JPS58124866A - Magnetic fluid seal - Google Patents

Abstract

PURPOSE:To facilitate the assemblage of a seal and prevent the seal from deformation due to swelling and disturbance, by pressing fixedly a magnetic liquid impregnated member along the outer wall of a magnet member with a righting moment of an outer peripheral annular elastic body due to elastic deformation. CONSTITUTION:When an annular elastic body 16 is attached by elastic deformation, a magnetic fluid impregnated member 15 is pressed against the outer peripheral wall of a magnet member 12 to be firmly fixed thereto. Then, an annular elastic body 16 is expanded and fitted after the insertion of said member 15 to simplify extremely the assemblage. When magnetic fluid is filled between the outer peripheral wall of the magnet member 12 and the annular elastic member 16, the magnetic fluid leaches into and remains in a space formed by the magnetic fluid impregnated member 15. Namely, said member 15 serves to hold the magnetic fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a magnetic fluid seal that seals between a fixed shaft and a rotating body of a device or the like having a rotating body that rotates around a fixed shaft.

Problems with the Prior Art Conventionally, as shown in FIG. 1, this type of magnetic fluid seal has a fixed shaft 2 fixed to a housing 1, a permanent magnet 3 having a substantially cylindrical shape such as a complete cylinder or a polygon, and a permanent magnet 3 having a substantially cylindrical shape such as a complete cylinder or a polygon. An annular yoke (hereinafter abbreviated as yoke) 4a that sandwiches the permanent magnet 3 from both sides and has an outer diameter larger than the outer diameter of the permanent magnet 5.
, 4b are added, and the space between the fixed shaft 2 and the yokes 4a and 4b is made airtight with adhesive or an O-ring, etc., and the yaw j'
4 (Insert the rotating body 5 made of ferromagnetic material such as steel while maintaining a small gap with the outer periphery of L, 4b, and rotate the permanent magnet 6 → yoke 4a → rotating body 5 → yoke 4b → permanent magnet 6. By forming a magnetic circuit in the rotating body 5 and the yokes 4a, 4b, and holding the magnetic fluids 6a, 6b filled in the small gaps between the rotating body 5 and the yokes 4a, 4b, the rotating body 5 and the yokes 4a can be connected to each other.

4b is completely sealed.

Since the m injection fluid is a colloidal bath liquid in which magnetic powder is suspended in a solvent, the solvent evaporates after long-term use and the sealing performance deteriorates. Therefore, the outer circumference of the permanent magnet 3 and the yokes 4α, 4b
Impregnated material 7 as a replenishing magnetic fluid holding member in which a magnetic fluid seal is impregnated into the space formed between the oIl11 surface
It is a self-supplying type. Porous sintered metal, porous metal material, felt, etc. are used as the impregnating material, but porous sintered metal is difficult to cut and must be fixed with adhesive to the yokes 4α and 46 during assembly. As a result, it was difficult to process and assemble, and there were also drawbacks such as adhesive parts peeling off due to vibrations caused by rotation.

Porous polymer materials have drawbacks such as poor dimensional accuracy and the risk of swelling and coming into contact with rotating bodies when used for a long period of time. Felt also has disadvantages such as poor dimensional accuracy and the fact that its fibers separate and contaminate the surrounding area.On the other hand, instead of self-replenishing using impregnated materials, magnetic Some systems have been designed to supply water from the outside, but they have drawbacks such as a complicated structure, high production costs, and regular maintenance costs.

Purpose of the Invention The present invention has been made to improve the above-mentioned drawbacks.The purpose of the present invention is to make it possible to easily assemble a magnetic fluid holding member for replenishment, and to prevent the material from changing or deteriorating over a long period of time. The goal is to make sure that there is no such thing. Examples will be explained in detail below.

Embodiment of the Invention FIG. 2 is a perspective sectional view showing essential parts of an embodiment of the invention, in which 111 is a fixed shaft, 12 is a cylindrical magnet member, 1311
．． 136 is an annular yoke disposed closely on both sides of the magnet member 12, and the magnet member 12 and the yoke 1
3cL, 136 is fixed to the fixed shaft 11 through the back plate 14 or directly in a bundling condition. Furthermore, a rotating body made of ferromagnetic material (
(not shown) is inserted, and this minute gap is filled with magnetic fluid. The magnet member 12 includes yokes 13G, 13
If the magnetic flux passing through the small gap between 6 and the rotating body is sufficient to hold the magnetic fluid in the small gap, it is not necessary to use permanent magnets entirely, for example, ferromagnetic material and permanent magnets. It is also possible to form a sandwich shape with a permanent magnet, and only a part thereof may be a permanent magnet, and the shape is not completely cylindrical, but may be approximately cylindrical, such as a regular polygon. Reference numeral 15 denotes a magnetic fluid-containing member made of a corrugated band-shaped plate of plastic, metal, etc., which is inserted into the space between the yokes 158 and 156 along the outer cylindrical wall of the magnet member 12. There is. Reference numeral 16 denotes a ring-shaped elastic body made of a band-shaped member of plastic (e.g., nylon), metal (e.g., stainless steel, phosphor bronze), etc., which has sufficient elasticity, and presses the magnetic fluid containing member 15 toward the center. .

When the annular 511111 body 16 is elastically deformed and attached, the magnetic fluid containing member 15 is pressed against the outer peripheral wall of the magnet member 12 and is firmly fixed in that position. After inserting the magnetic fluid-containing member 15 in this way, the annular elastic body 16 can be extended and fitted to make it stand upright, so assembly is extremely simple. When the magnetic fluid is filled between the outer circumferential wall of the magnet member 12 and the annular elastic member 16, the magnetic fluid seeps into the cavity formed in the magnetic fluid containing member 15 and stays there. That is, the magnetic fluid containing member 15 has the function of holding the magnetic fluid.

Fig. 6 is a cross-sectional view of a main part of another embodiment of the present invention, in which a wavy magnetic fluid containing member 15 is wound in a plurality of circles, and a ring-shaped 51! The L-shaped member 16 is elastically deformed and inserted.

Further, FIG. 4 is a side view of still another example of the present invention, in which one turn each of the magnetic fluid containing member 15 and the annular elastic body 16 are alternately inserted.

In FIGS. 3 and 4, the same reference numerals as in FIG. 2 represent the same parts.

5th and 1 to 9 are perspective views showing other examples of the magnetic fluid containing member 15, in which -17 in the width direction is arranged in a row, and FIG. is lengthwise @18
Figure 7 shows one with many mound-shaped protrusions 19, and Figure 8 shows one with many hollows 20 shaped like ゛\1.
The phase-breaking member 15 is not limited to the above example, and may be any material as long as it has the function of holding a magnetic fluid, and felt or the like may also be used. Further, the number of 150 layers of the magnetic fluid-containing member may be appropriately selected so that only the necessary amount of magnetic fluid can be held. Magnetic fluid containing member 15 and annular elastic body 16
can be manufactured extremely easily by pressing, etching, etc.

When the magnetic shingles held in the gap between the rotating body and the yokes 13G and 13b evaporate into the outside air, leakage occurs in the gap 41
The replenishing magnetic fluid held by the magnetic fluid collecting cylinder/material is drawn into the gap by the force of the magnetic lines of force of the fi flux. Since the replenishing magnetic fluid is automatically supplied to the sealing portion in this way, even if the magnetic fluid evaporates, complete ball performance can be maintained for a long period of time.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention involves pressing an aphrodisiac fluid-containing member and a magnetic fluid-containing member inserted into the outer circumferential wall of a magnet member against the outer circumferential wall of the magnet member to firmly secure the member. Since the annular elastic body and the Oa flow for replenishment are easy to fix, there is an advantage that a magnetic fluid seal that can maintain accuracy for a long period of time can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a perspective sectional view of a conventional example, FIG. 2 is a perspective sectional view of an embodiment of the present invention, FIGS. 6 and 4 are sectional views of other different embodiments of the present invention, and FIG. 9 to 9 are perspective views showing different shapes of magnetic fluid-containing members, respectively. 1 is a housing, 2-1 is a fixed shaft, 3 is a permanent magnet, 4G
, 46, 138, 136 are yokes, 5 is a rotating body, 6cL
. 6b is an ah fluid, 7 is an impregnation material, 12 is a magnet member, 14 is a back plate, 15 is a magnetic fluid containing member, and 16 is an annular elastic body. Patent Applicant Japan Telegraph Telephone Public Corporation Patent Attorney Hisashi Tamamushi Department (3 others) Figure 1 Figure 2 Figure 3 Figure 14 Figure 5

Claims (1)

[Scope of Claims] t Annular yokes are disposed facing each other in contact with both ends of a magnet member fixed by passing the page through a fixed shaft, and an inner wall is circularly connected to the outer periphery of the block-shaped yoke disposed oppositely through a minute gap. A planar rotating body is disposed, the minute gap is sealed with a magnetic fluid, a replenishment magnetic fluid holding member is disposed in the space formed between the magnet member and the annular yoke, and the replenishment magnetic fluid is In the magnetic fluid seal configured such that the magnetic fluid held by the holding member is supplied to the minute gap, the replenishing magnetic fluid holding member is configured to move the magnetic fluid containing member along the outer peripheral wall of the magnetic member. A ring-shaped elastic body is elastically deformed and inserted around the outer circumference of the magnetic fluid containing member, and the magnetic fluid containing member is attached to the outer wall of the magnet member by the restoring force of the elastic body against the elastic deformation. A magnetic fluid seal characterized in that it is configured to be suppressed and fixed. 2. The magnetic fluid seal according to item 1, characterized in that the magnetic fluid containing member is a band-shaped member having an uneven surface.