JPH045809Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mechanical seal for sealing the circumference of a rotating shaft of a device, and particularly relates to an improvement of a mechanical seal used under dry conditions.

[Conventional technology]

Conventionally, as shown in Figs. 3 and 4,
A non-rotating sliding ring 52 that is airtightly fitted to the inner periphery of the housing 51 and a rotating sliding ring 54 that is airtightly fitted and rotated while being circumferentially engaged with the outer periphery of the shaft 53 are connected to the spring 55. Of the mechanical seals that perform shaft sealing by sliding closely against each other due to the axial load from It is known to form an annular groove 56 on the soft side (sliding surface 54' in the illustrated example) that extends circumferentially and is concentric with the sliding surface.

In other words, if the object to be sealed is a liquid,
The presence of a liquid film between the sliding surfaces 52' and 54' provides lubrication and removes the heat of sliding, but if the object to be sealed is gas, the sliding surfaces 52' and 54' must be kept under dry conditions. The lubrication is provided by both sliding rings 5.
2, 54, the annular groove 56 is designed to reduce sliding resistance without changing the surface pressure per unit area.
This reduces the sliding area and reduces the axial load on the sliding surfaces 52' and 54'.

[The problem that the idea attempts to solve]

However, in the dry sliding type mechanical seal as described above, as the sliding surfaces 52' and 54' wear out over time, abrasion powder generated thereby accumulates in the sealed annular groove 56. There was a problem in that part of the abrasion powder was caught between the sliding surfaces 52' and 54', causing abnormal wear and abnormal heat generation.

[Means to solve the problem]

Therefore, in the dry sliding mechanical seal of the present invention, a through hole is bored in the hard side sliding ring, with one end opening toward the annular groove and the other end opening at a location below the opening location. , the inside of the annular groove is opened to the outside through the through hole, and the end face of the hard side sliding ring is located near the annular groove side opening of the through hole and on the rotation direction side when viewed from the opening. The structure is such that a protrusion protruding into the annular groove is provided at the position.

[Effect]

Wear powder generated by sliding of both sliding rings and entering the annular groove is moved in the rotational direction by the gas co-rotating within the annular groove, and eventually flows from the end face of the hard sliding ring to the annular groove. It is blocked by a protrusion that protrudes inward, falls into a through hole opened just before the protrusion (on the opposite rotation side when viewed from the protrusion), and is discharged to the outside.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 and 2.

This mechanical seal seals the periphery of a shaft installed in the vertical direction, and is airtightly attached to the inner circumference of the housing 1 via O-rings 9, 9, and is a non-rotating seal made of a hard sliding material. The sliding ring 2 is made of a softer sliding material than the sliding ring 2, and is airtightly attached to the outer periphery of the shaft 3 via an O-ring 10, and is located below the sliding ring 4 which rotates together with the shaft 3. are doing.

An annular groove 5 extending concentrically with the sliding surface 4' is formed approximately in the widthwise center of the sliding surface 4' of the soft sliding ring 4, and a non-rotating hard groove 5 is formed below the sliding surface 4'. A required number of through holes 6 are bored in the sliding ring 2 (only one is shown in the figure), and one end of the through hole 6 faces into the annular groove 5 and faces the soft sliding ring 4. An opening 6a is formed in the end surface 2', and
Extending downward from the opening 6a, an opening 6b is formed between the O-rings 9 on the outer periphery of the housing 1.
It communicates with the space outside the machine via a discharge hole 8 provided in the machine. Further, on the end surface 2' of the hard sliding ring 2, there is a groove protruding into the annular groove 5 at a position near the opening 6a and on the rotational direction A side of the sliding ring 4 when viewed from the opening 6a. A protrusion 7 is provided. Reference numeral 11 denotes a coil spring whose rear end is supported by a collar 12 fixed to the outer periphery of the shaft 3 by a set screw 13, and which presses the rotating sliding ring 4 in the axial direction (downward) toward the non-rotating sliding ring 2. It is.

Now, assuming that the sliding ring 4 is rotating in the direction A, the abrasion powder (not shown) that has entered the annular groove 5 will also move in the annular groove 5 along the arrow B along with the rotation.
It moves as shown in , hits the protrusion 7 and falls into the through hole 6 through the opening 6a, and then falls into the opening 6b.
It is discharged from the machine via the discharge hole 8 of the housing 1.

In this example, the present invention was applied to a mechanical seal installed on a shaft extending in the vertical direction, but mechanical seals installed on a shaft extending horizontally or in other directions can also be used to remove wear particles in the annular groove from below the seal. It is possible to create a structure in which the liquid is dropped towards the target and released to the outside.

[Effect of idea]

The dry sliding type mechanical seal of the present invention makes the inside of the annular groove non-sealed by the through hole of the hard sliding ring, and the protrusion blocks the wear particles moving in the rotational direction inside the annular groove. Since the liquid is forcibly discharged from the through hole to the downward and external space,
It is possible to eliminate problems such as abrasion powder accumulated in the annular groove and bitten into the sliding surface, causing surface roughness, abnormal wear, and abnormal heat generation on the sliding surface.

[Brief explanation of drawings]

Fig. 1 is a side sectional view cut in half showing an embodiment of the present invention, Fig. 2 is a front view of the main parts, Fig. 3 is a side sectional view cut in half showing a conventional example, and Fig. 4 is a sliding ring. FIG. 1...Housing, 2...Sliding ring (hard),
2'... End face, 3... Shaft, 4... Sliding ring (soft), 5... Annular groove, 6... Through hole, 6a,
6b...Opening, 7...Protrusion.

Claims (1)

[Scope of utility model registration request] 1 made of materials with different hardness and facing in the axial direction
One of the pair of sliding rings is attached to the inner periphery of the housing and the other to the outer periphery of the shaft in an airtight manner, and both rings are closely slid together by the axial load from the spring. In a dry sliding mechanical seal having an annular groove concentric with the sliding surface of the sliding ring, the hard sliding ring has one end opening toward the annular groove and the other end opening at the opening location. A through hole is bored at a location lower than the annular groove, and the inside of the annular groove is opened to the outside through the through hole, and the annular groove of the through hole is formed on the end surface of the hard side sliding ring. At a position near the side opening and on the rotational direction side when viewed from the opening,
A dry sliding type mechanical seal characterized in that a protrusion projecting into the annular groove is provided.