JPH08277941A - Mechanical seal - Google Patents

Abstract

PURPOSE: To provide a mechanical seal capable of solving fault such that prescribed fluid pressure is not generated on a shaft seal surface, and abrasion and burning damage are generated on the shaft seal surface to deteriorate sealing property, when rotating speed is a low level and reverse rotation is carried out. CONSTITUTION: This device is composed of a circumferential groove 14 which is recessed in an annular shape on the rear end surface of a rotary ring 1 for forming a shaft sealing surface or on the front end surface of a fixing ring 2, a radial directional or spiral outer circumferential side groove 15 which is recessed on the rear end surface of the rotary ring of the outer circumferential side of the circumferential groove 14, and an inner circumferential side radial direction groove 16 whose outer circumferential end is opened to the circumferential groove 14 and inner circumferential end is arranged on the intermediate part between the inner diameter rim of the circumferential groove 14 and the inner diameter rim of the fixing ring 2. Fluid pressure which is fluctuated by the size of the clearance between the rotary ring 1 and the fixing ring 2 is generated on the shaft sealing surface. It is thus possible to prevent both ring 1, 2 from being brought in contact with each other, and prevent abrasion and burning damage of a sealing surface so as to maintain sealing property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical seal for preventing fluid from leaking from a shaft seal portion of a rotary shaft, and more particularly to a mechanical seal used for a shaft seal portion of a high pressure rotating machine such as a gas compressor or a pump. Regarding

[0002]

2. Description of the Related Art FIG. 7 is a longitudinal sectional view showing an example of a conventional mechanical seal, and FIG. 8 is a shaft sealing surface 1 of a rotary ring 1 thereof.
It is a partial front view showing 2 (sliding surface). As shown in these drawings, the mechanical seal includes a high pressure chamber 3 and a low pressure chamber 4, which are formed by the outer peripheral surface of the rotary shaft 5 and the inner peripheral surface of a casing 8 surrounding the rotary shaft 5, between the high pressure chamber 3 and the low pressure chamber 4. A rear end surface of the rotary ring fixed to the outer peripheral surface by a pair of shaft sleeves 6 and 7, and a seal housing 9 fitted and inserted into the inner peripheral surface of the casing 8.
The rear end of the rotary ring 1 is attached with the seal housing 9 and the spring 10 interposed therebetween, and the support ring 11 that moves back and forth inside the seal housing 9 is attached. Sealing is performed by a ring-shaped shaft sealing surface 12 formed by the front end surface of the fixing ring 2 which is pressed against.

In this seal, as shown in FIG. 8, a plurality of spiral grooves 13 are provided in the circumferential direction on the shaft sealing surface 12 of the rotary ring 1 from the outer peripheral portion toward the inner peripheral direction, Along with the rotation R of the rotating shaft 5, the fluid in the outer peripheral portion of the rotating ring 1 is transferred in the inner peripheral direction. That is, the rotation R of the rotating shaft 5 causes the shaft sealing surface 1 of the rotating ring 1 to rotate.
A plurality of spiral grooves 13 provided in 2 transfer the fluid on the high pressure chamber 3 side of the outer circumference of the rotary ring 1 in the inner circumferential direction, so that the fluid force generated on the shaft sealing surface 12 and the inner circumference from the outer circumferential portion. The fluid force flowing due to the pressure difference between the high pressure chamber 3 and the low pressure chamber 4 acting on the portion acts on the shaft sealing surface 12 of the rotating ring 1 and the fixed ring 2, and the rear end surface of the rotating ring 1 and the front end surface of the fixed ring 2 are I try to prevent contact.

Further, the magnitude of the fluid force generated by the effect of the spiral groove 13 of the rotating ring 1 changes depending on the magnitude of the sliding clearance between the rear end surface of the rotating ring 1 and the front end surface of the fixed ring 2. , The sum of the fluid force acting on the back surface of the fixed ring 2 and the force of the spring 10 pressed through the support ring 11, and the force acting on the front end surface of the fixed ring 2 due to the fluid force generated in the sliding clearance. The fixed ring 2 moves in the axial direction so that the sum becomes equal, and an axial clearance is maintained between the rear end surface of the rotating ring 1 and the front end surface of the fixed ring 2. In this way, both the rings 1 and 2 are held in a non-contact state through a minute clearance during rotation, and the leakage of fluid from the high pressure chamber 3 to the low pressure chamber 4 is suppressed.

However, in the mechanical seal described above, the rotating ring 1 and the fixed ring 2 are caused by the fluid force generated by the transfer of the outer peripheral fluid during rotation by the spiral groove 13.
In order to reduce the amount of fluid leaking from the high pressure chamber 3 to the low pressure chamber 4 side through the axial clearance between the rotary ring 1 and the fixed ring 2 in a non-contact manner. ,
Since it is necessary to reduce the axial clearance between the rings 1 and 2 and maintain the clearance stably, the spiral groove 3
Until the rotation of the rotary shaft 5 that increases the fluid transfer effect by 1 increases to a predetermined rotation speed, the opposing end surfaces of both rings 1 and 2 come into contact and slide.

Therefore, in the mechanical seal used under the condition that the pressure difference between the high pressure chamber 3 and the low pressure chamber 4 is large, the contact force between the rings 1 and 2 becomes large, and the rotation at this time causes the rings 1 and 2 to contact with each other. There is a problem that the shaft sealing surface 12 of No. 2 is roughened and the sealing property is deteriorated. Also, spiral groove 1
Since the fluid is transferred by means of 3 and the generated fluid force is utilized, in the rotation direction opposite to the predetermined rotation direction,
When the rotary shaft 5 rotates, the fluid is transferred in the opposite direction in the spiral groove 13, a predetermined fluid pressure is not generated on the shaft sealing surface 12, and the sliding surfaces of both rings 1 and 2 come into contact and slide. However, there is a problem that both rings 1 and 2 are worn and burned.

[0007]

According to the present invention, in order to solve the above-mentioned problems of the conventional mechanical seal, the rotating ring and the fixed ring are brought into contact with each other and slide under a low rotation speed condition or a reverse rotation condition. It is an object of the present invention to provide a mechanical seal capable of preventing the above-mentioned problem and reducing the axial gap between both rings to reduce the fluid from the high pressure chamber to the low pressure chamber and maintaining a stable gap.

[0008]

Therefore, the mechanical seal of the present invention has the following means. (1) An annular circumferential groove formed by the facing surfaces of the rotating ring and the fixed ring is provided in the circumferential direction on at least one of the end surface of the rotating ring and the fixed ring. The circumferential groove may be provided on the facing surface of the rotating ring facing the fixed ring forming the shaft sealing surface, or on the facing surface of the fixed ring facing the rotating ring. Further, the circumferential groove is recessed so as to be housed in the annular shaft sealing surface, so that the opening to the shaft sealing surface does not directly open to the outer circumference or the inner circumference of the shaft sealing surface,
It is desirable to provide it at a substantially middle portion. However, the inside of the circumferential groove may be communicated with the outer periphery of the fixed ring by a communication hole or the like. (2) A plurality of outer peripheral side grooves are recessed in the circumferential direction of the shaft sealing surface of the rotary ring forming the shaft sealing surface outside the outer circumference of the circumferential groove. The outer peripheral side grooves may be provided radially in the radial direction, or may be provided so as to be inclined in the circumferential direction from the radial direction. Further, it may be linear or curved. (3) The inner circumferential radial groove whose outer peripheral end is open to the circumferential groove and whose inner circumferential end is located between the inner circumference of the circumferential groove and the inner circumference of the fixed ring is the circle of the shaft sealing surface of the rotating ring. A plurality of threads are provided in the circumferential direction in the radial direction. The inner circumferential radial groove may be linear or curved, or may be provided so as to be inclined from the radial direction to the circumferential direction.

The mechanical seal of the present invention according to claim 2 has the following means in addition to the above-mentioned means (1) to (3). (4) A circumferential groove is formed in an annular shape on the shaft sealing surface of the fixing ring. (5) Positioned between the outer circumference of the fixed ring and the outer circumference of the circumferential groove, the outer circumferential end of which is opened at the outer circumferential edge of the rotating ring and the inner circumferential end of which is recessed in the shaft sealing surface of the fixed ring that faces the outer circumferential side groove. Then
An outer peripheral radial groove was formed in a concave shape with the shaft sealing surface of the rotating ring directed in the radial direction.

Further, the mechanical seal of the present invention according to claim 3 has the following means in addition to the above-mentioned means (1) to (3). (6) A circumferential groove is formed in an annular shape on the shaft sealing surface of the rotating ring. (7) The outer circumferential radial groove similar to the above-described means (5) is provided as the outer circumferential groove.

In addition to the above-mentioned means (1) to (3), the mechanical seal of the present invention according to claim 4 has the following means. (8) A circumferential groove is formed in a ring shape on the shaft sealing surface of the fixing ring, and the inside of the fixing ring is communicated with the outer circumference of the fixing ring by a communication hole formed in the radial direction. It was (9) As the outer peripheral side groove, the inner peripheral end communicates with the opening to the shaft sealing surface of the circumferential groove, and the outer peripheral end is located on the shaft sealing surface of the rotating ring located between the outer periphery of the peripheral groove and the outer periphery of the fixed ring. A spiral groove, which is recessed in a spiral shape, is provided. The spiral groove has a shape that is inclined from the inner peripheral side to the outer peripheral side of the rotating ring and in the rotating direction of the rotating ring.

[0012]

The mechanical seal of the present invention has the above-mentioned (1) to (1).
By means of (3), (1) the high pressure fluid in the outer peripheral portion of the rotating shaft flows through the clearance of the shaft sealing surface formed between the rotating ring and the fixed ring due to the pressure difference between the high pressure chamber and the low pressure chamber, It leaks to the low pressure side of the circumference. At this time, a part of the fluid in the outer peripheral part flows in the shallow groove of the outer peripheral side groove provided in the circumferential direction, and a large amount of the fluid is provided in the circumferential groove regardless of the rotation speed and the rotating direction. Flow into. Also, in the circumferential groove,
The fluid with a reduced pressure imbalance in the circumferential direction passes through the radial groove on the inner peripheral side and reaches a large amount between the inner circumference of the fixed ring and the inner circumference of the circumferential groove regardless of the number of rotations and the rotational direction. Can transfer the fluid. Next, it flows out from the inside radial groove into the clearance of the flat portion having no groove.

Next, the pressure distribution in the shaft sealing surface of the fluid when flowing out from the groove portions of the outer peripheral side groove and the inner peripheral side radial groove to the flat clearance portion without the groove will be described. The pressure distribution in the shaft sealing surface is determined by the ratio of the resistance of the fluid flowing in the groove to the resistance of the fluid flowing in the flat clearance, and these resistances are the depth of the groove + the size of the clearance and the clearance. Is proportional to the cube of the magnitude of. Therefore, when the clearance is narrow, the resistance of the flat clearance increases, and the pressure drop of the fluid in the groove decreases. Conversely, when the clearance increases, the resistance of the flat clearance decreases and the pressure drop of the fluid in the outer circumferential groove decreases. Is larger than the former case.

As described above, by providing a plurality of outer circumferential grooves and inner circumferential radial grooves in the circumferential direction of the shaft sealing surface, the fixed ring approaches the rotating ring, and the axial clearance between the two is small. Then, the axial force due to the fluid pressure in the axial clearance increases due to the effect of the groove described above, and tends to separate the two rings. On the contrary, when the fixed ring moves away from the rotating ring, the axial force due to the fluid pressure in the axial clearance becomes small due to the effect of the groove described above, and the rotating ring and the fixed ring are The fluid moves on the back side and the spring force moves in an approaching direction.

In this way, due to the bearing effect of the plurality of grooves provided in the circumferential direction, the rotary ring and the rotary ring are not affected by the rotational speed and the rotational direction, and even under the condition that there is a large pressure difference between the high pressure chamber and the low pressure chamber. The clearance of the fixing ring can be made small and stable, and contact between the rotating ring and the fixing ring can be prevented. In addition, this action occurs evenly over the entire circumference of the shaft-sealing surface formed in an annular shape by providing the circumferential groove, and it is possible to prevent the occurrence of partial contact between the rotating ring and the fixed ring.

Furthermore, since the fluid is supplied to the inner peripheral portion of the fixed ring, which is apt to run out of fluid, by the inner radial groove regardless of the rotation direction, the fluid can be transferred under both forward and reverse rotation conditions. Since the fluid is efficiently supplied, the fluid does not run out at the inner peripheral portion of the shaft sealing surface. Further, since the inner peripheral end of the inner peripheral side radial groove is arranged between the inner periphery of the fixed ring and the circumferential groove, the contact between the rotating ring and the fixed ring described above can be prevented, and the high pressure chamber It is possible to reduce the amount of fluid leaked from the low pressure chamber to the low pressure chamber.

According to the mechanical seal of the present invention of claim 2, in addition to the above (1), (2) a circumferential groove is formed on the sliding surface of the fixed ring by means of the above (4) and (5). By providing it, the fluid pressure in the circumferential groove can be set to an intermediate pressure between the pressures in the high pressure chamber and the low pressure chamber, the unbalance of the pressure in the circumferential direction can be reduced, and the processing becomes easy. Further, the same action as the inner circumferential side of the circumferential groove occurs on the outer circumferential side of the circumferential groove, and even pressure distribution is achieved in the radial direction of the shaft sealing surface, so that a mechanical seal with high reliability can be obtained. , The sealability may be changed.

Further, according to the mechanical seal of the present invention of claim 3, in addition to the above (1), (3) a circumferential groove is formed on the sliding surface of the rotating ring by means of the above (6) and (7). By providing them, the relative positional relationship between the outer circumferential side radial groove and the inner circumferential side radial groove and the circumferential groove is uniquely determined, which facilitates the assembly of the mechanical seal, and has the same effect as (2) above. Occurs.

According to the mechanical seal of the present invention of claim 4, in addition to the above (1), (4) the high pressure side fluid is provided in the fixed ring by means of the above (8) and (9). It is introduced into the circumferential groove provided on the shaft sealing surface of the fixing ring by the communication hole. The fluid introduced into the circumferential groove is transferred to the outer circumferential shaft sealing surface of the circumferential groove by the spiral groove provided in the rotating ring in the outer circumferential direction of the circumferential groove as the rotary shaft rotates. , Increase fluid pressure. Further, to the inner circumferential side shaft sealing surface of the circumferential groove, it flows out to the inner circumferential side through the inner circumferential side radial groove provided in the rotating ring. At this time, the effect of the spiral groove is the effect that occurs when the rotating ring rotates,
The effect of the inner circumferential radial groove is an effect caused by the pressure difference between the high pressure chamber and the low pressure chamber. Therefore, on the inner circumferential side of the circumferential groove farther from the high-pressure chamber, the same action as (1) above is produced and the same effect is obtained even when the rotation speed is low or the reverse rotation is performed.

Further, since the fluid supplied to the circumferential groove from the communication hole flows into the spiral groove, the fluid pressure in this spiral groove is also the groove at the same radial position as in the inner radial groove. It can be made higher than the fluid pressure of the sliding surface of the portion without. Therefore, the total fluid force generated in the axial clearance between the rotating ring and the fixed ring is greater than when the inner radial groove and spiral groove are not provided, compared to when the groove is not provided. It is possible to increase the force for preventing contact between both rings on the sealing surface.

[0021]

Embodiments of the mechanical seal of the present invention will be described below with reference to the drawings. In the drawings showing the embodiments of the present invention, the same parts as those of the conventional example shown in FIGS. 7 and 8 are designated by the same reference numerals, and a duplicate description will be omitted.

FIG. 1 is a vertical sectional view showing a first embodiment of the mechanical seal of the present invention, and FIG. 2 is a view taken along the line A--A of FIG.

As shown in the figure, in this embodiment, a fixed ring 2 which forms a shaft sealing surface in opposition to the rear end surface of the rotary ring 1.
A circumferential groove 14 is provided on the sliding surface at the front end of the. Further, on the sliding surface of the rear end of the rotary ring 1 located on the outer periphery of the circumferential groove 14, the circumferential groove 14 is formed on the outer peripheral portion of the rotary ring 1.
A plurality of shallow outer peripheral radial grooves 15 as outer peripheral grooves extending in the middle of the outer peripheral edge of the sliding surface of the fixed ring 2 opposed to the outer peripheral edge of the fixed ring 2 are provided in the circumferential direction. A plurality of shallow inner circumferences extending in the circumferential direction extending from the sliding surface position of the rotating ring 1 facing the center of the circumferential groove 14 to the outer peripheral side of the position facing the inner peripheral edge of the sliding surface of the fixed ring 2. A lateral radial groove 16 is provided.

In the mechanical seal of this embodiment, the high pressure fluid in the high pressure chamber 3 at the outer peripheral portion of the rotary shaft 5 has the above-mentioned structure.
The outer peripheral radial groove 15 provided in the clearance between the rotating ring 1 and the fixed ring 2 is caused to flow toward the low pressure side of the inner peripheral portion due to the pressure difference between the high pressure chamber 3 and the low pressure chamber 4, It flows into the clearance of the sliding surface where the side radial groove 15 is not provided. Further, the high-pressure fluid that has flown to the inner peripheral end of the outer radial groove 15 flows into the circumferential groove 14 through the sliding surface clearance between the rotating ring 1 and the fixed ring 2, and the entire high pressure fluid inside the circumferential groove 14. The pressure in the circumferential direction is made uniform, and then a part of the high-pressure fluid from the outer peripheral portion flows in a plurality of radial inner circumferential radial grooves 16 provided in the circumferential direction, and a flat clearance without a groove from the groove portion. Flow out to.

At this time, the pressure distribution of the high-pressure fluid is such that the resistance of the fluid flowing through the outer peripheral side radial groove 15 and the inner peripheral side radial groove 16 and the plane clearance where these grooves 15 and 16 are not provided. It is determined by the ratio with the resistance of the fluid, and this resistance is proportional to the depth of the groove + the size of the clearance and the cube of the size of the clearance, respectively.

Therefore, by providing a plurality of outer circumferential side and inner circumferential side radial grooves 15 and 16 in the circumferential direction, the fixed ring 2 approaches the rotating ring 1,
When the axial clearance between the two becomes smaller, the axial force due to the fluid pressure in the axial clearance becomes larger due to the effect of these grooves, and tends to separate the two rings. On the contrary, when the fixed ring 2 moves in the direction away from the rotary ring 1, the axial force due to the fluid pressure in the axial clearance becomes small due to the effect of these grooves, and the fixed ring 2 has a rear surface in the axial direction. And the force of the spring 10 provided on the rear side through the support ring 11 move in the direction of approaching the rotating ring 1.

As described above, due to the bearing effect of the outer peripheral radial groove 15 and the inner radial groove 16 provided in the circumferential direction, there is a large pressure difference between the high pressure chamber 3 and the low pressure chamber 4. However, the shaft sealing surfaces of the rear end surface of the rotating ring 1 and the front end surface of the fixed ring 2 can prevent both rings from coming into contact with each other. Further, since this action does not depend on the rotation direction of the rotary shaft 5, it works effectively under both forward rotation and reverse rotation conditions.

Further, since the circumferential groove 14 is provided on the sliding surface of the fixed ring 2, the fluid pressure in the circumferential groove 14 can be set to an intermediate pressure between the pressures in the high pressure chamber 3 and the low pressure chamber 4. The unbalance of the pressure in the circumferential direction can be reduced and the processing becomes easy. Further, the same fluid pressure acts on the outer peripheral side and the inner peripheral side of the circumferential groove 14, and even pressure distribution can be made even in the radial direction of the shaft sealing surface, and a mechanical seal with high reliability can be obtained. The sealability may be changed.

Next, FIG. 3 is a longitudinal sectional view showing a second embodiment of the present invention, and FIG. 4 is a view taken along the line BB of FIG. Here, the overall structure of this embodiment is the same as that of the first embodiment, and FIG. 3 shows only the layout of the rotating ring 1 and the fixed ring 2, and FIG. 4 shows the sliding surface of the rotating ring 1. There is.

In this embodiment, the circumferential groove 14 provided on the sliding surface of the fixed ring 2 in the first embodiment is provided on the sliding surface of the rotary ring 1. As a result, in this embodiment as well, the same effects as those of the above-described first embodiment can be obtained, and in addition, a circumferential groove 14 is provided on the sliding surface of the same rotary ring 1, and an outer circumferential radial groove is provided on the outer circumferential side thereof. Further, since the inner peripheral side radial groove 16 is provided on the inner peripheral side, the relative position adjustment of these is unnecessary at the time of assembly, and there is an advantage that the assembly work is facilitated.

Next, FIG. 5 is a longitudinal sectional view showing a third embodiment of the present invention, and FIG. 6 is a view taken along the line CC in FIG. As shown in the figure, in this embodiment, the shaft sealing surface of the fixing ring 2 is provided with the circumferential groove 14 as in the first embodiment described above, and the fixing ring 2 is The inside of the circumferential groove 14 communicates with the high pressure chamber 3 on the outer circumference of the rotary shaft 5,
A plurality of communication holes 17 are provided in the circumferential direction.

Further, as shown in FIG. 6, the spiral groove 1 for transferring the fluid in the circumferential groove 14 of the fixed ring 2 to the high pressure chamber 3 side by the rotation R of the rotary shaft 5 on the shaft sealing surface of the rotary ring 1.
A plurality of 8 are provided in the circumferential direction. As described above, the inner circumferential end of the spiral groove 18 is open to the circumferential groove 14 in order to transfer the fluid in the circumferential groove 14 to the high-pressure chamber 3 side, but the outer circumferential end has the outer circumferential end. Is arranged in the middle of the outer peripheral edge of the fixing ring 2 and the outer peripheral surface of the fixing ring 2. Further, on the shaft sealing surface of the rotary ring 1, as in the first and second embodiments, a plurality of circumferentially arranged inner circumferential sides of the circumferential groove 14 provided on the shaft sealing surface of the fixed ring 2 are provided. An inner circumferential radial groove 16 is provided.

The high-pressure fluid in the high-pressure chamber 3 flows into the circumferential groove 14 through the communication hole 12 of the fixed ring 2, and the fluid in the circumferential groove 14 is the spiral groove 18 of the rotating ring 1 and the inner radius. Through the directional grooves 16, they flow in the outer circumferential direction and the inner circumferential direction of the circumferential groove 14, respectively. That is, the shaft sealing surface formed between the rear end surface of the rotating ring 1 and the front end surface of the fixed ring 2 is rotated by the rotating shaft 5 to form a plurality of spiral grooves 18 provided on the shaft sealing surface of the rotating ring 1. The fluid pressure generated by transferring the high-pressure fluid flowing into the circumferential groove 14 of the fixed ring 2 through the communication hole 17 to the high-pressure chamber 3 side and the inner circumferential side from the circumferential groove 14 of the fixed ring 2. The pressure due to the fluid flowing into the low pressure chamber 4 side through the radial groove 16 acts.

In this case, since the fluid force generated in the spiral groove portion 18 of the rotating ring 1 changes depending on the shaft sealing surface clearance between the rotating ring 1 and the fixed ring 2, the fluid force on the back surface acting on the fixed ring 2 is changed. The fixed ring 2 moves in the axial direction so that the sum of the force of the spring 10 and the sum of the force of the fluid generated in the gap of the shaft sealing surface becomes equal, and the gap between the rotary ring 1 and the fixed ring 2 in the axial direction is made. Is properly held. Further, to the inner peripheral side of the circumferential groove 14, it flows out to the inner peripheral side through the inner peripheral side radial groove 16 provided in the rotary ring 1, and the same operation as in the first and second embodiments, The effect is obtained.

Although the effect of the spiral groove 18 is an effect that occurs during rotation, the inner circumferential radial groove 1 provided on the inner circumferential side.
The effect of 6 is an effect generated by the pressure difference between the high pressure chamber 3 and the low pressure chamber 4, and the fluid pressure in these grooves can be made higher than the fluid pressure of the sliding surface without a groove at the same radial position. . Therefore, as compared with the case where the inner circumferential side radial groove 16 is not provided, the total fluid force generated in the axial clearance between the rotating ring 1 and the fixed ring 2 is when the inner circumferential side radial groove 16 is not provided. The force for preventing contact between the end faces of both rings can be increased.

[0036]

As described above, according to the mechanical seal of the present invention, due to the structure shown in the claims, (1) a remarkably large pressure difference between the high pressure chamber and the low pressure chamber on the outer circumference of the rotary shaft. Even under certain conditions, contact between the end faces of the rotating ring and the fixed ring that form the shaft sealing surface is prevented, wear and burning are prevented, surface roughness of the shaft sealing surface is prevented, and good sealing performance is maintained. be able to. (2) Due to the fluid pressure generated in the inner radial side radial groove provided on the shaft sealing surface, the outer radial side radial groove forming the outer peripheral side groove, or the spiral groove, and the fluid pressure generated in the flat portion where the groove is not provided, Since the rotating ring and the fixed ring can always form and hold a small gap, it is possible to reduce the amount of fluid leaking from the high pressure chamber to the low pressure chamber, and to obtain good sealing performance. (3) Depending on the number of rotations of the rotation shaft or the rotation direction,
Proper fluid pressure can be generated on the shaft sealing surface, and (1),
The effect of (2) is obtained.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a mechanical seal of the present invention.

FIG. 2 is a partial front view showing a rear end surface of a rotating ring in the direction of arrow AA shown in FIG.

FIG. 3 is a partial vertical cross-sectional view of a rotary ring and a fixed ring according to a second embodiment of the present invention.

FIG. 4 is a partial front view showing a rear end surface of the rotating ring taken along the line BB shown in FIG.

FIG. 5 is a vertical cross-sectional view showing a third embodiment of the present invention.

6 is a partial front view of the rear end face of the rotating ring taken along the line CC shown in FIG.

FIG. 7 is a vertical sectional view showing an example of a conventional mechanical seal.

FIG. 8 is a partial front view of the rotating ring taken along the line DD of FIG.

[Explanation of symbols]

 1 rotating ring 2 fixed ring 3 high pressure chamber 4 low pressure chamber 5 rotating shaft 6 shaft sleeve 7 shaft sleeve 8 casing 9 seal housing 10 spring 11 support ring 12 shaft seal surface of rotating ring 13 spiral groove 14 circumferential groove 15 outer circumferential radial groove 16 Inner peripheral radial groove 17 Communication hole 18 Spiral groove

Claims (4)

[Claims] 1. A rotating ring fixed to an outer peripheral surface of a rotating shaft, and a fixed ring which is attached to an inner peripheral surface of a casing surrounding the rotating shaft via a spring and presses an end surface of the rotating ring. In a mechanical seal that forms a shaft sealing surface, and seals between the high pressure chamber and the low pressure chamber on the outer periphery of the rotating shaft with the shaft sealing surface, the end surface of the rotating ring that forms the shaft sealing surface, or the fixed ring. A circumferential groove provided in at least one circumferential direction of the end surface, a plurality of outer circumferential side grooves provided in the shaft sealing surface of the rotary ring outside the outer circumference of the circumferential groove, and the circumferential direction. An outer peripheral end portion is opened in the groove, an inner peripheral end is arranged between an inner peripheral surface of the circumferential groove and an inner peripheral surface of the fixed ring, and is radially provided in the shaft sealing surface of the rotating ring. A member characterized by having a plurality of inner radial grooves Canical seal. 2. The circumferential groove is provided on the shaft-sealing surface of the fixed ring, the outer circumferential side groove opens an outer circumferential end to the outer circumference of the rotating ring, and the outer circumference of the circumferential groove and the outer circumference of the fixed ring. 2. The mechanical seal according to claim 1, wherein an inner peripheral end is disposed between the two, and is formed by an outer peripheral radial groove provided in a radial direction on the shaft sealing surface of the rotating ring. 3. The circumferential groove is provided on the shaft sealing surface of the rotary ring, the outer circumferential groove has an outer circumferential end opening to the outer circumference of the rotary ring, and the outer circumference of the circumferential groove and the outer circumference of the fixed ring. 2. The mechanical seal according to claim 1, wherein an inner peripheral end is disposed between the outer peripheral side and the outer peripheral side radial groove provided in the radial direction on the shaft sealing surface of the rotary ring. 4. The communication hole, wherein the circumferential groove is provided in the shaft sealing surface of the fixing ring, and is formed in the fixing ring.
It communicates with the outer periphery of the fixed ring, the outer peripheral side groove is recessed in the shaft sealing surface of the rotating ring, the inner peripheral end opens to the circumferential groove, and the outer peripheral end is the outer periphery of the fixed ring and the circumferential groove. The mechanical seal according to claim 1, wherein the mechanical seal is formed by a spiral groove arranged between the outer circumferences of the two.