JPS6322373Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a mechanical seal device.

The mechanical seal device shown in FIG. 1 is for the stern tube, and is designed to prevent seawater from entering the ship interior 23 from the space 24 outside the rotating shaft, that is, the propulsion shaft 4. This mechanical seal device includes a fixed casing 2 having a first cylindrical portion 2a surrounding a rotating shaft 4 and fixed to a stern tube end surface 1, and a rotating ring 5 fitted to the rotating shaft 4.
and a driven ring 3 having a second cylindrical part 8 surrounding the rotating shaft 4, loosely engaged with the first cylindrical part 2a, and forming an annular gap 25 therebetween. It is equipped with Further, the driven ring 3 is loosely fitted onto a fixed rod 20 extending parallel to the rotating shaft 4, biased to the right by a spring 22, and fixed to the driven ring 3. A seal ring 7, which forms part of the rotating ring 5, is fixed to the rotating ring 5 and is in pressure contact with a seal ring 6, which forms a part of the rotating ring 5. Further, an annular packing 10 is installed in an annular gap 25 between the first cylindrical portion 2a and the second cylindrical portion 8. Seal rings 6 and 7 above
constitute a mechanical seal portion that is in surface contact with each other in a sealing relationship, and prevents seawater from entering the inside of the ship 23. The seal 10 also functions to prevent seawater from entering the ring ring.

In the mechanical seal device of the above-mentioned type, the driven ring 3 is pressed against the rotating ring 5 by the spring 22, but
When the rotating ring 5 moves left and right together with the rotating shaft 4, the driven ring 3 follows the movement and expands and contracts the spring 22 while smoothly moving left and right along the fixed rod 20. It is desirable that the mechanical seal portions between the rotary ring 3 and the rotary ring 5 are always brought into good surface contact.

FIG. 2 shows a packing 10' conventionally used in the above-mentioned mechanical seal device. This packing 10' is a rubber-like elastic body consisting of a base 11 and a seal lip 12 that projects radially outward from the base 11. It is installed in the annular gap 25 so as to be in pressure contact with the inner circumferential surface of the cylindrical portion 2a. When mounted, a fairly large gap is formed between the outer periphery 11a of the base 11 and the outer periphery of the annular gap 25. Therefore, depending on the movement of the rotating shaft 4, a predetermined amount or more in the radial direction (the first A relative displacement occurs between the fixed rod 20 and the driven ring 3 (in the vertical direction in the figure).
There is a problem in that friction may occur in the loose portion between the fixed rod 20 and the smooth movement of the driven ring 3 along the fixed rod 20. Furthermore, there is a problem in that the tightness of the seal lip portion 12 increases or decreases drastically in response to the above-mentioned relative displacement, which may cause early damage to the seal.

The object of the present invention is to provide a mechanical seal device that solves the above problems by improving the seal.

Figures 3 and 5 show an example of the packing 10 used in the present invention, Figure 1 shows a mechanical seal for a stern tube using this packing 10, and Figure 4 shows an enlarged view of the main parts. This is what is shown. The packing 10 used in the present invention, like the conventional packing 10', has a base 11 that fits into the inner circumferential surface of the annular gap 25 (i.e., the outer circumferential surface of the second cylindrical part 8 in FIG. 1), and A seal lip portion 12 protrudes radially outward from the base portion 11, and a support portion 13 protrudes radially outward from the base portion 11.
It is equipped with The outer diameter of the support portion 13 is smaller than the outer diameter of the lip edge 16 of the seal lip portion. As is clear from FIG. 4 showing the state in which the packing 10 is attached to the groove 9 provided on the outer circumferential surface of the second cylindrical portion 8 of the driven ring 3, the outer circumferential surface of the support portion 13 and the annular gap 25 (i.e. In Fig. 4, the first cylindrical part 2
The gap H between the inner circumferential surface 14) of a and the inner peripheral surface 14) is smaller than that of a conventional packing. This support part 13 serves as a load receiver when a relative displacement occurs in the radial direction between the first cylindrical part 2a and the second cylindrical part 8, and suppresses the relative displacement to a small value below a predetermined amount to form an annular shape. This brings about the effect of always maintaining the tightness of the seal lip portion 12 appropriately between the outer peripheral surface of the gap and the outer circumferential surface of the gap. Moreover, by suppressing the relative displacement to a small value, it is possible to always make the movement of the driven ring 3 along the rod 20 smooth, and to always maintain good sealing between the seal rings 6 and 7. It brings about the effect of

Figure 5 shows the packing 1 used in this invention.
Another example of 0 is shown. In this example, a self-lubricating ring 15 is embedded in the base 11 of the packing, and its tip is used as the support 13. Therefore, even when the first cylindrical part 2a contacts the support part 13 of the ring 15 during operation, it can slide smoothly and, as described above, can support the load.

Although the mechanical seal device in the above embodiment is for a stern tube, the present invention is not limited thereto.

[Brief explanation of the drawing]

FIG. 1 is an axial sectional view of a mechanical seal device according to an embodiment of the present invention, FIG. 2 is an axial sectional view of a conventional packing, and FIG. 3 is an axial sectional view of a packing used in the above embodiment. FIG. 4 is an enlarged sectional view of the main part of FIG. 1, and FIG. 5 is a sectional view showing another example of the packing used in the present invention. 2... fixed casing, 2a... first cylindrical part,
3... Driven ring, 4... Rotating shaft, 8... Second cylindrical part, 10... Packing, 11... Base, 12...
...Seal lip portion, 13... Support portion, 16... Lip edge, 20... Fixed rod, 22... Spring, 25... Annular gap, H... Gap.

Claims (1)

[Scope of utility model registration request] A fixed casing 2 having a first cylindrical part 2a surrounding the rotating shaft 4, a rotating ring 5 fitted to the rotating shaft 4, and a first cylindrical part 2 surrounding the rotating shaft 4.
a, and an annular gap 2 between the first cylindrical part 2a and the first cylindrical part 2a.
a driven ring 3 having a second cylindrical portion 8 forming a shaft 5, the driven ring 3 being slidably engaged on a fixed rod 20 extending parallel to the axis of rotation 4; It is urged by a spring 22 to be brought into pressure contact with the rotating ring 5, and the pressed part becomes a mechanical seal part that makes surface contact with each other in a sealing relationship. Packkin 10 is installed, and this Packkin 10
However, the base 1 fits into the inner peripheral surface of the annular gap 25.
1 and an annular gap 2 protruding radially outward from the base.
between the seal lip part 12 having a seal edge 16 at the tip that is in close contact with the outer circumferential surface of the annular gap 25 and the outer circumferential surface of the annular gap 25 which projects radially outward from the base and has a smaller diameter than the seal lip part 12. It has a support part 13 that forms a minute gap H, and a relative displacement of a predetermined amount or more in the radial direction between the first cylindrical part 2a and the second cylindrical part 8 is caused between the support part 13 and the annular part 8. A mechanical seal device characterized in that it is configured to be prevented by engagement with the outer circumferential surface of the gap 25.