JP7166985B2 - Anti-rotation pin for mechanical seal - Google Patents

Description

The present invention relates to a detent pin applied to a mechanical seal that seals a rotating shaft.

A mechanical seal is used by being mounted between a housing of a fluid device and a rotating shaft arranged to pass through the housing. The sliding surface of the ring and the sliding surface of the rotary seal ring that rotates together with the rotary element such as the rotary shaft are brought into sliding contact in the circumferential direction to prevent leakage of the sealed fluid.

In such a mechanical seal, a drive pin (anti-rotation pin) projecting axially from a rotating element such as a collar fixed to the rotating shaft is fitted into a recess formed on the back surface of the rotary seal ring. By joining, the rotary seal ring is prevented from rotating with respect to the rotating side element, and has a structure that rotates together with the rotating shaft. Similarly, the stationary seal ring is prevented from rotating with respect to the stationary side element by fitting a knock pin (rotation stop pin) protruding from the stationary side element such as the housing into a concave portion on the back surface of the stationary seal ring, and the stationary seal ring is in a stationary state. It has a structure that maintains That is, these anti-rotation pins function to receive sliding torque between the seal rings that slide against each other via the sliding surfaces and to restrict co-rotation of the seal rings (for example, Patent Document 1).

JP 2017-207147 A (page 2, FIG. 1)

However, in the anti-rotation pin applied to such a mechanical seal, due to the rotation and sliding of the seal rings, vibration occurs at the contact point between the inner surface of the recess on the back side of the seal ring and the outer surface of the anti-rotation pin. Due to these factors, wear and damage are likely to occur, and the anti-rotation pin lacks durability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a detent pin for a mechanical seal that suppresses the occurrence of wear and damage and has high durability.

In order to solve the above problems, the detent pin for a mechanical seal according to the present invention includes:
It is used in a mechanical seal in which a rotary seal ring that rotates in the circumferential direction together with a rotary element attached to a rotary shaft and a stationary seal ring that is fixed to a stationary element slide relative to each other, and the rotary seal ring is connected to the rotary element. a detent pin that detents against or detents the stationary seal ring with respect to the stationary element,
The anti-rotation pin has a fixed portion fixedly provided on the rotating side element or the fixed side element, and a circular recess formed in the back surface of the sliding surface of the rotating seal ring or the stationary seal ring. A pillar-shaped fitting portion is provided, and a spiral groove extending spirally along the circumferential direction is provided on the outer surface of the fitting portion in contact with the inner surface of the recess,
The spiral groove turns around one or more times in the circumferential direction of the fitting portion and extends continuously to both ends of the fitting portion in the axial direction. is open to
Furthermore, the spiral groove portion is formed in a rectangular shape in a cross-sectional view, and is turned with the same pitch, the same width, and the same depth in the circumferential direction of the fitting portion.
According to this, by introducing the surrounding fluid into the recess through the spiral groove of the fitting portion of the anti-rotation pin fitted in the recess of the seal ring, the outer surface of the anti-rotation pin and the inner surface of the recess of the seal ring are brought together. Since a fluid film extending in the circumferential direction and the axial direction can be generated between them, this fluid film lubricates the contact point between the rotation stop pin and the recess, thereby suppressing wear and damage of the rotation stop pin.
In addition, since the spiral groove portion is rotated one or more times in the circumferential direction of the fitting portion, a fluid film can be formed over the entire circumference of the outer surface of the anti-rotation pin.
Further, since the spiral groove extends continuously over both ends of the fitting portion in the axial direction, the fluid can be easily introduced into the recess, and a fluid film can be reliably formed between the anti-rotation pin and the recess.
Furthermore, since the end of the spiral groove is open toward the tip in the axial direction of the fitting portion, it is easy to introduce the fluid deep inside the recess through the end of the spiral groove that is open toward the tip in the axial direction. .
In addition, since the spiral groove is rectangular in cross section, the width of the groove is maintained even if the outer surface of the anti-rotation pin is worn, ensuring fluidity and stable lubrication. be able to.
In addition, since the spiral groove portion is rotated in the circumferential direction of the fitting portion at the same pitch, the same width, and the same depth, a homogeneous fluid film can be generated in the recess.

The anti-rotation pin may be attached to the liquid to be sealed.
According to this, it is possible to form a fluid film in the recess using the liquid to be sealed around the anti-rotation pin.

A plurality of spiral grooves may be provided on the outer surface of the fitting portion.
According to this, the lubricity in the recess can be enhanced.

It is a sectional view showing the structure of the mechanical seal of the example of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; FIG. 5 is a cross-sectional view of a main part showing how the locking pin and the stationary seal ring fit together; It is a figure which shows the aspect by which the mechanical seal of an Example is filled with the to-be-sealed fluid and barrier liquid. It is a perspective view which shows the fitting aspect of the detent pin of an Example, and a stationary seal ring. FIG. 4 is a cross-sectional view of a main part showing a manner in which a detent pin and a stationary seal ring are fitted together and a manner in which a fluid film is formed;

A mode for carrying out the detent pin for a mechanical seal according to the present invention will be described below based on an embodiment.

A detent pin for a mechanical seal according to an embodiment will be described with reference to FIGS. 1 to 6. FIG. In the following description, the right side of FIG. 1 is taken as the outside of the plane, which is an atmospheric region, and the left side of the page is taken as the inside of the plane.

As shown in FIG. 1, the mechanical seal 1 of this embodiment includes a rotary seal ring 4 that rotates together with a rotary shaft 2, and a stationary seal ring 6 that is biased by a coil spring 8 disposed on a seal cover 10. , is a stationary mechanical seal 1. Further, in the mechanical seal 1 of this embodiment, annular stationary seal rings 6, 6' are arranged side by side in a facing state on a seal cover 10 on the inside of the machine and a seal cover 10' on the outside of the machine. It is a double type mechanical seal 1 in which rotary sealing rings 4, 4' connected to a sleeve 3 fixed to a rotary ring 2 are arranged between 6, 6' with their back surfaces close to each other. This mechanical seal 1 comprises a stationary side element S having annular stationary seal rings 6, 6' fixed to seal covers 10, 10' via knock pins 7, 7' as detent pins; It is mainly composed of a rotary side element R having rotary seal rings 4, 4' rotating therewith.

The rotation side element R and the stationary side element S will be described in more detail with reference to FIGS. 1 and 2. FIG. As shown in FIG. 1, the rotation-side element R includes a sleeve 3 fixedly attached to the rotary shaft 2, and a rotating shaft fixed to the sleeve 3 and extending substantially horizontally from the sleeve 3 to the inside and outside of the machine. Drive pins 5, 5' as stop pins and annular rotary seal rings 4, 4' that rotate in the circumferential direction due to the rotational force transmitted from the rotary shaft 2 via the drive pins 5, 5'. is configured to

The stationary side element S is arranged so that annular seal covers 10, 10' face each other in the axial direction, and is connected to each other by inserting a connecting bolt 11 axially through the seal covers 10, 10'. there is Further, the seal covers 10, 10' are in sliding contact with coil springs 8, 8' for urging the stationary seal rings 6, 6' in the axial direction from the rear side, and the rotary seal rings 4, 4'. Dowel pins 7, 7' are attached to prevent co-rotation of the stationary seal rings 6, 6'. In addition, annular cases 13, 13' are fitted inside the seal covers 10, 10' on the outer diameter side of the stationary seal rings 6, 6'. Further, as shown in FIG. 1, the seal cover 10 has a barrier liquid inlet 9 formed in the radial direction, and the seal cover 10' has a barrier liquid outlet 9' formed in the radial direction. ing. The barrier liquid B that has flowed in from the barrier liquid inlet 9 passes through a communication path L1 that communicates with the case 13 in the radial direction, flows into a space Z described later, and flows from the space Z through a communication path L2 of the case 13'. It passes through and flows to the barrier liquid outlet 9'. Moreover, the fluid pressure of the barrier liquid B is controlled so that the pressure of the barrier liquid B is higher than that of the fluid H to be sealed. The mechanical seal 1 of this embodiment is of the double type as described above, and has a similar configuration that is arranged oppositely in the axial direction. will be described, and the description of the configuration outside the machine will be omitted.

As shown in FIG. 2, the seal cover 10 has an annular shape when viewed in the axial direction, and a plurality of coil springs 8 are evenly distributed in the circumferential direction so as to urge the stationary seal ring 6 in the axial direction. is set. By disposing a plurality of coil springs 8 at equal intervals in this manner, the biasing force directed toward the rotary seal ring 4 is transmitted in the axial direction with uniform surface pressure on the back surface 6a of the stationary seal ring 6. It is configured. Further, the seal cover 10 is formed with holes 10a equally spaced in the circumferential direction on the outer peripheral side of the coil springs 8 which are equally spaced in the circumferential direction. is press-fitted and fixed.

Next, the knock pin 7 will be explained in detail. As shown in FIG. 3, the knock pin 7 is formed in a substantially cylindrical shape and has a diameter substantially the same as that of the hole portion 10a of the seal cover 10. 27 and a fitting portion 17 formed to have a larger diameter than the press fitting portion 27 and protruding substantially horizontally from the seal cover 10 .

Further, the fitting portion 17 of the knock pin 7 is fitted in the notch portion 6b as a concave portion formed corresponding to the arrangement of the knock pin 7 on the back surface 6a side of the stationary seal ring 6 so as to be axially loosely fitted. , so that the stationary seal ring 6 is allowed to move axially while restricting circumferential movement of the stationary seal ring 6 due to sliding against the rotary seal ring 4 . The cutout portion 6b is formed to have a larger diameter than the fitting portion 17 of the knock pin 7 and to be longer in the axial direction.

The fitting portion 17 is formed in a columnar shape, and a groove having a substantially rectangular cross-sectional view is spirally drilled on the outer peripheral surface 17b of the fitting portion 17 from the base end side (that is, the press fitting portion 27 side) in the axial direction of the fitting portion 17 to the tip end side. A spiral groove portion 17a is formed. In this embodiment, the spiral groove portion 17a is formed by turning four or more turns on the outer peripheral surface 17b of the fitting portion 17, and turns from the proximal end side to the distal end side at the same pitch, the same width, and the same depth. there is Further, the tip portion 17c of the spiral groove portion 17a is open in the axial direction. The spiral groove portion 17a may be wound at least once or more. Furthermore, although not shown, the outer peripheral surface of the drive pin 5 that prevents the stationary seal ring 6 from rotating with respect to the sleeve 3 may also have a spiral groove formed in the same manner as the knock pin 7 described above.

Next, with reference to FIG. 4, regions occupied by the sealed fluid H, the barrier liquid B as the sealed liquid, and the atmosphere A on the leak side during operation of the mechanical seal 1 of this embodiment will be described. As shown in FIG. 4, a fluid H to be sealed such as CFC alternative is sealed by a sliding portion E between a rotary seal ring 4 and a stationary seal ring 6 on the left side of the drawing, which is the inside of the machine. Atmosphere A is partitioned by the sliding portion E' between the rotary seal ring 4' and the stationary seal ring 6' on the right side of the drawing, which is the outside of the machine.

In addition, the barrier liquid B introduced from the barrier liquid inlet 9 flows through the sliding portion E between the rotary seal ring 4 and the stationary seal ring 6 and the sliding portion E between the rotary seal ring 4' and the stationary seal ring 6'. ' and the seal covers 10, 10', and is introduced to the side of the sliding portions E, E' through the communication path L1 formed through the cases 13, 13' in the radial direction, It is designed to flow out from the barrier liquid outflow port 9' through the communicating path L2. Further, since the barrier liquid B is controlled to have a higher pressure than the sealed fluid H, even if an abnormality occurs due to poor sliding of the sliding portion E, the sealed fluid H does not flow into the space Z side. is configured to reduce

The manner in which the knock pin 7 and the stationary seal ring 6 fit together when the mechanical seal 1 of this embodiment is in operation will be described in detail with reference to FIG. As shown in FIG. 5, when the rotary seal ring 4 facing the stationary seal ring 6 biased by the coil spring 8 rotates in the circumferential direction, the notch portion 6b formed in the back surface 6a of the stationary seal ring 6 is opened. The peripheral surface of the fitting portion 17 of the knock pin 7 fitted in the ring 7 presses against one inner wall surface 6c of the notch portion 6b in the circumferential direction, thereby restricting the stationary seal ring 6 from co-rotating. Since the fitting portion 17 of the knock pin 7 is formed with a spiral groove portion 17a, the barrier liquid B flowing into the space Z is introduced into the notch portion 6b through the spiral groove portion 17a.

As shown in FIG. 6, the spiral groove portion 17a is swirled in the circumferential and axial directions on the outer peripheral surface 17b of the fitting portion 17, so that the barrier liquid B introduced through the spiral groove portion 17a is and the notch portion 6b on the back side 6a of the stationary seal ring 6, more specifically, the outer peripheral surface 17b of the fitting portion 17 and the inner wall surface 6c of the notch portion 6b that contacts the outer peripheral surface 17b in a pressed state. A fluid film F is formed at the abutting portion with the . The fluid film F is formed over the entire surface of the abutting portion as described above by the barrier liquid B leaking through the spiral groove portion 17a of the fitting portion 17 to the outer peripheral surface 17b.

As described above, the rotary seal ring 4 that rotates in the circumferential direction together with the rotating element R attached to the rotating shaft 2 and the stationary seal ring 6 that is fixed to the stationary element S are used in the mechanical seal in which the relative sliding is performed. and a knock pin 7 as a detent pin for preventing rotation of the rotary seal ring 4 with respect to the rotation side element R or preventing rotation of the stationary seal ring 6 with respect to the stationary side element S. The knock pin 7 is the rotation side element. In the press-fit portion 27 as a fixed portion fixedly provided to R or the stationary side element S, and the notch portion 6b as a recess formed in the back surface 6a of the sliding surface E of the rotary seal ring 4 or the stationary seal ring 6 A spiral groove portion 17a extending spirally along the circumferential direction is provided on the outer peripheral surface 17b of the fitting portion 17 that is in contact with the inner surface of the notch portion 6b, so that sealing is achieved. By introducing the surrounding fluid into the notch portion 6b through the spiral groove portion 17a of the fitting portion 17 of the knock pin 7 fitted in the notch portion 6b of the ring, the gap between the outer surface of the knock pin 7 and the inner surface of the recess of the seal ring is reduced. In addition, since the fluid film F that spreads in the circumferential direction and the axial direction can be generated, the fluid film F lubricates the contact point between the knock pin 7 and the notch 6b, thereby suppressing the occurrence of wear and damage of the detent pin. be able to. Further, when the rotation of the rotating element R accompanying the rotating shaft 2 causes axial vibration in the entire device of the mechanical seal 1, the vibration facilitates movement of the fluid along the spiral groove portion 17a. can be generated over a wide range.

In addition, since the spiral groove portion 17a is rotated one or more times in the circumferential direction of the fitting portion 17, the fluid film F can be formed on the outer peripheral surface 17b of the knock pin 7 over the entire circumference.

Further, since the spiral groove portion 17a extends continuously over both ends of the fitting portion 17 in the axial direction, the barrier liquid B can be easily introduced into the notch portion 6b. A fluid film F can be reliably generated between them.

Further, since the end 17c of the spiral groove portion 17b is open toward the tip in the axial direction of the fitting portion 17, the notch portion is passed through the end 17c opened toward the tip in the axial direction of the spiral groove portion 17b. It is easy to introduce the fluid to the inner depth in the axial direction of 6b, and the fluid can form the fluid film F to the inner depth side.

In addition, since the spiral groove portion 17a is formed in a rectangular shape in a cross-sectional view, the width of the groove is maintained even if the outer peripheral surface 17b of the knock pin 7 is worn. You can get sex.

Further, since the spiral groove portion 17b turns in the circumferential direction of the fitting portion 17 at the same pitch, the same width, and the same depth, it is possible to generate a homogeneous fluid film F in the notch portion 6b.

Further, as shown in FIG. 3, the communication passage L1 of the case 13 arranged on the outer diameter side of the stationary seal ring 6 is formed in substantially the same phase with the fitting portion 17 of the knock pin 7 in the axial direction. , the barrier liquid B flowing through the communication path L1 is easily introduced into the spiral groove portion 17a formed in the fitting portion 17. As shown in FIG.

A plurality of spiral groove portions 17b may be provided on the outer peripheral surface 17b of the fitting portion 17. By doing so, the lubricity in the notch portion 6b can be enhanced.

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 within the scope of the present invention are included in the present invention. be

For example, in the above embodiment, the knock pin 7 is described as having a cylindrical shape, but it is not limited to this, and may be a square column or a hexagonal column.

Further, in the above embodiment, the spiral groove portion 17a is formed in the knock pin 7, but the present invention is not limited to this, and the drive pin 5 may be formed with the spiral groove portion 17a.

In the above-described embodiment, the anti-rotation pin is applied to the double-type mechanical seal 1, but the anti-rotation pin according to the present invention is not limited to this, and may be applied to single-type or tandem-type mechanical seals. good.

1 mechanical seal 2 rotary shaft 3 sleeve 4, 4' rotary seal ring 5, 5' drive pin (rotation stop pin)
6, 6' Stationary seal ring 7, 7' Dowel pin (non-rotating pin)
8 coil spring 9 barrier liquid inlet 9' barrier liquid outlet 10 seal cover 10a hole 11 connecting bolt 17 fitting portion 17a spiral groove portion 17b outer peripheral surface 17c end portion 27 press fitting portion

Claims (3)

It is used in a mechanical seal in which a rotary seal ring that rotates in the circumferential direction together with a rotary element attached to a rotary shaft and a stationary seal ring that is fixed to a stationary element slide relative to each other, and the rotary seal ring is connected to the rotary element. A rotation stop pin for a mechanical seal that stops rotation against or prevents rotation of the stationary seal ring with respect to the stationary side element,
The anti-rotation pin has a fixing portion fixedly provided on the rotating side element or the stationary side element, and a circular recess formed in the back surface of the sliding surface of the rotating seal ring or the stationary seal ring. A pillar-shaped fitting portion is provided, and a spiral groove extending spirally along the circumferential direction is provided on the outer surface of the fitting portion in contact with the inner surface of the recess,
The spiral groove turns around one or more times in the circumferential direction of the fitting portion and extends continuously to both ends of the fitting portion in the axial direction. is open to
Further, the spiral groove portion is formed in a rectangular shape in a cross-sectional view, and rotates in the circumferential direction of the fitting portion at the same pitch, the same width, and the same depth. 2. The anti-rotation pin for a mechanical seal according to claim 1, wherein said anti-rotation pin is attached to the liquid to be sealed. 3. The mechanical seal anti-rotation pin according to claim 1, wherein a plurality of the spiral grooves are provided on the outer surface of the fitting portion.

Images