JP4586002B2 - mechanical seal - Google Patents

Description

  The present invention relates to a mechanical seal having a rotation side seal ring, a stationary side seal ring, and elastic means for pressing the two seal rings.

  As this type of mechanical seal, like the one disclosed in Patent Document 1, the rotating side seal ring and the sealing ring such that the wear powder does not color the object to be sealed such as food and chemicals like the carbon seal ring. A technique is known in which all of the stationary side seal rings are made of synthetic resin.

  However, in the technology in which both the seal rings are made of a synthetic resin material, the synthetic resin material is likely to be deformed by a spring load or an in-machine pressure, and the sealing performance is likely to deteriorate. In addition, it is difficult to increase the processing accuracy due to the strain remaining in the synthetic resin material. As described above, the sealing performance is not good for the high cost, and it is necessary to replace both seal rings when worn. In addition, there is a disadvantage that is susceptible to heat due to temperature changes.

  Therefore, as disclosed in Patent Document 2, both the rotating and stationary seal rings are composed of a hard member such as metal or ceramics and a sliding film made of a resin material or the like coated on the surface thereof. It has been developed to make a composite sliding material. This realizes a mechanical seal that exhibits excellent slidability and wear resistance in an atmosphere where there is no lubricating oil or liquid, or in an environmental condition where fluid cannot be lubricated.

According to the technique disclosed in Patent Document 2, it is possible to improve excellent lubricity and wear resistance, and the introduction of the technique (sliding material having a composite structure) was studied. However, there is a limit to the thickness of the sliding film formed by coating, and it is difficult to obtain the required thickness. Moreover, since the thickness of the sliding film is thin, a sufficient finishing allowance cannot be secured, and there is a disadvantage that final finishing is very difficult.
JP-A-9-280382 JP 2001-26792 A

  The purpose of the present invention is to make the final finishing process easy while following the means with the advantage of excellent sealing performance and wear resistance by the composite structure in which sliding members are laminated and integrated on the surface of rigid base material such as hard material The present invention is to provide a further improved seal ring for a mechanical seal, and a mechanical seal using the seal ring, so that the durability sufficient to withstand practical use can be exhibited. .

The invention according to claim 1 includes a rotary seal ring 2 that rotates integrally with the rotary shaft 1, a stationary seal ring 4 that is relatively fixed to the casing 3, and each of the rotary and stationary seal rings 2. In the mechanical seal having the elastic means 5 that presses the sliding surfaces 2a and 4a of the four,
The seal ring 4 on either the rotating side or the stationary side is composed of a composite structure in which a sliding member 4A is bonded to a rigid substrate 4B, and the other seal ring 2 is a hard member. The sliding surface 4a of any one of the sealing rings 4 is formed by the sliding member 4A, and the sliding surface 2a of the other sealing ring 2 is formed by the hard member, The rigid base material 4B is selected from ceramics, carbon, metal, and a composite material of metal and ceramics, and the sliding member 4A is obtained by blending a solid lubricant material into a binder, and the sliding member The thickness of 4A is set in the range of 0.5 mm to 5 mm .

  The invention according to claim 2 is characterized in that, in the mechanical seal according to claim 1, a circumferential groove 18 having a depth within the thickness range is formed in the sliding member 4A. .

  The invention according to claim 3 is the mechanical seal according to claim 1 or 2, characterized in that the sliding member 4A is made of a fluorine-based resin.

  According to the first aspect of the present invention, the seal ring on either the rotating side or the stationary side is configured as a sliding material having a composite structure including a rigid base material and a sliding member bonded to the surface thereof. Therefore, excellent slidability and wear resistance can be exhibited even in an atmosphere where there is no lubricating oil or liquid, or even in an environmental condition where lubrication with a fluid cannot be expected. And since either the rotating side or the stationary side seal ring is made of a hard member, it is mainly worn out while exhibiting excellent sealing performance by sliding between this and the sliding member. Since it is a seal ring on the side having the sliding member, there is an advantage that at the time of wear, only one of the parts on the rotating side or the stationary side can be replaced. In addition, since the sliding member and the rigid base material are laminated and integrated by bonding, the thickness of the sliding member can be easily and sufficiently increased as compared with the case where the sliding base material is equipped on the surface of the rigid base material by coating, for example. Therefore, it is possible to maintain the above-mentioned good functions for a longer period of time and to have excellent durability, and to slide the final finishing process such as mirror finish by precision cutting. It becomes possible to apply to the member, and it becomes possible to further improve the sealing performance by finishing the sliding surface with high accuracy.

  As a result, a composite structure in which sliding members are laminated and integrated on the surface of a rigid base material such as a hard material, further improving the sealing performance and practical use while following the means with the advantage of excellent sealing performance and wear resistance It is possible to provide a mechanical seal that is further improved so as to be able to exhibit sufficient durability to withstand. In this case, the sliding member is preferably made of a fluorine-based resin from the viewpoint of excellent self-lubricating property and being hardly affected by the atmospheric fluid.

According to the invention of claim 1, by setting the thickness of the sliding member in the range of 0.5 mm to 5 mm , which is a thickness that cannot be achieved by coating, the effect of claim 1 can be achieved even in various mechanical seals. Can be fully demonstrated in practical use.

  According to the invention of claim 2, by using a sliding member in which a circumferential groove having a depth within the thickness range is formed, it is possible to generate dynamic pressure caused by the circumferential groove with rotation. Thus, there is an advantage that a “non-contact type mechanical seal” that exhibits a sealing function in a non-contact state between both rotating and stationary seal rings can be configured.

  Embodiments of a mechanical seal according to the present invention will be described below with reference to the drawings. 1 and 2 are sectional views of mechanical seals according to Examples 1 and 2, respectively. FIG. 3 is a front view of a stationary seal ring used for the mechanical seal of FIG.

[Example 1]
As shown in FIG. 1, the mechanical seal S includes a rotary seal ring 2 that rotates integrally with the rotary shaft 1, a stationary seal ring 4 that is relatively fixed to the casing 3, and rotary and stationary seals. It has a winding spring (an example of elastic means) 5 for pressing the sliding surfaces 2a, 4a of the rings 2, 4 together. In FIG. 1, the portion on the right side of the stationary seal ring 4 is the inside of the can (inner side), and the portion on the left side is the atmosphere side.

The stationary seal ring 4 cannot be rotated by the casing 3 via a pair of seal rings 6, 6 and a presser case portion 7 that is bolted to the outer peripheral projection 4 g and is attached to the rotary shaft 1. On the other hand, it is supported so as to be fitted with a slight gap. The stationary-side seal ring 4 is composed of a composite structure in which a sliding member 4A is bonded to a rigid base 4B. Specifically, an annular ring formed of a fluororesin material containing a special filler is used. The sliding member 4A, which is a stationary seal plate, and the rigid base material 4B, which is an annular stationary support member formed of stainless steel, are joined and integrated using an adhesive. Here, the thickness of the sliding member 4A is set in the range of 0.5 mm to 5 mm .

  The rotation-side seal ring 2 is externally fitted to the distal end side small-diameter portion 9a of the support base 9 together with a holder 10 that fits the base side of the rotation side so as to be slidable in the direction of the axis P of the rotation shaft 1, and the holder 10 On the other hand, relative rotation is impossible due to loose fit between the head 11a of the stopper bolt 11 screwed to this and the recessed hole 2b. The support base 9 relatively fixed to the rotating shaft 1 by the screw 8 is formed with a support hole 13 through which a support bolt 12 screwed to the holder 10 is slidably inserted within a predetermined range in the axis P direction. A concave insertion hole (not shown) is formed for accommodating the winding spring 5 for pressing and urging the holder 10 toward the stationary seal ring 4.

  The rotation-side seal ring 2 is loosely fitted to the rotary shaft 1 so as to have a slight radial gap, and is configured to be sealed by the seal ring 14. With such a configuration, the rotation-side seal ring 2 formed of a hard member such as stainless steel or aluminum alloy is pressed and biased in a state of rotating integrally with the rotation shaft 1 and toward the stationary-side seal ring 4. Is done. Accordingly, a mechanical seal S is formed that seals between the inner side of the can and the atmosphere side by relative rotation while the sliding surfaces 2a, 4a of the rotary and stationary seal rings 2, 4 are pressed against each other. Yes.

  Here, the material of the hard member applied to the rotation-side seal ring 2 may be cemented carbide, SiC, ceramics, or the like. As the material of the stationary seal ring 4, the material of the sliding member 4A may be fluororesin (PTFE, etc.), PEEK, etc. The material of the rigid substrate 4B is metal, non-ferrous metal, low specific heat strength It may be a member. Next, the materials and characteristics of the sealing rings 2 and 4 on the fixed side and the rotating side will be described in more detail.

  The sliding member 4A may be made of a material in which an appropriate amount of a solid lubricating material is blended in a binder. In this case, the rigid base 4B is preferably made of ceramic, carbon, metal, and a composite material of metal and ceramic. As the solid lubricant material, one or more kinds of self-lubricating materials such as ethylene tetrafluoride resin, molybdenum disulfide, graphite, tungsten disulfide, and graphite fluoride are selected.

  Ceramics, carbon, metal, composite materials of metal and ceramics, etc. used for the rigid base material 4B as the base material of the sliding member 4A are excellent in corrosion resistance, hardly elastically deformed, and excellent in thermal conductivity. It itself has the required self-lubricating properties. It is possible to prevent damage to the sliding member 4A due to corrosion of the bonding interface with the sliding member 4A to be bonded, and it is possible to prevent deformation due to a load such as pressure in the use atmosphere. The initial surface roughness of the member 4A can be easily maintained, and the change in the friction coefficient can be reduced. Due to the good thermal conductivity, the heat generated by sliding is easily radiated, and the thermal load on the sliding member 4A can be reduced. Further, even if the sliding member 4A is worn and thinned over time, the rigid base material is exposed on the sliding surface due to wear, for example, as in the case where the sliding member 4A is formed by coating. There is an advantage that a good sealing state by the sliding member 4A can be stably supplied.

  In addition, the solid lubricating material and the binder constituting the sliding member 4A each have a low coefficient of friction but poor wear resistance. Therefore, the solid lubricating material and the binder are not suitable as a sliding material alone. Only used. However, such a mixture of the solid lubricating material and the binder is hard and hardly deformed, and is bonded to the surface of the rigid base material 4B made of ceramics, carbon, or the like having good thermal conductivity, so that it has a remarkable wear resistance. The improvement in performance is realized. That is, as a result of the rigid base material 4B compensating for the hardness and thermal conductivity that the solid lubricant and the binder constituting the sliding member 4A do not originally have, it is possible to improve the wear resistance.

  For the rigid substrate 4B, ceramics such as silicon carbide, alumina, silicon nitride, zirconia, and sialon, or carbon, chromium oxide, chromium carbide, various cermets, and metals can be used. The surface of the rigid base material 4B to which the sliding member 4A is bonded is flattened by applying fine irregularities in advance and polishing with a lapping or the like so that the tips of the fine convex portions in the surface roughness are flat. Is preferably ensured. As a method of imparting surface roughness to the rigid base material 4B made of a metal material, sand blasting with ceramic abrasive grains is effective, and it is desirable to pay attention so that the surface roughness does not become rough.

  The solid lubricating material is typically selected from one or more well-known self-lubricating materials such as ethylene tetrafluoride resin, molybdenum disulfide, graphite, tungsten disulfide, and graphite fluoride. From the viewpoint of excellent lubricity and being hardly affected by the atmospheric fluid, ethylene tetrafluoride resin is most preferable. In addition, the binder that binds the particles of the solid lubricant material as the sliding member 4A and adheres to the surface of the rigid base material 4B has excellent heat resistance, bonding force, film-forming property, and wear resistance. Desired. Typically, tetrafluoroethylene resin, epoxy resin, polyamideimide, polyimide, polyamide, polyarylate, polyetherimide, polysulfone, polybenzimidazole, polyester resin, phenol resin, acetal resin, polyphenylene sulfide, polyether ether ketone , Selected from synthetic resin materials such as aromatic polyester resin, polyethersulfone, polycarbonate, polybutylene terephthalate and the like, dissolved or dispersed in a medium such as an appropriate solvent.

  The sliding member 4A bonded to the surface of the rigid substrate 4B is preferably cured by a curing process including a heat treatment. In the seal ring 4 having such a configuration, the sliding member 4A has excellent self-lubricating properties and excellent wear resistance due to hardness compensation by the rigid base material 4B. In a mechanical seal mounted on a shaft or a shaft seal part of a multifunction filter dryer that performs solid-liquid separation, washing and drying with a single unit, it can be used as a seal ring on the rotating side or stationary side, thereby providing a dry lubrication atmosphere In particular, a significant improvement in wear resistance is realized, and the generation of wear powder can be effectively suppressed.

  The sliding member 4A, in which a solid lubricant material is blended in a binder, is bonded to the surface of a rigid base material 4B that is hard, hard to deform, and has good thermal conductivity. In addition to exerting lubricity, a significant improvement in wear resistance can be realized. Moreover, the sliding member by bonding can have a sufficient thickness as compared with the case where the thickness is coated, etc., so that the above-mentioned good effect can be sustained over a long period of time. There is an advantage of superiority. Therefore, it is possible to provide the above-described excellent effects as a mechanical seal that slides in a dry state or a seal ring for the device in an apparatus that needs to prevent the generation of foreign matters due to wear powder or the like as much as possible.

[Example 2]
As shown in FIG. 2, the mechanical seal S according to the second embodiment is fitted into a rotary seal ring 2 and a casing 3 that are externally fitted to the rotary shaft 1 via a cylindrical boss member 15. The case portion 16 includes a stationary seal ring 4 that is slidably supported in the direction of the axis P of the rotary shaft 1. The rotation-side seal ring 2 is accommodated in a state of being fitted into the ring-shaped recessed portion 15 a of the cylindrical boss member 15. In addition, the same code | symbol shall be attached | subjected to the location functionally the same as the mechanical seal of Example 1, and the description is omitted here.

  The mechanical seal S of the second embodiment has a structure in which the stationary seal ring 4 is pressed and urged in the direction of the axis P by the winding spring 5 and is slidable into the lateral ring-shaped recessed portion 16A of the case portion 16. A ring-shaped pressing plate 17 is interposed between the outer periphery and the winding spring 5. The stationary-side seal ring 4 includes a rigid base 4B that is in contact with the pressing plate 17 and a sliding member 4A that is bonded to an end surface of the rigid base 4B in the axis P direction. The seal ring 2 is made of a hard member.

  As shown in FIG. 3, a ring-shaped circumferential groove 18 having a depth within the thickness range is formed at a location close to the outer diameter side of the ring-shaped sliding member 4 </ b> A. The circumferential groove 18 is formed in a ring groove having a rectangular cross section having an inner circumferential wall 18a and an outer circumferential wall 18b along the axis P, and a side circumferential wall (groove bottom wall) 18c orthogonal to the axis P. Although not shown, the stationary-side seal ring has a structure in which the circumferential groove 18 is formed through the sliding member 4A in the thickness direction so that the groove bottom is formed on the surface of the rigid base 4B. 4 may be configured. The circumferential groove 18 may be filled with a lubricant as necessary.

[Another Example]
Although not shown, a seal ring in which a circumferential groove having a depth within the thickness range is formed in the sliding member 4A in a discontinuous state in the circumferential direction is a seal ring 2 of a rotating ring or a seal on the stationary side. A mechanical seal S having a configuration of the ring 4 may be used. This is a structure in which a stationary seal ring and a rotation-side seal ring can be brought into a non-contact state due to a configuration in which a plurality of circumferential grooves are formed in the circumferential direction with rotation, so-called “non-contact” Type mechanical seal ". In addition, the rotation-side seal ring 2 is a composite structure formed by bonding a rigid base material and a sliding member, and the stationary-side seal ring 4 is made of a hard member, and has both the seal rings. A mechanical seal may be used.

Sectional drawing which shows the structure of the mechanical seal by Example 1 Sectional drawing which shows the structure of the mechanical seal by Example 2 The front view which shows the stationary-side seal ring | wheel in FIG.

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Rotating side sealing ring 2a Sliding surface 3 Casing 4 Static side sealing ring 4a Sliding surface 4A Sliding member 4B Rigid base material 5 Elastic means 18 Circumferential groove S Mechanical seal

Claims (3)

A rotation-side seal ring that rotates integrally with the rotation shaft; a stationary-side seal ring that is fixed relatively to the casing; and elastic means that presses against the sliding surfaces of the rotation-side and stationary-side seal rings. A mechanical seal consisting of
The seal ring on either the rotating side or the stationary side is composed of a composite structure in which a sliding member is bonded to a rigid substrate, and the other seal ring is composed of a hard member. The sliding surface of any one of the sealing rings is formed by the sliding member, the sliding surface of the other sealing ring is formed by the hard member, and the rigid base material is ceramic, carbon, The sliding member is selected from a metal and a composite material of metal and ceramics, and the sliding member is a mixture of a solid lubricant material in a binder, and the thickness of the sliding member is in the range of 0.5 mm to 5 mm . Mechanical seal set.   The mechanical seal according to claim 1, wherein a circumferential groove having a depth within the thickness range is formed in the sliding member.   The mechanical seal according to claim 1, wherein the sliding member is formed of a fluorine-based resin.

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