JPH0453490Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a mechanical seal that seals around the rotating shaft of equipment, and is particularly concerned with improving mechanical seals that seal gas and are used under drive conditions. .

[Conventional technology]

Conventionally, as shown in Figs. 3 and 4,
A non-rotating sliding ring 52 is airtightly attached to the inner periphery of the housing 51, and a rotating sliding ring 54 is airtightly attached to the outer periphery of the shaft 53 while being engaged in the circumferential direction. Among mechanical seals that perform shaft sealing by sliding closely against each other due to an axial load, in the case of sealing gas, the sliding surfaces 52' and 54' of the sliding rings 52 and 54, which have different hardness, It is known to form a circumferentially extending annular groove 56 concentric with the sliding surface on the soft side (sliding surface 52' in the illustrated example).

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 sealing target 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 formed in order to reduce the sliding resistance without changing the surface pressure per unit area. Therefore, the sliding area is reduced, and the axial load by the spring 55 is set accordingly.

[The problem that the idea aims to solve]

However, in the dry sliding type mechanical seal described above, the shaft 53 is inserted into the housing 51 in the vertical direction (vertical or a direction similar thereto) as shown in the figure, and a non-rotating soft sliding ring having an annular groove 56 is formed. 52 is located below the hard sliding ring 54, both rings 52,
Abrasion powder generated by wear over time due to sliding of the groove 54 gradually accumulates at the bottom of the annular groove 56 and is never discharged, so that the abrasion powder eventually reaches the sliding surface 52. There was a problem in that it got caught between the parts ' and 54', causing surface roughness, abnormal wear, and abnormal heat generation.

[Means for solving problems]

Therefore, the present invention provides a lower soft sliding ring that is airtightly installed on the inner surface of a shaft hole that vertically passes through the housing, and a lower soft sliding ring that is airtightly installed on the outer peripheral surface of the shaft that is inserted into the shaft hole. A dry sliding type mechanical seal comprising a soft sliding ring and an upper hard sliding ring that closely slides thereon, and having an annular groove concentric with the sliding surface on the upper end sliding surface of the soft sliding ring. Among the sliding surfaces of the soft sliding ring, a notch is provided on the auxiliary sliding surface on the outer periphery of the annular groove to connect the annular groove and the space on the outer periphery of the seal, and the bottom surface of the notch is made such that the outer periphery side is lower. The groove is inclined, and the inner circumferential end of the bottom surface has a height below the bottom surface of the annular groove.

[Effect]

In other words, the wear particles that have entered the annular groove move in a certain direction along with the gas flow in the annular groove as the upper hard sliding ring rotates, and eventually move along the sloped bottom surface of the notch. It falls towards the outer periphery.

〔Example〕

The present invention will be explained below based on an embodiment shown in FIGS. 1 and 2.

1 is a housing, 2 is a shaft hole that penetrates the housing 1 vertically (or in a direction similar to this), 3 is a shaft that is inserted into the shaft hole 2, and 4 is airtightly attached to the inner peripheral surface of the housing 1. A non-rotating sliding ring 5 is installed above the sliding ring 4 in an airtight manner on the outer peripheral surface of the shaft 3, and is a rotating sliding ring that is loaded downward by a spring (not shown). It's a ring.

The lower non-rotating sliding ring 4 is made of a softer material than the upper rotating sliding ring 5, and has a sliding surface 6 protruding from its upper end that is concentric with the sliding surface 6. An annular groove 7 extending circumferentially is recessed.

Of the sliding surfaces 6, the shaft sealing function is performed on the sliding surface 6a on the inner circumferential side of the annular groove 7, and the required number of notches 8 are provided on the auxiliary sliding surface 6b on the outer circumferential side of the annular groove 7. It is formed in equal directions. This notch 8 communicates the inside of the annular groove 7 with the outer peripheral space of the seal, and its bottom surface 8' is inclined so that the outer peripheral side is lower, and the inner peripheral end of the bottom surface 8' is connected to the annular groove 7. The groove is lower than or equal to the bottom surface 7' of the notch 8, and the abrasion particles moving in the annular groove 7 slide down the inclined bottom surface 8' of the notch 8 toward the outer peripheral space of the seal. .

Further, by forming a tapered surface 9 on the outer peripheral surface of the auxiliary sliding surface 6b, the width of the auxiliary sliding surface 6b is reduced and the sliding surface 6 as a whole is located on the inner peripheral side, Efforts are being made to reduce sliding resistance.

[Effect of idea]

As described above, the drive sliding type mechanical seal of the present invention has an annular groove on the upper sliding surface of the sliding ring, and a notch with an inclined bottom surface is formed on the sliding surface located on the outer periphery of the annular groove. By providing this, the wear particles that move within the annular groove as it rotates slide down the inclined bottom surface of the notch, and even when the sliding ring is not rotating, the wear particles in the annular groove can reliably move outward. Therefore, it is possible to eliminate problems caused by the accumulation of wear particles in the annular groove and being bitten by the sliding surface, causing abnormal wear particles and abnormal heat generation, as well as improving the screw pump action. It also does not cause leakage, unlike when using

[Brief explanation of the drawing]

Fig. 1 is a side sectional view cut in half showing an embodiment of the present invention, Fig. 2 is a partial perspective view of the sliding ring, Fig. 3 is a side sectional view cut in half showing a conventional example, and Fig. 4 is also a front view of the sliding ring. DESCRIPTION OF SYMBOLS 1...Housing, 2...Shaft hole, 3...Shaft, 4...Soft sliding ring, 5...Hard sliding ring, 6...Sliding surface, 6a...Auxiliary sliding surface, 7...
Annular groove, 7', 8'...bottom surface, 8...notch.

Claims (1)

[Scope of utility model registration request] a lower soft sliding ring that is airtightly attached to the inner circumferential surface of a shaft hole that vertically passes through the housing; and a lower soft sliding ring that is airtightly attached to the outer circumferential surface of the shaft that is inserted into the shaft hole. A drive sliding type mechanical seal comprising an upper hard sliding ring that closely slides with the ring, and an annular groove concentric with the sliding surface on the upper end sliding surface of the soft sliding ring. Among the sliding surfaces of the dynamic ring, a notch is provided on the auxiliary sliding surface on the outer periphery of the annular groove to connect the annular groove and the space around the outer periphery of the seal, and the bottom surface of the notch is inclined so that the outer periphery side is lower, and A dry sliding mechanical seal characterized in that the inner circumferential end of the bottom surface is at a height lower than the bottom surface of the annular groove.