JP2018189098A - Annular dust lip and sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an annular dust lip having excellent anti-dust function and capable of excellently maintaining the anti-dust function for a long period, and a sealing device.SOLUTION: An annular dust lip 1 comprises an elastic material, is supported by a housing 101, and contacts with an outer peripheral surface 102a of a reciprocable shaft 102 arranged in the housing 101. When the annular dust lip contacts with the outer peripheral surface 102a of the reciprocable shaft 102, a lip end surface 2d facing the atmosphere side is formed into such a tapered shaped as to project to the atmosphere side as approaching the outer peripheral surface 102a of the reciprocable shaft 102.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an annular dust strip and a sealing device, and more particularly to an annular dust strip and a sealing device that have an excellent dust resistance function and can maintain the dust resistance function well for a long period of time.

  2. Description of the Related Art Conventionally, a sealing device used for a rod seal portion in an automobile shock absorber or the like includes an annular dust strip 400 slidably sealingly contacting an outer peripheral surface of a reciprocating shaft (rod) 200 as shown in FIG. (Patent Document 1).

  The reciprocating shaft 200 is disposed in the housing 202 and can reciprocate in the axial direction as indicated by an arrow A in FIG. The reciprocating shaft 200 has a base end side (left side in FIG. 7) positioned in the housing 202 and a tip end side (right side in FIG. 7) outside the opening end of the housing 202 in the axial direction (hereinafter “atmosphere side”). ”).

  The annular dust strip 400 is integrally formed in an annular shape from a rubber-like elastic material. The annular dust strip 400 is disposed in an annular groove 300 formed in the housing 202. The annular groove 300 is formed so as to surround the outer peripheral surface of the reciprocating shaft 200.

  The annular dust strip 400 has a substantially U-shaped longitudinal section, with the U-shaped opening facing the atmosphere. That is, the annular dust lip 400 has a shape in which the inner circumferential side cylindrical portion 401 and the outer circumferential side cylindrical portion 402 are connected at the side edge on the axially inner side (hereinafter referred to as “mechanism side”). The connecting portion between the inner peripheral cylindrical portion 401 and the outer peripheral cylindrical portion 402 is fixed to the side wall portion on the mechanism side of the annular groove 300. In the annular dust strip 400, the inner peripheral portion of the inner peripheral cylindrical portion 401 is brought into contact with the outer peripheral surface of the reciprocating shaft 200.

  An annular leaf spring 500 is disposed between the inner peripheral cylindrical portion 401 and the outer peripheral cylindrical portion 402 of the annular dust strip 400. The annular leaf spring 500 is a chrysanthemum spring and is elastically biased in the direction in which the inner peripheral cylindrical portion 401 is separated from the outer peripheral cylindrical portion 402 as indicated by an arrow B in FIG.

  The annular dust strip 400 presses the inner peripheral portion of the inner peripheral cylindrical portion 401 against the outer peripheral surface of the reciprocating shaft 200 by the urging force of the annular leaf spring 500. The housing 202 is sealed by the inner peripheral portion of the inner peripheral cylindrical portion 401 being pressed against the outer peripheral surface of the reciprocating shaft 200.

  In this sealing device, the annular dust strip 400 has a dust resistance function that prevents external foreign matter (such as earth and sand, ore, oil, water, ice, and sap) from entering the housing 202. This sealing device contributes to extending the service life of the equipment by maintaining a good lubrication state of the hydraulic holding parts and the sliding parts such as bearings and gears that are closer to the mechanism than the annular dust strip 400 for a long period of time. .

Japanese Utility Model Publication No. 63-27763

  The annular dust strip 400 is formed of various rubbers, urethane, PTFE, or the like as an elastic material that can seal a gap between the outer peripheral surface of the reciprocating shaft 200 in order to prevent intrusion of external foreign matter into the housing 202. . Further, the annular dust strip 400 needs to scrape off the external foreign matter fixed to the outer peripheral surface of the reciprocating shaft 200, so that rigidity is required, and the annular dust strip 400 is formed of a synthetic resin material such as high hardness rubber or urethane.

  However, the annular dust strip 400 made of these materials has a limit in long-term maintenance of the dust-proof function due to deformation (sagging) due to creep or deterioration with time. In order to maintain the dust resistance function for a long time, it is necessary to maintain the interference margin and the seal surface pressure for a long time. For this purpose, the inner peripheral cylindrical portion 401 shown in FIG. 8B is more advantageous than the thin inner peripheral cylindrical portion 401 shown in FIG.

  However, when the inner peripheral cylindrical portion 401 is thickened, as shown in FIG. 8B, the area of the lip end surface 401a facing the atmosphere is increased, and the foreign matter retention area (lip end surface 401a) where the external foreign matter d stays. To the outer peripheral surface of the reciprocating shaft 200) also becomes wide, and the amount of the external foreign matter d staying increases. When the amount of the external foreign matter d staying increases, it becomes difficult to scrape the external foreign matter d from the outer peripheral surface of the reciprocating shaft 200, resulting in a decrease in the dust resistance function.

  Then, this invention makes it a subject to provide the annular dust strip and sealing device which have the outstanding dust-proof function and can maintain a dust-proof function favorably for a long period of time.

  The other subject of this invention becomes clear by the following description.

  The above problems are solved by the following inventions.

1.
An annular dust strip made of an elastic material, supported by a housing and brought into contact with an outer peripheral surface of a reciprocating shaft disposed in the housing;
An annular dust strip having a taper shape in which a lip end surface facing the atmosphere side when coming into contact with the outer peripheral surface of the reciprocating shaft has a taper shape protruding toward the atmosphere side closer to the outer peripheral surface of the reciprocating shaft. .
2.
An annular dust strip made of an elastic material, supported by a housing and brought into contact with an outer peripheral surface of a reciprocating shaft disposed in the housing;
When the outer peripheral surface of the reciprocating shaft contacts with the outer peripheral surface of the reciprocating shaft at least near the outer peripheral surface of the reciprocating shaft of the lip end surface facing the atmosphere side is 90 ° or more. A featured annular dust strip.
3.
The inner circumferential side cylindrical portion and the outer circumferential side cylindrical portion are connected to each other at the side edge so that the longitudinal section is formed in a substantially U shape, and the opening portion of the substantially U shape is directed to the atmosphere side. Bringing the inner periphery into contact with the outer periphery of the reciprocating shaft;
An annular leaf spring is disposed between the inner peripheral cylindrical portion and the outer peripheral cylindrical portion,
The annular leaf spring is a chrysanthemum spring configured in a ring shape, and is formed of a cylindrical portion and a plurality of pressing pieces projecting from the side edges of the cylindrical portion, and each pressing piece is formed of the cylindrical portion. Folded so as to overlap the inner peripheral side, the vertical cross section is substantially V-shaped, the open side of the substantially V-shaped is directed to the atmosphere side, and the tip side of the pressing piece causes the inner peripheral side cylindrical portion to 3. The annular dust strip according to claim 1 or 2, wherein the vicinity of the lip end facing the atmosphere side is elastically biased in the centripetal direction, and the vicinity of the lip end is pressed against the outer peripheral surface of the reciprocating shaft. .
4).
The annular dust strip has a portion excluding the vicinity of the lip end portion separated from the outer peripheral surface of the reciprocating shaft, and reinforcing bands are provided at equal angular intervals on the inner peripheral surface of the portion separated from the outer peripheral surface. 4. The annular dust strip according to 3 above, wherein the annular dust strip is provided.
5.
An annular dust strip made of an elastic material, supported by the housing, and in contact with the outer peripheral surface of the reciprocating shaft disposed in the housing;
An annular leaf spring which is disposed along the annular dust strip to urge the annular dust strip and presses the outer peripheral surface of the reciprocating shaft against the vicinity of the lip end facing the atmosphere side of the annular dust strip; With
The sealing device according to claim 1, wherein the lip end portion of the annular dust strip is a maximum point of surface pressure with respect to the outer peripheral surface of the reciprocating shaft.
6).
6. The sealing device according to 5 above, wherein the annular dust strip has a tapered shape in which a lip end surface facing the atmosphere side protrudes toward the atmosphere side closer to the outer peripheral surface of the reciprocating shaft.
7).
7. The annular dust strip according to the above 5 or 6, wherein an angle formed by at least an outer peripheral surface of the reciprocating shaft of a lip end surface facing the atmosphere side with respect to a generatrix of the outer peripheral surface is 90 ° or more. Sealing device.
8).
The annular dust strip has an inner circumferential side cylindrical portion and an outer circumferential side cylindrical portion connected at a side edge to form a substantially U-shaped longitudinal section, with the substantially U-shaped open portion facing the atmosphere side, Bringing the inner peripheral portion of the inner peripheral cylindrical portion into contact with the outer peripheral surface of the reciprocating shaft;
An annular leaf spring is disposed between the inner peripheral cylindrical portion and the outer peripheral cylindrical portion,
The annular leaf spring is a chrysanthemum spring configured in a ring shape, and is formed of a cylindrical portion and a plurality of pressing pieces projecting from the side edges of the cylindrical portion, and each pressing piece is formed of the cylindrical portion. Folded so as to overlap the inner peripheral side, the vertical cross section is substantially V-shaped, the open side of the substantially V-shaped is directed to the atmosphere side, and the tip side of the pressing piece causes the inner peripheral side cylindrical portion to 8, 6, or 7, wherein the vicinity of the lip end facing the atmosphere side is elastically biased in the centripetal direction, and the vicinity of the lip end is pressed against the outer peripheral surface of the reciprocating shaft. Sealing device.
9.
The annular dust strip has a portion excluding the vicinity of the lip end portion separated from the outer peripheral surface of the reciprocating shaft, and reinforcing bands are provided at equal angular intervals on the inner peripheral surface of the portion separated from the outer peripheral surface. 9. The sealing device according to any one of 5 to 8, wherein the sealing device is provided.

  According to the present invention, it is possible to provide an annular dust strip and a sealing device that have an excellent dust resistance function and can maintain the dust resistance function well for a long period of time.

The fragmentary sectional view which shows 1st Embodiment (mounting state) of the sealing device of this invention FIG. 1 is an enlarged cross-sectional view showing a main part of an annular dust strip of the sealing device shown in FIG. The graph which shows the surface pressure with respect to the reciprocating motion axis | shaft of the annular | circular dust strip of the sealing device shown in FIG. The fragmentary sectional view which shows 1st Embodiment (non-mounting state) of the sealing device of this invention The fragmentary sectional view which shows 2nd Embodiment of the sealing device of this invention The fragmentary sectional view which shows 3rd Embodiment of the sealing device of this invention Partial sectional view showing a conventional sealing device The principal part expanded sectional view which shows the conventional sealing device

  Hereinafter, modes for carrying out the present invention will be described.

[First Embodiment]
FIG. 1 is a partial sectional view showing a first embodiment (mounted state) of a sealing device of the present invention.

  The first embodiment of the sealing device 1 is used for a rod seal in an automobile shock absorber or the like.

  As shown in FIG. 1, the shock absorber has a housing 101 that holds fluid (oil). The housing 101 has an opening 101a on the atmosphere side (right side in FIG. 1), and the mechanism side (left side in FIG. 1) not shown is closed. A reciprocating shaft (rod) 102 is disposed in the housing 101. The reciprocating shaft 102 is positioned on the mechanism side in the housing 101, and the atmosphere side is projected outwardly in the axial direction of the housing 101 from the opening 101 a of the housing 101. The reciprocating shaft 102 can reciprocate in the axial direction as indicated by an arrow A in FIG. The speed of the reciprocating shaft 102 is regulated by the fluid in the housing 101 in the axial direction. Note that this shock absorber is used in an automobile or the like in which the housing 101 is held by a chassis (chassis) and the atmosphere side of the reciprocating shaft 102 is attached to a lower part of a spring including the axle.

  The sealing device 1 includes an annular dust strip 2 that slidably comes into contact with an outer peripheral surface 102 a of a reciprocating shaft 102. The annular dust strip 2 is integrally formed in an annular shape by a rubber-like elastic material. The material forming the annular dust strip 2 is preferably a synthetic resin material such as various rubbers, urethane, and PTFE as an elastic material capable of sealing a gap between the outer peripheral surface 102a of the reciprocating shaft 102.

  The annular dust strip 2 is disposed in the annular groove 3 provided in the housing 101 via the retaining ring 4. The annular groove 3 is located in the vicinity of the opening 101 a of the housing 101, surrounds the outer peripheral surface 102 a of the reciprocating shaft 102, and is formed coaxially with the reciprocating shaft 102. The sealing device 1 seals between the groove bottom of the annular groove 3 and the outer peripheral surface 102 a of the reciprocating shaft 102.

  The holding ring 4 is formed in an annular shape whose longitudinal section is L-shaped by a hard material such as metal. The retaining ring 4 has a shape in which a cylindrical portion arranged along the groove bottom portion of the annular groove 3 and an annular disk portion arranged along the side wall portion on the mechanism side of the annular groove 3 are provided. ing. The annular dust strip 2 is vulcanized and bonded to the retaining ring 4.

  The annular dust strip 2 has a substantially U-shaped longitudinal section, with the U-shaped opening facing the atmosphere. That is, the annular dust strip 2 has a shape in which the inner circumferential side cylindrical portion 2a and the outer circumferential side cylindrical portion 2b are connected at the side edge on the mechanism side. A connecting portion between the inner peripheral cylindrical portion 2 a and the outer peripheral cylindrical portion 2 b is vulcanized and bonded to the annular disk portion of the holding ring 4. The annular dust strip 2 has the inner peripheral portion of the inner peripheral cylindrical portion 2 a in contact with the outer peripheral surface 102 a of the reciprocating shaft 102.

  An annular leaf spring 5 is disposed along the annular dust strip 2 between the inner cylindrical portion 2 a and the outer cylindrical portion 2 b of the annular dust strip 2. The annular leaf spring 5 is a chrysanthemum spring configured in a ring shape from a spring steel material. The annular leaf spring 5 is formed of a cylindrical portion 5a and a plurality of pressing pieces 5b that protrude from the side edges of the cylindrical portion 5a. Each pressing piece 5b is folded back so as to overlap the inner peripheral side of the cylindrical portion 5a. Each pressing piece 5b and the cylindrical portion 5a forming the annular leaf spring 5 have a substantially V-shaped longitudinal section. The annular leaf spring 5 has the open side of the V-shaped longitudinal section facing the atmosphere side. As indicated by an arrow B in FIG. 1, the annular leaf spring 5 is elastically biased in a direction in which the inner peripheral cylindrical portion 2a is separated from the outer peripheral cylindrical portion 2b.

  The annular dust strip 2 presses the inner peripheral portion of the inner peripheral cylindrical portion 2 a to the outer peripheral surface 102 a of the reciprocating shaft 102 by the urging force of the annular leaf spring 5. In particular, the annular leaf spring 5 is elastically biased in the centripetal direction in the vicinity of the lip end 2c facing the atmosphere side of the inner peripheral cylindrical portion 2a by the front end side of the pressing piece 5b, and reciprocally moves in the vicinity of the lip end 2c. The shaft 102 is pressed against the outer peripheral surface 102a. The housing 101 is sealed by the inner peripheral portion of the inner peripheral cylindrical portion 2 a being pressed against the outer peripheral surface 102 a of the reciprocating shaft 102.

  In the annular leaf spring 5, the cylindrical portion 5a has an angle substantially along the inner circumferential portion of the outer circumferential side cylindrical portion 2b of the annular dust strip 2, and the distance from the cylindrical portion 5a to the pressing piece 5b (the width of the annular leaf spring 5). ) Is larger than the distance from the inner circumferential side cylindrical portion 2a to the outer circumferential side cylindrical portion 2b from the viewpoints of wearability and stability.

  FIG. 2 is an enlarged cross-sectional view showing a main part of an annular dust strip of the sealing device shown in FIG.

  As shown in FIG. 2, it is preferable that the annular leaf spring 5 elastically urges the lip end 2c of the inner peripheral cylindrical portion 2a in the centripetal direction by the distal end side of the pressing piece 5b. That is, it is preferable that the annular dust strip 2 is more strongly pressed against the outer peripheral surface 102a of the reciprocating shaft 102 as the position is closer to the lip end 2c of the inner peripheral cylindrical portion 2a.

  FIG. 3 is a graph showing the surface pressure with respect to the reciprocating axis of the annular dust strip of the sealing device shown in FIG.

  When the annular leaf spring 5 elastically urges the vicinity of the lip end 2c of the inner peripheral cylindrical portion 2a in the centripetal direction, the annular duster 2 has a reciprocating shaft 102 in the vicinity of the lip end 2c as shown in FIG. It becomes the maximum point of the surface pressure with respect to the outer peripheral surface 102a. The surface pressure of the annular dust strip 2 against the outer peripheral surface 102a of the reciprocating shaft 102 rises steeply in the vicinity of the lip end 2c. Therefore, in the vicinity of the lip end 2c, the liquid film (oil, water, sap, etc.) adhering to the outer peripheral surface 102a of the reciprocating shaft 102 can be thinned to cut the liquid film.

  The annular dust strip 2 is preferably thin in the vicinity of the lip end 2c. Thereby, the surface pressure with respect to the outer peripheral surface 102a of the reciprocating shaft 102 can be abruptly raised in the vicinity of the lip end portion 2c by the urging force of the annular leaf spring 5. The thickness in the vicinity of the lip end 2c is preferably about 0.5 mm to 3.0 mm, for example, considering creep resistance and wear resistance, although it depends on the use conditions.

  As shown in FIG. 1, the annular dust strip 2 has a tapered shape in which the lip end surface 2 d facing the atmosphere side of the inner circumferential side cylindrical portion 2 a protrudes toward the atmosphere side closer to the outer circumference surface 102 a of the reciprocating shaft 102. It is preferable.

  As described above, the shape of the lip end surface 2d is a taper shape that protrudes toward the atmosphere toward the side closer to the outer peripheral surface 102a of the reciprocating shaft 102, so that the lip end surface 2d scrapes off foreign matter adhering to the outer peripheral surface 102a. Can be performed satisfactorily.

  Further, the lip end surface 2d of the annular dust strip 2 does not have to be a conical surface (the longitudinal section is a straight line), and an angle formed by at least a portion in the vicinity of the outer peripheral surface 102a of the reciprocating shaft 102 with respect to the generatrix of the outer peripheral surface 102a. May be 90 ° or more.

  The portion of the lip end surface 2d in the vicinity of the outer peripheral surface 102a makes an angle of 90 ° or more with respect to the generatrix of the outer peripheral surface 102a, whereby the foreign matter attached to the outer peripheral surface 102a can be scraped off satisfactorily. When the angle of the portion near the outer peripheral surface 102 a of the lip end surface 2 d with respect to the generatrix of the outer peripheral surface 102 a is less than 90 °, the foreign matter adhering to the outer peripheral surface 102 a accompanies the reciprocating motion of the reciprocating shaft 102. As a result, there is a risk that it will flow between the reciprocating shaft 102 and the annular dust strip 2 without being scraped off well.

  FIG. 4 is a partial cross-sectional view showing a first embodiment (unmounted state) of the sealing device of the present invention.

  As shown in FIG. 4, when the annular dust strip 2 is not mounted around the reciprocating shaft 102, the lip end surface 2d of the inner peripheral cylindrical portion 2a is the outer peripheral surface of the mounted reciprocating shaft 102. The angle formed with respect to the generatrix of 102a may be less than 90 °, and may have a tapered shape that protrudes toward the atmosphere side as it is farther from the outer peripheral surface 102a. That is, when the annular dust strip 2 is mounted around the reciprocating shaft 102, the inner peripheral cylindrical portion 2a is pressed against the outer peripheral surface 102a, and is displaced against the urging force of the annular leaf spring 5, The angle formed with respect to the generatrix of the outer peripheral surface 102a of the lip end surface 2d is 90 ° or more, and the side closer to the outer peripheral surface 102a has a tapered shape protruding toward the atmosphere. The amount of displacement of the annular dust strip 2 at this time becomes the interference.

  In the sealing device 1, the annular dust strip 2 has an excellent dust resistance function that prevents external foreign matters (such as earth and sand, ore, oil, water, ice, and sap) from flowing into the housing 101. 2. The hydraulic pressure holding parts closer to the mechanism than 2 and sliding parts such as bearings and gears are in a good lubricating state.

  Further, in the sealing device 1, even when the inner peripheral portion of the inner peripheral side cylindrical portion 2a is worn, the pressing force of the inner peripheral side cylindrical portion 2a against the reciprocating shaft 102 is maintained by the annular leaf spring 5. . Therefore, the sealing device 1 can maintain an excellent dust resistance function for a long period of time, and can contribute to a long life of the device.

[Second Embodiment]
FIG. 5 is a partial cross-sectional view showing a second embodiment of the sealing device of the present invention.
In FIG. 5, since the site | part of the same code | symbol as FIG. 1, FIG. 4 is a site | part of the same structure, these description uses the description of the said embodiment, and abbreviate | omits here.

  In the second embodiment of the sealing device 1, as shown in FIG. 5, the annular dust lip 2 has a reciprocating shaft 102 at a portion (mechanism side) excluding the vicinity of the lip end 2 c of the inner peripheral cylindrical portion 2 a. Reinforcing bands 2e are provided in the axial direction at equal angular intervals on the inner peripheral surface of this portion, spaced apart from the outer peripheral surface 102a. The reinforcing band 2e is a ridge in which only the portion of the inner circumferential cylindrical portion 2a is thickened.

  Even when the inner peripheral side cylindrical portion 2a is thinned by providing the reinforcing band 2e so that the surface pressure against the outer peripheral surface 102a of the reciprocating shaft 102 in the vicinity of the lip end portion 2c rises sharply, the inner peripheral side cylindrical portion The axial rigidity of 2a is maintained, and stick-slip (self-excited vibration caused by microscopic frictional surface adhesion and slippage) and turning can be prevented near the lip end 2c.

[Third Embodiment]
FIG. 6 is a partial cross-sectional view showing a third embodiment of the sealing device of the present invention.
In FIG. 6, since the site | part of the same code | symbol as FIG. 1, FIG. 2 is a site | part of the same structure, these description uses the description of the said embodiment, and abbreviate | omits here.

  In the third embodiment of the sealing device 1, as shown in FIG. 6, even when the inner peripheral portion of the inner peripheral cylindrical portion 2a is worn and the lip end portion 2c becomes thin, the lip end surface 2d The angle formed with respect to the generatrix of the outer peripheral surface 102a of the reciprocating shaft 102 is set to 90 ° or more.

  That is, in this embodiment, the lip end surface 2d has a substantially arc shape centered on the reciprocation shaft 102 side (point C in FIG. 5) of the displacement center of the inner peripheral side cylindrical portion 2a. Even when 2c becomes thin due to wear and the displacement amount of the inner cylindrical portion 2a decreases, the angle of the lip end surface 2d with respect to the generatrix of the outer peripheral surface 102a in the vicinity of the reciprocating shaft 102 (the tangent and outer periphery of the lip end surface 2d) The angle formed by the generatrix of the surface 102a is 90 ° or more.

  Even if the lip end portion 2c is worn, the lip end surface 2d of the foreign matter adhering to the outer peripheral surface 102a is formed by the angle formed by the lip end surface 2d with respect to the generatrix of the outer peripheral surface 102a of the reciprocating shaft 102 being 90 ° or more. The scraping off due to is maintained well over a long period of time.

1: Sealing device 2: Annular dust strip 2a: Inner peripheral side cylindrical part 2b: Outer peripheral side cylindrical part 2c: Lip end part 2d: Lip end surface 2e: Reinforcement band 3: Annular groove 4: Retaining ring 5: Annular leaf spring 5a: Cylindrical part 5b: Pressing piece 101: Housing 101a: Opening part 102: Reciprocating shaft (rod)
102a: outer peripheral surface

Claims (9)

An annular dust strip made of an elastic material, supported by a housing and brought into contact with an outer peripheral surface of a reciprocating shaft disposed in the housing;
An annular dust strip having a taper shape in which a lip end surface facing the atmosphere side when coming into contact with the outer peripheral surface of the reciprocating shaft has a taper shape protruding toward the atmosphere side closer to the outer peripheral surface of the reciprocating shaft. . An annular dust strip made of an elastic material, supported by a housing and brought into contact with an outer peripheral surface of a reciprocating shaft disposed in the housing;
When the outer peripheral surface of the reciprocating shaft contacts with the outer peripheral surface of the reciprocating shaft at least near the outer peripheral surface of the reciprocating shaft of the lip end surface facing the atmosphere side is 90 ° or more. A featured annular dust strip. The inner circumferential side cylindrical portion and the outer circumferential side cylindrical portion are connected to each other at the side edge so that the longitudinal section is formed in a substantially U shape, and the opening portion of the substantially U shape is directed to the atmosphere side. Bringing the inner periphery into contact with the outer periphery of the reciprocating shaft;
An annular leaf spring is disposed between the inner peripheral cylindrical portion and the outer peripheral cylindrical portion,
The annular leaf spring is a chrysanthemum spring configured in a ring shape, and is formed of a cylindrical portion and a plurality of pressing pieces projecting from the side edges of the cylindrical portion, and each pressing piece is formed of the cylindrical portion. Folded so as to overlap the inner peripheral side, the vertical cross section is substantially V-shaped, the open side of the substantially V-shaped is directed to the atmosphere side, and the tip side of the pressing piece causes the inner peripheral side cylindrical portion to 3. The annular die according to claim 1, wherein the vicinity of the lip end facing the atmosphere side is elastically biased in the centripetal direction, and the vicinity of the lip end is pressed against the outer peripheral surface of the reciprocating shaft. strip.   The annular dust strip has a portion excluding the vicinity of the lip end portion separated from the outer peripheral surface of the reciprocating shaft, and reinforcing bands are provided at equal angular intervals on the inner peripheral surface of the portion separated from the outer peripheral surface. 4. An annular dust strip as defined in claim 3 wherein: An annular dust strip made of an elastic material, supported by the housing, and in contact with the outer peripheral surface of the reciprocating shaft disposed in the housing;
An annular leaf spring which is disposed along the annular dust strip to urge the annular dust strip and presses the outer peripheral surface of the reciprocating shaft against the vicinity of the lip end facing the atmosphere side of the annular dust strip; With
The sealing device according to claim 1, wherein the lip end portion of the annular dust strip is a maximum point of surface pressure with respect to the outer peripheral surface of the reciprocating shaft.   6. The sealing device according to claim 5, wherein the annular dust lip has a tapered shape in which a lip end surface facing the atmosphere side protrudes toward the atmosphere side closer to the outer peripheral surface of the reciprocating shaft.   The annular dust strip has an angle formed by at least 90 ° or more of the outer peripheral surface of the reciprocating shaft of the lip end surface facing the atmosphere side with respect to a generatrix of the outer peripheral surface. The sealing device as described. The annular dust strip has an inner circumferential side cylindrical portion and an outer circumferential side cylindrical portion connected at a side edge to form a substantially U-shaped longitudinal section, with the substantially U-shaped open portion facing the atmosphere side, Bringing the inner peripheral portion of the inner peripheral cylindrical portion into contact with the outer peripheral surface of the reciprocating shaft;
An annular leaf spring is disposed between the inner peripheral cylindrical portion and the outer peripheral cylindrical portion,
The annular leaf spring is a chrysanthemum spring configured in a ring shape, and is formed of a cylindrical portion and a plurality of pressing pieces projecting from the side edges of the cylindrical portion, and each pressing piece is formed of the cylindrical portion. Folded so as to overlap the inner peripheral side, the vertical cross section is substantially V-shaped, the open side of the substantially V-shaped is directed to the atmosphere side, and the tip side of the pressing piece causes the inner peripheral side cylindrical portion to 8. The vicinity of the lip end facing the atmosphere side is elastically biased in the centripetal direction, and the vicinity of the lip end is pressed against the outer peripheral surface of the reciprocating shaft. The sealing device as described.   The annular dust strip has a portion excluding the vicinity of the lip end portion separated from the outer peripheral surface of the reciprocating shaft, and reinforcing bands are provided at equal angular intervals on the inner peripheral surface of the portion separated from the outer peripheral surface. The sealing device according to claim 5, wherein the sealing device is provided.

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