CN111350824B

CN111350824B - Bidirectional rotary mechanical sealing structure for end face of bidirectional crescent-shaped groove

Info

Publication number: CN111350824B
Application number: CN202010078001.3A
Authority: CN
Inventors: 何秀华; 单春铭; 杨航; 濮泽吉
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2020-02-02
Filing date: 2020-02-02
Publication date: 2022-02-15
Anticipated expiration: 2040-02-02
Also published as: CN111350824A

Abstract

The invention discloses a bidirectional crescent-like groove end surface bidirectional rotary mechanical sealing structure.A groove top surface and an outer side surface of each upstream crescent-like groove are opened on a sealing contact end surface of a movable ring and are enclosed by an upstream short arc line side surface, an upstream long arc line side surface, an upstream inner side surface and an upstream inclined bottom surface; from the opening of the outer side surface of the upstream side to the inner side surface of the upstream side, the side surface of the short arc line of the upstream side and the side surface of the long circular arc line of the upstream side gradually deflect along the clockwise direction; the top surface and the inner side surface of each downstream side crescent-like groove are open and are surrounded by a downstream side long circular arc side surface, a downstream side short circular arc side surface, a downstream side outer side surface and a downstream side inclined bottom surface; from the opening of the downstream inner side surface to the downstream outer side surface, the downstream long arc side surface and the downstream short arc side surface deflect gradually along the anticlockwise direction; no matter the sealing machine rotates clockwise or anticlockwise, the sealing end face can generate a strong dynamic pressure effect, and the sealing effect is guaranteed.

Description

Bidirectional rotary mechanical sealing structure for end face of bidirectional crescent-shaped groove

Technical Field

The invention relates to a mechanical sealing structure of a rotating part, which is suitable for shaft end sealing of various rotating machines such as pumps, compressors and the like, in particular to the shaft end sealing of the rotating part under the working condition of positive and negative bidirectional rotation.

Background

The mechanical seal is an axial end face seal which achieves sealing by means of pre-tightening of a sealing end face by an elastic element and pressing of medium pressure and elastic element pressure. With the rapid development of modern technology, the structural requirements for mechanical seals are also higher and higher, such as the running performance under extreme working conditions of high temperature, high pressure, high speed or ultra-low speed, vacuum and the like. In addition, the bidirectional rotating mechanical sealing structure also widely exists, and particularly, the problem of poor mechanical sealing performance is prominent when the shaft rotates reversely, so that the mechanical sealing structure is required to have good start-stop stability and strong enough dynamic pressure effect, a stable fluid film is formed, the friction and abrasion of the end face of the mechanical sealing structure are reduced, and the service life of the rotating part can be prolonged. However, the existing mechanical seal end face structure does not consider dynamic pressure balance between the inner side and the outer side, and bidirectional rotation after starting and stopping is not smooth, for example, chinese patent publication No. CN108869749A mentions an open elliptical slot end face bidirectional rotation mechanical seal structure, which only has elliptical slots on the moving ring and the stationary ring, and the inclined directions of the elliptical slots are the same, so that under the bidirectional rotation working condition, an oil film with proper thickness is not formed between the moving ring and the stationary ring of the structure, and a good seal effect is not achieved, especially when the rotating shaft rotates reversely, the problem of poor mechanical seal performance is prominent.

Disclosure of Invention

The invention aims to solve the problems that when the existing rotary machine rotates bidirectionally, the mechanical sealing structure has poor sealing performance, cannot form good fluid dynamic pressure effect, cannot obtain more stable fluid film and further shortens the service life of the rotary machine, and provides a bidirectional rotary machine sealing structure of an end face of a bidirectional crescent-like groove to solve the problems.

The invention relates to a bidirectional crescent-shaped groove end surface bidirectional rotating mechanical sealing structure, which adopts the technical scheme that: a plurality of groups of bidirectional crescent-like groove groups are uniformly distributed on the sealing contact end surface of the movable ring along the circumferential direction, and each group of crescent-like groove groups consists of a plurality of upstream crescent-like grooves positioned on the radial outer side and a plurality of downstream crescent-like grooves positioned on the radial inner side; a plurality of upstream side crescent-like grooves are arranged at intervals along the circumferential direction, a plurality of downstream side crescent-like grooves are arranged at intervals along the circumferential direction, and a sealing dam is formed between two adjacent two groups of bidirectional crescent-like groove groups. A radial sealing dam is formed between two adjacent upstream side crescent-shaped grooves in the same group of bidirectional crescent-shaped groove groups, and a circumferential sealing dam is formed between the upstream side crescent-shaped grooves and the downstream side crescent-shaped grooves in the same group of bidirectional crescent-shaped groove groups; the top surface and the outer side surface of each upstream side crescent-like groove are open, and each upstream side crescent-like groove is surrounded by four surfaces, namely an upstream side short arc line side surface, an upstream side long circular arc line side surface, an upstream side inner side surface and an upstream side inclined bottom surface; from the opening of the outer side surface of the upstream side to the inner side surface of the upstream side, the side surface of the short arc line of the upstream side and the side surface of the long circular arc line of the upstream side gradually deflect along the clockwise direction; the top surface and the inner side surface of each downstream side crescent-like groove are open, and each downstream side crescent-like groove is surrounded by four surfaces, namely a downstream side long circular arc side surface, a downstream side short circular arc side surface, a downstream side outer side surface and a downstream side inclined bottom surface; from the downstream inner side surface opening to the downstream outer side surface, the downstream long circular arc side surface and the downstream short circular arc side surface are gradually deflected along the anticlockwise direction.

The invention adopts the technical proposal with the prominent effects that:

when the rotating direction of the movable ring is clockwise, under the flow guiding effect of the crescent-shaped groove on the upstream side, fluid flows in rapidly, a strong fluid dynamic pressure effect is generated, the sealing end faces are separated rapidly, and the end face abrasion is reduced; when the rotating direction of the movable ring is anticlockwise, the dynamic pressure effect generated by the upstream crescent-like groove is slightly weakened compared with the dynamic pressure effect generated by clockwise rotation, and the guide effect of the downstream crescent-like groove is that more fluid rapidly flows into the downstream crescent-like groove, so that the dynamic pressure effect is generated and supplemented. Therefore, no matter the sealing machine rotates clockwise or anticlockwise, the sealing end face can generate a strong dynamic pressure effect, the sealing end face is rapidly separated when the sealing machine is started and stopped, a stable and uniform fluid film is formed, the friction and the wear of the sealing end face are reduced, the lubricating performance is improved, the service life of sealing is ensured, meanwhile, the pumping capacity of the downstream side is improved, and the effect of mechanical sealing is ensured.

Drawings

FIG. 1 is an axial sectional view of a bidirectional rotary mechanical seal structure of an end face of a bidirectional crescent-shaped groove of the present invention in an operating state;

FIG. 2 is an enlarged top plan view of the structure of the first embodiment of the present invention shown in FIG. 1;

FIG. 3 is an enlarged view of one of the bi-directional crescent-shaped groove sets of FIG. 2;

FIG. 4 is a partial cross-sectional view A-A of FIG. 2;

FIG. 5 is a partial cross-sectional view B-B of FIG. 3;

FIG. 6 is a partial cross-sectional view C-C of FIG. 3;

FIG. 7 is an enlarged, fragmentary scale view of the upstream crescent-like groove and the radially opposite downstream crescent-like groove of FIG. 3;

FIG. 8 is an enlarged top plan view of the structure of the second embodiment of the present invention shown in FIG. 1;

fig. 9 is an enlarged top view of the structure of the third embodiment of the present invention shown in fig. 1.

In the figure:

1. 2, 3, the upstream side is similar to a crescent groove; 4. 5, 6, the downstream side is similar to a crescent groove; 8. sealing dams between the groove groups; 9. a moving ring;

10. a stationary ring; 11. the side surface of the short arc line at the upstream side; 12. the side surface of the long circular arc at the upstream side; 13. an upstream-side inner side surface; 14. an upstream-side inclined bottom surface;

20. a bidirectional crescent-shaped groove;

41. a downstream side oblong side; 42. a downstream short arc side; 43. a downstream-side outer side surface; 44. a downstream side inclined bottom surface;

71. a radial seal dam; 72. and a circumferential sealing dam.

Detailed Description

Referring to fig. 1 and 2, the bidirectional rotary mechanical sealing structure of the bidirectional crescent-shaped groove end face is arranged on the sealing contact end face of the movable ring 9, and the sealing contact end face of the movable ring 9 is opposite to the sealing contact end face of the static ring 10. The movable ring 9 and the static ring 10 are coaxially sleeved on the rotating shaft, and the movable ring 9 can rotate clockwise or anticlockwise. The movable ring 9 is on the outer side in the diameter direction, an upstream high-pressure side H, and on the inner side in the diameter direction, a downstream low-pressure side L. In practical application, the movable ring 9 and the stationary ring 10 are contacted together in the axial direction, i.e. the sealing contact end faces are contacted together.

Referring to fig. 1 and 2, a plurality of groups of bidirectional crescent-shaped groove groups 20 are uniformly distributed on the sealing contact end surface of the movable ring 9 along the circumferential direction. Each set of crescent-like groove sets 20 is composed of a plurality of upstream crescent-like grooves located on the upstream high-pressure side H, i.e., radially outward, and a plurality of downstream crescent-like grooves located on the downstream low-pressure side L, i.e., radially inward. The number of the groups of the bidirectional crescent-shaped groove groups 20 is 6-20, and only 6 groups are shown in FIG. 1. The number of the upstream crescent-like grooves and the downstream crescent-like grooves is 3-10, and only 3 upstream crescent-like grooves and 3 downstream crescent-like grooves are shown in fig. 1, namely the upstream crescent-

like grooves

1, 2 and 3 and the downstream crescent-

like grooves

4, 5 and 6. The present invention is described by taking the structure of 3 upstream side crescent-

like grooves

1, 2 and 3 downstream side crescent-

like grooves

4, 5 and 6 as an example.

A plurality of crescent-shaped grooves are arranged at intervals on the upstream side along the circumferential direction. The downstream sides of the grooves are arranged at intervals along the circumferential direction. The upstream crescent-

like grooves

1, 2 and 3 and the downstream crescent-

like grooves

4, 5 and 6 are arranged in a one-to-one correspondence on the outer side and the inner side in the radial direction, that is, in the radial direction, one upstream crescent-

like groove

1, 2 and 3 and one downstream crescent-

like groove

4, 5 and 6 are arranged face to face. The radial groove length of the upstream crescent-like grooves which are arranged in a face-to-face mode is L1, the radial groove length of the downstream crescent-like grooves is L2, and the range of L1/L2 is 1-3.

Due to the existence of the tooth-shaped grooves, an inter-groove-group sealing dam 8 is formed between two adjacent groups of bidirectional crescent-shaped groove groups 20. In the same group of bidirectional crescent-like groove groups 20, a radial sealing dam 71 is formed between two adjacent upstream crescent-

like grooves

1, 2 and 3, and a circumferential sealing dam 72 is formed between the upstream crescent-

like grooves

1, 2 and 3 and the downstream crescent-

like grooves

4, 5 and 6 in the same group of bidirectional crescent-like groove groups 20.

As shown in fig. 2, 3, 4, 5, and 6, each upstream side crescent-

like groove

1, 2, and 3 has a groove top surface at an end surface facing the stationary ring 10, an outer side surface at an upstream side, and an inner side surface at a downstream side, and the groove top surface and the outer side surface are both open, so that each upstream side crescent-

like groove

1, 2, and 3 is defined by four surfaces, i.e., an upstream side short arc line side surface 11, an upstream side long circular arc line side surface 12, an upstream side inner side surface 13, and an upstream side inclined bottom surface 14. The arc line segment of the upstream side short arc line side 11 projected on the radial cross section is shorter than the upstream side long arc line side 12. The upstream side inner side surface 13 is a circular arc surface, which opens toward the outer side surface, and the circular arc radius is located on the groove top surface. From the upstream side outer side surface opening to the upstream side inner side surface 13, both the upstream side short arc line side surface 11 and the upstream side long arc line side surface 12 gradually deflect in the clockwise direction.

Each of the downstream crescent-

like grooves

4, 5, 6 has a groove top surface at an end surface facing the stationary ring 10, an outer side surface at an upstream side, and an inner side surface at a downstream side, and the groove top surface and the inner side surface are open, and therefore, each of the downstream crescent-

like grooves

4, 5, 6 is defined by four surfaces, i.e., a downstream long arc side surface 41, a downstream short arc side surface 42, a downstream outer side surface 43, and a downstream inclined bottom surface 44. The arc line segment of the downstream side short arc side 42 projected on the radial cross section is shorter than the downstream side long arc side 41. The downstream side outer surface 43 is an arc surface with an arc opening toward the downstream side inner surface, and an arc center point is located on the groove top surface. The downstream side long arc side 41 and the downstream side short arc side 42 are each gradually deflected in the counterclockwise direction from the downstream inner side surface opening to the downstream side outer side surface 43.

The upstream side short arc line side 11 and the upstream side long arc line side 12 of each upstream side crescent-

like groove

1, 2, 3 are arranged in sequence along both sides in the clockwise direction. The downstream side short arc side surface 42 and the downstream side long arc side surface 41 of each of the downstream side crescent-

like grooves

4, 5, 6 are arranged in this order on both sides in the counterclockwise direction. Thus, in one upstream-side crescent-

like grooves

1, 2, 3 and one downstream-side crescent-

like grooves

4, 5, 6 arranged facing each other in the radial direction, the upstream-side short arc side surface 11 faces the downstream-side long arc side surface 41 in the radial direction, and the upstream-side long arc side surface 12 faces the downstream-side short arc side surface 42 in the radial direction.

Referring to fig. 6, the upstream inclined bottom surface 14 connected to the upstream short arc side surface 11 and the upstream long arc side surface 12 is inclined from the top to the bottom from the upstream short arc side surface 11 to the upstream long arc side surface 12, so that the fluid in the entire tank generates more potential energy, accelerates the flow of the fluid, and forms stronger collision. The axial depth h1 of the deepest part of each upstream crescent-

like groove

1, 2, 3 is 1-50 μm. In the axial longitudinal section, the included angle a1 between projection lines of the upstream side inclined bottom surface 14 and the upstream side long circular arc side surface 12 on the axial longitudinal section is 10-50 degrees.

Referring to fig. 5, the downstream inclined bottom surface 44 connected to the downstream long arc-shaped side surface 41 and the downstream short arc-shaped side surface 42 is inclined from the top toward the bottom from the downstream long arc-shaped side surface 41 to the downstream short arc-shaped side surface 42. The axial depth h2 of the deepest part of each downstream crescent-

like groove

4, 5, 6 is 5-100 μm. In the axial longitudinal section, the included angle a2 between projection lines of the downstream side inclined bottom surface 44 and the downstream side short arc side surface 42 on the axial longitudinal section is 10-50 °.

The projection lines of the upstream-side inner surface 13 and the downstream-side outer surface 43 in the radial cross section are parallel to each other.

Referring to fig. 3, the radial direction from the upstream high pressure side H to the downstream low pressure side L is the groove length direction, and the circumferential direction is the groove width direction. The upstream crescent-

like grooves

1, 2 and 3 in each group of crescent-like groove groups 20 have successively increasing groove lengths in the clockwise direction and increasing groove widths in the clockwise direction, i.e. the groove lengths and the groove widths are both increased in the clockwise deflection direction.

Referring to fig. 2, the radial seal dam 71 has a linear width in the circumferential direction of 1 to 5 mm, and the ratio of the radial linear dimension of the circumferential seal dam 72 to the outer diameter of the movable ring 9 is 0.1 to 0.5. The inner and outer diameter sizes of the sealing dam 8 between the groove groups are correspondingly the same as the inner and outer diameter sizes of the movable ring 9.

Referring to fig. 7, in a radial cross section, an included angle a5 between two tangents of the upstream side long circular arc side surface 12 and the upstream side inner side surface 13 of the upstream side crescent-

like grooves

1, 2 and 3 at an intersection point is 50-80 degrees. The included angle a3 between tangents of the upstream side short arc line side 11 and the upstream side long arc line side 12 at the front-to-face position is 5-30 degrees. The included angle a6 between two tangents of the downstream side short arc side face 42 and the downstream side outer side face 43 of the downstream side crescent-

like grooves

4, 5 and 6 at the intersection point is 100-160 degrees. The angle a4 between tangents of the downstream-side long arc-side surface 41 and the downstream-side short arc-side surface 42 at the front-surface facing position is 5 ° to 30 °.

Referring to fig. 8, a second embodiment of the present invention is shown, which is different from the first embodiment shown in fig. 2 in that: the positions of the upstream side short arc line side surface 11 and the upstream side long circular arc line side surface 12 in the upstream side similar crescent-shaped

grooves

1, 2 and 3 are changed, so that the trend of the upstream side inner side surface 13 connected between the upstream side short arc line side surface 11 and the upstream side long circular arc line side surface 12 is changed, and the projection line of the upstream side inner side surface 13 and the downstream side outer side surface 43 on the radial cross section is not parallel but forms a certain included angle.

Referring to fig. 9, a third embodiment of the present invention is shown, which is different from the first embodiment shown in fig. 2: the upstream side inner side surface 13 and the downstream side outer side surface 43 are removed, the upstream side short arc line side surface 11 and the upstream side long arc line side surface 12 are directly connected together, and the projections on the radial transverse plane are intersected at a point to form a cuspid shape. The downstream-side long arc-shaped side surface 41 and the downstream-side short arc-shaped side surface 42 are directly connected together, and the projections on the radial transverse surfaces intersect at a point to form a cuspid shape.

When the invention works, when the movable ring 9 rotates clockwise (positive direction), the pressure generated by the upstream high-pressure side H can make the fluid enter the upstream crescent-shaped

grooves

1, 2 and 3 due to the influence of the radial pressure difference between the inner diameter and the outer diameter of the sealing end surface, and because the upstream crescent-shaped

grooves

1, 2 and 3 are deflection grooves along the clockwise direction, more fluid can more rapidly enter the upstream crescent-shaped

grooves

1, 2 and 3 under the action of shearing force and rotating Coriolis force. At the side surface 12 of the long circular arc at the upstream side, the fluid is impacted by the influence of Coriolis force to form a large dynamic pressure effect, the fluid is extruded and transited to the side surface 11 of the short circular arc at the upstream side under the action of the inclined bottom surface 14 at the upstream side, and the fluid is transited to the end surface more rapidly by the inner side surface 13 at the upstream side. Fluid is continuously extruded and collided in the upstream side crescent-

like grooves

1, 2 and 3 to form a high-pressure area of the fluid, dynamic pressure opening force is generated, and therefore a good and stable fluid film is formed on the sealing end face of the movable ring 9, contact abrasion between the end faces is reduced, and the start-stop effect is obviously improved. At this time, the downstream crescent-

like grooves

4, 5, 6 also flow into a small portion of the fluid, and also provide a partial minute dynamic pressure opening force.

When the movable ring 9 rotates anticlockwise (reversely), due to the influence of the inner and outer diameter pressure difference of the sealing end surface, the pressure generated by the upstream high-pressure side H can enable the fluid to enter the upstream crescent-

like grooves

1, 2 and 3, and due to the fact that the deflection direction of the upstream crescent-

like grooves

1, 2 and 3 is opposite to the rotation direction, more fluid can strongly collide with the upstream short arc line side surface 11 and rapidly enter the crescent-like grooves, and due to the existence of the upstream inclined bottom surface 14, the fluid has larger kinetic energy; on the other hand, since the deflection direction of the downstream crescent-

like grooves

4, 5, 6 is the same as the rotation direction, the centrifugal force and the rotational coriolis force cause more fluid to enter the downstream crescent-

like grooves

4, 5, 6, and the downstream inclined bottom surface 44 provides more kinetic energy to the fluid flowing into the downstream crescent-

like grooves

4, 5, 6. The upper and lower stream crescent-like grooves are integrated to form a high-pressure area of fluid to generate dynamic pressure opening force, so that a good and stable fluid film is formed on the end face, the contact abrasion between the end faces is reduced, and the problem of insufficient power during reverse rotation is obviously solved. Therefore, the structure of the invention can not only avoid the failure of the sealing element when the high-speed rotating machinery rotates reversely accidentally, but also can be applied to the occasions needing to rotate forwards and reversely simultaneously when the machine operates.

Claims

1. A bidirectional mechanical sealing structure with bidirectional crescent-shaped groove end faces is characterized in that: a plurality of groups of bidirectional crescent-like groove groups (20) are uniformly distributed on the sealing contact end surface of the movable ring along the circumferential direction, and each group of crescent-like groove groups (20) consists of a plurality of upstream crescent-like grooves positioned on the radial outer side and a plurality of downstream crescent-like grooves positioned on the radial inner side; a plurality of upstream side crescent-like grooves are arranged at intervals along the circumferential direction, a plurality of downstream side crescent-like grooves are arranged at intervals along the circumferential direction, an interbody sealing dam (8) is formed between two adjacent groups of two-way crescent-like groove groups (20), a radial sealing dam (71) is formed between two adjacent upstream side crescent-like grooves in the same group of two-way crescent-like groove groups (20), and a circumferential sealing dam (72) is formed between the upstream side crescent-like grooves and the downstream side crescent-like grooves in the same group of two-way crescent-like groove groups (20); the top surface and the outer side surface of each upstream side crescent-like groove are open, and each upstream side crescent-like groove is surrounded by four surfaces, namely an upstream side short arc line side surface (11), an upstream side long arc line side surface (12), an upstream side inner side surface (13) and an upstream side inclined bottom surface (14); from the opening of the outer side surface of the upstream side to the inner side surface (13) of the upstream side, the short arc line side surface (11) of the upstream side and the long arc line side surface (12) of the upstream side deflect gradually along the clockwise direction; the top surface and the inner side surface of each downstream side crescent-like groove are open, and each downstream side crescent-like groove is surrounded by four surfaces, namely a downstream side long circular arc side surface (41), a downstream side short circular arc side surface (42), a downstream side outer side surface (43) and a downstream side inclined bottom surface (44); the downstream side long arc side surface (41) and the downstream side short arc side surface (42) are gradually deflected along the counterclockwise direction from the downstream inner side surface opening to the downstream side outer side surface (43).

2. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 1, wherein: an upstream side short arc line side surface (11) and an upstream side long arc line side surface (12) of each upstream side crescent-like groove are sequentially arranged along two sides in the clockwise direction, and a downstream side short arc line side surface (42) and a downstream side long arc line side surface (41) of each downstream side crescent-like groove are sequentially arranged along two sides in the anticlockwise direction; from the upstream side short arc side surface (11) to the upstream side long arc side surface (12), the upstream side inclined bottom surface (14) inclines from the top to the bottom, from the downstream side long arc side surface (41) to the downstream side short arc side surface (42), and the downstream side inclined bottom surface (44) inclines from the top to the bottom; the projection lines of the upstream side inner surface (13) and the downstream side outer surface (43) in the radial cross section are parallel to each other.

3. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 1, wherein: the radial groove length and the circumferential groove width of a plurality of upstream side crescent-shaped grooves in each group of crescent-shaped groove groups (20) are increased in sequence in the clockwise direction.

4. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 1, wherein: the axial depth of the deepest part of each upstream crescent-like groove is 1-50 mu m, and the axial depth of the deepest part of each downstream crescent-like groove is 5-100 mu m; the included angle between the projection lines of the upstream side inclined bottom surface (14) and the upstream side long circular arc side surface (12) on the axial longitudinal section and the included angle between the projection lines of the downstream side inclined bottom surface (44) and the downstream side short circular arc side surface (42) on the axial longitudinal section are both 10-50 degrees.

5. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 1, wherein: the upstream side inner side surface (13) and the downstream side outer side surface (43) are both arc surfaces, the arc centers are both positioned on the groove top surface, the arc opening of the upstream side inner side surface (13) faces the upstream side outer side surface, and the arc opening of the downstream side outer side surface (43) faces the downstream side inner side surface.

6. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 1, wherein: the linear width of the radial sealing dam (71) along the circumferential direction is 1-5 mm, the ratio of the radial linear dimension of the circumferential sealing dam (72) to the outer diameter of the movable ring is 0.1-0.5, and the inner and outer diameter dimensions of the inter-groove sealing dam (8) are correspondingly the same as those of the movable ring.

7. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 2, wherein: the positions of two side surfaces, namely an upstream side short arc line side surface (11) and an upstream side long arc line side surface (12) in the upstream side crescent-like groove are exchanged, and an included angle is formed between the projection line of the upstream side inner side surface (13) and the downstream side outer side surface (43) on the radial cross section.

8. The bi-directional crescent-shaped groove end face bi-directional rotary mechanical seal structure of claim 1, wherein: an upstream side inner side surface (13) and a downstream side outer side surface (43) are removed, an upstream side short arc line side surface (11) and an upstream side long arc line side surface (12) are directly connected together, and projections on a radial transverse plane are intersected at one point.