JP2021089002A - Sealing device - Google Patents

Abstract

To provide a sealing device for developing high durability against foreign matters by lubricating oil given to a lip.SOLUTION: The sealing device includes a first cylindrical part mounted to a housing, a first annular part, a first seal member having a first lip which the outer peripheral face of a rotary shaft slidably contacts, a second cylindrical part fitted into the first cylindrical part, a second annular part, and a second seal member having a second lip which the outer peripheral face of the rotary shaft slidably contacts. The outer peripheral face of the rotary shaft, the housing, the first cylindrical part, and the second seal member define an internal space where lubricating oil is sealed. The outer peripheral face of the rotary shaft, the first annular part, the first lip, the second cylindrical part, the second annular part, and the second lip define an additional space where the lubricating oil is sealed. In the second seal member, a passage is formed to communicate the internal space with the additional space. The maximum size of the cross section of the passage is 50 μm or smaller.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sealing device having two sealing members.

Patent Document 1 discloses a sealing device having two sealing members. In this sealing device, the cylindrical portion of the other sealing member is fitted into the cylindrical portion of one sealing member. The outer cylinder is attached to the housing and both sealing members each have a lip that contacts the shaft.

Patent No. 3911857

In the above sealing device, it is desirable that the lip is always lubricated in order to prolong the life of the lip.

Further, the sealing device is provided in, for example, an axle box for accommodating bearings for axles of railway vehicles, and seals lubricating oil used for the bearings. Such an environment contains a large amount of foreign matter (eg, iron powder produced by wear of bearing components). Therefore, a sealing device having high durability against foreign matter is required.

Therefore, the present invention provides a sealing device in which the lip is always lubricated and has high durability against foreign matter.

The sealing device according to an aspect of the present invention is a sealing device that seals a gap between a housing and a rotating shaft arranged in a shaft hole provided in the housing. The sealing device includes a first cylindrical portion attached to the housing, a first annular portion extending radially inward from the first cylindrical portion, and a radial inner portion of the first annular portion. A first sealing member that is arranged and has a first lip that slidably contacts the outer peripheral surface of the rotating shaft, and a second cylindrical portion that is fitted into the first cylindrical portion of the first sealing member. A second annular portion extending radially inward from the second cylindrical portion and a second annular portion arranged radially inward of the second annular portion so that the outer peripheral surface of the rotating shaft can slide. Has a second sealing member having a second lip in contact with. The outer peripheral surface of the rotating shaft, the housing, the first cylindrical portion, and the second sealing member define an internal space in which the lubricating oil is sealed. The outer peripheral surface of the rotating shaft, the first annular portion, the first lip, the second cylindrical portion, the second annular portion, and the second lip are lubricated. Define an additional space where the oil is sealed. At least one passage for communicating the internal space with the additional space is formed in the second sealing member, and the maximum dimension of the cross section of the passage orthogonal to the extending direction of the passage is 50 μm or less.

In this embodiment, at least one passage is provided to communicate the internal space in which the lubricating oil is sealed to the additional space. Therefore, the first lip forming the additional space is always lubricated, and the lubricating oil cools and lubricates the first lip. Therefore, the deterioration of the first lip due to the temperature rise and the wear of the first lip due to the sliding of the rotating shaft are suppressed. Further, since the maximum dimension of the cross section of the passage is 50 μm or less, it is suppressed that a large foreign matter from the internal space passes through the passage and reaches the additional space. Therefore, there is little possibility that foreign matter will damage the first lip that forms the additional space, and there is also little possibility that foreign matter will enter between the first lip and the rotating shaft and the lubricating oil will leak from here.

It is sectional drawing which shows the sealing device which concerns on embodiment of this invention which is in use. It is a perspective view of the 2nd sealing member of a sealing device. It is sectional drawing which shows the variation of the slit which forms the passage which can be formed in the 2nd seal member. It is a graph which shows the relationship between the diameter of the foreign matter and the leakage of the lubricating oil in the sealing apparatus which concerns on embodiment. It is sectional drawing which shows the sealing device which concerns on the modification of embodiment of this invention which is in use. It is a perspective view of the 2nd sealing member of the sealing device of FIG. It is sectional drawing which shows the sealing device which concerns on other modification of embodiment of this invention which is in use.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. Drawing scales are not always accurate and some features may be exaggerated or omitted.

As shown in FIG. 1, the sealing device 1 according to the embodiment is arranged in the shaft hole 2A provided in the housing 2. A rotating shaft 4 is inserted into the shaft hole 2A, and the sealing device 1 seals a gap between the housing 2 and the rotating shaft 4. The housing 2 is an axle box for accommodating bearings (not shown) for the axles of railway vehicles, and the rotating shaft 4 is an axle.

The sealing device 1 has a first sealing member 10 and a second sealing member 30 arranged substantially coaxially with each other. The first seal member 10 and the second seal member 30 have an annular shape, and FIG. 1 shows the left portion of the first seal member 10 and the second seal member 30.

The first sealing member 10 has a composite structure having an elastic ring 11 made of an elastic material, for example, an elastomer, and a rigid ring 12 made of a metal material. The rigid ring 12 reinforces the elastic ring 11.

The first sealing member 10 has a first cylindrical portion 13, a first annular portion 14, an inner cylindrical portion 15, a main lip (first lip) 16 and a dust strip 17.

The first cylindrical portion 13 has an elastic cylinder 13a which is a part of the elastic ring 11 and a rigid cylinder 13b which is a part of the rigid ring 12. The elastic cylinder 13a is in close contact with the outer peripheral surface of the rigid cylinder 13b. The first cylindrical portion 13 is attached to the housing 2 by, for example, being press-fitted into the shaft hole 2A of the housing 2.

The first annular portion 14 extends radially inward from the atmosphere-side end of the first cylindrical portion 13. The first ring portion 14 has an elastic ring that is a part of the elastic ring 11 and a rigid ring that is a part of the rigid ring 12. The elastic ring is in close contact with the surface of the rigid ring on the atmosphere side.

The inner cylindrical portion 15 extends substantially concentrically with the first cylindrical portion 13 from the inner end of the first annular portion 14 toward the bearing side. A main lip 16 is formed at the end of the inner cylindrical portion 15 on the bearing side, and a dust strip 17 is formed at the end of the inner cylindrical portion 15 on the atmosphere side. The inner cylindrical portion 15, the main lip 16 and the dust strip 17 are part of the elastic ring 11. The outer peripheral surface of the rotating shaft 4 is slidably contacted with the main lip 16 and the dust strip 17.

The main lip 16 has two truncated cone-shaped inclined surfaces with the lip edge 16A as a boundary. In FIG. 1, the rotating shaft 4 is shown by an imaginary line, and the main lip 16 is actually deformed by receiving contact pressure from the rotating shaft 4. The main lip 16 seals the lubricating oil for the bearing stored on the bearing side.

Although not essential, a plurality of protrusions 16B are formed on the inclined surface of the main lip 16 on the atmospheric side. The protrusion 16B exerts a pumping action of returning the lubricating oil leaking from the bearing side to the atmosphere side to the bearing side.

Although not essential, a garter spring 18 is wound around the inner cylindrical portion 15. The garter spring 18 presses the main lip 16 inward in the radial direction to increase the contact pressure between the main lip 16 and the rotating shaft 4.

The dust strip 17 is a truncated cone-shaped plate extending radially inward and toward the atmosphere from the end of the inner cylindrical portion 15 on the atmosphere side. The dust strip 17 suppresses the intrusion of foreign matter from the atmosphere side to the bearing side.

Although not essential, a plurality of protrusions 17A are formed on the inner peripheral surface of the dust strip 17 at intervals from each other. The protrusion 17A is located on the space 19 and the atmosphere side when the pressure in the space 19 defined by the main lip 16, the dust strip 17, and the outer peripheral surface of the rotating shaft 4 is excessively reduced and the dust strip 17 is excessively deformed. Communicate the space.

The second seal member 30 is arranged on the bearing side of the first seal member 10 so that the main lip 16 of the first seal member 10 does not receive an excessively large pressure from the lubricating oil on the bearing side. ..

The second sealing member 30 has a composite structure having an elastic ring 31 made of an elastic material, for example, an elastomer, and a rigid ring 32 made of a metal material. The rigid ring 32 reinforces the elastic ring 31.

The second sealing member 30 has a second cylindrical portion 33, a second annular portion 34, and an auxiliary lip (second lip) 35.

The second cylindrical portion 33 is composed of a rigid cylinder that is a part of the rigid ring 32. The second cylindrical portion 33 is press-fitted into the first cylindrical portion 13 of the first sealing member 10. Specifically, the second cylindrical portion 33 has a large diameter portion 33A arranged on the atmosphere side and a small diameter portion 33B arranged on the bearing side, and the outer diameter and inner diameter of the large diameter portion 33A are the small diameter portion 33B. Each of them is larger than those of. The second sealing member 30 is fixed to the first sealing member 10 by the large diameter portion 33A being tightly fitted to the first cylindrical portion 13.

Therefore, the large-diameter portion 33A of the second cylindrical portion 33 that contacts the first cylindrical portion 13 is formed of metal, and is a rigid cylinder that contacts the second cylindrical portion 33 of the first cylindrical portion 13. 13b is also made of metal.

The second annular portion 34 extends radially inward from the end of the second cylindrical portion 33 on the bearing side. The second ring portion 34 has an elastic ring that is a part of the elastic ring 31 and a rigid ring that is a part of the rigid ring 32. The elastic ring is in close contact with the bearing-side surface of the rigid ring.

The auxiliary lip 35 is a truncated cone-shaped plate extending radially inward from the inner end of the second cylindrical portion 33 and toward the bearing side. The outer peripheral surface of the rotating shaft 4 is slidably contacted with the auxiliary lip 35. The auxiliary lip 35 prevents a large amount of foreign matter (for example, iron powder) contained in the lubricating oil on the bearing side from flowing toward the main lip 16 of the first sealing member 10.

In this sealing structure, the internal space 40 on the bearing side can be regarded as being terminated by the first cylindrical portion 13 of the first sealing member 10 and the second sealing member 30. That is, the outer peripheral surface of the rotating shaft 4, the housing 2, the first cylindrical portion 13, and the second sealing member 30 (the second cylindrical portion 33, the second annular portion 34, and the auxiliary lip 35 are included. The second lip defines an internal space 40 in which the lubricating oil is sealed.

Further, by combining the first sealing member 10 and the second sealing member 30, the outer peripheral surface of the rotating shaft 4, the first annular portion 14, the main lip 16, and the second cylindrical portion 33 are formed. The second annular portion 34 and the auxiliary lip 35 define an additional space 42 in which the lubricating oil is sealed.

A plurality of slits 46 are formed on the outer peripheral surface of the large-diameter portion 33A in contact with the first cylindrical portion 13 of the second cylindrical portion 33. Each slit 46 communicates the internal space 40 with the additional space 42. Therefore, except for the slit 46, the outer peripheral surface of the large-diameter portion 33A press-fitted into the first cylindrical portion 13 of the first sealing member 10 faces the inner peripheral surface of the rigid cylinder 13b of the first cylindrical portion 13. Although they come into contact with each other, the cavity formed on the inner peripheral surface of the slit 46 and the rigid cylinder 13b functions as a lubricating oil passage between the internal space 40 and the additional space 42, and the main lip 16 can always be supplied with the lubricating oil. ..

The outer diameter of the small diameter portion 33B of the second cylindrical portion 33 is smaller than the inner diameter of the rigid cylinder 13b of the first cylindrical portion 13. Therefore, an annular gap 47 is provided between the small diameter portion 33B of the second cylindrical portion 33 and the rigid cylinder 13b of the first cylindrical portion 13. The lubricating oil can flow from the internal space 40 to the additional space 42 (or vice versa) through the gap 47 and the slit 46.

In this way, the main lip 16 is always lubricated, so that the lubricating oil cools and lubricates the main lip 16. Therefore, the deterioration of the main lip 16 due to the temperature rise and the wear of the main lip 16 due to the sliding of the rotating shaft 4 are suppressed, and the life of the main lip 16 and thus the sealing device 1 is extended.

The dust strip 17 may be coated with grease as a lubricant. The main lip 16 and the auxiliary lip 35 are always provided with a lubricating oil for bearings, but the main lip 16 and the auxiliary lip 35 may also be coated with grease as a lubricant different from the lubricating oil.

As shown in FIG. 2, the plurality of slits 46 are arranged at equiangular intervals. Each slit 46 extends linearly along the axial direction of the sealing device 1. However, each slit 46 may be inclined with respect to the axial direction of the sealing device 1, and may be curved or bent.

In this embodiment, the number of slits 46 is 4, but the number of slits 46 is one or more and is not limited. When only one slit 46 is formed in the second cylindrical portion 33, the slit 46 is arranged below the sealing device 1 in which the lubricating oil is stored, and the lubricating oil is supplied from the internal space 40 to the additional space 42. It is desirable that it can be supplied through.

As the number of slits 46 increases, the concern about insufficient lubrication of the main lip 16 decreases. This is because even if one of the slits 46 is blocked by a foreign substance, the other slit 46 can supply the lubricating oil from the internal space 40 to the additional space 42. Even if the number of slits 46 is large, by limiting the dimensions of the slits 46 as described later, it is possible to reduce the concern that foreign matter flows from the internal space 40 into the additional space 42.

FIG. 3 is a cross-sectional view showing variations of slits that can be formed in the large diameter portion 33A of the second cylindrical portion 33 of the second sealing member 30. Each cross-sectional view shows a cross section orthogonal to the direction in which the slit extends.

The cross section of the slit 46 has a semi-circular shape having two parallel wall surfaces and an arcuate curved surface connecting the two parallel wall surfaces. The maximum dimension M of this cross section of the slit 46 is the depth of the slit 46.

The cross section of the slit 46A has a semi-elliptical shape. The maximum dimension M of this cross section of the slit 46A is the depth of the slit 46A.

The cross section of the slit 46B is semi-circular. The maximum dimension M of this cross section of the slit 46B is the width of the slit 46B.

The cross section of the slit 46C is rectangular. The maximum dimension M of this cross section of the slit 46C is the width of the slit 46C.

The cross section of the slit 46D is rectangular. The maximum dimension M of this cross section of the slit 46D is the diagonal of the rectangle.

As described above, the main lip 16 is always provided with a lubricating oil for bearings, but the lubricating oil for bearings for the axles of railway vehicles contains a large amount of foreign matter (for example, iron powder). Foreign matter may damage the main lip 16, and if it enters between the main lip 16 and the rotating shaft 4, the lubricating oil may leak from the additional space 42 to the space 19, and further leak from the space 19 to the atmosphere side. is there.

Therefore, in this embodiment, the maximum dimension M of the cross section of each of the slits 46, 46A, 46B, 46C or 46D that communicates the internal space 40 with the additional space 42 is 50 μm or less, and a large foreign matter from the internal space 40 passes through the slit 46. Passing through and reaching the additional space 42 is suppressed. Therefore, there is little possibility that the main lip 16 forming the additional space 42 is damaged by foreign matter, and there is little possibility that the foreign matter enters between the main lip 16 and the rotating shaft 4 and the lubricating oil leaks from the main lip 16.

FIG. 4 is a graph showing the experimental results of investigating the relationship between the diameter of the foreign matter and the leakage of the lubricating oil in the sealing device 1 according to the embodiment. In the experiment, a large amount of iron powder (foreign matter) having different diameters was mixed with the lubricating oil, and whether or not the main lip 16 could seal the lubricating oil (more than a predetermined amount of lubricating oil leaked from the additional space 42 to the space 19). Whether or not) was investigated. Iron powder was mixed in the lubricating oil in an amount of 2.5% by weight. In the experiment, the rotating shaft 4 was rotated at 2000 rpm for 5 hours in one direction, then kept stationary for 2 minutes, then rotated at 2000 rpm for 5 hours in the opposite direction, and lubrication leaked from the additional space 42 to the space 19. The amount of oil was examined. The type of slit used was the slit 46 in FIG.

Further, in the experiment, samples of a plurality of sealing devices 1 having main lips 16 having different degrees of wear were used. The horizontal axis of the graph of FIG. 4 indicates the contact width W of the main lip 16 with respect to the rotation axis 4. The contact width W is the length in the axial direction in which the tip of the main lip 16 contacts the rotating shaft 4, as shown in the circle of FIG. The greater the wear of the main lip 16, the greater the contact width W.

The imaginary line in FIG. 4 is assumed to be the maximum value of the diameter of the foreign matter when the main lip 16 can seal the lubricating oil. As is clear from FIG. 4, when the contact width W is small, the sealing performance of the main lip 16 is relatively low, so that the lubricating oil leaks due to the smaller iron powder in other cases. However, the lubricating oil containing iron powder having a diameter of 57 μm or less could be reliably sealed.

As described above, the slits 46, 46A, 46B, 46C or 46D are formed in the large diameter portion 33A of the second cylindrical portion 33, and the large diameter portion 33A is formed of metal. Therefore, even if the second cylindrical portion 33, particularly the large diameter portion 33A, is fitted into the first cylindrical portion 13 and receives high pressure from the first cylindrical portion 13, the slits 46, 46A, 46B, 46C or The amount of deformation of 46D is small. That is, there is little possibility that the passage formed by the slits 46, 46A, 46B, 46C or 46D and the inner peripheral surface of the first cylindrical portion 13 is blocked due to the ambient pressure. The maximum dimension M of the cross section of each slit is 50 μm or less, which is very small, but the slits are not easily deformed, so that the flow of lubricating oil in the passage is ensured.

FIG. 5 shows a sealing device 50 according to a modified example of the embodiment of the present invention. In the sealing device 50, the first cylindrical portion 13 of the first sealing member 10 has double elastic cylinders 13a and 13c. That is, the first cylindrical portion 13 has an elastic cylinder 13a which is a part of the elastic ring 11, a rigid cylinder 13b which is a part of the rigid ring 12, and an elastic cylinder 13c which is a part of the elastic ring 11. The elastic cylinder 13a is in close contact with the outer peripheral surface of the rigid cylinder 13b, and the elastic cylinder 13c is in close contact with the inner peripheral surface of the rigid cylinder 13b and covers the entire inner peripheral surface of the rigid cylinder 13b. That is, the elastic cylinder 13c reaches the first ring portion 14.

The large diameter portion 33A of the second cylindrical portion 33 is tightly fitted to the first cylindrical portion 13, so that the second seal member 30 is fixed to the first seal member 10. Therefore, in the sealing device 50, the large-diameter portion 33A of the second cylindrical portion 33 that contacts the first cylindrical portion 13 is formed of metal, but the second cylindrical portion of the first cylindrical portion 13 The elastic cylinder 13c in contact with 33 is made of an elastic material.

Other features are substantially the same as those of the embodiment of FIG. 1, and the slit 56 is formed on the outer peripheral surface of the large diameter portion 33A of the second cylindrical portion 33. The cavity formed in the inner peripheral surface of the elastic cylinder 13c of the slit 56 and the first cylindrical portion 13 functions as a lubricating oil passage between the internal space 40 and the additional space 42, and always supplies the lubricating oil to the main lip 16. be able to.

The slit 56 has the same cross section as any of the slits 46, 46A, 46B, 46C and 46D shown in FIG. 3, and extends linearly along the axial direction of the sealing device 1. However, each slit 56 may be inclined with respect to the axial direction of the sealing device 1, and may be curved or bent.

However, in this modification, the cross-sectional area at both ends of the slit 56 is enlarged as compared with the slits 46 of FIGS. 1 and 2 so that the elastic cylinder 13c, which is easily deformed, does not block both ends of the slit 56. ..

The same effect as that of the embodiment can be achieved in the sealing device 50 according to this modification.

The passage connecting the internal space 40 and the additional space 42 is not the outer peripheral surface of the large diameter portion 33A of the second cylindrical portion 33 of the second sealing member 30, but the first cylindrical portion 13 of the first sealing member 10. It is also conceivable to form it on the inner peripheral surface of the elastic cylinder 13c. However, in this case, the elastic cylinder 13c may be deformed by receiving high pressure from the large diameter portion 33A, and the passage may be blocked. In this modification, since the slit 56 is formed on the outer peripheral surface of the large diameter portion 33A of the second cylindrical portion 33 made of metal, it is formed on the inner peripheral surface of the slit 56 and the first cylindrical portion 13. There is little risk of the passage being blocked, and the flow of lubricating oil in the passage is ensured.

In order to secure the flow of lubricating oil, the large diameter portion 33A of the second cylindrical portion 33 is tightly fitted to the first cylindrical portion 13 and is inside the slit 56 and the elastic cylinder 13c of the first cylindrical portion 13. The maximum dimension M of the cross section of the passage formed on the peripheral surface is 50 μm or less.

FIG. 7 shows a sealing device 60 according to another modification of the embodiment of the present invention. The sealing device 60 has a structure similar to that of the sealing device 50 shown in FIG. 5, but the slit 56 is not formed. Instead, a through hole 62 is formed in the second cylindrical portion 33 of the second seal member 30, and a through hole 64 is formed in the second annular portion 34 of the second seal member 30. The through hole 62 penetrates the second cylindrical portion 33 in the thickness direction thereof, and the through hole 64 penetrates the second annular portion 34 in the thickness direction thereof.

Each of the through holes 62 and 64 functions as a lubricating oil passage between the internal space 40 and the additional space 42, and the main lip 16 can always be supplied with the lubricating oil. In this way, the main lip 16 is always lubricated, so that the lubricating oil cools and lubricates the main lip 16. Therefore, the deterioration of the main lip 16 due to the temperature rise and the wear of the main lip 16 due to the sliding of the rotating shaft 4 are suppressed, and the life of the main lip 16 and thus the sealing device 1 is extended.

The maximum size of each cross section of the through holes 62 and 64 is 50 μm or less, and it is suppressed that a large foreign matter from the internal space 40 passes through the slit 46 and reaches the additional space 42. Therefore, there is little possibility that the main lip 16 forming the additional space 42 is damaged by foreign matter, and there is little possibility that the foreign matter enters between the main lip 16 and the rotating shaft 4 and the lubricating oil leaks from the main lip 16.

As the number of through holes 62, 64 increases, the concern about insufficient lubrication of the main lip 16 decreases. This is because even if any of the through holes 62 and 64 is blocked by a foreign substance, the other through holes can supply lubricating oil from the internal space 40 to the additional space 42. Even if the number of through holes is large, by limiting the dimensions of the through holes, it is possible to reduce the concern that foreign matter flows from the internal space 40 into the additional space 42.

In this modification, the through holes 62 and 64 are provided, but the through hole 62 is formed in the second cylindrical portion 33, and the through hole 64 is formed in the second annular portion 34 of the second sealing member 30. It does not have to be formed. On the contrary, the through hole 62 may not be formed in the second cylindrical portion 33, and the through hole 64 may be formed in the second annular portion 34 of the second sealing member 30.

The number of through holes is one or more and is not limited. When only one through hole is formed in the second sealing member 30, a through hole is arranged below the sealing device 60 in which the lubricating oil is stored, and the lubricating oil passes through the through hole from the internal space 40 to the additional space 42. It is desirable that it can be supplied through.

In the sealing device 60 according to this modification, at least one slit 56 may be formed.

The sealing device 60 according to this modification is based on the sealing device 50, but the sealing device 1 without the elastic cylinder 13c may be provided with through holes 62 and / or 64. In this case, a slit may or may not be formed in the sealing device 1.

Although the present invention has been illustrated and described above with reference to preferred embodiments of the present invention, those skilled in the art can change the form and details without departing from the scope of the invention described in the claims. It will be understood that there is. Such changes, modifications and modifications should be within the scope of the invention.

For example, in the above embodiment, the housing 2 is an axle box of a railroad vehicle, and the rotating shaft 4 is an axle. However, the application of the present invention is not limited to the embodiment, and the sealing device 1 according to the present invention can be used to seal the gap between the rotating shaft of the automobile or other machine and the housing.

In the above embodiment, the main lip 16, the dust strip 17, and the auxiliary lip 35 come into contact with the rotating shaft 4, but may come into contact with a member fixed around the rotating shaft 4. In this case, the members fixed around the rotating shaft 4 can also be regarded as a part of the rotating shaft.

Aspects of the invention are also described in the numbered clauses below.

Clause 1. A sealing device that seals a gap between a housing and a rotating shaft arranged in a shaft hole provided in the housing.
A first cylindrical portion attached to the housing, a first annular portion extending radially inward from the first cylindrical portion, and a radial inner side of the first annular portion, said to be arranged. A first sealing member having a first lip that slidably contacts the outer peripheral surface of the rotating shaft, and
A second cylindrical portion fitted into the first cylindrical portion of the first sealing member, a second annular portion extending radially inward from the second cylindrical portion, and the second circle. It has a second sealing member that is arranged radially inside the ring and has a second lip that slidably contacts the outer peripheral surface of the rotating shaft.
The outer peripheral surface of the rotating shaft, the housing, the first cylindrical portion, and the second sealing member define an internal space in which the lubricating oil is sealed.
The outer peripheral surface of the rotating shaft, the first annular portion, the first lip, the second cylindrical portion, the second annular portion, and the second lip are lubricated. Define an additional space where the oil is sealed,
The second seal member is formed with at least one passage for communicating the internal space with the additional space, and the maximum dimension of the cross section of the passage orthogonal to the extending direction of the passage is 50 μm or less. Sealing device.

Clause 2. Of the second cylindrical portion, the portion in contact with the first cylindrical portion is formed of metal.
The sealing device 1 according to Clause 1, wherein the passage is formed by a slit formed on an outer peripheral surface of the metal portion and an inner peripheral surface of the first cylindrical portion.

According to this clause, since the slit is formed in the metal part of the second cylindrical portion, the second cylindrical portion is fitted into the first cylindrical portion and is higher than the first cylindrical portion. Even if pressure is applied, the amount of deformation of the slit is small. That is, there is little possibility that the passage formed by the slit and the inner peripheral surface of the first cylindrical portion is blocked due to the ambient pressure. The maximum dimension of the cross section of the passage is 50 μm or less, which is very small, but the slit is not easily deformed, so that the flow of lubricating oil in the passage is ensured.

Clause 3. The sealing device 1 according to Clause 1, wherein the passage is a through hole penetrating the second cylindrical portion or the second annular portion in the thickness direction.

According to this clause, since the passage is a through hole, the passage is not affected even if the second cylindrical portion is fitted into the first cylindrical portion.

1 Sealing device 2 Housing 2A Shaft hole 4 Rotating shaft 10 First sealing member 13 First cylindrical portion 14 First annular portion 16 Main lip (first lip)
30 Second sealing member 31 Elastic ring 32 Rigid ring 33 Second cylindrical portion 34 Second annular portion 35 Auxiliary lip (second lip)
40 Internal space 42 Additional space 46, 46A, 46B, 46C, 46D Slit M Maximum size 50 Sealing device 60 Sealing device 62,64 Through hole

Claims (3)

A sealing device that seals a gap between a housing and a rotating shaft arranged in a shaft hole provided in the housing.
A first cylindrical portion attached to the housing, a first annular portion extending radially inward from the first cylindrical portion, and a radial inner side of the first annular portion, said to be arranged. A first sealing member having a first lip that slidably contacts the outer peripheral surface of the rotating shaft, and
A second cylindrical portion fitted into the first cylindrical portion of the first sealing member, a second annular portion extending radially inward from the second cylindrical portion, and the second circle. It has a second sealing member that is arranged radially inside the ring and has a second lip that slidably contacts the outer peripheral surface of the rotating shaft.
The outer peripheral surface of the rotating shaft, the housing, the first cylindrical portion, and the second sealing member define an internal space in which the lubricating oil is sealed.
The outer peripheral surface of the rotating shaft, the first annular portion, the first lip, the second cylindrical portion, the second annular portion, and the second lip are lubricated. Define an additional space where the oil is sealed,
The second seal member is formed with at least one passage for communicating the internal space with the additional space, and the maximum dimension of the cross section of the passage orthogonal to the extending direction of the passage is 50 μm or less. Sealing device. Of the second cylindrical portion, the portion in contact with the first cylindrical portion is formed of metal.
The sealing device 1 according to claim 1, wherein the passage is formed by a slit formed on an outer peripheral surface of the metal portion and an inner peripheral surface of the first cylindrical portion. The sealing device 1 according to claim 1, wherein the passage is a through hole penetrating the second cylindrical portion or the second annular portion in the thickness direction.

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