JPS63303271A - Sealing device - Google Patents

Abstract

PURPOSE:To improve the sealing performance and reduce the labor for manufacture, etc., by fitting a sealing body formed integrally with a core metal and an elastic body onto one out of the inner and outer members which relatively revolve and holding the magnetic fluid by constituting magnetic circuit between the top edge of the extended core metal and other members. CONSTITUTION:A sealing body 20 consisting of an elastic body 23 formed integrally with an annular core metal 22 is fitted onto one out of the inner and outer rings 12 and 11 which relatively revolve, for example onto the outer ring 11, and a magnetic circuit is constituted of the top edge of the core metal 22 extended in the radial direction and the core metal 22 magnetized between the stepped part 12a of the inner ring 12, and the magnetic fluid is held. Therefore, the sealing performance can be improved by the magnetic fluid 35. Further, since the core metal 22 is installed onto the outer ring 11 through the elastic body 23 constituting the sealing body 20, the need of fitting the outer ring 11 and the sealing body 20 with the correct dimension accuracy is avoided, and the labor for manufacture, etc., can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sealing device used in equipment, equipment, bearings, etc. used in a highly clean atmosphere or in a vacuum.

<Prior Art> In general, conventional sealing devices for ball bearings have a structure in which grease, which serves as a lubricant sealed inside the bearing, is sealed by a contact type or non-contact type sealing member fixed to the outer ring of the bearing. It has become.

However, when a bearing equipped with such a sealing device is used as a bearing for equipment or equipment used in a highly clean atmosphere such as a clean room or in a vacuum, the sealing performance is not sufficient and the sealing property is not sufficient. Evaporated grease and scattered bones leak to the outside of the bearing and contaminate the atmosphere. Furthermore, in products that use contact type seal members, in addition to the above problems, abrasion powder is generated due to contact between the seal member and the inner ring of the bearing, and this scatters to the outside of the bearing and pollutes the atmosphere. It was also supposed to happen.

Therefore, recently, sealing devices that use magnetic fluid instead of conventional sealing members have been developed as sealing devices suitable for use in environments that require high cleanliness. - An example is shown in FIG.

This sealing device is called a three-piece type, and is magnetized in the axial direction with a small sealing gap left between the outer ring 41 and the inner ring 42 of the bearing 40. A seal main body 45 consisting of an annular magnet 43 and a pair of plate members 44 and 44 sandwiching the magnet is attached to the outer ring 1, and a magnetic fluid 46 is held in the seal gap. In addition, in the figure, the reference numeral 47 indicates a rolling element (ball) interposed between the outer ring 41 and the inner ring 42.
, 48 is a retainer for the rolling element 47, and G is grease.

A sealing device having this structure is characterized in that it has poor sealing performance compared to the conventional sealing member described above, and does not have the disadvantage of generating abrasion powder.

<Problems to be Solved by the Invention> However, the above-described sealing device that uses magnetic fluid for sealing also has the following problems.

That is, it is inevitable that the magnetic fluid 46 and the grease G will come into contact with each other and the grease G will be mixed into the magnetic fluid 46 due to agitation during rotation of the bearing, resulting in a decrease in the concentration of the magnetic fluid 46. Therefore, the pressure resistance of the seal gap portion sealed by the magnetic fluid 46 decreases, and the grease G leaks to the outside of the bearing 40. Furthermore, due to the structure, the axial width of the seal becomes longer, and the width of the bearing 40 to which the seal is attached, that is, the axial dimension becomes longer.

Further, in order to avoid such inconvenience, it is possible to configure the seal body 45 using an annular magnet 43 magnetized in the rotational radial direction, but if this is done, the bearing 4
The leakage magnetic flux passing through the space inside and outside of the seal increases, and the magnetic flux density between the inner ring 42 and the seal body 45, that is, the seal gap, decreases. Therefore, the required amount of magnetic fluid 46 cannot be held in this seal gap, and the grease G may leak to the outside of the bearing 40 or the magnetic fluid 46 may leak out of the bearing 40.
In some cases, G itself leaked and contaminated the atmosphere.

Furthermore, in all of these magnetic fluid sealing devices, the seal body 45 is directly attached to the outer ring 41 of the bearing 40, so in order to prevent grease leakage, both must be attached with precise dimensional accuracy. must be fitted. Alternatively, a seal bonding process using an adhesive is required. Therefore, manufacturing and assembling them has been troublesome and time-consuming.

The present invention has been made in view of such conventional problems, and aims to provide a sealing device that can improve sealing performance and reduce the labor required for manufacturing.

<Means for Solving the Problems> In order to achieve such an object, the present invention provides an annular core metal and an elastic core integrated with the core metal in one of the pair of inner and outer members that rotate relative to each other. At the same time, the core metal is magnetized along the rotational radial direction, and a magnetic field is formed between the leading edge of the core metal extending in the rotational radial direction and the other member side. It constitutes a circuit and holds a magnetic fluid between the leading edge of the metal core and the other member.

<Function> According to the above configuration, the core metal of the seal body itself is a magnet that is magnetized along the rotational radial direction, so even if a core metal with strong magnetic force is used, the axial dimension of the seal body becomes long. Never.

In addition, in this sealing device, since the core metal is attached to one member through the elastic body that constitutes the seal body, it is not necessary to fit this member and the seal body with exact dimensional accuracy, and manufacturing etc. The effort required for this is reduced.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. In this embodiment, a case will be described in which the sealing device is used in a bearing.

FIG. 1 is a partially omitted sectional view of a bearing showing a first embodiment of the present invention.

The reference numeral 10 in this figure is a bearing such as a ball bearing,
This bearing 10 is composed of an outer ring 11 as a first member, an inner ring 12 as a second member, rolling elements (poles) 13 and a cage 14 interposed between them. A circumferential groove 11a is formed at the end of the inner circumferential surface of the outer ring 11 over the entire circumference, while an annular step portion 12f1 is formed over the entire circumference at the outer circumferential surface of the inner ring 12 at a position facing the circumferential groove 11a. ing.

A bearing 1 is formed between an outer ring 11 and an inner ring 12.
A pair of sealing devices are attached to both openings of the annular gap along the axial direction of the bearing 10, and grease G is applied to the internal space of the bearing 10 surrounded by the outer ring 11, the inner ring 12, and the sealing devices.
is included as a lubricant.

The sealing device in this embodiment is for preventing the grease G sealed inside the bearing 10 from leaking to the outside and ensuring sealing performance, and is for at least one of the pair of sealing devices. That is, the sealing device on the high-cleanliness atmosphere side has a structure that seals using magnetic fluid. And this sealing device is the outer ring II of the bearing ]O.
It is composed of a seal main body 20 attached to the inner ring 12 and a seal ring 21 attached to the inner ring 12.

The seal body 20 includes an annular core metal 22 having an inverted rLJ-shaped cross section that is magnetized in the rotational radial direction, and a protrusion 22a that protrudes inward in the axial direction is provided in the middle of the cored metal 22 in the rotational radial direction. is formed around the entire circumference. The outer peripheral edge 22b of this core metal 22 is bent inward in the axial direction,
The outer peripheral edge 22b and the outer surface of the core bar 22 are covered with a non-magnetic elastic body 23 such as rubber, which is integrated therewith.

The outer peripheral edge 22b of the core metal 22, which is the base end of the seal body 20, is connected to the outer ring 11 of the bearing 10 through the elastic body 23.
It is fitted and fixed to lla. Further, the inner peripheral edge, that is, the leading edge of the core metal 22 extends along the rotational radial direction and enters the stepped portion 12a of the inner ring 12. As a result, an annular seal gap with a small size is formed between the inner circumferential edge of the core bar 22 and the outer circumferential surface of the stepped portion 12a of the inner ring 12, and this seal gap is filled with the magnetic fluid 35 over its entire circumference. has been done. This magnetic fluid 35 is held in the seal gap by a magnetic circuit formed between the core metal 22 and the inner ring 12.

The magnetic fluid 35 is a non-magnetic oil medium containing solid ferromagnetic fine powder such as magnetite in the form of a colloid.

On the other hand, the seal ring 21 is formed into an annular shape having a substantially "L"-shaped cross section, and is arranged so that the seal piece 21a provided along the rotational radial direction of the inner ring 12 is on the inside in the axial direction. It is fixed in place. therefore,
This seal piece 21a is arranged at a predetermined distance from the inner surface of the core metal 22 of the seal body 20 in the axial direction, and forms a labyrinth seal with the protrusion 22a of the core metal 22. In addition, in the figure, as described above, a labyrinth seal is formed between the core metal 22 and the flat seal ring 21 by forming the protrusion 22a, but the present invention is not limited to this. Not a thing, but a core metal 2
2 is formed into a flat plate shape, and a core metal 22 is attached to the seal ring 21.
A labyrinth seal may be constructed by forming a seal portion that projects laterally. Seal ring 2
1 can be made of either non-magnetic material or magnetic material. When using a magnetic material, there is a possibility that the tip 21b of the seal piece 21a is magnetized by the protrusion 22a of the seal body 20, but the existence of a space H formed by the seal body 20 and the seal ring 21 The magnetic fluid 3 of the seal body 20 is
There is no possibility that the particles 5 will scatter to the tip of the seal piece 21.

In this manner, in this embodiment, even if the magnetic force of the core metal 22 becomes stronger, the axial length of the seal body 20 does not become longer. Moreover, since the outer surface of the magnetized core metal 22 is covered with the non-magnetic elastic body 23, leakage of magnetic flux to the outside of the bearing 10 is blocked by the elastic body 23, and this core metal 22 and The magnetic flux density in the magnetic circuit between the inner ring 12 increases and the magnetic fluid 35 is reliably held.

Furthermore, since the protrusion 22a of the core bar 22 and the seal ring 21 form a labyrinth seal, this labyrinth effect is added to the sealing effect by the magnetic fluid 35, making it difficult for the grease G to leak.

Owner side 1 FIG. 2 shows a second embodiment of the invention.

FIG. 2 is a diagram corresponding to FIG. 1, and corresponding parts are denoted by the same reference numerals, and their explanation will be omitted.

In this second embodiment, the core bar 22 of the seal body 20 is
The inner IPil edge 22c is bent inward in the axial direction. As a result, the magnetic circuit formed between the inner circumferential edge 22C of the core bar 22 and the outer circumferential surface of the inner ring 12 expands along the axial direction. This increases the amount of magnetic fluid 35 that can be held. Therefore, the sealing performance (pressure resistance) of the magnetic fluid sole is improved.

1st stage eyebrows FIG. 3 shows a third embodiment of the invention.

FIG. 3 is a diagram corresponding to FIG. 1, and corresponding parts are denoted by the same reference numerals, and their explanation will be omitted.

The protrusion 22a formed on the core metal 22 in this embodiment is formed at a position closer to the inner ring 12 along the rotational radial direction than that in the first embodiment, and the protrusion 22a is located closer to the inner ring 12 in the rotational radial direction. The point position is opposed to the outer peripheral edge of the seal ring 21. As a result, the interval between the labyrinth seals constituted by both of them becomes narrower, and the labyrinth effect becomes larger, so that the grease G becomes even more difficult to leak than in the first embodiment.

By the way, in the description of each of the above embodiments, the seal body 20 is attached to the outer ring 11 side of the bearing 10, but the seal body 20 is not limited to this, and the seal body 20 may be attached to the inner ring 12 side. You may also do so. Furthermore, it goes without saying that the sealing device of the present invention is not only used for bearings, but can also be used as a sealing device for other equipment or devices consisting of a pair of inner and outer members that rotate relative to each other.

<Effects of the Invention> As described in 2 below, according to the present invention, since the core metal itself of the seal body is magnetized along the rotational radial direction, the axial dimension of the seal body becomes long. , the seal body can be constructed using a core metal with strong magnetic force. Therefore, by attaching such a seal body to one of the pair of inner and outer members that rotate relative to each other,
It is possible to prevent a decrease in the concentration of the magnetic fluid caused by the mixing of lubricant, and to prevent a decrease in its pressure resistance. Therefore, leakage of lubricant and magnetic fluid can be reliably prevented, and the sealing performance can be improved.

In addition, when manufacturing and assembling this sealing device, since the core metal is attached to one member through the elastic body that makes up the seal body, it is necessary to fit this member and the seal body with exact dimensional accuracy. do not have. Therefore, manufacturing and assembly are simplified, and the effort required for these operations can be reduced.

[Brief explanation of the drawing]

1 to 3 relate to the present invention, FIG. 1 is a partially omitted sectional view showing a bearing equipped with a sealing device as a first embodiment, and FIG. 2 is a partially omitted sectional view showing a second embodiment. FIG. 3 is a partially omitted sectional view showing a third embodiment. Moreover, FIG. 4 is a partially omitted sectional view showing a bearing equipped with a conventional sealing device. DESCRIPTION OF SYMBOLS 10... Bearing, 11... Outer ring (one member), 12... Inner ring (other member), 20... Seal body, 22... Core metal, 23... Elastic body.

Claims (3)

[Claims] (1) A seal body consisting of an annular core bar and an elastic body integrated with the core bar is fitted into one of a pair of inner and outer members that rotate relative to each other, and the core bar is rotated in the radial direction of the core bar. A magnetic circuit is formed between the leading edge of the cored metal that is magnetized along the direction and extends in the rotational radial direction and the other member, and a magnetic fluid is introduced between the leading edge of the cored metal and the other member. A sealing device characterized by holding. (2) The sealing device according to claim 1, wherein an annular seal ring is attached to the other member at a distance from the seal body in the axial direction. (3) A labyrinth seal is formed by providing at least one of the seal body and the annular seal ring with a protrusion that protrudes toward the other side in the axial direction. sealing device.