JPH10169781A - Segment seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize sealing performance by blanching pressure between the primary seal face and the secondary seal face. SOLUTION: A dynamic pressure generating groove 7 is provided in the inner periphery (the primary seal face 5) of a seal ring 4 in slide contact with a shaft 17, pressure balancing grooves 12 are provided in the axial end faces (the secondary seal faces 9) of the seal ring 4 and a cover ring 8 in contact with a housing 3, and a pressure guide hole 13 is provided to be communicated between the grooves 7, 12. Dynamic pressure generated by the dynamic pressure generating groove 7 in the primary seal face 5 is guided through the pressure guide hole 13 to the secondary seal faces 9. As a result, the thrust of the secondary seal faces 9 is reduced, the frictional force of the secondary seal faces 9 is reduced, the follow-up of the shaft 17 to radial displacement is improved, and sealing performance is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a segment seal, and more particularly to a dynamic pressure type segment seal.

[0002]

2. Description of the Related Art In general, segment seals (sliding seals of cylindrical surfaces) are used as shaft seals for rotating parts of rotating equipment, and the main purpose is to seal gas. Therefore, it is used as a shaft seal or the like of a rotating part of a jet engine of an aircraft.

An aircraft jet engine compresses air, sends it to a combustor, mixes and burns it with fuel in the combustor, and rotates a turbine with the combustion gas. A compressor or a combustion gas compresses the air. The rotating turbine is supported by bearings, and lubricating oil is supplied to the bearings during operation of the jet engine, and the lubricating oil supplied to the bearings is forcibly collected by a drain pump or the like.

[0004] Air and combustion gas compressed by a compressor are present inside the jet engine, and these enter the bearing portion by pressure. Therefore, a seal is required to separate the lubricating atmosphere of the bearing from the intruding gas. This seal is a gas seal because the pressure of the intruding gas is higher than that of the lubricated bearing portion.

FIGS. 5 to 7 show an example of a segment seal used as a shaft seal for a rotating portion of a jet engine of such an aircraft. This segment seal 31
The stationary unit 32 includes a stationary unit 32 fixed to the device body 50 and a seal runner 48 that is a rotating unit 46 fixed to the rotating shaft 47 via a sleeve or the like.

The stationary unit 32 includes a housing 33 fixed to the apparatus main body 50 via bolts and the like, a seal ring 34 housed on the inner peripheral side of the housing 33 via a spring retainer 44 and a snap ring 45, and a cover. Ring 38, seal ring 34 and cover ring 38
Extension spring 40 that presses radially
And a compression spring 41 pressing in the axial direction.
, A key (not shown) for preventing rotation of the seal ring 34 and the cover ring 38, and a rotation lock pin (not shown).

[0007] The seal ring 34 is a carbon ring divided into two or more in the circumferential direction. The inner peripheral surface of the seal ring 34 is formed so as to uniformly contact the outer peripheral surface of the seal runner 48. It is formed with the same curvature as the surface. The inner peripheral surface of each divided piece of the seal ring 34 serves as a primary seal surface 35 that seals between the outer peripheral surface of the seal runner 48.

[0008] The cover ring 38 is a carbon ring divided into two or more in the circumferential direction. The inner peripheral surface of the cover ring 38 is so formed as to uniformly contact the outer peripheral surface of the seal ring 34. It is formed with the same curvature as the surface. Then, one end face in the axial direction of the cover ring 38 and one end face in the axial direction of the seal ring 34 serve as a secondary sealing surface 39 for sealing between the end face in the axial direction of the housing 33.

The dividing portion (not shown) of the seal ring 34 has a step-like step dividing structure. With this structure, a predetermined gap is formed in the divided portion of the seal ring 34 in the circumferential direction, and the gap is eliminated in the axial direction. This is because when the inner diameter of the seal ring 34 is worn by sliding with the seal runner 48,
This is to prevent a gap from being formed between the inner diameter of the seal ring 34 and the seal runner 48.

The seal in the axial direction of the divided portion of the seal ring 34 is ensured by the above-described step division structure. For sealing in the circumferential direction, a cover ring 38 is mounted on the outer peripheral side of the seal ring 34 so that the divided portion is circumferentially shifted from the divided portion of the seal ring 34 to close a gap between the divided portions of the seal ring 34. Is secured.

A key (not shown) is mounted between the divided pieces of the cover ring 38, and a tip end of each key is provided with a key groove (not shown) provided on the outer peripheral side of each divided piece of the seal ring 34. ), Which prevents relative rotation of the cover ring 38 and the seal ring 34. An engagement groove (not shown) is provided in a part of the key, and the tip of a rotation lock pin (not shown) fixed to the housing 33 is engaged in the engagement groove to provide a seal. The ring 34 and the cover ring 38 are prevented from rotating together with the rotation shaft 47.

The extension spring 40 has an annular shape mounted in a groove 38a provided on the outer peripheral side of the cover ring 38. The diameter of the extension spring 40 reduces the diameter of the cover ring 38 and the seal ring 34. And a key (not shown) are pressed inward in the radial direction, and the inner peripheral surface side of each divided piece of the seal ring 34 is pressed against the outer peripheral surface of the seal runner 48, and the seal ring 34 is pressed.
Initially, a necessary sealing load is applied to the primary sealing surface 35.

A pressure balance groove 36 is provided on the primary seal surface 35 of each divided piece of the seal ring 34. The pressure balance groove 36 has a circumferential groove 36a extending in the circumferential direction, and a plurality of axial grooves extending in the axial direction having one end communicating with the vertical groove 36a and the other end opening at the axial end surface of each divided piece. 36b. The pressure balance groove 36 balances the pressure in the radial direction.

The compression spring 41 is mounted between the axial end faces of the seal ring 34 and the cover ring 38 and the axial end face of the spring retainer 44.
Ring 34 and cover ring 3 by the urging force of
8 are pressed in the axial direction, their axial end faces are pressed against the axial end faces of the housing 33, and an initial necessary sealing load is applied to the secondary seal surfaces 39 of the seal ring 34 and the cover ring 38. .

A pressure balance groove 42 is provided on the secondary seal surface 39 of each of the divided pieces of the seal ring 34 and the cover ring 38. The pressure balance groove 42 of each of the divided pieces of the seal ring 34 has a longitudinal groove (not shown) extending in the circumferential direction, one end communicating with this longitudinal groove, and the other end opened to the outer peripheral surface side of each divided piece. And a plurality of lateral grooves (not shown) extending in the radial direction. The pressure balance groove 42 of each divided piece of the cover ring 38 is composed of a plurality of radially extending lateral grooves (not shown) communicating between the inner and outer peripheral surfaces. It is designed to communicate with each lateral groove of the divided piece. The pressure balance grooves 42 balance the pressure in the axial direction.

When the jet engine of the aircraft equipped with the segment seal 31 having the above structure is operated, the seal runner 48 rotates integrally with the rotating shaft 47, and the primary seal surface 35 of the seal ring 34 is sealed. Sliding contact is made with the outer peripheral surface of the runner 48, the space between them is sealed over the entire circumference, and the secondary sealing surfaces 39 of the seal ring 34 and the cover ring 38 contact the axial end surfaces of the housing 33, and Is sealed over the entire circumference.

The sliding portion generates heat due to sliding contact, and the amount of heat generated increases as the rotation of the rotary shaft 47 increases. For this reason, a so-called oil jet method is used in which a low-temperature oil is injected to the inner side of the seal runner 48 to cool the sliding portion so that the sliding portion exceeds the thermal limit and abrasion does not progress rapidly. Have been.

In the conventional segment seal 31 configured as described above, as described above, the seal ring 3
4, pressure balance grooves 36, 42 are provided on the primary seal surface 35, the seal ring 34, and the secondary seal surface 39 of the cover ring 38, respectively.
2, the pressure in the radial direction and the pressure in the axial direction are balanced, the sealing load due to the fluid pressure is reduced, and the torque is reduced.

Further, when the load due to the pressure is large,
A dynamic pressure generating groove 37 is provided on the primary sealing surface 35 of each divided piece of the seal ring 34. The dynamic pressure generating groove 37 is provided between the vertical groove 36a and the horizontal groove 36b of the pressure balance groove 36, and a part thereof communicates with the horizontal groove 36b. This dynamic pressure generating groove 37
The seal fluid is introduced from the lateral groove 36b of the pressure balance groove 36 by the rotation of the rotating shaft 47, and the dynamic pressure generating groove 37
Generates dynamic pressure inside The dynamic pressure causes the inner peripheral surface side of the seal ring 34 to
The force of pressing against the outer peripheral surface of the rim is reduced. When the dynamic pressure is greater than the pressing force of the seal fluid, the seal ring 3
4 rises from the outer peripheral surface of the seal runner 48, and the primary seal surface 35 is brought into a non-contact state.

However, in the pressure balance grooves 36 and 42 and the dynamic pressure generation groove 37 having the above-described structures, as shown in FIG. 8, although the radial force can be balanced, the axial force can be reduced. Since an unbalanced load due to the fluid force is present, the followability of the seal ring 34 and the cover ring 38 to the vibration of the rotating shaft 47 is significantly reduced, and the frictional force of the secondary seal surface 39 is increased. In addition, the radial displacement of the rotary shaft 47 causes the contact load of the primary seal surface 35 of the seal ring 34 to be excessive, so that the primary load of the seal ring 34 cannot be kept up with the radial displacement of the rotary shaft 47. An excessive gap is generated on the sealing surface 35 side, and the sealing performance is significantly reduced.

The present invention solves the above-mentioned problems of the prior art, and introduces the pressure generated by the dynamic pressure generating groove of the primary seal surface to the secondary seal surface to thereby reduce the secondary seal surface. It is an object of the present invention to provide a segment seal capable of reducing the pressing force of the seal ring, thereby improving the followability of the seal ring and the cover ring against the vibration of the rotating shaft, and stabilizing the seal performance. .

[0022]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a primary seal surface on the inner peripheral side which is in contact with the rotating shaft side, and has one end in the axial direction which is in contact with the housing side. Having a secondary sealing surface,
In the segment seal wherein the secondary seal surface is slidably contacted with the rotating shaft side and the secondary seal surface is mutually contacted with the housing side, the primary seal surface is provided. And a means for providing a dynamic pressure generating groove to the secondary seal surface.

[0023]

According to the present invention, the pressure generated by the dynamic pressure groove on the primary seal surface is reduced to 2 by adopting the above means.
It will be guided to the next sealing surface. Therefore, the pressing force of the secondary seal surface is reduced, the followability of the seal to axial vibration is enhanced, and the seal performance can be stabilized.

[0024]

Embodiments of the present invention shown in the drawings will be described below. 1 to 3 show an embodiment of a segment seal according to the present invention.
1 is a cross-sectional view showing the whole, FIG. 2 is a partial explanatory view of the one shown in FIG. 1, and FIG. 3 is an explanatory view of the one shown in FIG.

That is, the segment seal 1 shown in this embodiment is similar to the conventional one in that
The stationary unit 2 is fixed to the side and a seal runner 18 which is a rotating unit 16 fixed to a rotating shaft 17 via a sleeve or the like.

The stationary unit 2 includes a housing 3 fixed to the device main body 20 via bolts or the like, and a housing 3.
A seal ring 4 and a cover ring 8 housed on the inner peripheral side of the seal ring via a spring retainer 14 and a snap ring 15, an extension spring 10 for pressing the seal ring 4 and the cover ring 8 in a radial direction, and an axial press And a key (not shown) for preventing rotation of the seal ring 4 and the cover ring 8 and a rotation lock pin (not shown).

The seal ring 4 is a carbon ring which is divided into two or more in the circumferential direction. The inner peripheral surface of the seal ring 4 is in contact with the outer peripheral surface of the seal runner 18 uniformly. It is formed with the same curvature as the surface.
A primary sealing surface 5 for sealing between the inner peripheral surface of each divided piece of the seal ring 4 and the outer peripheral surface of the seal runner 18
There is something that becomes.

The cover ring 8 is a carbon ring divided into two or more in the circumferential direction. The inner peripheral surface of the cover ring 8 is so formed as to uniformly contact the outer peripheral surface of the seal ring 4. It is formed with the same curvature as the surface. And
One end face in the axial direction of the cover ring 8 and one end face in the axial direction of the seal ring 4 serve as a secondary seal face 9 for sealing between the end face in the axial direction of the housing 3.

The dividing part (not shown) of the seal ring 4 has a step-like step dividing structure. With this structure, a predetermined gap is formed in the divided portion of the seal ring 4 in the circumferential direction, and the gap is eliminated in the axial direction.

The seal in the axial direction of the divided portion of the seal ring 4 is ensured by the above-described step division structure. For sealing in the circumferential direction, a cover ring 8 is mounted on the outer peripheral side of the seal ring 4 so that the divided portion is circumferentially shifted from the divided portion of the seal ring 4.
Is secured by closing the gap between the divided portions.

A key (not shown) is mounted between the divided pieces of the cover ring 8, and a tip end of each key is provided with a key groove (not shown) provided on the outer peripheral side of each divided piece of the seal ring 4. ), Whereby the relative rotation of the cover ring 8 and the seal ring 4 is prevented. An engagement groove (not shown) is provided in a part of the key, and the tip of a rotation lock pin (not shown) fixed to the housing 3 is engaged in the engagement groove.
The rotation of the seal ring 4 and the cover ring 8 together with the rotating shaft 17 is prevented.

The extension spring 10 has an annular shape mounted in a groove 8 a provided on the outer peripheral side of the cover ring 8. The diameter of the extension spring 10 reduces the diameter of the cover ring 8 and the seal ring 4.
And a key (not shown) are pressed inward in the radial direction, and the inner peripheral surface (primary seal surface 5) of each divided piece of the seal ring 4 is pressed against the outer peripheral surface of the seal runner 18, and the primary seal surface 5 is pressed. Initially, a necessary seal load is added.

A pressure balance groove 6 and a dynamic pressure generation groove 7 are provided on the primary seal surface 5 of each divided piece of the seal ring 4.
The pressure balance groove 6 has a longitudinal groove 6a extending in the circumferential direction and a shaft having one end communicating with the longitudinal groove 6a and the other end opening to the axial end face of each of the divided pieces, similarly to the conventional one. And a plurality of lateral grooves 6b extending in the direction.
The dynamic pressure generating groove 7 is provided between the vertical groove 6a and the horizontal groove 6b of the pressure balance groove 6, and a part thereof communicates with the horizontal groove 6b.

The compression spring 11 is mounted between the axial end faces of the seal ring 4 and the cover ring 8 and the axial end face of the spring retainer 14, and is compressed by the biasing force of the compression spring 11. The ring 4 and the cover ring 8 are pressed in the axial direction, their axial end faces are pressed against the axial end face of the housing 3, and the seals necessary for the seal ring 4 and the secondary seal surface 9 of the cover ring 8 are initially required. A load is applied.

A pressure balance groove 12 is provided on the secondary seal surface 9 of each of the divided pieces of the seal ring 4 and the cover ring 8. Pressure balance groove 12 of each divided piece of seal ring 4
Like the above-mentioned conventional one, a circumferential groove (not shown) extending in the circumferential direction, and one end communicates with the longitudinal groove and the other end extends in the radial direction opening to the outer peripheral surface side of each divided piece. It is composed of a plurality of lateral grooves (not shown). The pressure balance groove 12 of each divided piece of the cover ring 8 is formed of a plurality of radially extending lateral grooves (not shown) communicating between the inner and outer peripheral surfaces, as in the conventional case, and has an inner diameter of each lateral groove. The end communicates with each lateral groove of each divided piece of the seal ring 4.

The seal ring 4 and the cover ring 8 include:
A plurality of pipes that mutually communicate between a portion 7a on the back side of the dynamic pressure generation groove 7 of the primary seal surface 5 of the seal ring 4 and the pressure balance groove 12 of the secondary seal surface 9 of the seal ring 4 and the cover ring 8 Are provided. That is, one end of each pressure introducing hole 13 opens in a portion 7 a on the back side of the dynamic pressure generating groove 7 of the primary seal surface 5, and the other end opens in each lateral groove of the pressure balance groove 12 of the secondary seal surface 9. It is supposed to.

When the jet engine of the aircraft equipped with the segment seal 1 according to the embodiment constructed as described above is operated, the seal runner 18 rotates integrally with the rotating shaft 17 and the primary of the seal ring 4 is rotated. The seal surface 5 is in sliding contact with the outer peripheral surface of the seal runner 18, the space between them is sealed over the entire circumference, and the secondary seal surfaces 9 of the seal ring 4 and the cover ring 8 are in the axial direction of the housing 3. The end faces are contacted and the space between them is sealed all around.

In this case, the relationship between the forces applied to the seal ring 4 and the cover ring 8 is as shown in FIG.
That is, the radial force can be balanced by the pressure balance groove 6 provided on the primary seal surface 5 of the seal ring 4 and the dynamic pressure generated by the dynamic pressure generation groove 7 of the primary seal surface 5 , Through the pressure introduction hole 13
Since the pressure is guided into the dynamic pressure generating groove 12 of the next seal surface 9, the axial pressure can be balanced.

Therefore, the pressing force of the secondary seal surface 9 can be reduced, so that the frictional force on the secondary seal surface 9 is reduced, and the followability of the rotary shaft 17 to the radial displacement is improved. In addition, the contact load of the primary seal surface 5 becomes excessive due to the radial displacement of the rotating shaft 17,
A gap is not generated in the primary seal surface 5 because the primary seal surface 5 cannot follow the displacement of the rotating shaft 17 in the radial direction. As a result, the sealing performance can be stabilized.

In the above description, the segment seal having the cover ring 8 has been described. However, a segment seal having no cover ring can be applied. Further, the dynamic pressure generating groove 7 is not limited to the above-mentioned shape, and the opening position of the pressure introducing hole 13 is not limited to the above-mentioned position, but can be various depending on the application.

[0041]

According to the present invention, a dynamic pressure generating groove is provided on the primary sealing surface, and the dynamic pressure generating groove is communicated with the secondary sealing surface. Since the dynamic pressure generated by the generated groove is guided to the secondary seal surface, the radial force due to the fluid force can be balanced, and the axial force can be balanced. Therefore, the pressing force of the secondary seal surface can be reduced, the frictional force of the secondary seal surface can be reduced, the contact load of the primary seal surface becomes excessive, and the radial displacement of the rotating shaft can be reduced. Thus, there is no possibility that a gap is formed on the primary seal surface due to failure to follow the above-mentioned conditions, and excellent effects such as stable sealing performance can be exhibited.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a segment seal according to the present invention.

FIG. 2 is a partial explanatory view of what is shown in FIG.

FIG. 3 is an explanatory diagram of what is shown in FIG. 2 viewed from the inner peripheral side.

FIG. 4 is an explanatory diagram of a force relationship acting on a seal ring and a cover ring of the one shown in FIG.

FIG. 5 is a sectional view showing an example of a conventional segment seal.

FIG. 6 is a partial explanatory view of what is shown in FIG. 5;

FIG. 7 is an explanatory diagram of what is shown in FIG. 6 as viewed from the inner peripheral side.

FIG. 8 is an explanatory view of a force relationship applied to a seal ring and a cover ring of the one shown in FIG.

[Explanation of symbols]

 1, 31 Segment seal 2, 32 Stationary unit 3, 33 Housing 4, 34 Seal ring 5, 35 Primary seal surface 6, 12, 36, 42 Pressure balance groove 6a , 36a ... vertical groove 6b, 36b ... horizontal groove 7, 37 ... dynamic pressure generation groove 8, 38 ... covering 8a, 38a ... groove 9, 39 ... secondary sealing surface 10, 40 ... extension Spring 11, 41: Compression spring 13: Pressure introduction hole 14, 44: Spring retainer 15, 45: Snap ring 16, 46: Rotating side unit 17, 47: Rotating shaft 18, 48: Seal runner 20, 50 ... Equipment main body

Claims (1)

[Claims] An inner peripheral side has a primary seal surface that comes into contact with the rotating shaft side, and one end in the axial direction has a secondary seal surface that comes into contact with the housing side, and the primary sealing surface when the rotating shaft rotates. Are brought into sliding contact with the rotating shaft side, and the secondary sealing surface is brought into contact with the housing side to seal between them. A segment seal, wherein a generating groove is provided, and the dynamic pressure generating groove communicates with the secondary seal surface.