JPH0614149Y2 - Dry sliding mechanical seal - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an improvement of a mechanical seal for sealing the circumference of a rotary shaft of an apparatus, particularly a mechanical seal used under dry conditions.

[Conventional technology]

Conventionally, as shown in FIG. 3 and FIG. 4, a non-rotating slide ring (5
2) and the sliding ring (54) that is airtightly attached to the outer periphery of the shaft (53) in a circumferentially engaged state and rotates, and is in close contact with each other due to the axial load from the spring (55). Among mechanical seals that seal the shaft, those that seal gas are the soft side of the sliding surfaces (52 ') (54') of the sliding rings (52) (54) with different hardness. In the example shown, the sliding surface (5
4 ')), an annular groove (56) concentrically extending with the sliding surface and extending circumferentially.
Is known to form.

That is, when the liquid to be sealed is a liquid (5
2 ') (54') is lubricated by the liquid film and the sliding heat is removed, but if the sealing target is gas, the sliding surfaces (52 ') (54') Sliding under dry conditions, and its lubrication depends only on the self-lubricating property of the sliding materials that make up both sliding rings (52) (54), so sliding without changing the surface pressure per unit area For the purpose of reducing resistance, the sliding area is reduced by forming the annular groove (56) and the sliding surface (5
The axial load on 2 ') (54') is relaxed.

[Problems to be solved by the device]

However, in the dry sliding type mechanical seal as described above, when the sliding surfaces (52 ′) and (54 ′) are gradually worn away, wear powder generated thereby is sealed in the annular groove (56). There is a problem that a part of the abrasion powder accumulated inside is trapped between the sliding surfaces (52 ') and (54'), causing abnormal wear and abnormal heat generation.

[Means for Solving the Problems]

Therefore, in the dry sliding mechanical seal of the present invention, the outer edge shape of the sliding surface of the stationary side sliding ring intersects the outer peripheral edge of the annular groove formed on the annular sliding surface of the rotating side sliding ring, The inner space of the annular groove is formed in a non-circular shape so as to open to the outer space of the sliding surface of the stationary side sliding ring at a part in the circumferential direction, so that abrasion powder is not accumulated in the annular groove. A protrusion for scraping out the abrasion powder in the annular groove to the outside may be provided on a part of the outer edge of the sliding surface of the stationary slide ring.

[Action]

According to the above configuration, even when both sliding rings are in contact with each other,
The inside of the annular groove is not hermetically sealed, and the wear particles that have penetrated into the annular groove are sent in the rotational direction as the rotary sliding ring rotates, and the annular groove slides on the sliding surface of the stationary sliding ring. Is discharged in a partially open position outside of the. Further, in the protrusion, the abrasion powder once sent to the open position tries to get into the annular groove and the stationary side sliding surface by riding on the gas flow accompanying the rotation. To reliably remove wear debris from the annular groove.

〔Example〕

In the embodiment of the present invention shown in FIGS. 1 and 2,
(1) is a stationary slide ring that is hermetically mounted on the inner circumference of the housing, and (3) is a rotating slide ring that is hermetically mounted on the outer circumference of the shaft.

On the annular sliding surface (4) provided on the front surface of the rotary side sliding ring (3), an annular groove (5) extending concentrically with the sliding surface (4) is provided at an intermediate position in the width direction thereof. Formed, and the sliding surface
The outer edge of the sliding surface (2) of the stationary side sliding ring (1) facing (4) is a substantially rectangular shape in which a pair of long sides (2a) (2b) intersects the outer peripheral edge of the annular groove (5). It has a shape. Then, in the contacting state of both sliding rings (1) and (3) shown, the sliding surface on the rotation side
The outer peripheral sliding surface (4 ') of (4) is exposed to the outside from both long sides (2a) (2b) of the stationary side sliding surface (2) outer edge,
A part of the annular groove (5) is also exposed from the long sides (2a) and (2b) and is open to the outside, as indicated by reference numerals (5a) and (5b).

In this configuration, if any one point in the annular groove (5) is (P), this point (P) moves in the same direction as the rotation side sliding ring (3) rotates in the (R) direction, Opening (5) of the annular groove (5)
It will appear alternately from a) and (5b). Therefore, the abrasion powder (not shown) that has penetrated into the annular groove (5) moves along with this movement and is discharged to the outside when it reaches the opening portions (5a) and (5b).

In addition, as shown by the reference numeral (6) in FIG. 2, the stationary side sliding surface (2)
At the position where the annular groove (5) enters the inside of the long side (2a) or (2b) of the sliding surface (2) on the stationary side as the sliding ring (3) rotates, Providing a protrusion projecting into the annular groove (5) allows the abrasion powder to be discharged more reliably by the scraping action of the protrusion (6).

In the illustrated embodiment, the stationary sliding surface (2) has a substantially rectangular shape, but it may be changed to, for example, an oval shape or a shape in which a part of the circumference is cut.

[Effect of device]

The dry-sliding mechanical seal of the present invention makes the inner space of the annular groove formed on the rotating sliding surface open to the outside at a part in the circumferential direction by making the outer edge shape of the stationary sliding surface non-circular. However, since the wear powder that has entered the annular groove can be discharged, the wear powder accumulates in the annular groove and is caught by the sliding surface, causing surface roughness, abnormal wear, and abnormal heat generation on the sliding surface. The above conventional problems can be solved, and in addition, by providing a projection protruding from the stationary sliding surface into the annular groove, the abrasion powder can be reliably discharged. Further, the present invention does not utilize the pumping action of a so-called spiral groove or the like, and since gas does not pass between the sliding surface on the rotating side and the stationary side, the abrasion powder is discharged without sacrificing the sealing property. It has an excellent effect that it becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing an embodiment of a dry sliding mechanical seal of the present invention, FIG. 2 is a front view of the same part, FIG. 3 is a half-cut side view showing a conventional example, and FIG. It is a front view of a sliding ring similarly. (1) …… static side sliding ring, (2) (4) …… sliding surface (3) …… rotating side sliding ring, (5) …… annular groove (5a) (5b) …… open part , (6) …… Protrusion

Claims (2)

[Scope of utility model registration request] 1. A stationary slide ring airtightly supported on a housing side and a rotary slide ring airtightly supported on a shaft slide in close contact with each other to form an annular ring of the rotary slide ring. In the dry sliding type mechanical seal having a circular groove concentric with the sliding surface on the sliding surface, the outer edge shape of the sliding surface of the stationary side sliding ring intersects the outer peripheral edge of the annular groove, A dry-sliding mechanical seal, characterized in that the inner space of the annular groove is formed in a non-circular shape so as to open to the outer space of the sliding surface of the stationary slide ring at a portion in the circumferential direction. 2. A projecting portion projecting into the annular groove is provided at a position on the outer edge of the sliding surface of the stationary sliding ring into which the annular groove enters as the rotating sliding ring rotates. The dry-sliding mechanical seal according to claim 1.