JPH1137302A - Shaft seal device for rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of bearing difference between the inner circum ference side and outer circumference side of a seal ring caused by its thermal expansion by forming either one or both of a supporting face of a retainer and a supporting face in the axial direction of the seal ring into an abutting face with the cross section in the circular arc shape. SOLUTION: A seal ring 4 is housed in a recess part formed at a portion opposed to a rotating ring 3 of a retainer 5, and in a recess part inner face 5b, a supporting face 4a in the radial direction is allowed to abut to a supporting face 5a at right angles to the recess part inner face 5b. A supporting face 4a in the axial direction of the seal ring 4 abutting to the retainer supporting face 5a is formed in the circular arc shape, and an abutting part of its supporting face 4a in the axial direction to the retainer supporting face 5a is brought into line contact. A radius Ro at a fulcrum 52 of the contact is constituted so that it is located in the middle of an inner radius R1 and an outer radius R2 of a nose 53 in a seal part 60. By this, one-sided abrasion of the rotating ring 3 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for a rotating body in a rotary machine such as a gas compressor or a pump, and more particularly to a shaft sealing device using a mechanical seal mechanism.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show a conventional example of a shaft sealing device for a rotating body by a mechanical seal mechanism used in a gas compressor. FIG. FIG. 5 is a cross-sectional view of a seal ring, taken along a line.

In FIGS. 4 and 5, reference numeral 1 denotes a casing, 2
Is a rotating shaft, 3 is a rotating ring, 4 is an annular seal ring,
5 is a retainer. The rotating ring 3 is fixed to the rotating shaft 2 by being pressed against the step portion of the rotating shaft 2 via the sleeve 9 by tightening the nut 7.
The retainer 5 is fitted on an insert 6 fixed to the casing 1 and is movable in the axial direction of the rotary shaft 2 via a spring 10.

The seal ring 4 has its axial contact surface 4a in contact with the support surface 5a of the retainer, and is fixed to the retainer 5 by a pin (not shown). On the opposite side, a sliding surface 50 that is in sliding contact with the side surface of the rotating ring 3 is formed. 20 high pressure chamber which high pressure gas of the pressure P ₁ is housed, 21 is a low-pressure chamber communicating with the atmosphere (the pressure P _2), and side 3a of the sliding surface 50 and the rotating ring 3 of the sealing ring 4 The sealing portion 60 for sealing the gas in the high-pressure chamber 20 by the sliding contact of. Reference numeral 8 denotes a gas interposed between the casing 1 and the insert 6, between the insert 6 and the retainer 5, between the retainer 5 and the seal ring 4, and between the rotary shaft 2 and the rotary ring 3. This is an O-ring for sealing.

The mechanical seal constructed as described above
When operating a gas compressor equipped with a mechanism,
The ring 4 has an axial force due to the elasticity of the spring 10
Pressure P of fluid in high-pressure chamber 20 applied to retainer 5₁By
And the axial force that presses the retainer 5 in the axial direction
I do. Such axial force is constantly applied to the seal ring 4.
By acting, the seal ring 4 becomes the rotating ring 3
And the fluid pressure P ₁High pressure chamber 20 and fluid pressure P_TwoLow
The space between the pressure chamber 21 and the pressure chamber 21 is sealed by the seal portion 60.
You.

[0006]

In the gas compressor provided with the above-mentioned conventional mechanical seal mechanism, during operation, the seal ring 4 and the rotary ring 3 are always in contact and sliding at the seal portion 60. , The fluid pressure P ₁ in the high-pressure chamber 20 is sealed, but as shown in FIG. 5, the seal ring 4 cools better on the outer peripheral side 4 a than on the inner peripheral side 4 b due to heat generated by sliding. In such a case, the inner peripheral side 4b1 of the seal ring 4 has a relatively larger thermal expansion amount than the outer peripheral side 4a1. For this reason, the seal ring 4
The surface pressure f on the inner peripheral side 4b1 is apparently larger than that on the outer peripheral side 4a1.

Thus, in the above-mentioned conventional mechanical seal, when the seal ring 4 and the rotary ring 3 are brought into sliding contact with each other in the above-mentioned state, the rotary ring 3 facing the seal ring 4 due to the difference in thermal expansion has a stripe shape. Abrasion occurs, and the fluid easily leaks from the high-pressure chamber 20 to the low-pressure chamber 21 side from the abraded portion, thereby deteriorating the function of the mechanical seal.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shaft seal device for a rotating body that prevents a difference in surface pressure between an inner peripheral side and an outer peripheral side due to a difference in thermal expansion or the like of a seal ring. An object of the present invention is to provide a shaft sealing device provided with a mechanical seal mechanism having stable sealing performance by preventing the occurrence of uneven wear.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a gist of the invention is to provide a rotating ring fixed to a rotating shaft and a casing capable of moving in the axial direction of the rotating shaft. A retainer supported, an annular seal ring having an axial support surface abutting on the support surface of the retainer and a sliding surface slidably in contact with a side surface of the rotating ring, and provided through the retainer. In a shaft sealing device in which a sliding surface of the seal ring is pressed against a side surface of the rotating ring by an applied axial force to form a fluid seal between the sliding surface and the side surface, the support of the retainer is provided. One or both of the surface and the axial support surface of the seal ring are formed as contact surfaces having a circular cross section.

[0010] In the above means, it is preferable that the arc-shaped contact surface is configured so that a radial position of a fulcrum thereof is located between an inner diameter and an outer diameter of the seal portion.

According to the above-mentioned means, during operation of the rotary machine, the seal ring generates heat due to sliding contact between the seal ring and the rotary ring, and the inner peripheral side of the seal ring undergoes a large thermal expansion. If it is attempted to increase the size, the axial support surface at the contact portion between the retainer and the seal ring is formed in an arc shape, so that the seal ring 4 easily rotates around the fulcrum of the contact portion to absorb the thermal expansion. However, a local increase in the surface pressure on the inner peripheral side is suppressed, and a uniform surface pressure distribution is always obtained in the seal portion.

As a result, it is possible to prevent the occurrence of streak-like wear on the side surface of the seal portion of the rotating ring as seen in the mechanical seal mechanism of the conventional shaft sealing device, and to obtain a stable sealing state and durability. Also improve.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a sectional view of a main part along a rotation axis of a shaft sealing device of a gas compressor according to a first embodiment of the present invention.

In FIG. 1, 1 is a casing, 2 is a rotating shaft, 3 is a rotating ring, 4 is an annular seal ring, and 5 is a retainer. The rotating ring 3 is fixed to the rotating shaft 2 by being pressed against the step portion of the rotating shaft 2 via the sleeve 9 by tightening the nut 7. Also,
The retainer 5 is fitted on an insert 6 fixed to the casing 1 and, via a spring 10,
It is movable in the axial direction of the rotary shaft 2.

The seal ring 4 is housed in a recess formed in a portion of the retainer 5 facing the rotary ring 3 side, and its radial support surface 4b is in contact with the recess inner surface 5b of the retainer 5, which will be described later. The axial supporting surface 4a is in contact with the supporting surface 5a perpendicular to the concave inner surface 5b.

The seal ring 4 has a nose 53 protruding from the rotary ring 3 opposite to the axial support surface 4a in the axial direction, and the end face of the nose 53 is in contact with the side surface 3a of the rotary ring 3. The sliding surface 50 is in sliding contact.

Further, the axial support surface 4a of the seal ring 4 which is in contact with the retainer support surface 5a is formed in an arcuate surface, whereby the arcuate axial support surface 4a is formed.
The contact portion between the retainer and the retainer support surface 5a is in line contact. The radius R ₀ of the fulcrum 52 of the contact is the inner radius R ₁ of the nose 53 and the outer radius R
It is configured to be located in the middle of ₂ . 20 high pressure chamber which high pressure gas of the pressure P ₁ is housed, 21 is a low-pressure chamber communicating with the atmosphere (the pressure P _2), and side 3a of the sliding surface 50 and the rotating ring 3 of the sealing ring 4 The sealing portion 60 for sealing the gas in the high-pressure chamber 20 by the sliding contact of. Reference numeral 8 denotes a gas interposed between the casing 1 and the insert 6, between the insert 6 and the retainer 5, between the retainer 5 and the seal ring 4, and between the rotary shaft 2 and the rotary ring 3. This is an O-ring for sealing.

FIG. 2 is a sectional view of an essential part of a mounting portion of a seal ring to a retainer according to a second embodiment of the present invention. In this embodiment, an axial support surface 51 of the retainer 5 is provided.
Are formed in a circular arc shape, and the axial support surface 4a of the seal ring 4 that is in contact with the arc is formed flat. The radius R ₀ of the fulcrum 52 at the contact portion is the same as in the first embodiment.
Inner radius R ₁ and outer radius R ₂ of nose 53 of seal ring 4
Are arranged in the middle of the above.

The mechanical seal constructed as described above
When operating a gas compressor equipped with a mechanism,
The ring 4 has an axial force due to the elasticity of the spring 10
Pressure P of fluid in high-pressure chamber 20 applied to retainer 5₁By
And the axial force that presses the retainer 5 in the axial direction
I do. Such axial force is constantly applied to the seal ring 4.
By acting, the seal ring 4 becomes the rotating ring 3
And the fluid pressure P ₁High pressure chamber 20 and fluid pressure P_TwoLow
The space between the pressure chamber 21 and the pressure chamber 21 is sealed by the seal portion 60.
You.

During the above operation, the seal ring 4 and the axial support surface 4a or 51 of the retainer 5 are formed in an arc shape and brought into contact with each other, and the fulcrum 52 of the arc is in contact with the outer diameter R ₂ of the nose 53 of the seal ring 4. Since the seal ring 4 and the rotary ring 3 are in sliding contact with each other, the seal ring 4 generates heat and the inner peripheral side thereof expands thermally due to the sliding contact between the inner diameter R ₁ and the inner peripheral side. If it gets bigger,
As shown in (A), the force F due to the surface pressure of the sliding contact acts on the inner peripheral side of the seal ring 4.

However, in the present invention, since the axially supporting surfaces 4a and 51 of the seal ring and the retainer are in an arc shape and are in contact with the counterpart, they are added to the radius _R0 to the fulcrum of the arc and the seal ring 4. Since there is a difference from the radius R ₁ on the inner peripheral side, which is the point of application of the force F due to the surface pressure, the seal ring 4 is subjected to a rotational moment M as shown in FIG. ₁ ) The contact pressure decreases.

That is, if the surface pressure inside the seal ring 4 increases due to thermal expansion due to heat generated by the seal portion 60 between the seal ring 4 and the rotating ring 3, the moment M causes the seal ring 4 to rotate around the fulcrum 52 of the arc. To rotate to
An increase in the surface pressure on the inner peripheral side of the seal ring 4 is suppressed, whereby a constant constant surface pressure distribution in the seal portion 60 can be ensured.

In addition to the first and second embodiments, both the seal ring 4 and the support surface of the retainer 5 in the axial direction may be formed in an arc shape.

[0024]

The present invention is configured as described above.
According to the present invention, since the cross-sectional shape of the axial support surface of the retainer or the seal ring is formed in an arc shape, the seal ring can be easily rotated around the fulcrum of the arc-shaped support surface with respect to its thermal expansion, A local increase in surface pressure at the contact surface between the seal ring and the retainer is suppressed, and a uniform surface pressure distribution is obtained.

As a result, it is possible to prevent the occurrence of uneven wear of the rotating ring as in the prior art, and it is possible to obtain stable water sealing performance and to improve durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view along a rotation axis of a shaft sealing device of a gas compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part near a seal ring of a shaft sealing device of a gas compressor according to a second embodiment of the present invention.

FIG. 3 is an operation explanatory view in the embodiment of the present invention.

FIG. 4 shows an example of a conventional shaft sealing device for a gas compressor.
Appropriate figure.

FIG. 5 is an operation explanatory view in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Rotating shaft 3 Rotating ring 3a Side surface 4 Seal ring 4a Axial support surface 5 Retainer 5a Retainer support surface 6 Insert 8 O-ring 9 Sleeve 10 Spring 20 High pressure chamber 21 Low pressure chamber 50 Sliding surface 51 Axial support surface (retainer) ) 52 fulcrum 53 nose 60 seal part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroomi Sakuma 2-1-1, Shinhama, Arai-machi, Takasago-shi, Hyogo Inside the Mitsubishi Heavy Industries, Ltd. Takasago Machinery Works

Claims (2)

[Claims] A rotating ring fixed to a rotating shaft, a retainer supported on a casing so as to be movable in an axial direction of the rotating shaft, an axial supporting surface abutting on a supporting surface of the retainer, and the rotation. An annular seal ring having a sliding surface slidably in contact with the side surface of the ring, and pressing the sliding surface of the seal ring against the side surface of the rotating ring by an axial force applied via the retainer, In a shaft sealing device that forms a fluid seal between the sliding surface and the side surface,
A shaft sealing device for a rotating body, wherein one or both of the support surface of the retainer and the axial support surface of the seal ring are formed as contact surfaces having an arc-shaped cross section. 2. The rotating body according to claim 1, wherein the arc-shaped contact surface is configured such that a radial position of a fulcrum thereof is located between an inner diameter and an outer diameter of the seal portion. Shaft sealing device.