JP2021196037A - Segment seal - Google Patents

Abstract

To achieve compactification in a segment seal which encloses a purge gas to form a double seal structure.SOLUTION: A segment seal 1 includes: a ring body 2 which is housed in a seal chamber 10 and comprises a single or multiple segment rings; a retainer 5 which is disposed between a first inner wall part 11 located at one axial side and the ring body 2 in the seal chamber 10 and configured to slide in an axial direction while contacting with an end surface 21b of the ring body; and a biasing member 7 which biases the retainer 5 from the one axial side to the other axial side to press the ring body 2 to a second inner wall part 12 facing the first inner wall part 11 in the seal chamber 10.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to segment seals.

Patent Document 1 discloses an example of a segment seal. Specifically, the segment seal disclosed in Patent Document 1 includes a first seal chamber and a second seal chamber partitioned around a rotation shaft (sleeve), and a segment ring housed in each seal chamber. It becomes. Here, the first seal chamber and the second seal chamber communicate with each other in a state of being arranged in the axial direction, and the first seal chamber is opened to a space on one side in the axial direction (for example, the atmosphere), while the second seal is opened. The room is opened to the space on the other side in the axial direction (for example, the space inside the aircraft).

According to Patent Document 1, by enclosing the purge gas in the first seal chamber and the second seal chamber, the communication between the first seal chamber and the space on one side in the axial direction, and the second seal chamber and the shaft It is possible to realize a so-called double seal structure in which the communication with the space on the other side in the direction is closed and the gap between the rotating shaft and the casing is sealed on both sides in the axial direction.

Japanese Unexamined Patent Publication No. 7-119840

However, when using the configuration according to Patent Document 1, it is necessary to prepare at least two seal chambers and two segment rings. Therefore, the configuration according to Patent Document 1 has a problem that the dimension in the axial direction becomes long. This is inconvenient for making the segment seal compact.

The present disclosure has been made in view of such a point, and an object thereof is to realize compactification of a segment seal having a double seal structure by enclosing a purge gas.

One aspect of the present disclosure relates to a segment seal that seals a gap between the rotary shaft and a casing through which the rotary shaft is inserted by enclosing gas in a seal chamber partitioned around the rotary shaft. This segment seal is housed in the seal chamber and is arranged between a ring body composed of a single or a plurality of segment rings and a first inner wall portion on one side in the axial direction of the seal chamber and the ring body. By urging the retainer that can slide in the axial direction in contact with the end face of the body and the retainer from one side in the axial direction toward the other side in the axial direction, the retainer faces the first inner wall portion in the seal chamber. It is provided with an urging member that presses the ring body toward the second inner wall portion.

According to this configuration, when the urging member urges the retainer, a sealing surface is formed between the retainer and the ring body on one side in the axial direction, and the ring body and the ring body are formed on the other side in the axial direction. 2 A sealing surface is also formed between the inner wall and the inner wall. As a result, the seal chamber can be sealed on both sides in the axial direction, and a double seal structure can be realized.

Here, in order to utilize the above configuration, it is only necessary to prepare one seal chamber and one set of ring bodies to be accommodated in the seal chamber. As a result, the dimensions in the axial direction can be suppressed, and by extension, the segment seal can be made compact.

As described above, according to the present disclosure, it is possible to realize compactification of the segment seal.

FIG. 1 is a vertical sectional view illustrating the configuration of a segment seal. FIG. 2 is a plan view illustrating the configuration of the first segment ring. FIG. 3 is a plan view illustrating the configuration of the second segment ring. FIG. 4 is a plan view illustrating the configuration of the third segment ring. FIG. 5 is a two-view view illustrating the configuration of the retainer. FIG. 6 is a partially enlarged view illustrating the filling of the purge gas. FIG. 7 is a diagram corresponding to FIG. 1 showing a modified example of the segment seal.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description is an example.

The segment seal 1 exemplified in FIG. 1 seals the gap G between the rotating shaft 100 of a pump, a blower, a powder device, or the like and the casing 200 into which the rotating shaft 100 is inserted, from the inside of the machine to the atmosphere. It is intended to prevent fluid leakage.

In particular, the segment seal 1 according to the present embodiment is configured to realize a so-called double seal structure. That is, in this segment seal 1, by enclosing the purge gas in the seal chamber 10 formed around the rotary shaft 100, the gap G between the rotary shaft 100 and the casing 200 is one in the axial direction when viewed from the seal chamber 10. The first gap G1 located on the side (atmosphere side) and the second gap G2 located on the other side (inside the machine) in the axial direction when viewed from the seal chamber 10 are configured to be sealed at the same time.

The "axial direction" here refers to a direction along the axis C of the rotating shaft 100. Similarly, in the following description, the "diametrical direction" refers to a direction orthogonal to the axis C, and the "circumferential direction" refers to a direction surrounding the axis C.

Further, in the example shown in FIG. 1 and the like, the rotary shaft 100 has a sleeve 101, and the segment seal 1 and the rotary shaft 100 are configured to come into contact with each other via the sleeve 101. Then, the description about the sleeve 101 will be omitted as appropriate.

As shown in FIG. 1, the segment seal 1 includes a ring body 2 housed in a seal chamber 10, a garter spring 3, a positioning pin 4, a retainer 5, a seal member 6, and an urging member 7. Be prepared.

The seal chamber 10 is formed at a portion around the rotation shaft 100 in the casing 200. Specifically, the seal chamber 10 according to the present embodiment is formed by inflating the gap G between the rotating shaft 100 and the casing 200 toward the outside in the radial direction.

Specifically, as shown in FIGS. 1 and 6, the seal chamber 10 has a first inner wall portion 11 located on one side in the axial direction, a second inner wall portion 12 located on the other side in the axial direction, and laterally outward in the axial direction. It is configured as a substantially annular space partitioned by a third inner wall portion 13 located and an outer peripheral surface 100a of a rotating shaft 100 located inside in the radial direction. In the examples shown in FIGS. 1 and 6, the outer peripheral surface 100a of the rotating shaft 100 is equal to the outer peripheral surface of the sleeve 101.

Here, the first inner wall portion 11 and the second inner wall portion 12 both extend along the radial direction and are arranged so as to face each other. A first gap G1 that communicates with the atmosphere is provided between the first inner wall portion 11 and the outer peripheral surface 100a. The seal chamber 10 communicates with the atmosphere through the first gap G1. Similarly, a second gap G2 leading to the inside of the machine is provided between the second inner wall portion 12 and the outer peripheral surface 100a. The seal chamber 10 communicates with the inside of the machine through the second gap G2.

Further, the third inner wall portion 13 extends along the axial direction and is arranged so as to face the outer peripheral surface 100a of the rotating shaft 100. The third inner wall portion 13 communicates with the outside through the introduction port 201. The introduction port 201 penetrates the casing 200 in the radial direction and is used to introduce the purge gas into the seal chamber 10 from the outside.

The ring body 2 is composed of a single or a plurality of segment rings. Specifically, the ring body 2 according to the present embodiment has a first segment ring 21 that is in close contact with the retainer 5 and a second segment ring 21 that is adjacent to the first segment ring 21, in order from one side in the axial direction to the other side in the axial direction. It has a segment ring 22 and a third segment ring 23 adjacent to the second segment ring 22 and in close contact with the second inner wall portion 12.

Here, as shown in FIGS. 2 to 4, the first segment ring 21, the second segment ring 22, and the third segment ring 23 are formed from a plurality of segment pieces 21a, 22a, 23a divided in the circumferential direction, respectively. Become.

As shown in FIG. 2, the first segment ring 21 is divided into three segment pieces 21a formed in a substantially arc shape. In the first segment ring 21 according to the present embodiment, the end surface 21b on one side in the axial direction is in close contact with the retainer 5, so that a sealing surface can be formed with the retainer 5. As shown in FIG. 2, the “end surface” here refers to either the front or back surface when the first segment ring 21 is viewed from the front along the axial direction. The inner peripheral surface 21c of the first segment ring 21 also slides on the outer peripheral surface 100a of the rotating shaft 100 and forms a sealing surface with the outer peripheral surface 100a.

Further, on the outer peripheral surface of each segment piece 21a, a groove 21d extending along the circumferential direction is provided when the first segment ring 21 is viewed in a plan view along the axis C of the rotating shaft 100. By winding the garter spring 3 around the groove 21d, the three segment pieces 21a are restrained from the outer peripheral side. Due to this constraint, the three segment pieces 21a form an integral ring shape as the first segment ring 21.

Further, on the outer peripheral surface of each segment piece 21a, a recess 21e recessed inward in the radial direction is provided when the first segment ring 21 is viewed in a plan view along the axis C of the rotating shaft 100. As shown on the lower side of the paper surface of FIG. 1, the rotation of the first segment ring 21 can be prevented by inserting the positioning pin 4 into the recess 21e.

Further, each dividing surface of the first segment ring 21 (a plane that divides the first segment ring 21 into three segment pieces 21a) extends along a direction inclined with respect to the radial direction (the inclination angle θ in FIG. 2). reference).

As shown in FIG. 3, the second segment ring 22 is divided into three segment pieces 22a formed in a substantially arc shape. In the second segment ring 22 according to the present embodiment, the end surface on one side in the axial direction (for example, the surface with the reference numeral 22b in FIG. 3) is brought into close contact with the first segment ring 21, and the end surface on the other side is the third segment. It can be brought into close contact with the ring 23. The inner peripheral surface 22c of the second segment ring 22 also slides into contact with the outer peripheral surface 100a of the rotating shaft 100, and forms a sealing surface with the outer peripheral surface 100a.

Further, on the outer peripheral surface of each segment piece 22a, a groove 22d extending along the circumferential direction and a recess 22e are provided. The groove 22d and the recess 22e in the second segment ring 22 are configured to have the same functions as the groove 21d and the recess 21e in the first segment ring 21.

Further, the segment pieces 22a constituting the second segment ring 22 face each other with a space in the circumferential direction. Specifically, the end of any one of the three segment pieces 22a (particularly the end in the circumferential direction) is spaced in the circumferential direction from the end of another segment piece 22a adjacent to that segment piece 22a. (See interval D in FIG. 3).

Further, each dividing surface of the second segment ring 22 (a plane that divides the second segment ring 22 into three segment pieces 22a) extends along the radial direction. Here, as can be understood from the comparison between FIGS. 2 and 3, each divided surface of the first segment ring 21 is offset in the circumferential direction with respect to each divided surface of the second segment ring 22. In other words, the angular position of each divided surface of the first segment ring 21 and the angular position of each divided surface of the second segment ring 22 are different from each other.

As shown in FIG. 4, the third segment ring 23 is divided into three segment pieces 23a formed in a substantially arc shape. In the third segment ring 23 according to the present embodiment, the end surface 23b on one side in the axial direction can be brought into close contact with the second segment ring 22, and the end surface on the other side can be brought into close contact with the second inner wall portion 12. Due to the latter adhesion, the third segment ring 23 forms a sealing surface with the second inner wall portion 12.

Further, the inner peripheral surface 23c of the third segment ring 23 does not slide in contact with the outer peripheral surface 100a of the rotating shaft 100. In other words, the inner peripheral surface 23c of the third segment ring 23 and the outer peripheral surface 100a of the rotating shaft 100 face each other with a radial distance.

Further, on the outer peripheral surface of each segment piece 23a, a groove 23d extending along the circumferential direction and a recess 23e are provided. The groove 23d and the recess 23e in the third segment ring 23 are configured to have the same functions as the groove 21d and the recess 21e in the first segment ring 21.

Further, each dividing surface of the third segment ring 23 (a plane that divides the third segment ring 23 into three segment pieces 23a) extends along the radial direction. Here, as can be understood from the comparison between FIGS. 3 and 4, each divided surface of the second segment ring 22 is offset in the circumferential direction with respect to each divided surface of the third segment ring 23. In other words, the angular position of each divided surface of the second segment ring 22 and the angular position of each divided surface of the third segment ring 23 are different from each other.

The positioning pin 4 is fixed to the casing 200 as shown in FIG. The positioning pin 4 is inserted into the recesses 21e, 22e, 23e of each segment ring 21, 22, 23, and positions each segment ring 21, 22, 23 in the circumferential direction.

The retainer 5 is arranged between the first inner wall portion 11 and the end surface 21b of the first segment ring 21 constituting the ring body 2. The retainer 5 is configured to be slidable in the axial direction in a state of being in contact with the end surface 21b of the first segment ring 21. The retainer 5 has a tubular shape and is inserted into the rotating shaft 100.

Specifically, as shown in FIGS. 1 and 5, the retainer 5 according to the present embodiment has a flange-shaped portion 51 arranged between the first inner wall portion 11 and the ring body 2, and the flange-shaped portion 51. A cylindrical portion 52 extending from the shaft toward the other side in the axial direction and arranged between the rotating shaft 100 and the casing 200 in the radial direction, and a detent portion protruding from the flange-shaped portion 51 toward the other side in the axial direction. 53 and.

The brim-shaped portion 51 has a brim shape extending along the radial direction. In the flange-shaped portion 51, the end surface 51a on one side in the axial direction faces the first inner wall portion 11 at a distance, and the end surface 51b on the other side in the axial direction is brought into close contact with the end surface 21b of the first segment ring 21. Can be done. Due to the latter adhesion, the retainer 5 forms a sealing surface with the first segment ring 21 as described above.

Further, the outer diameter of the flange-shaped portion 51 is larger than the outer diameter of each of the segment rings 21, 22, 23 constituting the ring body 2. On the other hand, the inner diameter of the flange-shaped portion 51 is larger than the outer diameter of the outer peripheral surface 100a of the rotating shaft 100. That is, the inner peripheral surface 51c of the flange-shaped portion 51 does not slide in contact with the outer peripheral surface 100a of the rotating shaft 100.

The outer diameter of the flange-shaped portion 51 may be the same as the outer diameter of each of the segment rings 21 and 22 and 23 constituting the ring body 2, or is compared with the outer diameter of each of the segment rings 21 and 22 and 23. It may be made smaller.

The tubular portion 52 has a tubular shape extending along the axial direction. The tubular portion 52 is integrated with the flange-shaped portion 51 at an end portion on the other side in the axial direction thereof. The inner peripheral surface 51c of the flange-shaped portion 51 is connected to the inner peripheral surface of the tubular portion 52 so as to be flush with each other. The inner peripheral surface 51c faces the outer peripheral surface 100a of the rotating shaft 100 at a distance. That is, the inner peripheral surface 51c of the retainer 5 does not slide in contact with the rotating shaft 100.

Further, as shown in FIG. 6, the tubular portion 52 is inserted into the above-mentioned first gap portion G1. A sealing member 6 is arranged between the cylindrical portion 52 thus inserted and the casing 200. The seal member 6 is configured as a so-called O-ring, and is a gap between the retainer 5 and the casing 200 in the first gap G1 (specifically, the outer peripheral surface of the tubular portion 52 and the rotation in the casing 200). The gap between the shaft 100 and the insertion hole) is sealed.

The detent portion 53 has a cylindrical shape protruding from the flange-shaped portion 51 toward the other side in the axial direction. The detent portion 53 is inserted into the wall surface of the first inner wall portion 11. This insertion suppresses the rotation of the retainer 5 in the radial direction.

The urging member 7 presses the ring body 2 toward the second inner wall portion 12 by urging the retainer 5 from one side in the axial direction toward the other side in the axial direction. By this pressing, the retainer 5 and the ring body 2 are brought into close contact with each other, and the ring body 2 and the second inner wall portion 12 of the seal chamber 10 are brought into close contact with each other.

Specifically, the urging member 7 according to the present embodiment is configured as a coil spring that expands and contracts in the axial direction and urges the flange-shaped portion 51. A plurality of urging members 7 are arranged in the flange-shaped portion 51 at positions that do not overlap with the detent portion 53, particularly centering on the axis C of the rotating shaft 100.

Further, as shown in FIG. 1, the seal member 6 is arranged in the space between the detent portion 53 and the urging member 7. Such arrangement contributes to the compactness of the segment seal 1 in the axial direction.

(About filling of purge gas)
As shown by the arrow A1 in FIG. 6, when the purge gas is filled from the introduction port 201, the gas enters the gap D between the segment pieces 22a in the second segment ring 22. The purge gas that has entered the gap D of the second segment ring 22 presses the first segment ring 21 toward one side in the axial direction and the third segment ring 23 toward the other side in the axial direction.

On the other hand, as shown by the arrow A2 in FIG. 6, the urging member 7 urges the retainer 5 from one side in the axial direction toward the other side in the axial direction. Due to this urging, the retainer 5 and the first segment ring 21 are in close contact with each other on one side in the axial direction, and a sealing surface is formed between the two members. At the same time, on the other side in the axial direction, the third segment ring 23 and the second inner wall portion 12 are in close contact with each other, and a sealing surface is formed between them. As a result, the seal chamber 10 can be sealed on both sides in the axial direction, and a double seal structure can be realized.

Further, both sealing surfaces formed by the urging member 7 are made more solid due to the combination of the pressing of the ring body 2 through the retainer 5 and the pressing by filling the purge gas. This makes it possible to further improve the sealing performance of the segment seal 1. In particular, by combining the filling of the purge gas and the pressing by the urging member 7, the third segment ring 23 and the retainer 5 can be pressed against each other so as to be sandwiched from both sides in the axial direction. This contributes to the improvement of sealing performance.

Further, the configuration according to the present embodiment does not use a plurality of seal chambers, but uses only one seal chamber 10 and a set of ring bodies 2 to be accommodated in the seal chamber 10. As a result, the dimensions in the axial direction can be suppressed, and by extension, the segment seal 1 can be made compact.

Further, in the configuration according to the present embodiment, since sufficient sealing performance is exhibited by only one set of segment rings (ring body 2), the number of parts such as sliding parts and consumables can be suppressed. This contributes to the cost reduction of the segment seal 1. Further, since sufficient sealing performance is exhibited only by one set of segment rings (ring body 2), maintenance can be performed more easily than before.

Further, as shown in FIGS. 1 and 5, the sealing member 6 seals between the tubular portion 52 and the casing 200 to prevent fluid leakage from the gap between the retainer 5 and the casing 200. can. This contributes to the improvement of sealing performance.

Further, as shown in FIG. 1, the urging member 7 configured as a coil spring is arranged between the first inner wall portion 11 and the retainer 5 in the axial direction. By arranging in this way, it is possible to press the ring body 2 through the retainer 5 while maintaining the contact state between the retainer 5 and the ring body 2.

Further, as shown in FIG. 1, by providing the retainer 5 with the detent portion 53, the rotation of the retainer 5 can be suppressed. This suppresses the sliding of the retainer 5 with respect to the ring body 2, which is advantageous for extending the life of the segment seal 1.

Further, as shown in FIG. 3, by providing a gap D between the ends of the segment pieces 22a constituting the second segment ring 22, the purge gas is guided to the gap D, and the purge gas is effectively pressed. You will be able to do it.

Further, as shown in FIGS. 2 and 3, each of the first segment rings 21 is offset by offsetting the divided surfaces of the first segment ring 21 and the divided surfaces of the second segment ring 22 in the circumferential direction. The inflow of purge gas to the split surface can be suppressed. This is advantageous for improving the sealing performance.

Further, as shown in FIG. 2, by inclining each divided surface of the first segment ring 21 diagonally, it is possible to secure a wider area of each divided surface. As a result, the outflow of purge gas from the first segment ring 21 is suppressed, which is advantageous for improving the sealing performance.

<< Other Embodiments >>
In the above embodiment, a ring body composed of three segment rings has been exemplified, but the present disclosure is not limited to such a configuration. As in the segment seal 1'shown in FIG. 7, a ring body 2'composed of the first segment ring 21 and the second segment ring 22 may be used, or a ring body composed of the second segment ring 22 alone (not shown). May be used. Since the configurations other than the above in FIG. 7 are the same as the configurations described with reference to FIGS. 1 to 6, they are designated by the same reference numerals and the description thereof is omitted.

1 Segment seal 2 Ring body 21 1st segment ring 21a Segment piece 22 2nd segment ring 22a Segment piece 23 3rd segment ring 23a Segment piece 3 Gata spring 4 Positioning pin 5 Retainer 51 flanged part 52 Cylindrical part 53 Detent part 6 Sealing member 7 Erasing member 10 Sealing chamber 11 First inner wall part 12 Second inner wall part 100 Rotating shaft 100a Outer peripheral surface 200 Casing G Gap G1 First gap G2 Second gap

Claims (7)

A segment seal that seals the gap between the rotary shaft and the casing through which the rotary shaft is inserted by enclosing gas in a seal chamber partitioned around the rotary shaft.
A ring body housed in the seal chamber and composed of a single or a plurality of segment rings,
A retainer arranged between the first inner wall portion on one side in the axial direction in the seal chamber and the ring body and slidable in the axial direction in contact with the end face of the ring body.
An urging member that presses the ring body toward the second inner wall portion facing the first inner wall portion in the seal chamber by urging the retainer from one side in the axial direction toward the other side in the axial direction. And, a segment seal characterized by being equipped with. In the segment seal according to claim 1,
The retainer is
A flange-shaped portion arranged between the first inner wall portion and the ring body,
It has a tubular portion extending from the flange-shaped portion toward the axial direction and arranged radially between the rotating shaft and the casing.
A segment seal characterized in that a sealing member for sealing a gap between the tubular portion and the casing is arranged between the tubular portion and the casing. In the segment seal according to claim 1 or 2.
The segment seal is characterized in that the urging member is arranged between the first inner wall portion and the retainer in the axial direction and is configured as a coil spring that expands and contracts in the axial direction. In the segment seal according to any one of claims 1 to 3.
The retainer is a segment seal having a detent portion that projects toward one side in the axial direction and is inserted into the first inner wall portion. In the segment seal according to any one of claims 1 to 4.
The ring body is sequentially formed from one side in the axial direction toward the other side in the axial direction.
The first segment ring that adheres to the retainer and
The second segment ring adjacent to the first segment ring and
A plurality of third segment rings adjacent to the second segment ring and in close contact with the second inner wall portion, and the second segment ring is divided in the circumferential direction and slidably in contact with the outer peripheral surface of the rotating shaft. Consists of segment pieces of
A segment seal characterized in that the segment pieces constituting the second segment ring face each other at intervals in the circumferential direction. In the segment seal according to claim 5,
The first segment ring is composed of a plurality of segment pieces that are divided in the circumferential direction and are in sliding contact with the outer peripheral surface of the rotating shaft.
A segment seal characterized in that each divided surface of the first segment ring is offset in the circumferential direction with respect to each divided surface of the second segment ring. In the segment seal according to claim 6,
A segment seal characterized in that each dividing surface of the first segment ring extends along a direction inclined with respect to the radial direction.

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