JP2570041Y2 - Sealing device - Google Patents

Description

[Detailed description of the invention]

[0001]

[Industrial application field] The present invention relates to a shock absorber,
The present invention relates to a sealing device provided on the outer periphery of a piston such as a hydraulic cylinder or a pneumatic cylinder.

[0002]

2. Description of the Related Art Conventionally, there is a sealing device provided on the outer periphery of a piston as shown in FIG. The sealing device 1 is made of, for example, a PTFE-based synthetic resin material having a small sliding resistance, and has a bearing portion 11 for operating the piston 3 smoothly in the axial direction on the inner periphery of the cylinder 2.
The lip portion 12 is formed integrally with one end of the piston 1 and is inclined to the outer diameter side. The bearing portion 11 is press-fitted with a plurality of annular irregularities 31 formed on the outer peripheral surface of the piston 3. The pressure fluid in the cylinder 2 is sealed by the outer peripheral surface of the tip 12a of the lip portion 12 that is inclined and developed in a tapered shape toward the radial side and hermetically slides on the inner peripheral surface of the cylinder 2.

In the sealing device 1 having the above structure, if the interference is reduced with time due to so-called settling of the lip portion 12, there is a possibility that a good sealing property against the fluid pressure in the space B in the figure may not be obtained. Therefore, as shown in FIG. 5, an O-ring 13 made of an elastomer is mounted in an annular groove 32 formed in the piston 3, and the lip portion 12 is backed up from the inner peripheral side by a repulsive force against the radial compression of the O-ring 13. A structure with the following structure has been developed.

[0004]

However, even in the structure of FIG. 5 described above, the inner circumference of the cylinder 2 is caused by the escape of the O-ring 13 in the compressed state, the deformation of the lip portion 12 at the pressure contact portion with the O-ring 13, and the like. At present, it is difficult to make the surface pressure of the tip 12a of the lip portion 12 against the surface sufficient.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make the surface pressure of the tip 12a of the lip portion 12 against the inner peripheral surface of the cylinder 2 sufficient, and to provide a seal. To improve the performance.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a bearing portion which is press-fitted on the outer peripheral surface of a piston, and which is integrally formed at one end of the bearing portion and has a tapered outer diameter. In the sealing device consisting of the lip developed to
A leaf spring is brought into contact with the inner periphery of the lip portion, and a tapered development portion of the leaf spring reaching the inner periphery of the tip of the lip portion is divided into a plurality of slits in the circumferential direction.

[0007]

According to the sealing device of the present invention, a lip portion is backed up by a tapered leaf spring in which a developing portion extending obliquely to the outer diameter side is divided in a circumferential direction by a plurality of slits, and an expanding force is applied. It is elastically close to the inner peripheral surface of the cylinder. Since the distal end of the leaf spring reaches the inner periphery of the distal end of the lip, a sufficient surface pressure of the distal end of the lip against the inner peripheral surface of the cylinder can be secured.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sealing device according to the present invention. In addition, in the illustrated embodiment, the same reference numerals are used for the same portions as those of the conventional sealing device of FIGS. 4 and 5 described above, and the description thereof is omitted.

First, in the first embodiment shown in FIG. 1, a thin leaf spring 4 which is in contact with the inner peripheral surface of the lip portion 12 is integrally formed on the outer peripheral surface of the piston 3. This leaf spring 4
The developed portion 41 extending in a tapered shape is the tip 12 of the lip portion 12.
As shown in FIG. 2, the developing portion 41 is divided in the circumferential direction by a plurality of equally arranged slits 42 as shown in FIG. In this case, it is desirable that the material of the piston 3 is spring steel to ensure excellent elasticity of the leaf spring 4.

That is, the sealing device 1 has a lip 12
Is backed up from the inner peripheral side by the leaf spring 4, and in the assembled state shown in the drawing, the deployed portion 41 of the leaf spring 4 to which good flexibility is given by the slit 42 is appropriately deformed toward the inner diameter side. The repulsive force elastically presses the tip 12a of the lip portion 12 against the inner peripheral surface of the cylinder 2. The unfolded portion 41 of the leaf spring 4 is
Since the inner peripheral position of the lip portion 12 reaches the inner peripheral position of the distal end 12a of the cylinder 2, a sufficient surface pressure of the distal end 12a of the lip portion 12 against the inner peripheral surface of the cylinder 2 is secured.

Here, the lip portion 12 has a directional sealing function due to its shape characteristics. In other words, with respect to the fluid pressure in the space A on the front side of the lip portion 12 in the figure, this pressure acts to press the lip portion 12 against the inner peripheral surface of the cylinder 2, so that excellent sealing performance is obtained. Although it exerts its effect on the fluid pressure from the opposite side B space, this pressure acts in the direction of reducing the diameter of the lip portion 12, so that the sealing performance against the fluid pressure in the B side space is ensured. , It is necessary to provide the lip portion 12 with a sufficient interference to the inner peripheral surface of the cylinder 2, and the sealing device 1 of the above embodiment sufficiently satisfies this requirement by the urging force of the leaf spring 4. Things. Moreover, according to this structure, since the leaf spring 4 is integral with the piston 3, the number of components does not increase.

Next, in a second embodiment shown in FIG. 3, an annular leaf spring 5 manufactured as a separate member from the piston 3 is mounted on the outer periphery of the piston 3 instead of the leaf spring 4. That is, in the leaf spring 5, a tapered developing portion 51 extending from a base portion 5a fitted to the piston 3 and reaching the inner peripheral position of the tip 12a of the lip portion 12 is divided in a circumferential direction by a slit 52. The developing portion 51 backs up the lip portion 12 from the inner periphery, and has the same operation as the first embodiment. Reference numeral 6 denotes a stop ring for fixing the leaf spring 5 to the outer peripheral surface of the piston 3.

[0013]

According to the sealing device of the present invention, the lip is backed up from the inner periphery by the leaf spring and elastically closely contacts the inner peripheral surface of the cylinder, and the tip of the leaf spring is the inner periphery of the tip of the lip. , A sufficient surface pressure of the tip of the lip against the inner peripheral surface of the cylinder can be secured, and therefore, the sealing performance against fluid pressure can be improved.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a first embodiment of a sealing device according to the present invention.

FIG. 2 is a half-cut front view of the embodiment.

FIG. 3 is a half sectional view showing a second embodiment of the sealing device according to the present invention;

FIG. 4 is a half sectional view showing an example of a sealing device having a conventional structure.

FIG. 5 is a half cut sectional view showing another example of the sealing device according to the conventional structure.

[Description of Signs] 1 Sealing device 2 Cylinder 3 Piston 4,5 Leaf spring 5a Base 6 Stop ring 11 Bearing portion 12 Lip portion 12a Tip 31 Annular unevenness 41,51 Development portion 42,52 Slit A, B Space

Claims (1)

(57) [Scope of request for utility model registration] A bearing ( 11 ) press-fitted to the outer peripheral surface of a piston ( 3 ) , and a lip ( 12 ) integrally formed at one end of the bearing ( 11 ) and tapered toward the outer diameter side. )
The sealing device (1) consisting of, the lip portion (1
2 ) A leaf spring ( 4,5 ) is brought into contact with the inner circumference of
The leaf spring ( 4, which reaches the inner periphery of the tip ( 12 a ) of ( 12 )
5 ) A sealing device characterized in that the tapered deployment portion ( 41, 51 ) is divided in the circumferential direction by a plurality of slits ( 42, 52 ) .