JP2020125805A - mechanical seal - Google Patents

Abstract

To provide a mechanical seal capable of adjusting energization force of energization means acting between sliding end surfaces of a stationary seal ring and a rotary seal ring with high accuracy, while being easily assembled in a fluid device.SOLUTION: In a stationary mechanical seal 1 having a rotary seal ring 5 rotating with a rotating shaft 3 inserted to a through hole of a housing 2, a stationary seal ring 4 forming a slide contact portion with the rotary seal ring 5, and energization means 9 for energizing the stationary seal ring 4 toward the rotary seal ring 5, an annular sleeve 15 constituting a stationary unit U by assembling the stationary seal ring 4 and the energization means 9, and a ring member 17 for detachably externally fitting and fixing the sleeve 15 in a sealed state in a manner of not relatively rotatable, at an opening side of the housing 2 with respect to the stationary seal ring 4, and being fixed to the housing 2 in a sealed state in a manner of not relatively rotatable.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mechanical seal used as a shaft sealing component such as a drive shaft of fluid equipment.

The mechanical seal is used by being installed between the housing of the fluid device and the rotary shaft arranged so as to penetrate the housing, and the stationary seal ring fixed to the housing of the fluid device and the rotary shaft. A rotary seal ring that rotates together with the rotary seal ring is urged by an urging means in the axial direction to bring the sliding end faces of the stationary seal ring and the rotary seal ring into sliding contact with each other to form a sliding contact portion. The fluid is prevented from leaking from the inside to the outside or from the outside to the inside.

As the mechanical seal, there is a static mechanical seal in which a static sealing ring and a biasing means are incorporated in an annular case (see Patent Document 1). In the mechanical seal of Patent Document 1, the case includes an outer peripheral cylindrical portion that is fitted and fixed to the inner peripheral surface of the housing of the fluid device, and an inner peripheral cylindrical portion that is provided around the outer peripheral surface of the rotating shaft in a separated state, and is statically sealed. The ring is externally fitted and held on one end side in the longitudinal direction of the inner peripheral tubular portion via an O-ring which is a sealing member. A ring-shaped member is attached to the outer periphery of the stationary seal ring so as not to rotate, and the ring-shaped member and the inner peripheral cylindrical portion of the housing are relatively movable in the axial direction of the rotating shaft via the biasing means and are prevented from rotating. Connected. The rotary seal ring is fitted and attached via a gasket to the inner peripheral surface of the step portion formed on the inner diameter side of the impeller that constitutes the fluid device and rotates together with the rotary shaft.

Japanese Utility Model Publication No. 2-5654 (page 8, FIG. 1)

As described above, in the mechanical seal of Patent Document 1, the stationary seal ring, the urging means, the ring-shaped member, and the O-ring are incorporated in the case and can be handled as an integrated stationary unit. It can be easily assembled to the housing. Further, the stationary unit and the fixed ring are fitted and attached in directions opposite to the housing and the impeller, respectively. The static sealing ring is pressed by the biasing means and the sliding end faces of the static sealing ring and the rotary sealing ring are pressed against each other, so that the sealed state can be maintained for a long period of time. .. However, if such a configuration is adopted, the urging force of the urging means acting between the sliding end faces of the stationary seal ring and the rotary seal ring depends on the axial installation position of the housing and the impeller. However, there was a problem that the pressure contact force related to the sealing performance of the mechanical seal could not be set finely.

The present invention has been made in view of such a problem, and is capable of easily assembling to a fluid device, while applying a biasing force acting between sliding end faces of a stationary seal ring and a rotary seal ring. An object of the present invention is to provide a mechanical seal capable of adjusting the biasing force of the means with high accuracy.

In order to solve the above problems, the mechanical seal of the present invention,
A rotary seal ring that rotates together with a rotary shaft that is inserted into a through hole of the housing, a stationary seal ring that forms a sliding contact portion with the rotary seal ring, and a biasing member that biases the static seal ring toward the rotary seal ring. In a static mechanical seal having a biasing means,
An annular sleeve that constitutes the stationary unit by assembling the stationary seal ring and the biasing means,
A ring member for removably fitting and fixing the sleeve in a sealed state so as to be relatively non-rotatable on the opening side of the housing with respect to the stationary sealing ring, and fixed to the housing in a non-rotatable state in the sealed state. That is a feature.
According to this feature, since the sleeve is fixed to the housing by the ring member on the opening side of the housing and the sleeve is detachably fixed to the ring member, it is easy to attach and detach the annular sleeve that constitutes the stationary unit. In addition, by changing the axial length of the ring member and using the gap adjusting member, the biasing force of the biasing means acting between the sliding end faces of the stationary seal ring and the rotary seal ring can be accurately adjusted. can do.

A part of the ring member is axially inserted into the inner peripheral step of the housing.
According to this, the ring member can be easily assembled to the housing.

The ring member has an inward flange extending toward the inner diameter side with respect to the inner peripheral surface on which the sleeve is fitted.
According to this, the assembly of the sleeve and the ring member is simple.

The ring member is fixed to the housing with fastening screws in the axial direction, and the sleeve is fixed to the ring member with fastening screws in the axial direction.
According to this, since the sleeve and the ring member are fixed from the same direction by the respective fastening screws, the stationary unit can be easily attached and detached.

A rubber bellows is disposed on the inner diameter side of the urging means, and the rubber bellows is fixed to the stationary seal ring and the sleeve in a sealed state.
According to this, since the rubber bellows is elastically deformable, it is difficult for an unbalanced pressure to act on the stationary seal ring.

On the outer diameter side of the rubber bellows, a case member is provided, which fixes and attaches the rubber bellows to the outer peripheral surface of the sleeve in a compressed state, and one end of the urging means abuts. One end is in contact with the sleeve.
According to this, since the urging force of the urging means is transmitted from the case member to the sleeve in the axial direction, the axial position of one end of the urging means does not change, and the urging force is maintained at a desired value. You can

The rotary seal ring is made of ceramics as a main component, and the stationary seal ring is made of carbon as a main component.
According to this, since the rotary seal ring is relatively hard to wear, the biasing force can be set to a desired value by replacing the stationary unit together.

FIG. 3 is a side sectional view showing the structure of the fluid device in which the mechanical seal according to the first embodiment of the present invention is used. It is a side sectional view showing structure of a rotation side element. It is a sectional side view which shows a stationary unit. (A) is a side sectional view showing a state in which a ring member having a long base is attached to a stationary unit, and (b) is a state showing a ring member having a short base attached to a stationary unit. It is a side sectional view shown.

Modes for carrying out the mechanical seal according to the present invention will be described below based on Examples.

A mechanical seal according to an embodiment will be described with reference to FIGS. 1 to 4.

In FIG. 1, the left side of the drawing is the inner side M, and the right side is the atmosphere side A.
In the mechanical seal 1 shown in FIG. 1, seal components such as a stationary seal ring 4 and a rotary seal ring 5 are attached to a shaft sealing portion formed between a housing 2 and a rotary shaft 3 to form a housing 2 and a rotary shaft. A coil spring 9 is a mechanical seal that seals between the stationary seal ring 4 and the rotary seal ring 5, and is disposed on the stationary side as a biasing means that applies a sealing surface pressure between the stationary seal ring 4 and the rotary seal ring 5. The mechanical seal 1 shown in FIG. 1 shows a mode in which the rotary element R described later is attached to the rotary shaft 3 and the stationary element S described later is attached to the housing 2 so that the mechanical seal 1 can be used.

The rotation-side element R attached to the rotation shaft 3 will be described with reference to FIG. The rotary element R is mainly composed of a collar 17, a set screw 18, a rotary seal ring 5, and a packing 21. The rotary seal ring 5 is mainly composed of ceramics, and the packing 21 and the rotary seal ring 5 are assembled from the opening 17a side formed on the collar 17 in the axial atmosphere side. It is attached to the rotating shaft 3. The concave portion on the outer circumference of the rotary seal ring 5 is fitted in the convex and concave portions on the inner circumference of the collar 17 so that it cannot rotate relative to the collar 17. Note that the configuration that makes relative rotation impossible is not limited to concave and convex fitting.

A set screw 18 is screwed into the hole 17b of the collar 17 in the radial direction. In this way, the collar 17, the set screw 18, the rotary seal ring 5, and the packing 21 are integrated as the rotary side element R. The rotation-side element R is fitted onto the rotation shaft 3.

After fixing the rotary side element R to the rotary shaft 3 with the set screw 18, the housing 2 is fixed to the main body of the fluid machine. In this way, the rotation-side element R is arranged in the space C between the inner peripheral surface of the housing 2 and the outer peripheral surface of the rotary seal ring 5.

FIG. 3 is a view showing the stationary side element S. Mainly, the stationary side element S includes a stationary sealing ring 4 formed mainly of carbon, a rubber bellows 10, a case 11, and a coil spring 9. The sleeve 15, the O-ring 16, and the ring member 7 are included. Further, the stationary seal ring 4, the rubber bellows 10, the case 11, the coil spring 9, the sleeve 15, and the O-ring 16 constitute a stationary unit U that is integrally united, and can be carried or the housing 2 It is easy to attach to.

On the outer periphery of the sleeve 15 having an inner diameter slightly separated from the outer peripheral surface of the rotary shaft 3, a stationary seal ring 4 having a sliding surface in sliding contact with the rotary seal ring 5 described above, and a rubber as a shaft packing of the stationary seal ring 4 are provided. A bellows 10 is arranged. A space between the stationary seal ring 4 and the sleeve 15 is radially sealed by a rubber bellows 10, and a case 11 is externally fitted to the rubber bellows 10.

The rubber bellows 10 is formed of, for example, an elastic material such as a rubber material, and the tip of a cylindrical portion extending in the axial direction extends in the inner side M direction to form a tip neck portion 10a. The metal case 11 is fitted in the outer periphery of the stationary seal ring 4 and radially compressed between the inner side of an annular end portion 13a of an outer case 13 to be described later of the metal case 11 and the stationary seal ring 4. 11 and the stationary seal ring 4 are fixed in a sealed state. Further, the tip neck 10a is in close contact with the back surface 4a of the stationary seal ring 4. Further, the outer diameter side of the base portion 10b of the rubber bellows 10 is radially compressed and tightened by an intermediate portion 12c of an inner case 12 described later of the case 11 fitted to the outer peripheral surface thereof, and the outer peripheral surface of the sleeve 15 is tightened. It is crimped in a sealed state with an appropriate tightening margin. In this way, the inner case 12 is attached so as not to rotate relative to the sleeve 15.

The case 11 includes an annular inner case 12 that is a case member and an annular outer case 13 that is a case member. The inner case 12 is composed of an annular end portion 12a, an annular intermediate portion 12c having a smaller diameter than the end portion 12a, and an engagement piece 12d formed by bending the intermediate portion 12c and extending in the axial direction and equally arranged in the circumferential direction. There is. The outer case 13 has an end portion 13a on the stationary seal ring 4 side, an annular radial plate portion 13b connected to the end portion 13a, and a diameter smaller than that of the end portion 13a. It is formed of engaging pieces 13c which are equally arranged in the direction.

The coil spring 9 is arranged so that both ends contact the radial plate portions 12b and 13b. The outer case 13 is axially movable by sliding the engagement pieces 12d and 13c with respect to the inner case 12, and the bent base of the engagement piece 12d and the engagement piece 13c are engaged in the circumferential direction. It is arranged so that it cannot rotate relative to each other. Further, the end portion 12a of the inner case 12 is in contact with the sleeve 15, and the inner case 12 is in contact with the radial surface 15d of the base portion 15a of the sleeve 15, so that the movement toward the atmospheric side A in the axial direction is restricted. There is. Further, the bent piece 13e formed on the end portion 13a of the outer case 13 is engaged with the slit on the outer periphery of the stationary seal ring 4 so that the stationary seal ring 4 does not rotate relative to the outer case 13. ..

The sleeve 15 is formed in a thin hollow cylindrical shape having an inner diameter slightly larger than the outer diameter of the rotating shaft 3. Specifically, the sleeve 15 has a long side in the axial direction of the rotating shaft 3 and includes a thick base portion 15a on the atmosphere side A in the longitudinal direction, and the base portion 15a is provided with an internal thread in the axial direction. The formed screw hole 15b is formed. Further, an annular groove 15c is formed on the outer diameter side of the base portion 15a so as to be recessed on the inner diameter side, and an O-ring 16 is arranged in the groove 15c. The O-ring 16 is compressed by the ring member 7 and the concave groove 15c of the sleeve 15 described later, and prevents the sealed fluid from leaking to the atmosphere side A.

Further, the concave groove 15c in which the O-ring 16 is arranged may be provided on the inner circumference of the ring member 7 described later. In addition, it is preferable that the O-ring 16 is not disposed at the end portion in the axial direction. Since the O-ring 16 is provided between the sleeve 15 and the ring member 7 in the radial direction, the biasing force of the coil spring 9 is not affected when the fastening screw 19 is fixed.

An annular step portion 2a having an inner peripheral surface having a diameter larger than that of the inner peripheral surface of the machine-inside M is formed near the opening on the atmosphere side A side of the housing 2, and the step portion 2a has a ring member described later. The tip portion 7c of 7 can be inserted from the axial direction.

The ring member 7 has an annular shape in which a hole through which the rotary shaft 3 is inserted is formed in the center, and a tip portion 7c of a substantially cylindrical convex portion that can be mainly inserted into the step portion 2a in the housing 2 described above. And a ring member 7 which is composed of a base portion 7b having a through hole 7a formed in contact with the side wall of the housing 2 and extending in the axial direction, and an inner flange 7f having an through hole 7d extending in the inner diameter direction on the atmosphere side of the base portion 7b. A stationary unit U is arranged between the rotating shafts 3.

A mode in which the stationary unit U is attached to the housing 2 will be described. After attaching the O-ring 14 to the housing 2 with reference to FIG. 2, referring to FIG. 1, the O-ring 14 is attached to the screw hole 15b formed in the sleeve 15 of the stationary unit U in the axial direction from the through hole 7d of the ring member 7. A headed fastening screw 19 having a male screw is inserted, and the stationary unit U and the ring member 7 are screwed together to assemble the stationary element S. Then, the stationary side element S, which is integrally formed as a unit, is inserted into the rotating shaft 3 and is brought closer to the inside M of the machine from the vicinity of the opening of the housing 2, and the sliding surfaces of the rotating seal ring 5 and the stationary seal ring 4 are contacted with each other. Contact.

Then, after the through hole 7a formed in the base portion 7b of the ring member 7 and the screw hole 2c formed in the side wall of the housing 2 are aligned, a headed fastening screw 20 having a male screw is axially attached. The stationary side element S is attached to the housing 2 by screwing and fastening the ring member 7 and the housing 2. As a result, the coil spring 9 is compressed in the axial direction, and the desired urging force is transmitted from the back side of the stationary seal ring 4, so that the sliding surface of the stationary seal ring 4 and the sliding surface of the rotary seal ring 5 are appropriate. It is designed to be pressed with various pressures.

When changing the urging force of the stationary seal ring 4 of the stationary element S against the rotary seal ring 5, the base portion 7b of the ring member 7 shown in FIG. The ring member 70 is formed in a small size, or the ring member 71 is formed in a short size by shortening the base portion 7b of the ring member 7 shown in FIG. 4B in the axial direction.

When weakening the urging force of the stationary seal ring 4 against the rotary seal ring 5, as shown in FIG. 4(a), a ring member 70 is used in which the base portion 7b extends in the axial direction and is elongated. In the base portion 70a of the ring member 70, since the distance X from the contact portion with the side wall of the housing 2 to the end portion on the atmosphere side A is long, the biasing force to the coil spring 9 is weakened and the coil spring 9 The biasing force transmitted from the to the stationary seal ring 4 is weakened.

To increase the urging force of the stationary seal ring 4 against the rotary seal ring 5, as shown in FIG. 4B, a ring member 71 is used in which the base portion 7b is shortened in the axial direction and formed in a short size. The base portion 71a of the ring member 71 has a short distance Y from the contact portion with the side wall of the housing 2 to the end portion on the atmosphere side A. Therefore, the biasing force to the coil spring 9 is increased, and the coil spring 9 is strengthened. The biasing force transmitted from the to the stationary seal ring 4 is strengthened.

In this way, the stationary unit U is arranged inside the step 2a outside the rotary shaft 3 on the opening side of the step seal 2a with respect to the rotary seal ring 5, is fitted onto the sleeve 15, and is attached to the step 2a of the housing 2. The ring member 7 fixed to the outside is immovably fixed to the housing 2 in the axial direction and the rotation direction. Since the stationary unit U and the ring member 7 are fixed in the same direction, the shaft of the ring member 7 is fixed. By changing the length in the direction, the biasing force of the coil spring 9 acting between the sliding end faces of the stationary seal ring 4 and the rotary seal ring 5 can be adjusted with high accuracy.

Further, since the ring member 7 is inserted into the housing 2 in the same direction as the fastening screw 20 fixed to the housing 2, the ring member 7 is inserted into the ring member 7 with respect to the housing 2. Easy to fix.

Further, since the ring member 7 and the sleeve 15 are connected in the same direction as the inserting direction of the fastening screw 20, the ring member 7 and the housing 2, and the ring member 7 and the sleeve 15 are connected in the same direction, and the mechanical seal 1 Is easy to assemble.

Further, since the ring member 7 is provided with the distal end portion 7c as a cylindrical convex portion that is fitted into the step portion 2a, the temporary installation of the ring member 7 to the housing 2 is easy.

Further, a rubber bellows 10 is disposed on the inner diameter side of the coil spring 9, the stationary seal ring 4 and the case 11 are fixed to each other in a sealed manner, and the rubber bellows 10 is elastically deformable. The biased pressure is less likely to act on the sealing ring 4, which can be relaxed.

Further, on the outer diameter side of the rubber bellows 10, an inner case 12 for fixing the rubber bellows 10 to the outer peripheral surface of the sleeve 15 in a compressed state and contacting one end of the coil spring 9 is provided. Since the end portion 12a of 12 abuts on the radial surface 15d of the sleeve 15, the biasing force of the coil spring 9 is transmitted to the sleeve 15 through the inner case 12 in the axial direction. The axial position does not change, and the biasing force can be maintained at the initial value.

Further, since the rotary seal ring 5 is made of ceramics and the stationary seal ring 4 is made of carbon, it is suitable for long-term use and durability. Further, when the stationary seal ring 4 which is easily worn is replaced with the stationary unit U, maintenance work is simple.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any modifications or additions within the scope of the present invention are included in the present invention. Be done.

For example, although the mechanical seal is described as an example of the inside/fixed type mechanical seal in the above embodiment, the outside type is a type that seals the liquid that is about to leak from the inner circumference to the outer circumference of the sliding surface. It can also be applied to mechanical seals.

Further, the biasing force is adjusted by changing the length of the base portion 7b of the ring member 7, but this is not restrictive, and the side wall 7e of the ring member 7 and the side wall 2d of the housing 2 on the atmosphere side A side ( The biasing force may be adjusted by sandwiching an annular spacer (gap adjusting plate) between (see FIG. 1).

Further, the inserting direction of the fastening screw 20 is not limited to the axial direction with respect to the rotating shaft 3 and may be, for example, the radial direction.

1 Mechanical Seal 2 Housing 2a Step 3 Rotating Shaft 4 Stationary Seal Ring 5 Rotating Seal Ring 7 Ring Member 7c Tip (Cylindrical Convex)
9 Spring coil (biasing means)
10 Rubber bellows 11 Case 12 Inner case (case member)
13 Outer case (case member)
15 Sleeve 19 Fastening Screw 20 Fastening Screw R Rotating Side Element S Stationary Side Element A Atmosphere Side M Machine Side U Stationary Unit

Claims (7)

A rotary seal ring that rotates together with a rotary shaft that is inserted into a through hole of the housing, a stationary seal ring that forms a sliding contact portion with the rotary seal ring, and a biasing member that biases the static seal ring toward the rotary seal ring. In a static mechanical seal having a biasing means,
An annular sleeve that constitutes the stationary unit by assembling the stationary seal ring and the biasing means,
A ring member for removably fitting and fixing the sleeve in a sealed state so as to be relatively non-rotatable on the opening side of the housing with respect to the stationary sealing ring, and fixed to the housing in a non-rotatable state in the sealed state. The characteristic mechanical seal. The mechanical seal according to claim 1, wherein a part of the ring member is axially inserted into an inner peripheral step portion of the housing. The mechanical seal according to claim 1, wherein the ring member has an inward flange that extends toward an inner diameter side of an inner peripheral surface on which the sleeve is fitted. 4. The mechanical seal according to claim 1, wherein the ring member is fixed to the housing with a fastening screw in the axial direction, and the sleeve is fixed to the ring member with a fastening screw in the axial direction. 5. A rubber bellows is disposed on the inner diameter side of the urging means, and the rubber bellows is hermetically fixed to the stationary seal ring and the sleeve. mechanical seal. On the outer diameter side of the rubber bellows, a case member is provided, which fixes and attaches the rubber bellows to the outer peripheral surface of the sleeve in a compressed state, and one end of the urging means contacts the case member. The mechanical seal according to claim 5, wherein one end is in contact with the sleeve. The mechanical seal according to claim 1, wherein the rotary seal ring is formed of ceramics as a main component, and the stationary seal ring is formed of carbon as a main component.

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