JP2017180482A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of improving holding performance of a lubricant even further.SOLUTION: A sealing device 1 seals between a reciprocation shaft 4 and a shaft hole inner surface on which the reciprocation shaft 4 is arranged, and separates the atmosphere side from a sealed fluid side. The sealing device 1 includes: a main seal lip part 22 on the sealed fluid side; and a sub seal lip part 24 arranged further on the atmosphere side than the main seal lip part 22. On an inclined surface of one of or both of the main seal lip part 22 and the sub seal lip part 24, a plurality of recess parts 30 for lubricant holding are arranged in an annular manner.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing device used for a sealing portion around an axis of an apparatus having a reciprocating shaft.

  As is well known, in a device having a reciprocating shaft such as a hydraulic cylinder device or a shock absorber, a sealing device is provided between the reciprocating shaft and the inner surface of the shaft hole to seal an annular gap between them. It is done.

  Conventionally, as this kind of sealing device, for example, a device shown in Patent Document 1 is known. FIG. 11 shows the configuration of the device. As shown in FIG. 11, the sealing device 100 is provided on the atmosphere A side with respect to the main lip portion 104 slidably sealingly contacting the reciprocating shaft 102. The second-stage lip portion 106 is provided. The second lip 106 supports the main lip 104 for sealing function. A parallel protrusion 108 is provided on the main lip portion 104, and a parallel groove 110 is provided on the second-stage lip portion 106. In the sealing device 100, a lubricant such as grease is held between the parallel protrusions 108 and in the parallel grooves 110 in order to reduce wear and extend its life.

Japanese Patent No. 3150861

  As for the sealing device, there is a demand for further extending its life, and therefore further improvement of the retention performance of the lubricant is required.

  Then, an object of this invention is to provide the sealing device which can further improve the retention capability of a lubricant.

  In order to solve the above-described problems, a sealing device according to the present invention is disposed between a reciprocating shaft and an inner surface of a shaft hole in which the reciprocating shaft is disposed, and slidably comes into sealing contact with the reciprocating shaft. A sealing device comprising: a main seal lip portion; and a sub-seal lip portion provided so as to be positioned on the atmosphere side from the main seal lip portion and slidably sealingly contacting the reciprocating shaft. A plurality of lubricant retaining recesses are provided at intervals in the circumferential direction on one or both of the inclined surfaces of the seal lip portion and the sub seal lip portion.

  In this sealing device, the lubricant is interposed between the main seal lip portion and the sub seal lip portion and the reciprocating shaft, and the lubricant is held in the plurality of recesses. Therefore, when the reciprocating shaft is driven, the lubricant is held in each recess, so that a good lubrication state is secured and wear of the seal lip portion is reduced.

  The plurality of recesses are preferably provided on an inclined surface of the main seal lip portion on the side of the sub seal lip portion. In this configuration, it is possible to secure a good lubrication state by suppressing a decrease in the surface pressure of the sub seal lip portion.

  It is preferable that the length of the recess in the axial direction of the reciprocating shaft is larger than the length of the recess in the circumferential direction. In this case, since the length of each recess in the movement direction of the reciprocating shaft is larger, even if the reciprocating shaft moves and the lubricant in each recess receives compressive force and tensile force, There is little risk of lubricant escaping.

  The plurality of recesses are annularly arranged at a plurality of positions by shifting the position in the axial direction of the reciprocating shaft, and the plurality of recesses arranged at one position and the plurality of recesses arranged at two positions are It is preferable to configure so as to overlap each other when projected in the axial direction. In this configuration, even if the recesses are arranged at intervals, the lubricant is arranged over the entire circumferential direction, so that wear of the seal lip portion can be further reduced.

  In the present invention, the lubricant is stored in the plurality of recesses. Since the plurality of recesses are spaced apart from each other, the lubricant is retained in the recesses for a long period of time compared to the case where the recesses are formed continuously, that is, when the recesses are circumferential grooves. Therefore, the retention performance of the lubricant is improved, and the life of the sealing device can be further extended.

It is sectional drawing of the sealing device which concerns on embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is an expanded view which shows the some recessed part which concerns on other embodiment. It is an expanded view which shows the some recessed part which concerns on other embodiment. It is an expanded view which shows the some recessed part which concerns on other embodiment. It is an expanded view which shows the some recessed part which concerns on other embodiment. It is an expanded view which shows the some recessed part which concerns on other embodiment. It is a fragmentary sectional view of the sealing device concerning other embodiments. It is an expanded view of the internal peripheral surface of the seal | sticker main body of the sealing device which concerns on embodiment of FIG. It is sectional drawing of the conventional sealing device.

Embodiments according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 to FIG. 3 are diagrams showing an embodiment of the present invention, and show a main part of a sealing device provided in a device having a reciprocating shaft.

  The sealing device 1 seals between the reciprocating shaft 4 and the inner surface of the shaft hole 6 of the housing in which the reciprocating shaft 4 is inserted, and fluid leaks from the sealed fluid L side to the atmosphere A side. This is to prevent or reduce this. The reciprocating shaft 4 has a cylindrical shape, the shaft hole 6 has a circular cross section, and the sealing device 1 is substantially annular, but only the upper half of them is shown in FIG. FIG. 1 shows a common central axis C of the reciprocating shaft 4, the shaft hole 6 and the sealing device 1.

  The sealing device 1 includes an annular seal body 8 formed of an elastic material, for example, an elastomer, and a rigid body, for example, a metal reinforcing ring 10 that is embedded in the seal body 8 and reinforces the seal body 8. The seal body 8 includes an outer annular body 12 which is an outer seal portion attached to the shaft hole 6 of the housing, an inner annular body 14 disposed coaxially with the outer annular body 12 on the radially inner side of the outer annular body 12, and an outer side. An annular body 12 and a flange 16 that connects the inner annular body 14 are provided.

  The reinforcing ring 10 is a ring with an L-shaped cross section, and the long side of the L-shape is embedded in the outer annular body 12 and the short side is embedded in the flange 16. However, the reinforcing ring 10 is not necessarily indispensable and may be exposed without being embedded in the seal body 8.

  The outer annular body 12 is fixed to the housing, for example, by being fitted into the inner surface of the shaft hole 6. A garter spring 18 for compressing the inner annular body 14 radially inward is wound around the inner annular body 14.

  The seal body 8 further includes a main seal lip portion 22, a sub seal lip portion 24 and a dust lip portion 26. The main seal lip part 22, the sub seal lip part 24, and the dust lip part 26 are all protrusions that protrude inward from the inner annular body 14 and are continuous in the circumferential direction. When the sealing device 1 is arranged around the reciprocating shaft 4, the main seal lip portion 22, the sub seal lip portion 24, and the dust lip portion 26 are in sealing contact with the outer peripheral surface of the reciprocating shaft 4, and the sealed fluid L side Prevents or reduces fluid leakage from the atmosphere to the atmosphere A side. When the reciprocating shaft 4 moves in the direction of the central axis C, the reciprocating shaft 4 slides with respect to the main seal lip portion 22, the sub seal lip portion 24 and the dust lip portion 26.

  The main seal lip portion 22, the sub seal lip portion 24 and the dust lip portion 26 are deformed radially outward from the state shown in FIG. 1 in order to contact the outer peripheral surface of the reciprocating shaft 4. FIG. 1 shows a state in which the sealing device 1 is not disposed around the reciprocating shaft 4 (the reciprocating shaft 4 is indicated by phantom lines), and the lip portions 22, 24, and 26 are deformed. Does not represent.

  The main seal lip portion 22 and the sub seal lip portion 24 mainly serve to seal fluid. The garter spring 18 applies a force to the lip portions 22 and 24 to press the main seal lip portion 22 and the sub seal lip portion 24 against the reciprocating shaft 4. The main seal lip portion 22 and the sub seal lip portion 24 can also be considered as parts of one seal lip portion. The object to be sealed may be oil or other fluid such as water. The main seal lip portion 22 is disposed on the sealed fluid L side, and the sub seal lip portion 24 is disposed on the atmosphere A side of the main seal lip portion 22.

  The main seal lip portion 22 is a triangular projection having two inclined surfaces. The inner tip edge of the main seal lip portion 22 has a smaller inner diameter than the inner tip edges of the other lip portions 24 and 26. That is, the main seal lip portion 22 has the largest protrusion amount from the inner annular body 14 and has the highest ability to seal the fluid as compared with the other lip portions 24 and 26.

  The sub seal lip portion 24 has a role of stabilizing the sealing ability of the main seal lip portion 22. The sub-seal lip portion 24 is also a triangular projection having two inclined surfaces. The inner tip edge of the sub seal lip portion 24 has a larger inner diameter than the inner tip edges of the other lip portions 22 and 26. That is, the sub seal lip portion 24 has the smallest protrusion amount from the inner annular body 14 and the deformation amount due to the reciprocating shaft 4 coming into contact is smaller than those of the other lip portions 22 and 26. When the reciprocating shaft 4 is eccentric, the sealing function in the circumferential direction of the main seal lip portion 22 is biased, but the sealing function of the entire sealing device 1 is reduced by the sealing function of the sub seal lip portion 24. It can be suppressed.

  The dust lip portion 26 extends obliquely from the connecting portion of the flange 16 and the inner annular body 14 to the atmosphere A side and to the inside. The dust lip 26 mainly serves to prevent foreign matter from entering from the atmosphere A side to the sealed fluid L side.

  As shown in FIGS. 1 to 3, a plurality of recesses 30 are formed on the inner peripheral surface of the seal body 8 to hold a lubricant such as grease or lubricating oil that reduces wear of the seal lip portions 22 and 24. The recesses 30 are annularly arranged at intervals over the entire inner peripheral surface of the seal body 8.

  The position where the concave portion 30 is disposed may be one of the inclined surfaces of the main seal lip portion 22 and the sub seal lip portion 24, or may be the inclined surfaces of both the seal lip portions 22, 24. However, as shown in FIGS. 1 to 3, it is preferable that the concave portion 30 is provided on the inclined surface of the main seal lip portion 22 on the sub seal lip portion 24 side. If a concave portion is formed on one or both of the two inclined surfaces of the sub seal lip portion 24, the strength of the sub seal lip portion 24 decreases, and the contact pressure between the inner end edge of the sub seal lip portion 24 and the reciprocating shaft 4 is reduced. It is because there exists a possibility that it may fall. In other words, if the concave portion 30 is provided on the inclined surface of the main seal lip portion 22 on the side of the sub seal lip portion 24, the strength of the sub seal lip portion 24, and consequently, the inner tip edge of the sub seal lip portion 24 reciprocates. It is possible to appropriately maintain the contact pressure with the shaft 4 (surface pressure of the sub seal lip portion 24).

  When the recess is a circumferential groove, the lubricant flows downward due to gravity while the reciprocating shaft 4 is stopped. Therefore, the lubricant is less above the seal body 8 when the reciprocating shaft 4 resumes motion. The frictional force may increase. However, in this embodiment, since the plurality of recesses 30 are spaced apart from each other, the lubricant is stably held in the recesses 30 over a long period of time compared to the case where the recesses are circumferential grooves. According to this configuration, the retention performance of the lubricant is improved, and the life of the sealing device 1 can be further extended. In particular, this effect is remarkable when the fluid to be sealed is a fluid having low lubricity (for example, water).

  In addition, since the plurality of recesses 30 are spaced apart from each other, the seal in which the recesses 30 are formed depends on the size, number, and specific arrangement of the recesses 30 compared to when the recesses are circumferential grooves. It is possible to increase the strength of the lip portion.

  As shown in FIG. 1, the plurality of recesses 30 have the same size, and the length of each recess 30 in the circumferential direction of the seal body 8 is larger than the length of each recess 30 in the central axis C direction. That is, each recess 30 is a vertically long type. The plurality of recesses 30 are arranged in a row in the circumferential direction. However, the illustrated recess 30 is merely exemplary. The shape of the recess 30 is an ellipse, but the shape of the recess 30 is not limited to an ellipse, and may be another shape.

  More generally speaking, the shape, dimensions (length and width) and depth of the recess 30 are not limited, the ability to retain the lubricant, the strength of the seal lip portion where the recess 30 is formed, and the manufacturing It can be appropriately selected from the viewpoint of ease. Further, the specific arrangement of the recesses 30 (for example, the interval between the recesses 30 and the number of rows) is not limited, and can be appropriately selected from the same viewpoint.

  4 to 8 are developed views of the inner peripheral surface of the seal body 8 showing a plurality of recesses 30 according to other embodiments. In the embodiment shown in FIG. 4, the length of each recess 30 in the direction of the central axis C is larger than the length of each recess 30 in the circumferential direction P. That is, each recess 30 is a horizontally long type. In this embodiment, since the length of each recess 30 in the movement direction of the reciprocating shaft 4 is larger, even if the reciprocating shaft 4 moves and the lubricant in each recess 30 receives a compressive force and a tensile force. The risk of the lubricant escaping from each recess 30 is small. That is, it is considered that the retention performance of the lubricant in each recess 30 is high.

  The plurality of recesses 30 may be arranged in two rows as shown in FIGS. In each row, a plurality of recesses 30 are arranged in the circumferential direction. That is, the plurality of recesses 30 are annularly arranged at two positions with their positions shifted in the direction of the central axis C. Although not shown, the number of rows of the recesses 30 may be larger than two.

  In the embodiment shown in FIG. 7, when the plurality of recesses 30 arranged in one row and the plurality of recesses 30 arranged in another row are projected in the direction of the central axis C, they overlap each other. Yes. As described above, the concave portions 30 belonging to one row overlap with the concave portions 30 belonging to the other rows in the movement direction of the reciprocating shaft 4, so that the entire circumferential direction can be obtained even if the concave portions 30 are arranged at intervals. Since the lubricant is disposed on the inner peripheral surface of the seal main body 8 without any breaks, the wear of the seal main body 8 can be further reduced. Although the recessed part 30 of FIG. 7 is a vertically long type, you may arrange | position the horizontally long recessed part 30 in the same format as FIG.

  In any of the above embodiments, the recesses 30 have the same shape and size as each other, but a plurality of recesses 30 having different shapes and different sizes may be provided in the sealing device 1 as shown in FIG.

  From the viewpoint of ease of manufacture, the recesses 30 are preferably arranged at regular intervals or regularly. However, the recesses 30 may be arranged irregularly. For example, since it is considered that the lubricant easily flows downward due to gravity while the reciprocating shaft 4 is stopped, the total area (or total volume) of the plurality of recesses 30 above the inner peripheral surface of the seal body 8 is considered. ) May be disposed so that the total area (or total volume) of the plurality of recesses 30 below is larger (not shown). In this case, when the movement of the reciprocating shaft 4 is resumed, the amount of lubricant above the inner peripheral surface of the seal body 8 can be ensured appropriately.

  9 and 10 show a sealing device according to still another embodiment. FIG. 9 is a partial cross-sectional view of the sealing device, and FIG. 9 is a development view of the inner peripheral surface of the seal body 8 of the sealing device according to the embodiment. In this embodiment, a plurality of parallel circumferential grooves 32 are formed on the inclined surface on the atmosphere A side of the sub seal lip portion 24. The groove 32 is formed over the entire circumference of the seal body 8. The groove 32 can store a lubricant. As described above, the present invention does not exclude provision of means for holding another lubricant in addition to the recess 30.

  Although various embodiments of the present invention have been described above, the above description is not intended to limit the present invention, and various modifications including deletion, addition, and replacement of components are included in the technical scope of the present invention. Conceivable.

DESCRIPTION OF SYMBOLS 1 Sealing device 4 Reciprocating shaft 6 Shaft hole 8 Seal main body 10 Reinforcement ring 12 Outer ring body 14 Inner ring body 16 Flange 18 Garter spring 22 Main seal lip part 24 Sub seal lip part 26 Dustrip part 30 Recess 32 Circumferential groove

Claims (4)

It is arranged between the reciprocating shaft and the inner surface of the shaft hole where the reciprocating shaft is arranged,
A main seal lip portion slidably sealingly contacting the reciprocating shaft;
A sealing device provided with an auxiliary seal lip portion provided to be located on the atmosphere side from the main seal lip portion and slidably sealingly contacting the reciprocating shaft;
A plurality of lubricant retaining recesses are provided at intervals in the circumferential direction on one or both of the inclined surfaces of the main seal lip portion and the sub seal lip portion. apparatus.   The sealing device according to claim 1, wherein the plurality of concave portions are provided on an inclined surface of the main seal lip portion on the side of the sub seal lip portion.   The sealing device according to claim 1, wherein a length of the concave portion in an axial direction of the reciprocating shaft is larger than a length of the concave portion in a circumferential direction.   The plurality of recesses are arranged annularly at a plurality of positions by shifting their positions in the axial direction of the reciprocating shaft, and the plurality of recesses disposed at one position and the plurality of recesses disposed at two positions are the axis line. The sealing device according to any one of claims 1 to 3, wherein the sealing devices overlap each other when projected in a direction.

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