JPS6322374Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a mechanical seal related to shaft sealing technology.

Conventionally, mechanical seals used in compressors for refrigerators or car coolers have been used to apply the driving force of a rotating shaft c to a fixed ring b airtightly supported on the casing a side, as shown in Fig. 1. It is known that a rotating ring e, which is transmitted via a case d and which is hermetically fitted to a rotating shaft c, is pressed into contact with a coil spring f, and is slidably rotated in a sealed manner. However, in recent years, as the compressors have become smaller, the operating conditions for mechanical seals have also tended to be higher speeds and higher pressures, and when the mechanical seals are used under such conditions, they are pressed by the coil spring f. Since the tracking function that moves in the axial direction is provided on the side of the rotating ring e that rotates driven by the rotating shaft c, large vibrations occur and sufficient sealing performance cannot be achieved.

The present invention has been developed in view of the above points, and includes bending the rear end of a sleeve that is airtightly fitted to the rotating shaft to support a rotating ring on the outer periphery of the sleeve. A fixing ring is engaged with the rear end of a metal bellows whose tip is fixed near the opening edge of the shaft hole of the casing into which the rotating shaft is inserted, and the tip of the sleeve is bent approximately in the outer radial direction. It is an object of the present invention to provide a mechanical seal in which the metal bellows and the fixed ring are interposed between a rotating ring, and the following function is provided on the fixed ring side to stabilize the sealing function.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG.
A sleeve airtightly fitted around the outer periphery,
The rear end (right end in the figure) is bent in the outer radial direction and further toward the distal end, and the rotating ring 3 is supported on the outer periphery of the sleeve 1 . Furthermore, the cylindrical portion 1a of this sleeve 1 is formed with a slightly smaller diameter at the center 1b from the tip to the rear end.
b, and is press-fitted onto the rotating shaft 2, and a sealing material 4 made of resin or rubber is provided on the inner circumferential surface between the central portion 1b and the rear end. 5 is a metal bellows whose tip is inserted and fixed to the opening edge of the shaft hole 7 of the casing 6 into which the rotating shaft 2 is inserted,
In the attached state shown in the figure, the length is shorter than the free length, and the fixed ring 8 attached to the rear end is pressed and brought into pressure contact with the rotating ring 3. a surface of the tip of the metal bellows 5 that comes into contact with the casing 6;
Seal members 9, 10, and 11 made of resin or rubber are provided on each of the surface of the rear end of the sleeve 1 that contacts the fixed ring 8 and the surface of the rear end of the sleeve 1 that contacts the rotating ring 3. Further, the tip of the sleeve 1 is bent in the outer diameter direction so that the leading edge thereof has a larger diameter than the inner diameter of the metal bellows 5.

In the mechanical seal having the above structure, the rotating ring 3 is fitted and fixed to the rotating shaft 2 via the sleeve 1, and the fixed ring 8 is configured to have a following function due to the elasticity of the metal bellows 5. Even under high-pressure conditions, the mechanical seal does not exhibit large vibrations and exhibits a stable sealing function, and has the following characteristics.

It is easy to select the balance value. In other words, conventional mechanical seals have a balance value of 100%.
In order to achieve the following, it was necessary to perform processing such as providing a step g on the rotating shaft c as shown in Fig. 1, but by using the bellows 5, the inner diameter dimension of the bellows 5 can be changed. The balance value can be easily changed by

Since the tip of the sleeve 5 is bent in the outer diameter direction and the bellows 5 and the fixed ring 8 are interposed between the tip and the rotating ring 3, the mechanical seal is made into one unit, which makes it easy to handle. Also, it is possible to prevent foreign matter and floating dust from adhering to the sliding surface.

Furthermore, regarding the stability of the sealing function described above, the following tests were conducted and the results are shown in the graph of FIG.

≪Conditions≫ Number of revolutions: 1000, 2000, 5000 and 10000rpm Pressure P: 8Kg/ ^cm2G Temperature T: 40℃oil Time H: 100Trs each ≪Graph≫ The graph in Figure 3 shows the
It shows the amount of leakage over time, where the "x" mark is the conventional product and the "〇" mark is the invented product.

As is clear from this test result, the mechanical seal of the present invention has a sleeve 1 and a rotating ring 3.
Since the weight balance on the rotating side is good, the amount of leakage can be kept low even during high speed rotation (5000, 10000 rpm).

As explained above, the mechanical seal of this invention not only stabilizes the sealing function under high-speed and high-pressure conditions, where conventional products had shortcomings, but also simplifies the selection of balance values and prevents damage to sliding surfaces. The practical effects of the present invention are extremely large. The seal members 4, 9, 10, and 11 in the above embodiments may be coated with resin or rubber material, or may be solid bodies.

[Brief explanation of drawings]

Fig. 1 is a half-cut sectional view showing an example of a conventional mechanical seal, Fig. 2 is a half-cut sectional view of a mechanical seal according to an embodiment of the present invention, and Fig. 3 is a comparison of the amount of leakage between the conventional product and the product of the present invention. It is a graph showing the test results. 1... Sleeve, 2... Rotating shaft, 3... Rotating ring, 4, 9, 10, 11... Seal material, 5... Metal bellows, 6... Casing, 7... Shaft hole, 8
...Fixed ring.

Claims (1)

[Scope of utility model registration request] The rear end of the sleeve that is airtightly attached to the rotating shaft is bent to support a rotating ring on the outer periphery of the sleeve, and a tip is provided near the opening edge of the shaft hole of the casing into which the rotating shaft is inserted. A fixed ring is attached to the rear end of the metal bellows to be fixed, and the tip of the sleeve is bent approximately in an outer diameter direction, and the metal bellows and the fixed ring are interposed between the tip and the rotating ring. Features mechanical seal.