JP2001099326A - Seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sealing property of a seal for sealing a space to be sealed while partitioning the space to be sealed and an atmospheric air pressure space from each other. SOLUTION: A seal 3 is arranged in an annular space A formed between a rotary shaft 1 and a housing 2, which are concentrically arranged with each other inside and outside in the radial direction, so as to partition the annular space A into two of a vacuum space B to be sealed and an atmospheric air pressure space C in the axial direction. Two lips 10, 11 to be brought in contact with the rotary shaft 1 are provided separately from each other in the axial direction, and both the lips have a shape for increasing the contact pressure with the pressure applied from the atmospheric air pressure space side to the space to be sealed, and the lubricating agent 13 is filled between both the lips.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal which is provided in a space facing two members arranged concentrically inside and outside in a radial direction to partition the space in the axial direction.

[0002]

2. Description of the Related Art A conventional seal of this type is used for dividing one of the above members into, for example, a rotary shaft and the other into a housing, for example, and partitioning an annular space between the rotary shaft and the housing into two spaces in the axial direction. Sometimes.

[0003] In such a seal, an elastic body is annularly attached to an annular core, and two annular lips which are brought into contact with a rotating shaft are axially separated from the inner peripheral end of the elastic body. There is a thing of the structure provided.

Meanwhile, in the conventional seal, one lip (main lip) has a substantially inverted triangular cross section in the upper half, and has a large interference with the rotating shaft. Is formed, thereby sealing the gap between the rotary shaft and the rotating shaft.

[0005] The other lip (auxiliary lip) is provided adjacent to the main lip, and has a structure inclined with respect to the axial direction to assist the sealing action of the main lip.

[0006]

However, even with the main lip and the auxiliary lip of the seal alone, the pressure difference between the annular space and the space to be sealed and the atmospheric pressure space is greatly different.
Although it is possible to partition one space to seal the space to be sealed, if the space to be sealed is a partition of a special space called a vacuum space, it is necessary to further secure sealing performance.

Further, since the main lip is worn by sliding contact with the rotating shaft, it is preferable to supply a lubricant to the sliding contact surface of the main lip in order to prevent this wear. The structure for holding the lubricant is complicated and costly. Therefore, it is desired that a simple and inexpensive structure surely holds the lubricant and that a long-term stable supply of the lubricant to the sliding contact surface is desired. .

Therefore, a common problem to be solved by the present invention is to provide a seal in which two members disposed inward and outward in the radial direction are provided in opposing spaces to partition the space into two spaces. It is an object of the present invention to further improve the sealing performance in a special environment such as a vacuum space by using the space as a space to be sealed.

Another problem to be solved by the present invention is that even in the special environment, a simple and inexpensive structure can reliably hold the lubricant and supply the lubricant to the sliding contact surface for a long period of time. Is to do so.

[0010]

A seal according to the present invention is provided in a space facing a rotating member and a fixed member which are concentrically arranged inside and outside in a radial direction, and the space is axially connected to a low-pressure space. A seal used for partitioning into a high-pressure space and a high-pressure space having a higher pressure, wherein a main lip and an auxiliary lip are provided separately on the high-pressure space side and the low-pressure space side in the axial direction, respectively. It is characterized in that a lubricant is filled between the lips.

Preferably, the two lips have a shape that increases the contact pressure by a pressure acting from the high-pressure space side to the low-pressure space side.

[0012] Preferably, the lubricant is a solid lubricant.

[0013] Preferably, the lubricant is a low vapor pressure lubricant.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the upper half of the seal of the embodiment of the present invention installed in the annular space between the housing and the rotating shaft, and FIG. It is half exploded longitudinal sectional view.

In the figure, reference numeral 1 denotes a rotating shaft as a rotating member;
Is a housing as a fixing member. The rotating shaft 1 and the housing 2 are arranged concentrically inside and outside the radial direction.
Constitutes one member.

The seal 3 of the embodiment is provided in an annular space A in which the rotating shaft 1 and the housing 2 are opposed to each other. The annular space A is divided into a low-pressure space such as a vacuum space B and a high-pressure space such as a high-pressure space such as an atmospheric pressure space. C and partition.

The seal 3 of this embodiment is used to shut off the inside and outside of the vacuum chamber, for example, in a situation where the seal 3 is disposed inside and outside the vacuum chamber through a rotating shaft.

The seal 3 is formed by attaching a second seal portion 5 (an adhered seal portion) to a first seal portion 4 (a main body seal portion). Note that the two seal portions 4, 5 of the embodiment are used.
Was initially a separate configuration, but is not limited to this, and may be an integrated configuration from the beginning.

The first seal portion 4 is formed by attaching an elastic body 7 to an annular core 6 whose upper half has a substantially L-shaped cross section in the radial direction, and the second seal portion 5 has an upper half cross section. The elastic body 9 is attached to a metal ring 8 which has a substantially concave shape and prevents the lip described below from rolling up in the direction of the space B to be sealed due to the negative pressure of the space B to be sealed.

In the first seal portion 4, the end of the elastic body 7 on the rotating shaft 1 side, that is, the inner peripheral portion extends toward the atmospheric pressure space C and has an upper half cross-sectional shape substantially similar to an inverted triangle. Of the edge 10a corresponding to the main lip 10 is rounded.

In the second seal portion 5, the end of the elastic body 9 on the side of the rotating shaft 1, that is, the inner peripheral portion is spaced apart from the main lip 10 and provided at a position closer to the space B to be sealed. The auxiliary lip 11 has a tapered shape whose upper half sectional shape gradually decreases in diameter toward the B side.

On the outer periphery of the main lip 10, the rotation
A garter spring 12 which is pressed against the outer peripheral surface of the diaper is mounted.

Main lip 10, auxiliary lip 11, and rotary shaft 1
Lubricant 1 such as oil or grease in the space surrounded by
3 are filled.

In the case of the seal 3 having the above-described structure, since the lubricant 13 is filled between the main lip 10 and the auxiliary lip 11, the annular space A is divided into the sealed space B and the atmospheric pressure space C.
The partition wall that separates two spaces having a large difference in pressure has a thick structure due to the addition of the lubricant 13 in addition to the lips 10 and 11, so that sufficient sealing performance can be obtained even when the space B to be sealed is a vacuum space. Can be secured.

Further, since the lubricant 13 can be supplied to the sliding surface of the main lip 10 between the lips 10 and 11, the abrasion due to the sliding contact with the rotating shaft can be prevented.

Furthermore, since the structure is simple, the manufacturing cost can be reduced, and the lubricant can be reliably held and the lubricant can be stably supplied to the sliding contact surface for a long period of time.

Note that the present invention is not limited to the above-described embodiment, and the following various modifications or applications are possible.

(1) The lubricant 13 of the above embodiment is
Basically, the lubricant itself has almost no shape retention like a fluid or liquid lubricant such as oil or grease, but it is limited to such a lubricant. Instead, mix lubricating oil such as mineral oil and poly-α-olefin oil or grease with a thickener added to resin such as high-density polyethylene polypropylene, and after filling in required places, heat to above the melting point of the resin. Then, it may be a so-called polymer lubricant which is cooled and solidified.

Since the solid lubricant can maintain the desired shape to some extent, the solid lubricant has a larger gap between the main lip 10 and the auxiliary lip 11 of the seal 3 than a lubricant such as liquid oil or grease. It is easy to densely fill the space according to the shape of the space, and in addition to this, even if the shape of the main lip 10 and the auxiliary lip 11 is changed by sliding contact with the rotating shaft 1, 1 is particularly effective for the seal 3 shown in FIG. 1, but also has excellent holding strength between the main lip 10 and the auxiliary lip 11 with respect to the conventional seal. Can be held.

As a result, even if the auxiliary lip 11 rises, it is preferable that the lubricant can be prevented from leaking to the sealed space B side.

The lubricant 13 described above is filled between the main lip 10 and the auxiliary lip 11,
The space between the inclined surface 10a of the main lip 10 and the rotating shaft 1 may be filled to have shape retention. In such a case, the distance of the lubricant to the auxiliary lip 11 increases, and the lubricant 13
It is preferable that the lubricant 13 can be stored therein even if the lubricant leaks, and the lubricant 13 can be more effectively prevented from leaking out of the auxiliary lip 11.

(2) In the above embodiment, the vapor pressure is 10
A lubricant 13 such as oil or grease having a pressure of ^-8 Pa or less (atmospheric temperature of 20 ° C.) may be filled between the main lip 10 and the auxiliary lip 11. Such a low vapor pressure lubricant 13
Is difficult to contaminate the atmosphere of the space B to be sealed because it does not dissipate gas components even if it leaks somewhat into the space B to be sealed via the auxiliary lip 11 because of its low volatility. There is no risk of causing an abnormality in the vacuum equipment disposed in B.

(3) The seal 3 of the above embodiment partitions the atmospheric pressure space C from the space B to be sealed as shown in FIG. 3, and the bearing 14 is sealed in the atmospheric pressure space C. In this case, the seal 3 may be integrally provided on one side of the rolling bearing 14 to form a unitized bearing unit.
The rolling bearing 14 has an outer ring 14a, an inner ring 14b, a plurality of rolling elements 14c, and a retainer 14d.

(4) In the above embodiment, the seal 3
The inner space in the radial direction, that is, the inner peripheral side of the rotary shaft 1 is a rotating member, and the outer surface in the radial direction, that is, the outer peripheral side thereof, is the housing 2 that is a fixed member. However, the present invention is not limited to this, and the inner peripheral side of the seal 3 may be a fixed member, and the outer peripheral side may be a seal against an annular space between two members that are rotating members.

(5) The top of the triangular main lip 10 may be sharply pointed. Further, as shown in FIG. 4, the auxiliary lip 11 may have a tapered shape whose upper half cross-sectional shape gradually decreases in diameter toward the atmospheric pressure space C side.

When the seal 3 provided with the auxiliary lip 11 having the above-described structure is used in the above-described special environment, the auxiliary lip 1
1 is in contact with the rotating shaft 1 in a structure inclined to the direction of the main lip 10, so that the main lip 10
And the auxiliary lip 11 have such a shape that the contact pressure is increased by the pressure acting from the atmospheric pressure space C side to the sealed space B side, whereby the atmospheric pressure space C side to the sealed space B side Is applied to the auxiliary lip 11, the auxiliary lip 11 does not rise from the rotating shaft 1. Therefore, the auxiliary lip 11
As a result, the interference with the rotating shaft 1 can be ensured, which contributes to the sealing action under such a special environment.

Further, since the auxiliary lip 11 has the above-described structure, even if the lubricant 13 is strongly drawn into the space B to be sealed due to a pressure difference between the space B to be sealed and the atmospheric pressure space C, the auxiliary lip 11 Due to the above inclination, the lubricant 13 can be held in the space between the main lip 10 and the auxiliary lip 11 with high holding ability. As a result, the lubricant 13 can be stably supplied to the sliding contact surface of the main lip 10 with the rotating shaft 1 for a long period of time, whereby the early prevention of wear of the main lip 10 can be stably prevented, which is preferable. .

In this case, since the auxiliary lip 11 does not rise from the rotary shaft 1, the main lip 10, the auxiliary lip 11, and the rotary shaft 1 are separated from each other even if the lubricant 13 is in a liquid state and has no shape-retaining property. The enclosed space is better sealed, and the lubricant 13 can be well held in the space.
It is preferable because a commercially available and easily available and inexpensive lubricant 13 can be used.

Further, as a result of the above-described structure of the auxiliary lip 11, the lubricant 13 can be favorably held, and as a result, the lubricant 13 may leak to the space B to be sealed and contaminate the space B to be sealed. This is a particularly preferable seal when the space to be sealed B needs to be maintained in a clean atmosphere.

[0041]

Since the seal of the present invention has a structure in which the lubricant is held between the main lip and the auxiliary lip brought into contact with the rotating member, the annular space is called the space to be sealed and the atmospheric pressure space. The partition wall that separates the two spaces with greatly different pressure differences has a thick structure with the lubricant added to both lips, so that sufficient sealing performance can be ensured even if the space to be sealed is a vacuum space. Become.

Further, since the lubricant can be supplied to the sliding surface of the main lip with the rotating shaft from between the two lips, early wear can be prevented by the sliding contact with the rotating shaft.

Furthermore, since the structure is simple, the manufacturing cost can be reduced and the lubricant can be reliably held and the lubricant can be supplied to the sliding contact surface for a long period of time.

In this case, when the two lips are shaped to increase the contact pressure by the pressure acting from the high-pressure space side to the low-pressure space side, even if the pressure applied from the high-pressure space side to the low-pressure space side is applied to the lips, Since the contact pressure of the lip against the rotating member increases, the lip does not float. For this reason, the lip is preferable because it contributes to the sealing action under such a special environment as a result of securing an interference with the rotating member.

In the present invention, when the lubricant is a solid lubricant, the lubricant can be maintained to a certain extent while maintaining the desired shape. It is easier to closely fill the space according to the shape of the space between the lips than in the case of the lip, and even if the lip changes its shape by sliding contact with the rotating member, the shape changes relatively. It is preferable because it can easily follow.

In the present invention, when the lubricant is a lubricant having a low vapor pressure, the lubricant does not easily volatilize, and does not dissipate gas components even if leaked somewhat through the lip. There is no possibility that the atmosphere of the space is contaminated. Therefore, for example, when the inside of the vacuum chamber is used as a sealed space, the seal is very effective in preventing the atmosphere in the vacuum chamber from being contaminated.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an upper half of a seal according to an embodiment of the present invention.

FIG. 2 is an exploded longitudinal sectional view of the upper half of the seal in FIG. 1;

FIG. 3 is a longitudinal sectional view of an upper half of a bearing unit made of a combination of the seal of FIG. 1 and a bearing using the seal.

FIG. 4 is a longitudinal sectional view of an upper half of a seal according to another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotating shaft 2 housing 3 seal 4 first seal portion 5 second seal portion 6 annular core 7 elastic body 8 metal ring 9 elastic body 10 main lip 11 auxiliary lip 12 garter spring 13 lubricant 14 bearing A annular space B sealing Target space C Atmospheric pressure space

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazutoshi Yamamoto 3-5-8 Minamisenba, Chuo-ku, Osaka-shi Koyo Seiko Co., Ltd. F-term (reference) 3J006 AE17 3J016 AA04 BB03 CA01

Claims (4)

[Claims] 1. A space provided between a rotating member and a fixed member which are arranged concentrically inside and outside in a radial direction, and the space is composed of a low-pressure space in an axial direction and a high-pressure space in which pressure is higher than the low-pressure space. A main lip and an auxiliary lip are provided on the high-pressure space side and the low-pressure space side in the axial direction, and a lubricant is filled between the two lips. A seal characterized by the above. 2. The seal according to claim 1, wherein the two lips have a shape that increases a contact pressure by a pressure acting from a high pressure space side to a low pressure space side. 3. The seal according to claim 1, wherein the lubricant is a solid lubricant. 4. The seal according to claim 1, wherein the lubricant is a lubricant having a low vapor pressure.