JPH034859Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a mechanical seal that seals the rotating shaft of a machine body such as a water pump.

[Conventional technology] Conventionally, in this type of mechanical seal,
As illustrated in FIG. 2, when sealing the stainless steel rotating shaft 3 inserted into the aluminum casting housing 2 of the fuselage 1, an iron casting impeller is attached and fixed to the rotating shaft 3 side. A ceramic floating sheet 6, which is a rotating ring, is inserted into the fitting recess 4a formed on the inner circumferential surface of 4, with a buffer rubber 5 interposed therebetween.
While the floating sheet 6 is fitted and fixed, a seal ring 7 made of carbon material as a fixed ring is slid into contact with the floating sheet 6, and an engagement recess 8 is formed on the inner circumferential surface of the seal ring 7. The extension part 10 of the outer cylindrical casing 9 fixed to the housing 2 side is engaged with the mating recess 8 to prevent rotation, and the seal ring 7 is further inserted into the packing 11 and the back-up inside the casing 9. Coil spring 1 via spring suppressing member 12
Some have a configuration in which the shaft is sealed by being pressed in the axial direction by the urging force of No. 3.

[Problems to be solved by the invention] However, in the mechanical seal of such a conventional structure, as shown in FIG. Therefore, when the water pump rotates at high speed, the outer diameter surface 72 side of the sliding surface 7a is
The inner diameter surface 71 which is on the atmosphere side is lubricated by a liquid film formed with the liquid to be sealed that fills the outer periphery.
Since it is difficult for a sufficient liquid film to be formed by the liquid to be sealed on the sides, high sliding heat is generated, which may cause surface roughness or distortion of the sliding surface 7a, or damage to the buffer rubber 5, packing 11, etc. The problem was that rubber hardening and cracking were likely to occur, reducing sealing performance.

[Purpose of the invention] The present invention was made under the above circumstances, and its purpose is to provide a mechanical seal that can improve the lubricity of sliding parts. .

[Means for solving the problems] In order to solve the above problems, the present invention has the following features:
A floating sheet whose outer periphery, excluding the sliding surface, is covered with cushioning rubber is fixed to the rotating shaft side of the machine body, and the floating sheet is fixed to the sliding surface of the floating sheet on the housing side of the machine body. In a mechanical seal in which the sliding surface of a seal ring made of a carbon material is brought into sliding contact and the seal ring is elastically pressed against the floating sheet side to seal the shaft, the sliding surface of the seal ring is The particle size of the carbon particles on the inner diameter side is made larger than the particle size of the carbon particles on the inner diameter side of the rocking surface.

[Function] In other words, in the present invention, since the particle size of the carbon particles on the inner diameter side of the sliding surface is larger than the carbon particles on the outer diameter side, a sufficient liquid film can be formed between the large diameter carbon particles. is maintained, and the lubricity of the inner diameter surface of the sliding surface can be improved, so it is possible to reduce the heat generated by sliding of the seal part during high-speed rotation of water pumps, etc., and thereby the sliding surface It is possible to prevent surface roughness and distortion, hardening of rubber such as buffer rubber and packing, and occurrence of cracks, and it is also possible to improve sealing performance and durability.

[Example] The present invention will be described below with reference to an example shown in FIG. In the illustrated embodiment of the present invention, parts having the same structure as the conventional mechanical seal shown in FIG. 2 are denoted by the same reference numerals, and a description thereof will be omitted.

That is, as shown in FIG. 1, in the present invention, the carbon particles b on the inner diameter surface 71 side of the sliding surface 7a of the seal ring 7 formed of a carbon material are coarse particles, and the carbon particles b on the outer diameter surface 72 side are coarse particles. By making the carbon particle a larger in diameter than the carbon particle a, a liquid film is also formed and retained on the inner diameter surface 71 facing the atmosphere.

It should be noted that the present invention is not limited to the embodiments described above, and it goes without saying that various modifications may be made without changing the gist of the present invention.

[Effect of the invention] As is clear from the above explanation, according to the invention, the particle size of the carbon particles on the inner diameter side of the seal ring sliding surface is made larger than the carbon particles on the outer diameter side. By maintaining a sufficient liquid film between large-diameter carbon particles and eliminating the unlubricated area on the inner diameter side of the sliding surface, lubricity is improved, reducing the heat generated by sliding of the seal part during high-speed rotation of water pumps, etc. This can prevent surface roughness and distortion of sliding surfaces, hardening and cracking of cushioning rubber and packing, and improve sealing performance and durability. It has the excellent effect of being able to

[Brief explanation of drawings]

Fig. 1 is a schematic enlarged sectional view of the sliding surface portion of a seal ring showing an embodiment of the mechanical seal according to the present invention, Fig. 2 is a schematic sectional view of the main part of a conventional mechanical seal, and Fig. 3 is FIG. 3 is a schematic enlarged view of a sliding surface portion of a conventional seal ring. DESCRIPTION OF SYMBOLS 1... Body, 2... Housing, 3... Rotating shaft, 5... Buffer rubber, 6... Floating sheet, 6a... Sliding surface, 7... Seal ring, 7a
...Sliding surface, 71...Inner diameter surface, 72...Outer diameter surface,
11...Putskin, 12...Spring suppressor, 1
3...Coil spring, a, b...Carbon particles.

Claims (1)

[Scope of utility model registration request] A floating sheet whose outer periphery excluding the sliding surface is covered with cushioning rubber is fixed to the rotating shaft side of the machine, and on the sliding surface of this floating sheet,
A mechanical seal in which the sliding surface of a seal ring made of a carbon material fixed to the housing side of the body is brought into sliding contact, and this seal ring is elastically pressed against the floating seat side to seal the shaft. . A mechanical seal characterized in that the particle size of the carbon particles on the inner diameter side of the sliding surface of the seal ring is larger than the particle size of the carbon particles on the outer diameter side of the sliding surface.