JPH0614148Y2 - 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. 2 and FIG. 3, a non-rotating sliding 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]

In view of this, the dry sliding mechanical seal of the present invention has a sliding surface provided with an annular groove on the sliding surface, which is slanted with respect to the circumferential direction on the sliding surface on the outer peripheral side of the annular groove and is opposite to each other. The required number of notches extending in the opposite direction are alternately formed, and the annular groove is configured to communicate with the seal outer peripheral space through the notches, so that the abrasion powder in the annular groove is discharged, and the above problem cannot be solved. It is what

[Action]

That is, the gas in the seal outer peripheral space flows into the annular groove through the notches that extend in the rotational direction when viewed from the annular groove among the notches that are opposed to each other with rotation, and the gas flows in the anti-rotational direction when viewed from the annular groove. The gas in the annular groove flows out from the extending notch to the seal outer peripheral space, and the wear powder in the annular groove can be discharged to the seal outer peripheral space by riding on the flow of this gas.

〔Example〕

Next, the present invention will be explained based on an embodiment shown in FIG.

(1) is a soft side sliding ring that is airtightly attached to the outer periphery of the shaft (6) and rotates among a pair of sliding rings of different hardness that form a mechanical seal. An annular groove (3) concentrically extending with the sliding surface (2) is formed at an intermediate position in the width direction of the moving surface (2).
The sliding surface (2 ′) located on the outer peripheral side of (3) has a notch extending obliquely to the circumferential direction and extending in directions opposite to each other.
(4) and (5) are alternately formed so as to be equally distributed in the circumferential direction. More specifically, of these notches (4) and (5), the annular groove
The notch (4) extending in the direction of rotation when viewed from (3) is the other notch.
It is formed larger than (5), and then the wall surface (4 ') receives the gas (air) in the seal outer peripheral space (S), and the gas is passed through the annular groove (3).
The other notch (5) extends tangentially to the counter-rotational direction side when viewed from the annular groove (3), so that the sliding ring (1) can be rotated. Along with this, the gas in the outer peripheral space (S) flows into the annular groove (3) through the notches (4) and again through the notches (5), as shown by arrows (A), (B) and (C). While flowing out to the outer peripheral space (S), a part thereof branches off at the inner end portion (5 ′) of the notch (5) and flows in the annular groove (3) as shown by an arrow (D). Therefore, the abrasion powder generated by the abrasion of the sliding surfaces (2) and (2 ') does not accumulate in the annular groove (3) between the sliding surfaces (2) and (2'), and Exhausted by the flow of gas through the groove (3).

Needless to say, the present invention can be implemented even when the annular groove is provided on the non-rotating side.

[Effect of device]

According to the present invention, as the mechanical seal rotates, the gas in the outer peripheral space flows into the annular groove in one of the notches extending in the opposite direction, and the gas in the outer peripheral space flows out from the annular groove in the other one. By such a vigorous flow of gas passing through the annular groove, the abrasion powder in the annular groove is discharged, and the abrasion powder is accumulated in the annular groove and is caught by the sliding surface to form a surface on the sliding surface. In addition to being able to solve the conventional problems such as roughening, abnormal wear, and abnormal heat generation, the heat dissipation effect is also enhanced by the active flow of gas through the annular groove.

[Brief description of drawings]

FIG. 1 is a front view of a sliding ring showing an embodiment of the dry sliding mechanical seal of the present invention, FIG. 2 is a half-cut side view showing a conventional example, and FIG. 3 is a front view of the sliding ring. Is. (1) …… Sliding ring, (2) (2 ′) …… Sliding surface, (3) …… Annular groove, (4) (5) …… Notch, (6) …… Shaft

Claims (1)

[Scope of utility model registration request] 1. A non-rotating sliding ring that is hermetically supported on the housing side and a sliding ring that is hermetically supported and rotating on the shaft side slide in close contact with each other, and one sliding ring slides. In a dry sliding mechanical seal having an annular groove concentric with the sliding surface on the moving surface, a sliding surface on the outer peripheral side of the annular groove is provided in a direction oblique to the circumferential direction and opposite to each other. A dry sliding mechanical seal characterized in that a required number of extending notches are alternately formed, and the annular groove communicates with the space on the outer peripheral side of the sliding surface through the notches.