JPH0854066A - Sealing structure - Google Patents

Abstract

PURPOSE:To perform the feed of lubricating oil even when a drain oil pipe is choked and besides to prevent lowering of seal performance owing to wear of a lip, in the seal structure of a space in which oil air is fed from an oil air lubricating system. CONSTITUTION:Each of oil seals 20A and 20B comprises a metallic ring 20a in an L-shape in cross section; a lip 20b formed of a rubbery resilient substance fixed to the inner side of the metallic ring 20a through vulcanization adhesion; and a garter spring 20c fitted in externally of the lip 20b and energized in a direction in which the diameter thereof is reduced. The lip 20b has an inner end part fixed to the ring part 20e of the metallic ring 20a. As size is reduced therefrom, a tip part is extended in a direction in which it is spaced far away from a seal space 21 and the inner peripheral surface of the tip part is brought into contact with the outer peripheral surface of a rotary shaft 15. Namely, the tip of the lip 20b is brought into an out state based on the seal space 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil supply device (oil-air lubrication system) for supplying lubricating oil to a lubrication target as a state (oil air) in which lubricating oil is moved along the inner wall surface of a pipe using compressed air. Regarding the sealing structure of the space where the oil air is supplied from, it is possible to supply the lubricating oil even when the drain pipe is blocked, and to prevent the deterioration of the sealing performance due to lip wear etc. It was done.

[0002]

2. Description of the Related Art As a lubricating oil supply device for supplying an oil air, which is a mixture of lubricating oil and compressed air, to a lubrication object such as a bearing, for example, Japanese Patent Application Laid-Open No. 2-271197 previously proposed by the present applicant. Japanese Patent Application Laid-Open No. 2004-187242 discloses such a conventional technique, a main unit that supplies lubricating oil and compressed air, a mixer that mixes the lubricating oil and compressed air into an oil-air state, and a variety of oil-air types. The basic configuration is a distributor for distributing.

On the other hand, for example, on the housing side of the bearing to which oil air is supplied, an oil seal is used for the purpose of preventing intrusion of water, dust, etc. from the outside of the housing, and preventing leakage of lubricating oil from the inside of the housing. . For example, when the object to be lubricated is a bearing, a pair of oil seals are arranged between the inner surface of the bearing housing and the outer peripheral surface of the rotating shaft supported by the bearing so as to be located on both sides in the axial direction with the bearing interposed therebetween. In general, a sealed space is formed between the pair of oil seals.

The lip of the oil seal, which is in sliding contact with the outer peripheral surface of the rotary shaft, has been studied in the direction in which the tip of the lip is inward with respect to the sealed space, as in the case of a lubricating system other than oil air. The main reason for making the lip of the oil seal inward is to improve the sealing performance due to it, and the sealing performance is improved by making it inward if the lip of the oil seal is inward.
This is because when oil air is supplied into the bearing housing and the internal pressure of the space surrounded by the oil seal increases, the lip of the oil seal comes into strong contact with the outer peripheral surface of the rotating shaft.

[0005]

Here, in the oil-air lubrication system, the lubricating oil supplied to the inside of the bearing housing or the like is recovered in consideration of prevention of contamination by the lubricating oil and recycling of the lubricating oil. It is common to connect an oil drain pipe for this purpose to the inside of the housing, but if the oil drain pipe is crushed or clogged with foreign matter, the supply of oil air will stop. There was a problem. This is because the oil-air lubrication system is a system that supplies lubricating oil using compressed air, so if the flow of compressed air stops due to blockage between the exhaust oil, lubricating oil will not be sent either. Is.

If the lip of the oil seal faces inward, the binding force of the lip increases as the internal pressure of the sealed space increases as described above, and the sealing performance is improved at that time. If the binding force is strong, a correspondingly strong frictional force is generated, so that there is a problem that the outer peripheral surface of the rotary shaft is worn or the wear of the lip is increased, which causes deterioration of the sealing performance. .

The present invention has been made by paying attention to the unsolved problems of the prior art as described above, and it is possible to supply the lubricating oil even if the drain pipe is blocked, and An object of the present invention is to provide a sealing structure in an oil-air lubrication system that can prevent deterioration of sealing performance due to lip wear and the like.

[0008]

In order to achieve the above-mentioned object, the present invention supplies the lubricating oil from a lubricating oil supply device that uses compressed air to move the lubricating oil along the inner wall surface of the pipeline. A structure for sealing the space, wherein the space is defined by an oil seal having a lip made of a rubber-like elastic body, and an oil drain line for discharging the lubricating oil from the space is provided, and the oil drain line An orifice was formed in the, and the tip of the lip of the oil seal was directed outward with respect to the space.

[0009]

The lubricating oil supplied to the space from the lubricating oil supply device is discharged together with the compressed air through the oil discharge line. Since the orifice is formed in the oil discharge line, the oil air is normally supplied. If the situation is
The inside of the space on the upstream side of the orifice is maintained at a pressure higher than the atmospheric pressure. Further, since the tip of the lip of the oil seal faces the outside with respect to the defined space, if the internal pressure of the space defined by the oil seal is higher than atmospheric pressure, the pressure will cause the lip of the oil seal to rise. Elastically deforms in the direction of floating from the contact surface.

As a result, compressed air leaks to the outside from the gap between the lip and the surface contacting the lip, so that an oil film of lubricating oil is formed in the gap to reduce the frictional resistance of the sliding surface. Further, since the compressed air always flows out from the inside of the space to the outside through the gap between the lip and the surface with which the lip contacts, water and dust are prevented from entering from the outside through the gap.

When the drain line is closed for some reason, the internal pressure of the space further increases, but the increase of the internal pressure acts in the direction of expanding the gap between the lip and the surface with which the lip comes into contact. The amount of compressed air leaking through the gap increases. Therefore, the internal pressure of the space does not rise extremely, and if the internal pressure of the space is maintained at a certain level, compressed air can be supplied from the lubricating oil supply device, and the drain line is blocked. However, oil air is supplied.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are diagrams showing an embodiment of the present invention, and FIG. 1 shows the overall configuration. First, the configuration will be described. The mixer 1 mixes compressed air supplied from a main unit (not shown) with lubricating oil to generate oil air, and distributes the oil air evenly to distribute each distribution port 1a. It is a device for sending out from 1f. Since the specific structures of the mixer 1 and the main unit are known (see the above-mentioned publication), the description thereof is omitted here.

Further, in this embodiment, six distributors 2A to 2F are provided for the mixer 1, and the mixer 1
The respective distribution ports 1a to 1f and the oil supply ports 2a of the respective distributors 2A to 2F are connected to each other via pipes 3a to 3f. Each of the distributors 2A to 2F has a distribution port 4 according to the number of lubrication targets that supply oil air. In this embodiment, four distributor ports 4 are provided for each distributor 2A-2F.
Is provided.

The structure prior to each distribution port 4 is as follows.
Since the same applies to any of the distribution ports 4, the following description will be made only for one distribution port 4 provided in the distributor 2A, and the other figures and description will be omitted. That is, an oil supply pipe 5 as an oil supply line is connected to the distribution port 4, and the other end of the oil supply pipe 5 is connected to the lubricating oil supply port 7 a of the bearing unit 7. On the other hand, the lubricating oil discharge port 7b of the bearing unit 7 and the oil tank 9 are connected via a drain pipe 8 as an oil discharge line.

An orifice 10 is formed in the middle of the drain pipe 8 and a pressure sensor 11 for measuring the pressure at a position upstream of the orifice 10 in the drain pipe 8 is provided. The bearing unit 7 is a device that rotatably supports the rotating shaft 15 by means of a rolling bearing 16 as shown in FIG. 2, which is a side sectional view, and the rolling bearing 16 has an inner ring 16 a that is external to the rotating shaft 15. The outer ring 16b is fitted into the housing 17 which covers the rotary shaft 15 in a non-contact manner. That is, the housing 1
A circular hole 17A that communicates between both end surfaces is formed in 7, and the rotary shaft 15 penetrates the cylindrical hole 17A in a non-contact manner.

The cylindrical hole 17A has a large diameter portion 17a, a tapered portion 17b, and a small diameter portion 17c in order from the left end surface in FIG.
And the oil seal groove 17d, and the large diameter portion 17a
The outer ring 16b of the rolling bearing 16 is fitted therein.
It should be noted that one end surface of the outer ring 16b abuts on the step portion between the large diameter portion 17a and the tapered portion 17b, and the other end surface is fitted into the large diameter portion 17a.
The end surface of the cylindrical portion 18a is in contact with the rolling bearing 16, and the rolling bearing 16 is positioned thereby.

The outer ring 16b of the rolling bearing 16 is
A plurality of through holes 16c that communicate between the inner and outer peripheral surfaces are radially formed, and a circumferential groove 17e that is continuous in the circumferential direction is formed in the large diameter portion 17a so as to surround the communication holes 16c. The circumferential groove 17e and the lubricating oil supply port 7a communicate with each other through a radial hole 17f formed in the housing 17.

On the other hand, the oil seal case 18 is formed with an axial hole 18b parallel to the rotary shaft 15 at a position shifted by approximately 180 degrees from the radial hole 17f. The outer end is closed by the plug 18c, and the inner end communicates with the space inside the large diameter portion 17a. The axial hole 18b and the lubricating oil discharge port 7b communicate with each other through a horizontal hole 18d formed in the oil seal case 18. Further, an oil seal groove 18e is formed in a portion of the inner peripheral surface of the oil seal case 18 opposite to the housing 17.

Both oil seal grooves 17d and 18e
Oil seals 20A and 20B are fitted in the space, and the space inside the housing 17 sandwiched between these oil seals 20A and 20B is a sealed space 21. Each of the oil seals 20A and 20B includes a metal ring 20a having an L-shaped cross section, and a lip 20b made of a rubber-like elastic body fixed to the inside of the metal ring 20a by vulcanization adhesion or the like.
And a garter spring 20c which is fitted onto the lip 20b and urges the lip 20b in a direction to reduce the diameter of the lip 20b.

The metal ring 20a includes an oil seal groove 17d,
A cylindrical portion 20d that is in close contact with the inner peripheral surface of 18e, and a ring portion 20e that is integral with this and that is in close contact with the inner end surfaces of the oil seal grooves 17d and 18e that face outwards are L-shaped in cross section. It is fixed in the oil seal grooves 17d and 18e and integrated with them. Also, lip 20
The inner end portion of b is fixed to the ring portion 20e of the metal ring 20a, and the tip portion extends in a direction away from the sealed space 21 while reducing the diameter thereof, and the inner peripheral surface of the tip portion has the rotating shaft 1
5 is in contact with the outer peripheral surface. That is, the tip of the lip 20b faces outward with respect to the sealed space 21.

A garter spring 20c is fitted on the tip of the lip 20b. The spring constant of the garter spring 20c is such that the internal pressure of the sealed space 21 is
When a value slightly exceeding the appropriate pressure (for example, 0.4 kgf / cm ² ) is reached, the diameter reducing force of the garter spring 20c loses the force of expanding the lip 20b due to the internal pressure, and the lip 20b Is set to a value that can be widely spread. However, even if the internal pressure of the sealed space 21 is in the proper range, the spring constant of the garter spring 20c is
The value is set so that the lip 20b is not strongly pressed against the rotary shaft 15.

Further, the housing 17 and the oil seal case 18 are protected by a circular shape in order to prevent the oil seals 20A and 20B from falling off and to prevent the lip 20b from being damaged by a relatively large foreign matter coming from the outside. The plates 22A and 22B are fixed. next,
The operation of this embodiment will be described.

The oil air supplied from the distributor 2A to the lubricating oil supply port 7a of the bearing unit 7 through the oil supply pipe 5 has radial holes 17f, circumferential grooves 17e, and communication holes 16 from there.
It reaches the lubrication surface of the rolling bearing 16 (the outer peripheral surface of the inner ring 16a, the inner peripheral surface of the outer ring 16b) through c. The sealed space 21 that accommodates the rolling bearing 16 is provided in the axial hole 18
b, the horizontal hole 18d, the lubricating oil discharge port 7b, and the drain pipe 8 communicate with the oil tank 9. However, since the drain pipe 8 has an orifice 10, the orifice 10 has a throttling effect. , Orifice 10
The pressure in the drain pipe 8, the sealed space 21, and the oil supply pipe 5 on the upstream side of the upstream side is within an appropriate pressure range (0.1 to 0.3 kg) unless abnormality occurs in the oil seals 20A and 20B.
f / cm ² ).

Since the tips of the lip 20b of the oil seals 20A and 20B face outward with respect to the sealed space 21, if the inside of the sealed space 21 has a certain pressure, the lip 20b will move the lip 20b due to the pressure. The force for expanding the diameter and the elastic restoring force of the lip 20b and the force for reducing the diameter of the lip 20b due to the urging force of the garter spring 20c are spread to a position where they are balanced.

Then, a gap is formed between the tip of the lip 20b and the outer peripheral surface of the rotary shaft 15, and a part of the air in the sealed space 21 leaks to the outside through the gap. That is, FIG. 3 shows the relationship between the flow rate of the compressed air supplied to the housing 17 (horizontal axis) and the flow rate of the compressed air discharged through the drain pipe 8 (vertical axis). The characteristic A is the oil seal. When the lips 20b of 20A and 20B are directed inward, the characteristic B is the case where the lips 20b are directed outward as in the present embodiment, and the difference between the two (the portion indicated by the broken line) is the tip of the lip 20b and the rotating shaft. 15 represents the amount of air leaking from the gap between the outer peripheral surface and the outer peripheral surface. From this, it can be seen that the greater the amount of compressed air supplied, the greater the amount of leaking air.

Since the lubricating oil moves as the air moves, a thin oil film is formed in the gap between the tip of the lip 20b and the outer peripheral surface of the rotary shaft 15, and between the tip of the lip 20b and the outer peripheral surface of the rotary shaft 15. The frictional resistance of becomes small. That is,
In this embodiment, the lubricating oil used to lubricate the rolling bearing 16 is also used to lubricate the lip 20b and the rotary shaft 15.

Further, since compressed air is constantly supplied into the sealed space 21, air constantly leaks from the gap between the tip of the lip 20b and the outer peripheral surface of the rotary shaft 15. Therefore, water or dust does not enter from the outside through the gap between the tip of the lip 20b and the outer peripheral surface of the rotating shaft 15. in this way,
According to the configuration of this embodiment, the tip of the lip 20b and the rotary shaft 1 are prevented while preventing foreign matter from entering the sealed space 21.
5. The frictional resistance between the outer peripheral surfaces can be reduced. If the frictional resistance is reduced, the abrasion of the sliding contact portion can be reduced, so that the oil seals 20A, 2
The life of 0B can be greatly improved.

Further, the structure of this embodiment has an advantage that oil air can be supplied even if the drain pipe 8 is closed. That is, for example, if the drain pipe 8 is clogged with foreign matter and is blocked, if the lip 20b of the oil seals 20A and 20B is directed inward, there is no escape for compressed air, so the internal pressure of the sealed space 21 is reduced. Becomes the same as the supply pressure of the compressed air, making it impossible to supply the compressed air. If the compressed air is not supplied, the lubricating oil will not be supplied either.
However, if the internal pressure of the sealed space 21 acts so as to expand the diameter of the lip 20b of the oil seals 20A and 20B as in this embodiment, the drain pipe 8 is closed and the pressure of the sealed space 21 increases. When the force for expanding the diameter of the lip 20b becomes large (for example, at the time of rising to about 0.4 kg / cm ² ), the gap between the lip 20b and the rotary shaft 15 is further widened, and a larger amount is released from the gap. Therefore, the air in the sealed space 21 does not become extremely high in pressure, and the state in which the oil air can be supplied is always maintained.

Further, in this embodiment, since the pressure sensor 11 is provided on the upstream side of the orifice 10, the lubricating oil is normally supplied to the bearing unit 7 by monitoring the measurement value of the pressure sensor 11. It can be determined whether or not. Specifically, if the pressure sensor 11 indicates the appropriate pressure range as described above, the bearing unit 7
It can be determined that a proper amount of lubricating oil has been supplied to the.

In the oil-air lubrication system, the lubricating oil moves along the inner wall surface of the pipe due to the flow of the compressed air, so that only the lubricating oil is supplied in the state where the compressed air is not supplied. Because that is impossible. The situation where only compressed air is supplied is a case where the lubricating oil is not normally supplied in the mixer 1, and this is easily detected by the technique disclosed in the above-mentioned publication.

More specifically, for example, if any of the pipe 3a, the distributor 2A, and the oil supply pipe 5 is clogged or crushed, and the oil air is not normally conveyed to the bearing unit 7, the clogging or clogging will occur. Since a pressure drop occurs at a portion where crushing or the like occurs, the pressure inside the drain pipe 8 becomes lower than that in a normal state. Further, for example, due to breakage in the pipe 3a or the oil supply pipe 5, leakage due to deterioration of the seal at the connecting portion between the distribution port 1a and the pipe 3a, or other abnormalities at each connecting portion, the pipe upstream of the orifice 10 or the like. Is released and the bearing unit 7
When the oil / air is not conveyed to the inside, the pressure in the drain pipe 8 also becomes lower than the normal state.

Further, when the oil seals 20A and 20B in the bearing unit 7 are damaged and foreign matter is mixed into the sealed space 21 from the outside, the drain pipe 8 is also used.
The pressure inside will be lower than normal. That is, according to the configuration of this embodiment, when the bearing unit 7 is in an abnormal state in which oil air is not normally conveyed, the pressure in the drain pipe 8 is reduced, and the pressure drop is caused by the pressure sensor 1.
Such anomalies are easily detected as they appear in the measured value of 1.

Since only the orifice 10 and the pressure sensor 11 are necessary for obtaining such an action, the cost is low. Therefore, even if it is applied to a continuous casting machine having a large number of guide rolls, pinch rolls, etc., and there may be several hundred lubrication points, enormous cost is not required. Further, according to the present embodiment, since the abnormality of the oil / air conveyance is detected by the change in the pressure in the pipe, the abnormality can be easily detected even when the flow rate of the lubricating oil conveyed as the oil air is very small. It has the advantage of being detectable.

In the case of this embodiment, since the pressure drops in the case of an abnormality, a pressure switch for detecting that the pressure has dropped below a predetermined pressure may be used instead of the pressure sensor 11. Then, since the pressure switch is generally cheaper, the cost can be further reduced. Also,
The pressure sensor 11 and the pressure switch may be provided not in the drain pipe 8 but in the oil supply pipe 5, and even in that case, if a clogging or breakage occurs on the upstream side of the pressure sensor 11, the clogging or breakage site will be located downstream of the clogging or breakage site. Side pressure drops,
An abnormality is detected by the decrease in the measured value of the pressure sensor 11.

Further, when blockage due to clogging or the like occurs on the downstream side of the pressure sensor 11, the pressure on the upstream side of the clogged position rises, so an abnormality is detected by an increase in the measured value of the pressure sensor 11. Furthermore, the pressure sensor 11
When the opening occurs due to breakage or the like on the downstream side, the pressure in the oil supply pipe 5 decreases, so that the abnormality is detected by the decrease in the measured value of the pressure sensor 11.

In this way, the pressure sensor 11 is connected to the oil supply pipe 5
Even if it is arranged in the above, the state in which the oil air is not normally supplied to the bearing unit 7 can be detected by the change in the measured value of the pressure sensor 11 as in the above embodiment.
Since the pressure of the pressure sensor 11 may increase or decrease depending on the type of abnormality, it is possible to determine the type of abnormality to some extent based on the change state of the measurement value of the pressure sensor 11.

Further, in the above embodiment, the bearing unit 7
The case where the present invention is applied to the oil-air lubrication system for supplying oil-air to the above has been described, but the present invention is not limited to this and can be applied to, for example, an oil-air lubrication system of a guide device that reciprocates a shaft.

[0038]

As described above, according to the present invention,
In addition to forming an orifice in the oil drain line and making the tip of the lip of the oil seal that defines the space where the oil air is supplied outward, the life of the oil seal can be greatly improved without deteriorating the sealing performance. The lubricating oil can be supplied into the space even when the oil drain line is blocked.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a side sectional view of a bearing unit.

FIG. 3 is a graph showing the relationship between the flow rate of air supplied to the housing and the flow rate of air discharged from the drain pipe.

[Explanation of symbols]

 1 Mixer 2A to 2F Distributor 5 Oil supply pipe 7 Bearing unit 8 Drain pipe (oil drain line) 10 Orifice 11 Pressure sensor 15 Rotating shaft 16 Rolling bearing 17 Housing 20A, 20B Oil seal 20b Lip 20c Garter spring 21 Sealed space

Claims (1)

[Claims] 1. A structure for sealing a space to which the lubricating oil is supplied from a lubricating oil supply device for moving the lubricating oil along an inner wall surface of a pipe by using compressed air, wherein the space is made of rubber. It is defined by an oil seal having a lip made of an elastic body, and an oil drain line for discharging the lubricating oil from the space is provided, an orifice is formed in the oil drain line, and the tip of the lip of the oil seal is formed. Is directed outward with respect to the space.