JPH0547901Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a shaft sealing device equipped with a double type mechanical seal, such as a submersible pump.

[Prior Art] Conventionally, in this type of shaft sealing device, as shown in FIG. To seal the inserted rotating shaft 4, a mating ring 5, which is a fixed sliding contact ring, is fitted to each of the upper and lower housings 1 and 2 through a cup gasket 6 and a case 7. A seal ring 8, which is a rotating sliding ring, is arranged on the sliding surface side of the bearing ring 5, and a rubber bellows 10 is fixed to the seal ring 8 by a drive ring 9.
and the seal ring 8 are fixed to the periphery of the rotary shaft 4 by a driving case 11 that holds the outer periphery of the abutting portion of the seal ring 8 and prevents them from rotating. A common coil spring 13 is interposed between the driving cases 11, 11 of the upper and lower seal assemblies 12, 12, which are arranged symmetrically in the axial direction, with an appropriate clearance a between them. It has a structure in which the shaft is sealed with a double type mechanical seal that is pressed in the axial direction by force.

[Problem to be solved by the invention] However, in the shaft seal device of the conventional structure described above, since mechanical seals are used especially for both the upper and lower seals, the engagement dimension between the seals is
There were problems in that not only did _L0 become longer and larger, but the number of assembled parts increased, which inevitably led to higher costs.

[Purpose of the invention] The present invention was made under the above circumstances, and its purpose is to provide a shaft sealing device that can be made compact and cost-reduced. It is in.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention has been developed so that the peripheries of the rotating shafts inserted into the oil bath between the upper housings on the motor chamber side and the lower housings on the pump chamber side are The shaft sealing device includes a double-type mechanical seal for sealing, and the upper mechanical seal has a mating ring that slides into contact with the back of a seal case that backs up the lower mechanical seal, and the mating ring is attached to the motor chamber side housing. The mating ring is fixed to the mating ring through an elastic body made of closed-cell porous plastic, and in this case, a ceramic coating may be applied to a part of the back surface of the seal case where the mating ring slides. preferable.

[Function] That is, in the present invention, by having the above configuration, the upper mechanical seal on the motor chamber side can
A seal case consisting of a combination of a mating ring and an elastic body made of closed-cell porous plastic that fixes the mating ring to the motor chamber side housing, and whose sliding surface backs up the lower mechanical seal. Since the rear surface is arranged on the back side, the overall cost is reduced, and the connecting dimensions between the seals are shortened, making it possible to achieve compactness.

In addition, ceramic coating is applied to a portion of the back surface of the seal case where the mating ring slides, which prevents deterioration of seal performance due to wear on the sliding surface.

[Example] The present invention will be described below with reference to an example shown in FIG. In the illustrated embodiment of the present invention, parts having the same structure as those of the conventional shaft sealing device shown in FIG. 2 will be described using the same reference numerals.

That is, in the present invention, as shown in FIG. 1, the lower seal on the pump chamber B side is a mechanical seal assembly part 12 as shown in FIG. 20
is composed of a mating ring 21 and an elastic body 22 made of closed-cell porous plastic (closed cell) that fixes this mating ring 21 to the motor chamber A side housing 1, and this mating ring 21 is assembled in sliding contact with the back surface of a seal case 23 that backs up the seal assembly part 12 of the mechanical seal constituting the lower seal on the pump chamber B side. This makes it possible to make the connecting dimension L shorter than the conventional one (L<L ₀ ). Further, reference numeral 24 in the figure is a ceramic coating applied on a part of the circumference of the back surface of the seal case 23 where the mating ring 21 slides. It is designed to press and slide due to its elasticity.

It should be noted that the present invention is not limited to the above-described embodiments in any way, and it goes without saying that various modifications can be made without changing the gist of the present invention.

[Effect of the invention] As is clear from the above description, according to the invention, the periphery of the rotating shaft inserted into the oil bath between the upper housing on the motor chamber side and the lower housing on the pump chamber side is sealed. The shaft seal device includes a double type mechanical seal, and the upper mechanical seal has a mating ring that slides into contact with the back of a seal case that backs up the lower mechanical seal, and this mating ring is attached to the motor chamber side housing independently. Since it is configured to be fixed via an elastic body made of porous plastic, the overall cost is reduced, and the joint dimensions between the seals can be shortened, making it more compact. can be achieved.

Furthermore, since a portion of the back surface of the seal case where the mating ring slides is coated with ceramic, it has the excellent effect of preventing deterioration of sealing performance due to wear of the sliding surface.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing an embodiment of a shaft sealing device according to the present invention, and FIG. 2 is a sectional view of a main part of a conventional shaft sealing device. DESCRIPTION OF SYMBOLS 1...Motor chamber side housing, 2...Pump chamber side housing, 3...Oil bath, 4...Rotating shaft, 12...Lower mechanical seal, 20...Upper mechanical seal, 21...Mating ring, 22 ...Elastic body (closed cell), 23...
...Seal case, 24...Ceramic coating.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A shaft sealing device consisting of a double mechanical seal that seals the periphery of a rotating shaft inserted in an oil bath between an upper housing on the motor chamber side and a lower housing on the pump chamber side, respectively. The upper mechanical seal is constructed by sliding a mating ring on the back surface of the seal case that backs up the lower mechanical seal, and attaching the mating ring to the motor chamber side housing using a holder made of closed-cell porous plastic. A shaft sealing device characterized in that it is configured to be fixed through the shaft. 2. The shaft sealing device according to claim 1, wherein a ceramic coating is applied to a portion of the back surface of the seal case in sliding contact with the mating ring.