JPH0227726Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in mechanical seals for sealing the rotating shafts of various types of equipment.

[Conventional technology]

Conventionally, as shown in Figures 2 to 4,
The rotating shaft a is hermetically fitted and fixed to the rotating shaft a.
A rotating side sealing element b rotates together with the rotating side sealing element b, and a fixed side sealing element f made of a carbon material is fitted and fixed to the inner periphery of the shaft hole stepped portion d of the equipment housing c via an O-ring e.
Therefore, mechanical seals in which the sealing elements b and f closely slide against each other to seal the fluid to be sealed are widely used in various types of equipment.

[Problem that the invention attempts to solve]

Among these mechanical seals, as shown in Fig. 2, there is a block type fixed side sealing element in which the rear surface g is fully supported by the radial rising surface d' of the housing c shaft hole step d. f1
is a high pressure condition because the pressures P and P' of the fluid acting in the thrust direction on the front surface h and the rear surface g of the fixed side sealing element f1 are balanced on the sliding surface i or the outer diameter side of the O-ring e. Stable sealing performance can be maintained under conditions of large pressure fluctuations.However, when the rotating shaft a rotates eccentrically in a conical shape, so-called swivel movement, the rear surface g is Since it is fully supported by the radial rising surface d' of section d,
Fixed side sealing element b accompanying the rocking rotation of the rotating shaft a
This has the problem that it cannot sufficiently follow the tilting of the sliding surface of the slider, and therefore leakage accidents are likely to occur.

In addition, as shown in FIG. 3, a step g' formed on the outer diameter side of the rear surface g is used to connect the shaft hole step d of the housing c in the radial direction via an O-ring e and a back-up spring j. The floating type fixed side sealing element f2, which is supported on the rising surface d', can sufficiently follow the tilting of the sliding surface of the rotating side sealing element b due to the rocking rotation of the rotating shaft a. , because the structure is such that the fluid pressure P does not act directly on the rear surface g, the thrust load increases as the pressure increases, and therefore the O-ring e and back-up spring j
There are problems in that deformation and protrusion occur, and leakage accidents are also likely to occur.

Furthermore, FIG. 4 shows that the float type fixed side sealing element f3 is balanced with the block type fixed side sealing element f1 shown in FIG. This is intended to reduce the thrust load under high pressure conditions, but in this case, the wall thickness of the skirt portion g'' on the inner diameter side of the rear surface g becomes thinner, which causes a new problem of easy breakage. becomes.

[Means for solving problems]

In view of the problems listed above, the mechanical seal of this invention has stable sealing performance under high pressure conditions, conditions with large pressure fluctuations, and conditions where the rotating shaft rotates eccentrically in a conical shape. A retaining ring made of a highly rigid material and having an approximately L-shaped cross section and a rearwardly protruding skirt portion on the inner diameter is loosely fitted to the inner periphery of the stepped portion of the housing shaft hole. An O-ring is formed on the inner diameter side between the rear rear surface of the retaining ring extending in the shape of a brim from the skirt portion toward the outer diameter side and the radially rising surface of the shaft hole stepped portion that is axially opposed thereto. It is kept airtight by packing, and
On the front surface of the retaining ring, a stationary sealing element that is in sliding contact with the rotating sealing element is abutted in the axial direction via a packing such as an O-ring.

[Effect]

According to the above configuration, fluid pressure is introduced to the outer diameter side of the packing such as the O-ring on the rear surface of the retaining ring, and is balanced with the fluid pressure acting on the outer diameter side of the sliding part on the front surface of the fixed side sealing element. , stable sealing performance is maintained under conditions of high pressure and large pressure fluctuations. In addition, since the combined shape of the stationary side sealing element and the retaining ring is a float type as a whole, when the rotating shaft rotates eccentrically in a conical shape, the rotating side sealing element slides due to the eccentric movement. It is also possible to sufficiently follow the tilting of the surface. Further, since the retaining ring is made of a material with high rigidity, the strength of the portion (skirt portion) that protrudes rearward on the inner diameter side of the stepped portion of the shaft hole is increased.

〔Example〕

Next, the specific structure and operation of the mechanical seal of the present invention will be explained in detail based on the embodiment shown in FIG.

In the figure, reference numeral 1 denotes a rotary shaft loosely rotatably inserted into a shaft hole 3 of a housing 2 of the device, 4 a rotary-side sealing element that is hermetically fitted onto the rotary shaft 1 and rotates auxiliary, and 5 It is loosely fitted into a stepped part 6 formed in the shaft hole 3 of the housing 2, and has a substantially L-shaped cross section with a skirt part 7 that protrudes rearward on the inner diameter part, and is made of metal, ceramic, cemented carbide, etc. Retaining ring made of material with high mechanical strength,
8 is formed on the inner diameter portion of the rising surface 6a for the purpose of maintaining airtightness between the rear surface 5a of the retaining ring 5 and the radial rising surface 6a of the shaft hole stepped portion 6 facing the rear surface 5a. The O-ring 10 is fitted into the annular groove 6b via the back-up spring 9, and the rear surface 10a is attached to the front surface 5b of the retaining ring 5.
This is a stationary side sealing element made of a carbon material, which is airtightly abutted and fixed via the rotary side sealing element 4 through a sliding surface 10c formed on the front surface 10b.

According to the present embodiment configured as described above, the pressure P' of the fluid A is introduced to the outer diameter side of the rear surface 5a of the retaining ring 5 and the close contact surface with the O-ring 8, and Since the pressure P applied to the outer diameter side of the sliding surface 10c of 10b is balanced, stable sealing performance is maintained even under conditions of high pressure and large pressure fluctuations, and the thrust load is reduced.
Excessive deformation of the ring 8, back-up spring 9 and stationary side sealing element 10, and the above-mentioned O due to the deformation.
The "protrusion phenomenon" of the ring 8 and the back-up spring 9 is prevented. Further, the shape of the combination of the retaining ring 5 and the fixed side sealing element 10 is the float type fixed side sealing element f shown in FIG.
3, so it also has the function of a float type. In other words, when the rotating shaft 1 rotates eccentrically in a conical shape, the sliding surface 4' of the rotating side sealing element 4 tilts due to the eccentricity. can be fully followed,
Stable sealing performance can be maintained. Furthermore, since the retaining ring 5 is made of highly rigid metal, ceramic, etc., the skirt portion 7 will not be deformed or damaged by high pressure. The fixed side sealing element 10 is simply abutted against the front surface 5b of the retaining ring 5 on its flat rear surface 10a, and is not restrained by shrink fitting or the like on the retaining ring 5, so that it cannot be assembled. This is simple, and if the stationary sealing element 10 is damaged or worn due to use, it is only necessary to replace the stationary sealing element 10.

[Effect of idea]

As mentioned above, the present invention has a substantially L-shaped cross-sectional shape and a highly rigid support ring on the rear surface of the fixed side sealing element, thereby achieving a pressure balance function as a block type and as a float type. It also has the ability to follow the eccentric rocking of the rotating shaft, maintains stable sealing performance, and provides a mechanical seal with an excellent structure in terms of strength.Moreover, the fixed side sealing element is attached to the retaining ring. Since it only abuts the front surface in the axial direction and is not integrated into the retaining ring, it is not only easy to assemble, but can also be replaced if it becomes necessary to replace it due to long-term use. It is only necessary to replace the parts, which has the effect of not causing an increase in the cost at the time of replacement.

[Brief explanation of the drawing]

FIG. 1 is a half-cut sectional view of a main part showing an embodiment of a mechanical seal according to the present invention, and FIGS. 2 to 4 are half-cut sectional views of main parts of a conventional mechanical seal. DESCRIPTION OF SYMBOLS 1...Rotating shaft, 2...Housing, 5...Retaining ring, 5a...Rear surface, 6...Step, 6a...Rising surface, 8, 11...O-ring, 10...Fixed side sealing element .

Claims (1)

[Scope of utility model registration request] A retaining ring made of a highly rigid material and having a substantially L-shaped cross section and having a skirt portion protruding rearward on the inner diameter portion is loosely fitted on the inner periphery of the stepped portion of the housing shaft hole,
A seal such as an O-ring is provided on the inner diameter side between the rear rear surface of the retaining ring extending in the shape of a brim from the skirt portion to the outer diameter side and the radial rising surface of the shaft hole stepped portion that is axially opposed thereto. A mechanical seal which is maintained airtight and has a stationary side sealing element which is in sliding contact with a rotating side sealing element and abuts against the front surface of the retaining ring in the axial direction via a packing such as an O-ring.