JPH08152068A - Mechanical seal - Google Patents

Abstract

PURPOSE: To provide an excellent mechanical seal as a gas seal by sandwiching the flange part with the end face of a primary ring and the presser face of a disc opposed to the end face, in the condition the seal is respectively made in contact with the outer circumferential face of a retainer sleeve and the inner circumferential face of the disc. CONSTITUTION: The flange part 18 of a resin seal 6 is sandwiched with the end face 19 of a primary ring 3 and the presser face 20 of a disc 9 constituting a presser means 5. Consequently, following the shaft run-out and axial variation of a mating ring 2 caused by accompanying the rotation of a rotary shaft 1, the primary ring 3 and the resin seal are integratedly variably moved in the axial direction, and the inside lip 15 of the resin seal 6 and the outer circumferential face 12 of an retainer sleeve 11 are slid in the axial direction so as to function as a piston motion seal. The primary ring 3 and the resin seal 6 are constituted into an end face seal, and hence follow-up to pressure, temperature, and fitting accuracy of the primary ring 3 is not restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical seal, and more particularly to a mechanical seal used as a shaft seal device for fluid equipment such as a gas turbine, a blower, a centrifugal compressor, etc., particularly as a gas seal.

[0002]

2. Description of the Related Art Conventionally, a non-contact mechanical seal for sealing between a rotary shaft and a casing of a compressor or the like has already been provided. For example, Japanese Patent Application Laid-Open No. 5-164249, which is a prior application of the present applicant, discloses a mating ring which is hermetically fixed to a rotary shaft and a primary ring which is hermetically attached to a seal housing and axially biased by a pressing means. A plurality of spiral grooves having an advancing angle with respect to the relative rotation direction are provided at a constant interval in the circumferential direction on one of the sealing surfaces facing each other, and the enclosed fluid is pumped between the sealing surfaces. Non-contact mechanical seals are provided.

The non-contact mechanical seal is
A dynamic pressure is generated between the seal surfaces of the primary ring and mating ring toward the center, and this dynamic pressure creates a gap in micron units between both seal surfaces to maintain a non-contact state and enable high peripheral speed rotation. It is the one.

Here, the primary ring follows a slight displacement of the mating ring due to axial runout of the rotating shaft and displacement in the axial direction, and a retainer sleeve is formed to form a gap due to a dynamic pressure between the seal surfaces. It is necessary to make it axially displaceable and to seal between them. Therefore, the one described in the above publication, between the outer peripheral surface of the retainer sleeve and the inner peripheral surface of the primary ring,
A rubber O-ring is interposed as a secondary seal.

However, when the O-ring is used as the secondary seal between the primary ring and the retainer sleeve, in order to secure the sealing property, the O-ring must be constantly in contact with each member with a pressing force enough to deform the O-ring. As a result, the sliding frictional resistance becomes large, and the followability of the primary ring that should fluctuate in the axial direction following the axial contact and axial fluctuation of the mating ring that occurs with the rotation of the rotating shaft is impaired. . In particular, when the sealing fluid is gas, since the O-ring and each member are dry contacts, the sliding friction resistance is larger than that when it is liquid, and further, there is a gap between the sealing surfaces of the mating ring and the primary ring. In the case of a non-contact seal, the dynamic pressure generated by rotation is smaller than that in the case of a liquid, so if the primary ring has poor followability, the non-contact state between the seal faces cannot be maintained and the seal faces It can be damaged. Moreover, the deformation of the O-ring may increase over time.

Therefore, the resin seal 100 shown in FIGS. 4 and 5 has been used instead of the O-ring. The resin seal 100 includes a main body 101 formed in a ring shape from tetrafluoroethylene (TFE) resin.
And the elastic ring 102, the main body 101 has an annular lip 104, which is radially inward and outward from one side of the base 103.
A concave groove 10 having a substantially U-shaped cross-section formed by a base 103 and inner and outer lips 104, 105.
6, the elastic ring 102 is fitted and both lips 10
4, 105 are elastically biased in the expanding direction.

A conventional use example of the resin seal 100 is shown in FIGS. 4 and 5, respectively. As shown in FIG. 4, an annular step portion 109 is formed on the inner peripheral portion on the end face 108 side of the primary ring 107, and the resin seal 100 is provided on the annular step portion 109 to form the inner and outer lips 104, 1.
05 is accommodated toward the process fluid side, and the inner lip 1
04 is pressed against the outer peripheral surface of the retainer sleeve 111 of the retainer 110, the outer lip 105 is pressed against the inner peripheral surface of the annular step portion 109, and is elastically attached in the axial direction by the preload spring 112 having one end held by the retainer 110. The inner and outer lips 1 protruding from the end surface 108 by the disk 113 that is biased and loosely inserted into the retainer sleeve 111.
This is a secondary seal structure in which the tips of 04 and 105 are axially pressed. In this case, since the axial length of the annular stepped portion 109 is short, the resin seal 100 integrally fluctuates with respect to the axial fluctuation of the primary ring 107, and
Although there is an advantage that the axial length in the assembled state can be shortened,
The tips of the inner and outer lips 104, 105 that come into contact with the disk 113 may be damaged.

Further, the structure shown in FIG. 5 is the structure shown in FIG. 4 in which the axial length of the annular step portion 109 is set sufficiently longer than the axial thickness of the resin seal 100. In this case, since the disk 113 directly contacts the end surface 108 of the primary ring 107, the tips of the lips 104 and 105 are not damaged as described above, but the resin is not affected by the axial fluctuation of the primary ring 107. The seal 100 may not follow and may be twisted to impair the sealing property. In addition, in order to secure a sufficient axial length of the annular step portion 109, the axial thickness of the primary ring 107 is increased to assemble the assembly. The problem that the axial length of the attached state becomes long occurs.

[0009]

Therefore, in view of the above situation, the present invention is to solve the problem by providing a resin seal on the secondary seal for sealing the process fluid between the primary ring and the retainer in the mechanical seal. In order to ensure the excellent followability of the primary ring by following the shaft runout and axial fluctuation due to the rotation of the mating ring, the resin seal is in sliding contact with the outer peripheral surface of the retainer sleeve and is integrated with the primary ring. It is possible to maximize the advantage that the sliding friction resistance of the resin seal is small and it can be changed in the axial direction.
The purpose of the present invention is to provide a mechanical seal that has a mounting structure that can reduce the axial length in the assembled state and is particularly excellent as a gas seal.

[0010]

In order to solve the above-mentioned problems, the present invention provides a sealing surface of a mating ring which is hermetically fixed to a rotating shaft, and a casing which is axially movable so as to be hermetically mounted and provided on a retainer. A mechanical seal for rotating and sealing the sealing surface of the primary ring biased to the mating ring side by the pressing means in a contact or non-contact state with a cylindrical inner peripheral surface of the disk of the pressing means. One side edge of a disc-shaped substrate with a circular opening formed in the center between the outer peripheral surface of the retainer sleeve and the cylindrical outer surface of the retainer sleeve. A ring-shaped lip projecting inward and outward, an elastic ring that urges them in the expansion direction is fitted between both lips, and extends radially outward from the outer lip. A resin seal having a flange portion on the outer peripheral portion of the substrate is used, the other side surface of the substrate of the resin seal is brought into contact with an end face orthogonal to the axial direction of the primary ring, and inner and outer lips are housed in the voids, and retainers are respectively provided. A mechanical seal is constructed by sandwiching the flange portion between the end surface of the primary ring and the pressing surface of the disk facing it while the outer peripheral surface of the sleeve and the inner peripheral surface of the disk are in contact with each other.

Here, the primary ring may have a contact end surface which is axially protruded more than other outer parts at least in a radially inner part of the end surface of the resin seal which comes into contact with the substrate.

Further, the primary ring slidably engages a rotation restricting portion projecting on its outer peripheral portion with a spline groove axially formed on the inner surface of the outer cylindrical portion of the retainer hermetically fixed to the casing. It is preferable that it is non-rotating and movable in the axial direction, and that the relative position of the primary ring and the resin seal does not change, and that it can slide in the axial direction only between the inner lip of the resin seal and the outer peripheral surface of the retainer sleeve. Here is an example.

Further, an annular groove for accommodating the retainer sleeve and securing an axial movement stroke of the primary ring with respect to the retainer is formed in an inner peripheral portion of the end face side of the primary ring, and the retainer is provided in the annular groove. The inner and outer lips of the resin seal are oriented toward the process fluid in the space surrounded by the outer peripheral surface of the retainer sleeve, the inner peripheral surface of the disc, and the contact end surface of the primary ring, with the tip of the sleeve always accommodated. More preferably, it is housed in.

The pressing means holds one end portion of the preload spring in a plurality of engagement holes provided in the circumferential direction between the outer cylinder portion of the retainer and the retainer sleeve on the process fluid side, and also has a cylindrical shape. The other end of the preload spring is held in a recess provided on the side opposite to the pressing surface of the disk having the inner peripheral surface and the pressing surface in the radial direction.

Further, a plurality of spiral grooves having an advancing angle with respect to the relative rotation direction are provided in one of the sealing surfaces of the mating ring and the primary ring at a constant interval in the circumferential direction to allow the process fluid to flow. The present invention is advantageous in a mechanical seal having a structure in which the seal faces are pressure-fed and the two seal faces are hermetically sealed in a non-contact state.

[0016]

In the mechanical seal of the present invention having the above-mentioned contents, in the state where the substrate of the resin seal is in contact with the end surface of the primary ring, the outer peripheral portion of the substrate extending radially outward from the outer lip is formed. Since the flange part is held between the end surface of the primary ring and the pressing surface of the disk that constitutes the pressing means, the primary ring and the resin follow the axial contact and axial fluctuation of the mating ring that occurs with the rotation of the rotating shaft. Since the seal and the seal integrally move in the axial direction and the primary ring and the resin seal form an end face seal, follow-up of pressure, temperature, and mounting accuracy of the primary ring is not restricted. Moreover, the resin seal accommodates the inner and outer lips in the space provided between the cylindrical inner peripheral surface of the disk and the cylindrical outer peripheral surface of the retainer sleeve located inward of the disk, and each of them is the outer peripheral surface of the retainer sleeve. Since it is brought into contact with the inner peripheral surface of the disk, the inner and outer lips have no constraint other than giving a tightening margin in the radial direction, and the excellent performance such as low friction inherent to the resin seal can be maximized. Further, since the axial space for accommodating the inner and outer lips that occupy most of the thickness of the resin seal can be shared with the disk that constitutes the pressing means and the preload spring that applies the elastic biasing force to the disk,
The axial length of the mechanical seal in the assembled state can be shortened as a whole.

[0017]

The present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows an essential part of a mechanical seal of the present invention, and FIG. 2 shows a resin seal used for a secondary seal. In the figure, 1 is a rotary shaft, 2 is a mating ring, and 3 is a ring.
Is a primary ring, 4 is a retainer, 5 is a pressing means, and 6 is a resin seal.

The mechanical seal of the present invention includes the sealing surface 7 of the mating ring 2 which is hermetically fixed to the rotary shaft 1 and the pressing means 5 which is axially movable in the casing so as to be hermetically mounted and provided on the retainer 4. Mating ring 2
The sealing surface 8 of the primary ring 3 biased to the side,
A mechanical seal for rotating and sealing in a contact or non-contact state, comprising a cylindrical inner peripheral surface 10 of a disk 9 of the pressing means 5 and a cylindrical outer peripheral surface 12 of a retainer sleeve 11 located radially inward thereof. A predetermined gap is set between them, and annular lips 15 and 16 are projected inward and outward in the radial direction on one side edge of the disk-shaped substrate 14 having a circular opening 13 into which the retainer sleeve 11 is inserted. An elastic ring 17 for biasing them in the expanding direction is fitted between the lips 15 and 16, and the outer peripheral portion of the base plate 14 extending radially outward from the outer lip 16 is provided with a flange portion 18.
And the substrate 1 of the resin seal 6 is used.
The other side surface 4 is brought into contact with the end surface 19 orthogonal to the axial direction of the primary ring 3 and the inner and outer lips 15, 16 are housed in the gap, and the outer peripheral surface 12 of the retainer sleeve 11 and the inner peripheral surface 10 of the disk 9 are respectively arranged. The flange portion 18 in contact with the primary ring 3
The gist is that it is sandwiched between the end surface 19 of the disk and the pressing surface 20 of the disk 9 facing it.

More specifically, the primary ring 3
At least forms a contact end surface 19a that protrudes in the axial direction more than other outer parts at the radially inner part of the end surface 19 of the resin seal 6 that contacts the substrate 14, and the retainer 4 is hermetically fixed to the casing. A rotation restricting portion 23 is projectingly provided on an outer peripheral portion of the outer cylindrical portion 21 so as to be slidably engaged with a spline groove 22 formed in an inner surface of the outer cylindrical portion 21 so as to be non-rotating and axially movable. The spline groove 22
The relative engagement between the primary ring 3 and the resin seal 6 is not changed by the sliding engagement between the rotation restricting portion 23 and the rotation restricting portion 23, and the axial direction is provided only between the inner lip 15 of the resin seal 6 and the outer peripheral surface 12 of the retainer sleeve 11. It is slidable to.

An annular groove 24 for accommodating the retainer sleeve 11 and securing an axial movement stroke of the primary ring 3 with respect to the retainer 4 is formed on the inner peripheral portion of the end face side of the primary ring 3. With the distal end portion of the retainer sleeve 11 always accommodated in the annular groove 24, in the space portion surrounded by the outer peripheral surface 12 of the retainer sleeve 11, the inner peripheral surface 10 of the disk 9 and the contact end surface 19a of the primary ring 3, Inner and outer lips 15, 16 of the resin seal 6 are accommodated so as to be oriented toward the process fluid side.

Incidentally, the inner and outer lips 15 of the resin seal 6,
The structure of 16 and the elastic ring 17 and their relationship are not different from the conventional ones, and the elastic ring 17 is fitted in the concave groove 25 having a substantially U-shaped cross section surrounded by the substrate 14 and the inner and outer lips 15, 16. Is. The main body of the resin seal 6 is formed of tetrafluoroethylene (TFE) resin having excellent properties such as low friction, heat resistance, and corrosion resistance. In this embodiment, the elastic ring 17 is formed from one edge to another. The slits 26, ... Extending to near the edge are alternately formed, and when viewed from the axial direction, they are in the shape of a leaf spring having a substantially U-shaped cross section, and the elastic ring 17 has an annular shape. A coil spring may be used.

Further, the pressing means 5 is provided with a preload spring 28 in a plurality of engagement holes 27 provided in the circumferential direction between the outer cylinder portion 21 of the retainer 4 and the retainer sleeve 11 on the process fluid side. A recess 29 which holds one end and is provided on the side of the disk 9 having the cylindrical inner peripheral surface 10 and the radial pressing surface 20 opposite to the pressing surface 20.
In addition, the other end of the preload spring 28 is held.

Although not shown, a plurality of spiral grooves having an advancing angle with respect to the relative rotation direction are circumferentially formed on either one of the sealing surfaces 8 and 9 of the mating ring 2 and the primary ring 3. It is suitable for high-speed rotation and gas sealing if the process fluid is pressure-fed between the sealing surfaces 8 and 9 so as to seal the sealing surfaces 8 and 9 in a non-contact state.

As described above, according to the present invention, the flange portion 18 of the resin seal 6 is held between the end surface 19 of the primary ring 3 and the pressing surface 20 of the disk 9 constituting the pressing means 5, so that the rotary shaft 1 is rotated. Following the axial contact or axial fluctuation of the mating ring 2 that occurs as a result, the primary ring 3 and the resin seal 6 integrally move and fluctuate in the axial direction.
Inner lip 15 of resin seal 6 and retainer sleeve 1
1 and the outer peripheral surface 12 slide in the axial direction to function as a piston motion seal. Also, the primary ring 3
Since the resin seal 6 and the resin seal 6 constitute an end face seal, follow-up to the pressure, temperature, and mounting accuracy of the primary ring 3 is not restricted. Moreover, the resin seal 6 accommodates the inner and outer lips 15 and 16 in a space provided between the cylindrical inner peripheral surface 10 of the disk 9 and the cylindrical outer peripheral surface 12 of the retainer sleeve 11 located inward of the disk 9. Moreover, since the outer peripheral surface 12 of the retainer sleeve 11 and the inner peripheral surface 10 of the disk 9 are brought into contact with each other, there is no constraint other than giving a tightening margin in the radial direction on the inner and outer lips 15 and 16, and the resin seal 6 originally has a low limit. It is possible to maximize the excellent performance such as friction. Also, the inner and outer lips 15, 16 of the resin seal 6 are
As shown in FIG. 1, most of them overlap the disc 9 and the preload spring 28 in the axial direction, and the axial space can be shared with the disc 9 and the preload spring 28. Therefore, the axial length of the mechanical seal in the assembled state can be increased. Can be shortened as a whole.

Here, the resin seal 6 has corrosion resistance, weather resistance, rapid decompression resistance, extrusion resistance, heat resistance, low temperature resistance, low frictional force and no change in comparison with conventional O-rings. It is excellent in that the flange portion 18 of the resin seal 6 is provided with the contact end surface 19 of the primary ring 3 as in the present invention.
a and the pressing surface 20 of the disc 9 hold the inner and outer lips 1
Since there is no restraint other than giving a tightening margin in the radial direction to 5 and 16, the original excellent sealing performance is exhibited.

Next, the non-contact mechanical seal for gas seal shown in FIG. 3 as a representative embodiment of the present invention will be briefly described, but the same applies to liquid seals. FIG. 3 shows the overall structure of a tandem type non-contact mechanical seal M, which is provided between a casing 30 which is a sealed container of a fluid device and a rotary shaft 1 which penetrates an open end of the casing 30. Here, in the figure, A indicates the atmospheric pressure (low pressure) side, and B indicates the process (high pressure) side.

In the non-contact mechanical seal of this embodiment, a labyrinth 31, a socket 32, an inner retainer 4a, a socket 33, and an outer retainer are provided in order from the process side in an opening penetrating the rotary shaft 1 of the casing 30. 4b
Are assembled by bolting each other to form a seal space between the labyrinth 31 and the inner retainer 4a and between the labyrinth 34 fixed to the outside of the retainer 4a and the outer retainer 4b. An inner mating ring 2a which is hermetically fixed to the rotary shaft 1 in each of the inside,
A primary ring 3a, which is hermetically attached to a retainer sleeve 11 formed in the retainer 4a and protruding into the seal space, is arranged, and an outer mating ring 2b that is hermetically fixed to the rotary shaft 1 and the retainer 4 are provided.
The primary ring 3b that is hermetically attached to the retainer sleeve 11 that is formed in b and protrudes into the seal space is arranged.
The sealing surfaces 7 and 8 of the mating ring 2 and the primary ring 3 are brought into contact with each other, and the primary rings 3a and 3b are non-rotatably and axially movable between the outer cylinder portion 21 of the retainer 4 and the retainer sleeve 11. While sealing the outer peripheral surface 12 of the retainer sleeve 11,
The pressing means 5 held by the retainer 4 urges the sealing surfaces 7 and 8 toward each other. Here, the pressing means 5 is composed of a plurality of preload springs 28 supported by engaging holes 27 arranged between the retainer 4 and the retainer sleeve 11 and a ring-shaped disc 9 arranged inward in the axial direction thereof. It is configured. Then, as described above, the flange portion 18 of the resin seal 6 is sandwiched between the pressing surface 20 of the disk 9 and the contact end surface 19a orthogonal to the axial direction of the primary ring 3, and the inner and outer lips 15 and 16 of the retainer sleeve 11 are held. The outer peripheral surface 12 and the inner peripheral surface 10 of the disk 9 are brought into contact with each other to seal between the primary ring 3 and the retainer sleeve 11.

Although not shown in this embodiment, the sealing surface 7 of the mating ring 2 is provided with a spiral groove extending inward from the outer peripheral edge of the mating ring 2 and having an advancing angle with respect to the rotational direction in the circumferential direction. Many are provided at regular intervals. As a result, the mating ring 2 rotates with respect to the primary ring 3 in the presence of the process gas, whereby a dynamic pressure is generated between the sealing surfaces 7 and 8 by the spiral groove toward the radial center, and the process gas is pumped. Both sealing surfaces 7,
8 and a small gap is formed, and a sealing pressure higher than the pressure on the process side is formed to seal.
Similarly, although not shown, a similar spiral groove is also formed on the sealing surface 8 of the primary ring 3, and the spiral groove may have an advancing angle with respect to the relative rotation direction.
It may have a reverse angle, when it has an advance angle, it has the same effect as the spiral groove, and when it has a reverse angle, it partially reverses the process gas pumped by the spiral groove, It acts to reduce leakage.
In this embodiment, the material of the mating ring 2 is silicon carbide, and the material of the primary ring 3 is carbon.

For fixing the mating ring 2 to the rotary shaft 1, first, the assembly sleeve 3 is attached to the rotary shaft 1.
5, the inner mating ring 2a is hermetically held by the flange 36 integrally formed on the outer circumference of the inner end of the assembly sleeve 35, and the spacer sleeve 37 is hermetically fitted on the outer side thereof. An outer mating ring 2b is hermetically held on a flange 38 integrally formed on the outer circumference of the outer end of the spacer sleeve 37, and a locking sleeve 39 is fitted on the outer side of the mating ring 2b.
Are fastened to the assembly sleeve 35 with bolts, and the mating ring 2a, the spacer sleeve 37, and the mating ring 2b are sandwiched and fixed between the flange 36 and the locking sleeve 39. Further, a tolerance ring 40, ... Is interposed between the rotary shaft 1 and the assembly sleeve 35, and between the assembly sleeve 35 and the mating ring 2a, the spacer sleeve 37, the mating ring 2b, and the locking sleeve 39. Rattling due to the difference in the coefficient of thermal expansion of each member is prevented and alignment is performed.

Then, the sealing between the flange 36 of the assembly sleeve 35 and the mating ring 2a, the sealing between the assembly sleeve 35 and the spacer sleeve 37, the flange 38 of the spacer sleeve 37 and the mating ring 2a.
Sealing between b is performed using a conventional type resin seal 41, ... Without the flange portion 18, and other sealing points are performed using normal O-rings 42.

Next, the assembling structure of the primary ring 3 will be described. An annular groove 24 formed in the balance diameter portion of the primary ring 3 is externally fitted to the distal end portion of the retainer sleeve 11 so as to be movable in the axial direction. , The outer peripheral portion 2 of the retainer 4 with the rotation restricting portion 23 protruding from the outer periphery.
Spline groove 22 formed in the inner peripheral surface of No. 1 in the axial direction
Is fitted to the primary ring 3 so as to be movable in the axial direction.
The non-rotating state of is maintained. Here, between the primary ring 3 and the retainer sleeve 11,
In order to ensure quick followability of the primary ring 3 with respect to the mating ring 2, it is preferable to provide a minute gap.

In this embodiment, a tandem type non-contact mechanical seal having two pairs of the mating ring 2 and the primary ring 3 in the axial direction is shown, but of course the mating ring 2 and the primary ring 3 are a pair of single. It may be of a mold type, or may be of a type in which both sealing surfaces 7 and 8 are in contact with each other for sealing.

[0033]

According to the mechanical seal of the present invention as described above, the outer circumference of the substrate extending radially outward from the outer lip in the state where the substrate of the resin seal is in contact with the end face of the primary ring. Since the flange part of the part is sandwiched between the end surface of the primary ring and the pressing surface of the disk that constitutes the pressing means, the primary ring follows the axial contact and axial fluctuation of the mating ring that occurs with the rotation of the rotating shaft. And the resin seal integrally move in the axial direction, the inner lip of the resin seal serves as a piston motion seal with respect to the retainer sleeve, and its low friction property significantly improves the followability of the primary ring.
Further, since the primary ring and the resin seal constitute an end face seal, the pressure, the temperature and the mounting accuracy of the primary ring are not restricted. Moreover, the resin seal accommodates the inner and outer lips in the space provided between the cylindrical inner peripheral surface of the disk and the cylindrical outer peripheral surface of the retainer sleeve located inward of the disk, and each of them is the outer peripheral surface of the retainer sleeve. Since it is brought into contact with the inner peripheral surface of the disk, the inner and outer lips have no constraint other than giving a tightening margin in the radial direction, and the excellent performance such as low friction inherent to the resin seal can be maximized. Further, since the axial space for accommodating the inner and outer lips that occupy most of the thickness of the resin seal can be shared with the disk that constitutes the pressing means and the preload spring that gives an elastic biasing force to the disk, the mechanical seal in the assembled state can be The axial length can be shortened as a whole.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a mechanical seal of the present invention.

FIG. 2 is a partially cutaway perspective view of a resin seal according to the present invention.

FIG. 3 is a partial cross-sectional view of a non-contact mechanical seal for a gas seal in an assembled state showing a typical embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part showing a conventional example.

FIG. 5 is a sectional view of an essential part showing another conventional example.

[Explanation of symbols]

 1 rotating shaft 2 mating ring 3 primary ring 4 retainer 5 pressing means 6 resin seal 7 sealing surface 8 sealing surface 9 disk 10 inner peripheral surface 11 retainer sleeve 12 outer peripheral surface 13 circular opening 14 substrate 15 lip 16 lip 17 elastic ring 18 flange Part 19 End face 20 Pressing face 21 Outer cylinder part 22 Spline groove 23 Rotation restricting part 24 Annular groove 25 Recessed groove 26 Slit 27 Engagement hole 28 Preload spring 29 Recess 30 Casing 31 Labyrinth 32 Socket 33 Socket 34 Labyrinth 35 Assembly sleeve 36 Flange 37 Spacer sleeve 38 Flange 39 Locking sleeve 40 Tolerance ring 41 Resin seal 42 O-ring

Claims (6)

[Claims] 1. A primary surface of a mating ring which is hermetically fixed to a rotary shaft, and a primary ring which is axially movable in a casing and hermetically mounted and biased toward the mating ring by a pressing means provided in a retainer. Is a mechanical seal for rotationally sealing the seal surface of the pressing means in a contact or non-contact state, the cylindrical inner peripheral surface of the disc of the pressing means and the cylindrical outer peripheral surface of the retainer sleeve located inward of the disk. A circular gap is formed in the center of the disk-shaped substrate with a circular opening for inserting the retainer sleeve, and an annular lip is projected inward and outward in the radial direction. A resin seal in which an elastic ring for urging the base plate is fitted and the outer peripheral portion of the substrate extending radially outward from the outer lip serves as a flange portion is used. , The other side of the substrate of the resin seal is brought into contact with the end face orthogonal to the axial direction of the primary ring, the inner and outer lips are accommodated in the gap, and the outer face of the retainer sleeve and the inner face of the disc are brought into contact with each other. In this state, the flange portion is sandwiched between the end surface of the primary ring and the pressing surface of the disk facing the end surface of the primary ring. 2. The primary ring is such that at least a contact end surface that axially protrudes more than other outer portions is formed at a radially inner portion of the end surface of the resin seal that contacts the substrate. Mechanical seal described. 3. The primary ring includes a spline groove axially formed on an inner surface of an outer cylindrical portion of a retainer hermetically fixed to a casing, and a rotation restricting portion projecting on an outer peripheral portion thereof slidably engaged with the spline groove. A non-rotating and axially movable structure that does not change the relative position of the primary ring and the resin seal and is slidable in the axial direction only between the inner lip of the resin seal and the outer peripheral surface of the retainer sleeve. The mechanical seal described in 2. 4. An annular groove for accommodating the retainer sleeve and securing an axial movement stroke of the primary ring with respect to the retainer is formed in an inner peripheral portion of an end surface side of the primary ring, and the retainer is provided in the annular groove. The inner and outer lips of the resin seal are oriented toward the process fluid in the space surrounded by the outer peripheral surface of the retainer sleeve, the inner peripheral surface of the disc, and the contact end surface of the primary ring, with the tip of the sleeve always accommodated. The mechanical seal according to claim 1, which is housed in. 5. The pressing means holds one end portion of a preload spring in a plurality of engagement holes provided in the circumferential direction between the outer cylinder portion of the retainer and the retainer sleeve on the process fluid side, and the cylindrical portion. The mechanical seal according to claim 1 or 2, wherein the other end of the preload spring is held in a recess provided on the opposite side of the disk having a circular inner peripheral surface and a radial pressing surface from the pressing surface. 6. A plurality of spiral grooves having an advancing angle with respect to a relative rotation direction are provided at one of the sealing surfaces of the mating ring and the primary ring at regular intervals in the circumferential direction to allow the process fluid to flow. The mechanical seal according to claim 1, wherein the mechanical seal is pressure-fed between the sealing surfaces and is sealed in a non-contact state between the sealing surfaces.