JP3836022B2 - Pressure vessel sealing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure vessel sealing device, and in particular, is used to seal between a cylinder tube and a cover of a fluid pressure cylinder.
[0002]
[Prior art]
Conventionally, in general industrial machines and the like, fluid pressure cylinders that reciprocate by hydraulic pressure, water pressure, or air pressure have been used.
[0003]
In a general fluid pressure cylinder, both end surfaces of a cylinder tube are closed with a cylinder cover, and both the cylinder covers are fastened with tie bolts.
Conventionally, various sealing devices have been proposed and put to practical use for sealing between the end of the cylinder tube and the cylinder cover.
[0004]
6 is a diagram showing an example of a conventional sealing device 80, and FIG. 7 is a diagram showing another example of a conventional sealing device 90. As shown in FIG.
In FIG. 6, an annular groove 82 is provided on the end surface of the cylinder cover 81, and a part of the end surface of the cylinder tube 83 is fitted in the groove 82. A gap between the end surface of the cylinder tube 83 is sealed by a seal member 84 provided in the concave groove 82. This sealing device 80 is often referred to as an “end face seal”. The cylinder cover 81 is provided with a port PT, and the cylinder tube 83 is provided with a piston PS that slides and moves in the axial direction.
[0005]
In FIG. 7, the cylinder cover 91 is provided with a columnar boss 92, and the inner peripheral surface of the end portion of the cylinder tube 93 is fitted with the boss 92. The space between the inner peripheral surface of the cylinder tube 93 is sealed by a seal member 94 provided on the boss 92.
[0006]
[Problems to be solved by the invention]
However, the conventional sealing device 80 shown in FIG. 6 has a simple structure, but a step is provided at the end of the cylinder tube 83 for positioning between the cylinder tube 83 and the cylinder cover 81, and the step is Since it is necessary to contact the end surface of the cylinder cover 81, the contact area with the seal member 84 is reduced accordingly. Since the step cannot be provided when the thickness of the cylinder tube 83 becomes thin, it is applicable only when the cylinder tube 83 having a certain thickness or more is used.
[0007]
In the sealing device 90 shown in FIG. 7, there is no problem even when the thickness of the cylinder tube 93 is thin, but in order to provide the boss 92, the outer periphery of the cylinder cover 91 must be scraped off by cutting, and the processing takes time. Cost, and the cost is high. Further, since the boss 92 protrudes into the cylinder chamber, there is a disadvantage that the total length of the fluid pressure cylinder becomes long.
[0008]
The present invention has been made in view of the above-described problems, and it is possible to ensure a sufficient contact area between the cylinder tube and the cover without increasing the total length of the pressure vessel, and to perform stable sealing. An object of the present invention is to provide a sealing device that can be used.
[0009]
[Means for Solving the Problems]
A sealing device according to the present invention is a sealing device that seals between a cover of a pressure vessel and a cylinder tube that contacts the end surface thereof, and has an outer diameter smaller than the inner diameter of the cylinder tube, and the end surface of the cover And an annular seal holding member concentrically attached to the inner peripheral side of the cylinder tube, and an inner peripheral surface of the cylinder tube mounted between the seal holding member and the inner peripheral surface of the cylinder tube. A seal member that seals between the end surfaces of the cover, and the seal holding member is provided continuously with the cylindrical portion, and the outer diameter increases as the distance from the cylindrical portion increases. made and a tapered peripheral surface portion, wherein is partially annular groove provided on the end face of the cylindrical portion of the cover is fixed by press-fitting, the tape in some circumferential direction Notches only cylindrical portion is left by forming the peripheral surface is removed is provided.
[0011]
Further, the piston sliding in the cylinder tube is provided with a small-diameter portion whose outer diameter is smaller than the inner diameter of the seal holding member on the side in contact with the cover.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a sectional view showing a configuration of a sealing device 3 according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing the sealing device 3. In FIG. 1, only a part of the fluid pressure cylinder 1 is shown. Since the structure of the fluid pressure cylinder 1 itself is conventionally known, its description is omitted or simplified.
[0013]
In these drawings, the fluid pressure cylinder 1 includes a cylinder tube 11, a cover 12 that closes one end face of the cylinder tube 11, a cover (not shown) that closes the other end face, a piston 14, and a piston rod (not shown). The The cover 12 is provided with a port PT. The end surface of the cylinder tube 11 is inserted into a groove 31 provided on the inner end surface of the cover 12. A seal device 3 seals between the cylinder tube 11 and the cover 12.
[0014]
That is, the seal holding member 21 is attached to the inner end surface of the cover 12, and the seal member 22 is mounted between the inner peripheral surface of the cover 12 and the seal holding member 21.
[0015]
The seal holding member 21 has an outer diameter smaller than the inner diameter of the cylinder tube 11 and has a substantially cylindrical shape as a whole. The one end portion 25 has a shape opened outward in a round shape.
[0016]
An annular groove 32 concentric with the groove 31 is formed on the end surface of the cover 12, and the seal holding member 21 is press-fitted into the groove 32 and fixed. It is also possible to use an adhesive instead of or together with press-fitting.
[0017]
As an example of the dimensions of the seal holding member 21, the thickness t is about 1.5 to 2 mm, the overall axial length L1 is about 5 mm, and the length L2 of the portion press-fitted into the cover 12 is about 2 mm. is there.
[0018]
The seal holding member 21 is manufactured by cutting a metal material or by sheet metal processing. For example, a metal pipe is cut into round pieces, and the end 25 is finished in a round shape by pressing. The edge portion is appropriately chamfered and finished smoothly.
[0019]
The seal member 22 is an O-ring made of nitrile rubber or the like, is held by the seal holding member 21, and is pressed against the surface of the cover 12 by the end portion 25. The seal member 22 contacts the inner peripheral surface of the cylinder tube 11 and the surface of the cover 12 and seals between them.
[0020]
The piston 14 moves by sliding in the axial direction on the inner peripheral surface of the cylinder tube 11. The piston 14 is provided with a small diameter portion 14 a whose outer diameter is smaller than the inner diameter of the seal holding member 21 on the side in contact with the cover 12-. The small diameter portion 14 a also serves as one wall surface that holds the packing 35 attached to the piston 14. When the small-diameter portion 14a abuts against the end surface of the cover 12, the piston 14 can move in the entire stroke range without interfering with the seal holding member 21. Actually, a small step portion is provided to prevent the end surface of the small-diameter portion 14 a from coming into close contact with the end surface of the cover 12.
[0021]
In the fluid pressure cylinder 1 configured as described above, the piston 14 is driven in the axial direction by supplying the pressure fluid from the port PT. The presence of the small diameter portion 14a prevents interference between the piston 14 and the seal holding member 21.
[0022]
A reliable and stable sealing is performed between the cylinder tube 11 and the cover 12 by the sealing member 22. Since the entire end face of the cylinder tube 11 contacts the bottom of the groove 31 of the cover 12, a sufficient contact area can be ensured. Since the cover 12 does not have a conventional boss, the piston 14 can directly contact the end surface of the cover 12, and the total length of the fluid pressure cylinder 1 does not increase.
[0023]
FIG. 3 is a cross-sectional view showing a sealing device 3B according to another embodiment.
In the sealing device 3B shown in FIG. 3, the seal holding member 21B has a tapered peripheral surface portion 26 that expands outward from the vicinity of the center in the length direction. The tapered peripheral surface portion 26 presses the seal member 22 against the inner peripheral surface of the cylinder tube 11 and the surface of the end surface of the cover 12, and a reliable seal is realized.
[0024]
FIG. 4 is a front view showing the entire seal holding member 21C used in the sealing device 3C of still another embodiment, and FIG. 5 is a view showing a state of work when press-fitting the seal holding member 21C of FIG.
[0025]
The basic shape of the seal holding member 21C shown in FIG. 4 is the same as that of the seal holding member 21 shown in FIG. However, the seal holding member 21 </ b> C shown here is provided with notches 27, 27... At four equally spaced intervals in the circumferential direction. As for each notch part 27, the edge part 25 formed in round shape is deleted, and only a cylindrical part is left.
[0026]
As shown in FIG. 5, the press-fitting jig JG has four blocks JGa that are fitted into the notches 27. The block JGa is brought into contact with the edge of the cylindrical portion of the seal holding member 21C, and the press-fitting jig JG is struck in the arrow direction with a hammer or the like, or pressed by a press to press-fit the seal holding member 21C into the groove 32 of the cover 12.
[0027]
Thus, the seal holding member 21C can be easily press-fitted into the cover 12 by using the press-fitting jig JG.
In the embodiment described above, the fluid pressure cylinder 1 may be operated by any one of hydraulic pressure, hydraulic pressure, and pneumatic pressure. The structure, shape, dimensions, number, material, etc. of the whole or each part of the seal holding members 21, 21B, 21C, the seal member 22, the seal devices 3, 3B, 3C, or the fluid pressure cylinder 1 are in accordance with the spirit of the present invention. It can be changed as appropriate. The present invention can be applied to various pressure vessels other than the fluid pressure cylinder.
[0028]
【The invention's effect】
According to the present invention, the abutting area between the cylinder tube and the cover can be sufficiently secured without increasing the total length of the pressure vessel, and stable sealing can be performed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a sealing device according to an embodiment of the present invention.
FIG. 2 is an enlarged sectional view showing a sealing device.
FIG. 3 is a cross-sectional view showing a sealing device according to another embodiment.
FIG. 4 is a front view showing an entire seal holding member used in a sealing device according to still another embodiment.
FIG. 5 is a diagram showing a state of work when press-fitting the seal holding member of FIG. 4;
FIG. 6 is a view showing an example of a conventional sealing device.
FIG. 7 is a view showing another example of a conventional sealing device.
[Explanation of symbols]
1 Fluid pressure cylinder (pressure vessel)
3, 3B, 3C Sealing device 11 Cylinder tube 12 Cover 14 Piston 14a Small diameter portions 21, 21, 21 Seal holding member 22 Seal member 25 End portion 26 Tapered peripheral surface portion 32 Groove

Claims (3)

A sealing device that seals between a cover of a pressure vessel and a cylinder tube that abuts on an end surface thereof,
An annular seal holding member having an outer diameter smaller than an inner diameter of the cylinder tube and concentrically attached to an inner peripheral side of the cylinder tube at an end surface of the cover;
A seal member mounted between the seal holding member and the inner peripheral surface of the cylinder tube and sealing between the inner peripheral surface of the cylinder tube and the end surface of the cover;
The seal holding member is
A cylindrical portion, and a tapered peripheral surface portion that is provided continuously with the cylindrical portion and has an outer diameter that increases with distance from the cylindrical portion;
A part of the cylindrical portion is press-fitted and fixed in an annular groove provided on an end surface of the cover,
The tapered peripheral surface portion is deleted in a part of the circumferential direction, and a notch portion formed by leaving only the cylindrical portion is provided,
A pressure vessel sealing device. The piston sliding in the cylinder tube is provided with a small-diameter portion whose outer diameter is smaller than the inner diameter of the seal holding member, on the side in contact with the cover.
The pressure vessel sealing device according to claim 1. The notch portions are provided at four equally spaced intervals in the circumferential direction of the tapered peripheral surface portion.
The pressure vessel sealing device according to claim 1.

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