JPS6225574Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a mechanical seal.

Conventionally, the one shown in Fig. 1 is widely known as an example of a mechanical seal, but this mechanical seal is airtightly fitted to the rotating shaft a by a set screw b via an O-ring c. a floating sheet f that is airtightly fitted to the collar d via a packing e;
and a stationary side sealing member having a floating sheet i that is airtightly fitted into the stepped portion of the shaft hole of the housing g via a packing h, and both floating sheets f. ,i
The sealing sliding surface j formed by the opposing end surfaces of the lubricating oil sealed inside the machine k and the pumped liquid outside the machine l is intended to be sealed off.

In the mechanical seal having the above configuration, both the floating sheets f, i and the packing e, h on the rotating side and the stationary side are made of metal or sic.
The latter is made of synthetic rubber and is formed in the same shape (symmetrical from front to back with the sliding surface j as the center), and the rotating side and On both fixed sides, the packings e and h are fitted onto the outer periphery of the small diameter portion on the rear end side of the floating sheets f and i, which are approximately L-shaped in cross section.With the above configuration, the mechanical seal has a relatively low It has the necessary and sufficient sealing performance as a seal for a circumferential speed truck roller.

However, when this mechanical seal is used in general pump equipment with a relatively high circumferential speed, (a) Firstly, both packings e and h are made only of synthetic rubber, and the elastic tightening force is used only. Because they are fitted onto each of the floating sheets f and i, there is a risk that the contact surfaces of the packings e and h may deteriorate locally after long-term use, and the pressing force may decrease due to this deterioration. Yotsutte packing e, h and floating sheet f,
A relative rotation (so-called slip) occurs between i and (b) secondly, the front end surfaces of each packing e, h and the back surface of the large diameter portion of each floating sheet f, i are brought into close contact; When the cooling mechanism is insufficient, the frictional heat generated on the sealing sliding surface j is directly transferred from the floating sheets f, i to packing e,
h, and these were one of the causes of early deterioration of packing e and h. In addition, when a large amount of slurry is contained in the pumped liquid on the outside l, the liquid contact surfaces of the packings e and h are worn out by the slurry, reducing the elastic force of the packings e and h. As a result, the pressing force against the floating sheets f, i decreases, and the relative rotation between the packings e, h in A and the floating sheets f, i is promoted.

In view of the above points, the present invention provides a mechanical seal having a floating seat having a substantially L-shaped cross section and having a packing fitted around the outer periphery of a small diameter portion on the rear end side. The purpose of this invention is to prevent early deterioration of the packing by preventing relative rotation between the floating sheet and the packing and preventing the propagation of frictional heat from the floating sheet to the packing as much as possible. The mechanical seal has a finger spring integrally formed with a required number of elastic tongues radially extending from the front end of the inner ring toward the outer circumference, and is integrally vulcanized on the front end side of the packing. A gap for heat insulation is provided between the back surfaces of the large-diameter portions of the floating sheet, and the above-described configuration is intended to eliminate the problems of the prior art described above.

Hereinafter, embodiments of the mechanical seal of the present invention will be explained with reference to the drawings. Figures 2 and 3 show the first embodiment, and 1 in the figure has a roughly L-shaped cross section and is made of metal, SIC, etc. A synthetic rubber packing 2 is fitted around the outer periphery of the small diameter portion 1a on the rear end side (left side in the figure) of the floating sheet. Reference numeral 3 denotes a finger spring in which a required number (28 equally spaced elastic tongues 3b in the figure) are integrally curved radially from the front peripheral end of the inner ring 3a toward the outer circumference. It is integrally vulcanized on the front end side of the packing 2 so as to face forward, and the front end surface of the elastic tongue piece 3b is exposed to the outside. Further, an annular depression is formed on the inner periphery of the front end of the packing 2, and a gap 4 extending over the entire circumference is formed between the front end surface of the packing 2 and the back surface of the large diameter portion 1b of the floating sheet 1.

The ring body configured as described above uses the end face of the large diameter portion 1b of the floating sheet 1 as a sealing sliding surface, and is used, for example, on the rotating side or the stationary side, or both, in a front-back symmetrical mechanical seal as shown in Fig. 1. The inner circumferential ring 3a of the finger spring 3, which is integrally vulcanized to the packing 2, provides the tightness of the packing 2 to the floating seat 1, and the relative relationship between the two 1 and 2 is This will prevent rotation of targets. Furthermore, the frictional heat generated due to the sealed sliding of the floating sheet 1 is prevented from propagating as much as possible by the gap 4 between the floating sheet 1 and the packing 2, and the synthetic rubber packing 2 prevent early deterioration. Further, the back surface of the large diameter portion 1b of the floating sheet 1 comes into local contact with the finger springs 3, and the finger springs 3, which are usually made of metal, also contribute to the heat insulation effect.

Next, FIGS. 4 and 5 show a second embodiment of the present invention. Only the parts that are different from the first embodiment will be explained. The finger spring 3 of this embodiment has an elastic tongue piece 3b. One piece is bent forward in the axial direction again to form an engagement piece 3c, which engages with a notch 1c on the back surface of the large diameter portion 1b of the floating seat 1 formed corresponding to the engagement piece 3c. This further ensures prevention of relative rotation between the floating sheet 1 and the packing 2.

The present invention has the above-mentioned configuration, in which a finger spring having a required number of elastic tongues integrally curved radially in the outer circumferential direction from the front end of the inner ring is integrally vulcanized on the front end side of the packing, and the finger spring is integrally vulcanized on the front end side of the packing. By creating a gap between the front end surface and the back surface of the large diameter part of the floating sheet, it is possible to prevent relative rotation between the floating sheet and the packing, suppress the propagation of frictional heat as much as possible, and prevent early deterioration of the packing. . In addition, the presence of finger springs allows long-term tightness to be obtained regardless of local deterioration of the packing, which not only extends the life of mechanical seals, but also improves mechanical seals that come in a variety of configurations. The scope of application is wide, and the practical effects of the present invention are extremely large.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a half-cut sectional view of a conventional mechanical seal, FIG. 2 is a half-cut sectional view of the main part of a mechanical seal showing the first embodiment of the present invention, and FIG. 3 is a view taken along the line in FIG. 2, FIG. 4 is a half-cut sectional view of the main part of a mechanical seal showing a second embodiment of the present invention, and FIG.
It is a V line arrow view in a figure. 1... Floating seat, 1a... Small diameter part, 1b... Large diameter part, 1c... Notch part, 2... Packing, 3... Finger spring, 3a...
...Inner peripheral ring, 3b...Elastic tongue piece, 3c...Engagement piece,
4... Gap.

Claims (1)

[Scope of utility model registration request] In a mechanical seal having a floating seat that has an approximately L-shaped cross section and has a packing fitted around the outer periphery of a small diameter portion on the rear end side, a required number of elastic tongues are integrally bent radially in the outer circumferential direction from the front circumferential end of the inner circumferential ring. A mechanical seal characterized in that a finger spring formed by the molding is integrally vulcanized on the front end side of the packing, and a gap is provided between the front end surface of the packing and the back surface of the large diameter part of the floating sheet.