JPS5947566A - Shaft seal device employing magnetic fluid - Google Patents

Abstract

PURPOSE:To improve the sealing performance by providing a brush-shaped sealing section on at least one of the rotor side or magnetic pole side in the portion of a rotary shaft to be sealed thereby reducing the gap between the rotor side and the magnetic pole side and preventing damage at the seal section. CONSTITUTION:Magnets 6 are arranged into a ring between two pole pieces 4, 5 formed into a ring, and assembled in a stuffing box 3 coaxially with a rotary shaft 1. A seal section 11 is provided at the portion in the vicinity of the outercircumferential face of rotary shaft 1 of two pole pieces 4, 5 or the outercircumferential face of a sleeve 2 to encapsulate magnetic fluid 12 into a gap formed by the seal section 11 and the outercircumferential face of the rotary shaft 1. Here the seal section 11 is formed with a brush body 11' and a spacer 11'' into a brush. The brush body 11' is formed by laminating a plurality of thin steel plates having thin-cut inner diameter side then welding at the outercircumferential section.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft sealing device using magnetic fluid.

A conventional shaft sealing device using a magnetic fluid has, for example, a configuration 11 shown in FIG. 3 is a sleeve, 3 is a stuffing box, 4 and 5 are magnetic pole pieces, 6 is a magnet, 7 and 8 are 01J rings, 9 is a comb-shaped seal portion, and 10 is a magnetic fluid. That is, the conventional magnetic fluid shaft seal device has a magnet 6 between two (pair) ring-shaped magnetic pole pieces 4 and 5.
Arrange them in a ring shape and repeat this step 1. In the stuff ink box 3, there are embossed on the rotation III 11 and the side core. The two magnetic pole pieces 4 and 5 have a plurality of 13. 9 grooves are machined, 111, and the seal part 9 has a comb-shaped cross section.

A gap S formed between this seal portion 9 and the outer peripheral surface of the rotating shaft
The magnetic fluid 10 is confined in the magnetic fluid 10, and a fluid film is formed by the action of the magnet, resulting in a sealing effect, but the sealing performance depends on the strength of the fluid film. Since the strength of the fluid film is determined by the difference in magnetic flux density within the fluid film, the smaller the 8fJ gap S, the better the sealing performance. That is, the sealing performance of the magnetic fluid shaft seal can be greatly improved by the technique of reducing the gap S. However, in general industrial machines, there are many problems in reducing the gap Sf, such as radial displacement or vibration of the shaft, and limitations on machining accuracy when the diameter becomes large.

The present invention can be used not only for small diameter shafts but also for human [
The purpose of the present invention is to provide a shaft sealing device using a magnetic fluid, which allows the sole gap to be extremely small even in the case of a single diameter shaft, and which has a structure that does not impair sealing performance even when the shaft moves in the radial direction. That is.

For this reason, the +4
The structure is characterized by the fact that the rotating body has a part of the rotary shaft that should be sealed, and that one of the magnetic poles is provided with a brush part.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 7.

FIG. 2 shows a first embodiment of the present invention, in which A and B and 1 to 8 are the same as in FIG. and,
Reference numeral 11 represents a brush-shaped sole portion to be described later, and reference numeral 12 represents a magnetic fluid.

In other words, in the case of Figure 2, the major difference from the conventional one is the magnetic pole)! Brush type sole part 1 on the inner diameter surface of I4 and 5
1 was established. And the brush-shaped seal part 11
As shown in an enlarged view in FIG.
1' as shown in FIG. 4 or 5 or 6.

A thin steel plate with an inner diameter of 111.11 mm cut into a thin piece,
It is made up of multiple sheets stacked one on top of the other and welded around the outer periphery. Of course, the shape of the cut at the inner diameter 111.11 of the thin steel plate can be made into an appropriate shape depending on the conditions, and it is also effective to combine the same shape or different shapes. Further, the brush body 11' can also be constituted by a collection of thin wires. In particular, by making the bluff body 11' have a shape that is not straight in the radial direction, as shown in Fig. 5 and Fig. 6, it will rotate when subjected to the action of the lines of force. It is displaced in the direction in which the gap with the outer periphery (see S in FIG. 6) becomes smaller.

As shown in Figure 2, even if the plurality of brush-shaped seals 11 provided on the inner diameter surfaces of the magnetic pole pieces 4 and 5 come into contact with the outer circumference of the rotating shaft (the outer circumference of the sleeve 2 in FIG. 2), the brush body The easy deformation of the parts 11' will not damage each other and will not impair the /-ru performance. Therefore, since the brush body 11' is easily deformed, there is no need to strictly limit the inner diameter dimension of the bluff body 11' during manufacture. In this way, rotation l1l1
Even if there is deformation in the radial direction of 111 or large shaft vibration, the sole performance will not be impaired, and even when applied as a large-diameter sealing device, it will not be subject to limitations due to processing accuracy. There is no.

FIG. 7 shows a second embodiment of the present invention. That is, although FIG. 2 shows the case of the cylindrical sole of the sleeve 2 as a rotating body attached to the rotating shaft 1,
As shown in FIG. 7, the same thing holds true in the case of the end face seal of the rotating disk 16 as a rotating body attached to the rotating shaft 1.

As mentioned above, the shaft sealing device using magnetic fluid is an interesting invention.
is equipped with a plano-shaped sealing part on either the rotating body side of the part of the rotating shaft that should be sealed or on one side of the magnetic pole.
The gap between the rotating body side and the magnetic pole piece ll1ll can be made extremely small, therefore, 1III11]
``Even if it comes into contact with the ribs, etc., it will not receive any scratches and the sole properties will not deteriorate.Also, the machining accuracy can be improved even for a 1-diameter shaft.'' Since it is not subject to the limitations of thickness, it does not have the problem of use due to the thickness of It is fire.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing two halves of a conventional magnetic fluid shaft sealing device. Figure 2 is a first embodiment of the present invention.
Figure 6 is a side view showing an enlarged view of the brush-shaped seal part in Figure 2, Figure 4 is
The figure is a partial front view showing one aspect of the brush body in FIG. 6, FIG. 5 is a partial front view showing another aspect, and FIG. 6 is a partial front view showing another aspect. FIG. 7d is a cross-sectional side view of the upper half of the second embodiment of the wooden invention. 1...1 rotation shaft, 2...sleeve, 4, 5...
・(1 piece of straightness, 6... Ishield stone, 11...)゛/shape/-ru part, 11'... Fla/, 12... Magnetic human fluid, 16... Rotating circle Board.

Claims (1)

[Claims] 1. A shaft sealing device using a magnetic fluid, characterized in that a brush-shaped seal portion is provided on either the rotating body side of the portion of the rotating shaft that should be closed or one side of the magnetic pole.