JPS58131474A - Sealing device - Google Patents

Abstract

PURPOSE:To provide high reliability sealing in a sealing device for a rotary shaft by interposing magnetic fluid between the thrust surfaces of a rotor and a non-rotor with a permanent magnet being fixed to either the rotor or non- rotor. CONSTITUTION:A disk-like projection 9 is fixed to a rotary shaft 8 and its thrust surface is opposed to a thrust surface of a housing 10. A ring-like permanent magnet 11 is fixed to the surface of the non-magnetic housing 10 to form a predetermined gap C between the magnet 11 and the projection 9. This permanent magnet 11 is magnetized annularly on the magnetic surface to generate 1 or plurality of magnetizing number. And magnetic fluid is interposed in the gap C between the projection 9 and the permanent magnet 11 for sealing. In the assemblage when a predetermined amount of magnetic fluid is applied on the surface of the permanent magnet 11, the magnetic fluid 12 is attached circularly or concentrically so that the magnetic fluid is not attached to the rotary shaft 8 when it is inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for maintaining a pressure difference between a first region and a second region, or for maintaining a pressure difference between a first region and a second region in a device having a rotating shaft.
The present invention relates to a sealing device that seals the flow of liquid or gas to and from a region.

A conventional sealing device of this kind, for example, as shown in FIG.
The structure is such that a magnetic fluid 6 is interposed in the gap between the rotating shaft 1 and the yokes 3 and 4, which are formed by fixing a magnetic circuit formed by the above to the outer housing 5.

According to such a configuration, if the rotating shaft 1 and the yoke 3.degree. 4 are not concentric, the sealing pressure when the rotating shaft 1 rotates will decrease. In addition, to improve the sealing effect,
As a result of the small spacing between the magnetic shaft 1 and the yoke, it is often difficult to inject the magnetic fluid later when assembling this device, that is, when inserting the rotating shaft 1 into the magnetic circuit. Therefore, as a result of inserting the rotating shaft 1 after applying the magnetic fluid into the magnetic circuit, the magnetic fluid ends up adhering to the rotating shaft 1. Therefore, it is often difficult to determine whether the amount of magnetic fluid present in the gap is appropriate until the device is actually operated, resulting in a drawback of reduced reliability. In order to further improve the degree of sealing, it is possible to consider an apparatus that forms a plurality of voids, but this has the drawback of increasing the number of processing steps required to form the voids.

In view of these points, the present invention provides a high degree of sealing without wasting the magnetic fluid when inserting the one-rotation shaft into the gap, and without increasing the number of processing steps to improve the degree of sealing, while also facilitating assembly work. The main purpose is to propose this type of sealing device that can

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 12 is a longitudinal sectional view showing an example of the present invention. 8 is a rotating shaft, and 10 is a housing. A disk-shaped convex portion 9 is formed integrally or separately on the rotating shaft 8 . When formed separately, the convex portion 9 is fixed to the rotating shaft 8. The side surface (thrust surface) of the protruding portion 9 is made to correspond to the side surface (thrust surface) of the nozzle 10. A ring-shaped permanent magnet 11 is fixed to the surface of the non-magnetic housing 10, and a predetermined gap C is formed between the permanent magnet 11 and the protrusion 9.
is formed. In this case, the magnetic surface of the permanent magnet 11 is magnetized in an annular shape. The number of magnetizations can be one or more. A magnetic fluid is interposed in the gap C between the convex portion 9 and the permanent magnet 11.

When the rotating shaft 8 is assembled into the housing 10.

When the magnetic fluid of the device is applied to the magnetized surface of the permanent magnet 11,
Since the magnetic fluid 12 adheres in a circular or concentric form, the magnetic fluid does not adhere to the rotating shaft 8 when the rotating shaft 8 is inserted thereafter.

FIG. 3 is a longitudinal sectional view showing another example of the present invention. In this example, a yoke 14 made of a soft magnetic material is provided on the opposite side of the magnetic pole of the permanent i-stone 11 and fixed to the nozzle 10.

Permanent magnets exhibit the following effects when using magnets that are anisotropic in the thickness direction. By providing the yoke 14, the magnetic field strength in the gap C can be increased. In this case, by setting the number of magnetizations of the permanent magnets 11 to be plural, the sealing effect by the magnetic fluid 12 can be further enhanced.

FIG. 4 is a longitudinal sectional view showing still another example of the present invention. In this example, the yoke 14 fixed to the permanent magnet 11 is formed into a cross-sectional shape. That is, the soft magnetic pole piece is formed to extend from the outer periphery of the yoke into a cylindrical shape, so that a surface that is the same as the thrust surface of the permanent magnet 11 is formed. Therefore, the magnetic circuit-h of the convex portion 9, the permanent magnet 11, and the yoke 14;
Thus, the magnetic fluid 12.17 is present in the gap between the protrusion 9 and the permanent magnet 11 and the gap C between the protrusion 9 and the yoke 14. A reserve quantity of magnetic fluid 12,17 can be stored in an annular recess 13 formed between the permanent magnet 11 and the yoke 14.

FIG. 5 is a longitudinal sectional view showing still another example of the present invention. In this example, a permanent magnet 11 and a yoke 14 are installed between a fixed central shaft 21 and a rotating housing 22 in the same manner as described above, and this example is suitable for application to an outer rotor motor, for example. . Of course, the permanent magnet 11 and the yoke 14 may be fixed to the rotating housing 22 in a manner other than that shown in the drawings.

FIG. 6 is a sectional view showing still another example.

23, a concentric annular groove 23 on the surface corresponding to the convex portion 9 side
A indicates a permanent magnet formed of one or more. Annular groove 23a
A magnetic pole is formed on each convex surface 23b formed between the two. Similar to the example in FIG. 5, the magnetic fluid 12 can be stored in the annular groove 23a. Of course, yokes can also intervene.

As described above, according to the present invention, a permanent magnet fixed to the rotating body or the non-rotating body is provided between the thrust surface of the rotating body and the thrust surface of the non-rotating body, and the permanent magnet is attached to the thrust surface of the rotating body. The structure has magnetic pole faces facing each other, and magnetic fluid is interposed in the gap between the rotating body or non-rotating body and the permanent magnet, so that the difference in diameter between the rotating body and the permanent magnet can be minimized. Since the degree of sealing can be maintained without changing the value, there is no need to make the inner diameter of the hole for penetrating the shaft of the permanent magnet needlessly strict, and therefore, the number of processing steps can be reduced.

In addition, in order to increase the degree of sealing, it is necessary to use multiple stages, but this can be easily solved by using an anisotropic magnet that is magnetized in the thickness direction. obtain.

Furthermore, when trying to fit the rotating body and the non-rotating body, there is no loss of magnetic fluid, so the seal can be faithfully produced by calculating the amount of magnetic fluid inserted, making this type of highly reliable product A sealing device can be obtained. In addition, since there is no adhesion of magnetic fluid, the fitting operation can be made easier.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the conventional method, FIG. 2 is a sectional view showing an example of the medicinal tree invention, and FIGS. 3, 4, 5, and 6 each show other examples of the present invention. FIG. 8... Rotating shaft, 9... Convex portion, 10... Housing, 11... Permanent magnet, 12... Magnetic fluid, 14...
...Yoke, 21...Fixed shaft, 22...Rotating nozzle. Agent Rishi Akiyama Takashi Akiyama Figure 1 Figure 2 Figure 3 rEJ /2 Figure 4 2 7

Claims (1)

[Claims] 1. A permanent magnet fixed to the rotating body or the non-rotating body is provided between the thrust surface of the rotating body and the thrust surface of the non-rotating body, and the permanent magnet is attached to the thrust surface. 1. A sealing device having opposing magnetic pole surfaces, wherein a magnetic fluid is interposed in a gap between the rotating body or non-rotating body and the permanent magnet. 2. The sealing device according to claim 1, wherein the magnetic pole faces of the permanent magnet are formed in a plurality of annular shapes. 3. The method according to claim 1 or 2, wherein a soft magnetic pole piece is provided between the rotating body or non-rotating body and the permanent magnet fixed to the rotating body or non-rotating body. Sealing device. 4. Claims in which the soft magnetic pole piece is extended to be flush with the permanent magnet, and the magnetic fluid is interposed in a gap between the soft magnetic pole piece and the rotating body or the non-rotating body. The sealing device according to paragraph 3.