward the rotation shaft 4 side, an opening is formed from the tip surface 9b of the main body 9 toward the holding ring 13 side, and communication is performed at the intersection of both openings. It may form a polygonal line shape as described above. By doing so, each cooling passage 16 can be easily formed and processed.

2 Seal case 3 Static sealing ring 3a Tip surface 3b Sealed end face 4 Rotating shaft 6 Rotating sealing ring 6a Sealed end face 9 Main body 9a Peripheral surface 9b Tip surface 10 Sealed end face forming part 16 Cooling passage 16a Inlet part 16b Exit part 17 Ring recess 18 Cover body 19 Cover body F Fluid H Inner peripheral fluid region L Outer peripheral fluid region

Claims (1)

The rotary sealing ring provided on the rotating shaft includes a main body portion and a sealed end surface forming portion having a diameter smaller than that of the main body portion and projecting from the tip surface of the main body portion.
The contact portion between the sealed end face forming portion of the rotary sealing ring and the static sealing ring provided on the seal case rotates relative to each other so as to shield and seal the outer peripheral side fluid region and the inner peripheral side region of the contact portion. Has been
The main body of the rotary sealing ring is formed with a linear cooling passage that penetrates from an inlet portion that opens to the outer peripheral surface to an outlet portion that opens from the sealed end surface forming portion on the tip surface to the outlet portion that opens to the outer peripheral portion. Is biased toward the inner peripheral direction of the rotary sealing ring with respect to the inlet portion and is biased in the direction opposite to the rotational direction of the rotary sealing ring .
A cylindrical cover body surrounding the outer peripheral region of the sealed end surface forming portion is provided on the outer peripheral surface of the main body portion.
A mechanical seal on the tip surface of the static sealing ring, which faces the outlet portion of the cooling passage and has an annular recess formed in the outer peripheral region of the contact portion.

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