JP6924254B2 - Fluid blockage plug - Google Patents

Description

The present invention relates to a fluid blocking plug (PLUG FOR FLUID BLOCKING), and more particularly to a fluid blocking plug for preventing fluid leakage from a hydraulic device.

Many devices or mechanical devices that use fluid force have a structure that stores the fluid inside the device.

Generally, a hydraulic device or machine using a high flood control is provided with a plug for closing a hole for guiding a processed fluid to prevent the fluid inside from leaking to the outside.

However, in a screw type plug, the tightening torque transmitted to the thread causes a thrust load in the part, and there is a structural limit to the increase in the tightening torque for greater airtightness. Further, there is a problem that the airtightness performance varies depending on the processing accuracy of the screw thread.

The present invention has been devised to solve the above-mentioned problems, and an object of the present invention is to provide a fluid blocking plug for preventing oil leakage of a hydraulic device.

The fluid blocking plug according to various embodiments of the present invention is a fluid closing plug coupled to a fluid hole provided in a hydraulic device, and has a head portion having a constant diameter and a threaded portion on the peripheral edge. And a sealing portion extending from the lower end of the head portion and at least partially pressed against the inner peripheral surface of the fluid hole; the sealing portion includes a plane perpendicular to the central axis of the head portion. , A first sealing portion arranged at a constant angle, and a second sealing portion arranged between the first sealing portion and the head portion can be included.

Preferably, the angle formed by the second sealing portion with respect to the plane perpendicular to the central axis of the head portion is formed by the first sealing portion with respect to the plane perpendicular to the central axis of the head portion. It can be less than or equal to the angle.

Preferably, a coating member applied to the threaded portion of the head portion can be included.

Preferably, the sealing portion may include a recess formed in a concave shape upward from the central portion of the lower end surface.

Preferably, the head portion includes a tool coupling groove portion, and the tool coupling groove portion is formed in a substantially star shape having a cross section including six corner portions, and each of the six corner portions is formed by rounding.

Preferably, the fluid hole includes an inner threaded portion screwed to the head portion and a pressure contact portion provided at the lower end portion of the inner threaded portion and having an inner peripheral surface having an upper wide and lower narrow shape. By tightening the head portion along the screw thread provided on the inner thread portion, the first sealing portion and the second sealing portion are respectively pressed against the inner peripheral surface of the pressure welding portion to form the fluid hole. Can be sealed.

The closed structure of the hydraulic device according to various embodiments of the present invention is a closed structure of the hydraulic device including the fluid closing plug according to the first to sixth paragraphs, and is formed by the pressure contact portion and the central shaft. The angle is formed to be smaller than the angle formed by each of the first inclined portion and the second inclined portion and the central axis.

The fluid blocking plug according to various embodiments of the present invention can increase the sealing effect by the first sealing portion and the second sealing portion.

Further, by providing a screw thread on the head portion, the sealing effect increases as the fastening force through the head portion increases.

Further, since the diameter of the head portion and the diameter of the sealing portion are substantially the same, it is possible to obtain the effect that the depth of the tool coupling groove portion can be formed deeply.

It is a figure which shows the plug for fluid blockage which concerns on various examples of this invention. It is a figure which shows the tool coupling groove part of the fluid closing plug which concerns on various examples of this invention. It is a figure which shows the sealing part of the fluid block plug which concerns on various examples of this invention. It is a figure which conceptually shows the fluid hole which is coupled with the fluid block plug which concerns on various examples of this invention.

Hereinafter, for convenience of explanation, some examples of the present invention will be described with reference to exemplary drawings. When assigning reference numerals to the components of each drawing, the same components are assigned the same reference numerals even if they are different drawings.

The terms and terms used herein and within the scope of the patent claim are not used as general or lexicographical meanings, but the inventor is a concept of terms to best describe his invention. Should be interpreted as a meaning and concept consistent with the technical idea of the present invention, based on the principle that can be properly defined. In addition, terms such as first, second, A, B, (a), and (b) can be used in explaining the components of the examples according to the present invention. Such terms are for distinguishing a component from other components, and the term does not limit the essence, order, procedure, or the like of the component. When a component is described as being "connected" or "combined" to another component, that component can be directly connected or combined to another component, but separate from that component. It should be understood that other components can also be "connected" or "combined" with a component of.

Therefore, the configurations described in the present specification and the configurations shown in the drawings are merely preferable examples of the present invention, do not represent the technical idea of the present invention, and can be substituted at the time of the present application. It should be understood that there can be equivalents and variants of. A detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted.

Hereinafter, the direction in which the tool is inserted into the head portion 100 will be described as an upper side or an upper side, and the opposite direction, that is, the direction toward the inside of the fluid hole 301 can be described as a lower side or a lower side.

Hereinafter, the fluid blocking plugs according to various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a fluid blocking plug according to various embodiments of the present invention, and FIG. 2 is a diagram showing a tool coupling groove portion of the fluid blocking plug according to various embodiments of the present invention. FIG. 3 is a diagram showing a sealing portion of the fluid blocking plug according to various embodiments of the present invention, and FIG. 4 is a fluid hole 301 coupled with the fluid blocking plug according to various embodiments of the present invention. It is a figure which shows conceptually.

The fluid blocking plug according to various embodiments of the present invention is a hole (fluid hole 301) opened to the inside or outside of the fluid device 300 in the flow path of the fluid (oil or gas) formed by the fluid device 300. Is for sealing. Applicable to many fields of equipment or machinery that use fluid force, especially in hydraulic equipment 300 or machines that use high hydraulic pressure, used to close externally machined fluid induction holes. It is a closing plug to be applied, and is applicable to the technical field of a mechanical element for preventing an internal fluid from leaking to the outside.

With reference to FIGS. 1 to 4, the fluid blocking plug according to various embodiments of the present invention may include a head portion 100 and a sealing portion 200. The fluid closing plug includes the head portion 100 and the sealing, and is provided so as to extend in the axial direction (vertical direction) with a constant length. In one embodiment, the axial length L of the fluid closing plug is obtained by dividing the axial length L of the fluid closing plug by the nominal diameter M of the threaded portion of the head portion 100. When the dimensionless value of the axial length L of the plug is 0.1 to 1.0, it is formed by adding the axial length L1 of the sealing portion described later to the dimensionless value. Can be done.

The head portion 100 forms a predetermined region of the upper end portion of the fluid closing plug. A screw portion 110 is formed on the peripheral edge of the head portion 100. The threaded portion 110 provided on the head portion 100 may include a male screw. The threaded portion 110 of the head portion 100 is screw-coupled to the inner threaded portion 310 of the fluid hole 301. The head portion 100 can have a cylindrical shape having a constant diameter M.

A coating member (not shown) is applied to the threaded portion 110. Through such a coating member, a further sealing effect can be provided together with the first sealing portions 210 and 220 and the second sealing portions 230 and 240. The coating member can be made of ethylene glycol dimethacrylate (EGDMA) material, but is not limited thereto.

On the upper end surface of the head portion 100, a tool coupling groove portion 150 formed in a concave shape downward is arranged. A tool is inserted into the tool coupling groove 150, and the tool is tightened with a predetermined torque to provide a fastening force for screw coupling between the threaded portion 110 of the head portion 100 and the inner threaded portion 310 of the fluid hole 301. Will be done.

With reference to FIG. 2, the cross section of the tool coupling groove 150 has six corners 151 and is formed in a substantially star shape. This is to minimize the surface pressure when tightening the tool. Each corner portion 151 is formed to be round with a constant radius of curvature R2, and a valley portion 152 formed to be round with a constant radius of curvature R1 is arranged between the corner portions 151.

In one embodiment, with respect to the distance A1 between the mutually symmetrical corner portions 151, the mutually symmetrical corner portions 151 obtained by dividing the distance A1 between the mutually symmetrical corner portions 151 by the nominal diameter (M) of the threaded portion. It can be formed so that the dimensionless value of the distance A1 between them is 0.15 to 0.96.

If the value of the distance A1 between the corners 151 is less than 0.15, it is difficult to maintain the tightening torque force for maintaining sufficient airtightness of the plug, and if it exceeds 0.96, the tool coupling is smooth. There is a problem that it is not done.

Regarding the distance A2 between the mutually symmetrical valleys 152, the distance between the mutually symmetrical valleys 152 obtained by dividing the distance A2 between the mutually symmetrical valleys 152 by the value of A1 calculated above. It can be formed so that the non-dimensional value of A2 is 0.21 to 1.2.

Regarding the depth H of the tool coupling groove 150, the dimensionless value of the depth H of the tool coupling groove 150 obtained by dividing the depth H of the tool coupling groove 150 by the value of A1 is 0.15. It can be formed to be ~ 1.5.

Regarding the radius of curvature R1 of the valley portion 152, the non-dimensional value of the radius of curvature R1 of the valley portion 152 obtained by dividing the radius of curvature R1 of the valley portion 152 by the value of A1 is 0.10 to 0. The radius of curvature R2 of the corner portion 151 can be formed to be 31, and the radius of curvature R2 of the corner portion 151 obtained by dividing the radius of curvature R2 of the corner portion 151 by the value of A1 is dimensionless. It can be formed so that the value is 0.01 to 0.2.

That is, in the present invention, the tool coupling groove portion 150 provided in the head portion 100 is formed in a substantially star shape, and the depth H and the curvature of the shape are formed with reference to the longest distance (distance between the corner portions 151, A1). By setting the radii R1 and R2, the maximum tightening torque can be limited, and the surface pressure at the time of tool tightening can be minimized.

The threaded portion 110 of the head portion 100 is tightened to the inner threaded portion 310 of the fluid hole 301 by the tool, so that the first sealing portion and the second sealing portion are pressed into the fluid hole 301 as described later. Can induce plastic deformation or mutual contact, and such deformation causes at least surface contact or line between the first sealing portion and the second sealing portion and the inner peripheral surface of the pressure welding portion 330. A contact is formed.

With reference to FIG. 3, the fluid blocking plug according to various embodiments of the present invention may include a sealing portion 200. The sealing portion 200 extends downward from the lower end portion of the head portion 100. The sealing portion is arranged coaxially with the head portion 100. The sealing portion 200 is formed in a shape of substantially upper wide and lower narrow. The sealing unit 200 can include a buffer unit 260, a first sealing unit 210 and 220, and a second sealing unit 230 and 240. The first sealing portions 210 and 220 and the second sealing portions 230 and 240 are pressed against the pressure welding portion 330 of the fluid hole 301 when the head portion 100 is tightened by a tool, and plastic deformation and contact occur. In one embodiment, with respect to the axial length L1 of the sealing portion 200, the sealing portion 200 obtained by dividing the axial length L1 of the sealing portion 200 by the nominal diameter M of the threaded portion 110 of the head portion 100. The dimensionless value of the axial length L1 of can be formed to be 0.1 to 0.9.

The buffer portion 260 extends from the lower end portion of the head portion 100 with a constant length. The buffer portion 260 can have a cylindrical shape having a constant diameter. The diameter D of the buffer portion 260 is formed to be smaller than the nominal diameter M of the screw portion 110 of the head portion 100. In one embodiment, with respect to the diameter D of the buffer portion 260, the dimensionless value of the diameter D of the buffer portion 260 obtained by dividing the diameter D of the buffer portion 260 by the nominal diameter M of the screw portion 110 of the head portion 100 is obtained. , 0.5 to 0.9. Second sealing portions 230 and 240 are extended below the buffer portion 260.

The second sealing portions 230, 240 can include a second inclined portion 240 and a second sealing surface 230. The second inclined portion 240 is provided so as to incline inward in the radial direction toward the lower side. That is, the diameters of the upper ends of the second sealing portions 230 and 240 correspond to the diameter of the buffer portion 260, and are formed in a shape of upper and lower narrower toward the lower side. In this case, the side surfaces of the second sealing portions 230 and 240 can be described as the second inclined portion 240.

The second inclined portion 240 is formed so as to be inclined by a preset angle θ4 with respect to the central axis CL. This is to bring the second sealing portion into contact with the pressure contact portion 330. In one embodiment, the second inclined portion 240 is formed so as to be inclined by about 15 degrees with respect to the central axis.

The second sealing portions 230 and 240 can include a second sealing surface 230. The second sealing surface 230 can mean the lower end surface of the second sealing portions 230, 240. The second sealing surface 230 is formed so as to be inclined by a preset angle θ2 with respect to a plane perpendicular to the central axis CL. This is because when the second sealing portions 230 and 240 come into contact with the pressure contact portion 330 in order to maintain the airtightness, the amount of plastic deformation or the line contact timing of the second sealing portions 230 and 240 can be adjusted. ..

Further, the angle θ2 formed by the second sealing surface 230 and the plane perpendicular to the central axis CL is smaller than or equal to the angle θ1 formed by the first sealing surface 210 and the plane perpendicular to the central axis CL. Is formed like this.

In one embodiment, the second sealing surface 230 can be tilted at an angle of 5 to 25 degrees with respect to the plane perpendicular to the central axis CL. If the inclined angle θ2 is less than 5 degrees or exceeds 25 degrees, the airtightness performance may be deteriorated due to the problem of the amount of plastic deformation and the contact timing of the second sealing portions 230 and 240.

When the second sealing portions 230 and 240 are pressure-welded to the pressure-welding portion 330 of the fluid hole 301, at least a part of the second sealing surface 230 and / or the second inclined portion 240 is plastically deformed, so that the pressure-welding is performed. It is in surface contact or line contact with the portion 330. The first sealing portions 210 and 220 are extended below the second sealing portions 230 and 240.

The first sealing portions 210 and 220 may include a first inclined portion 220 and a first sealing surface 210. The first inclined portion 220 is formed so as to incline inward in the radial direction toward the lower side. The diameter of the upper end portions of the first sealing portions 210 and 220 is formed to be smaller than the diameter of the lower end portion of the second sealing portion, and is formed in a shape of upper and lower narrower toward the lower side. In this case, the side surfaces of the first sealing portions 210 and 220 can be described as the first inclined portion 220.

The first inclined portion 220 is formed so as to be inclined by a preset angle with respect to the central axis CL. This is because the initial contact timing of the first sealing portions 210 and 220 can be adjusted depending on the initial contact timing of the second sealing portions 230 and 240 with the pressure contact portion 330. In one embodiment, the first inclined portion 220 is formed so as to be inclined by about 180 degrees with respect to the central axis CL.

The first sealing portions 210 and 220 can include the first sealing surface 210. The first sealing surface 210 can mean the lower end surface of the first sealing portion. The first sealing surface is formed so as to be inclined by a preset angle θ1 with respect to a plane perpendicular to the central axis CL. This is because when the first sealing portions 210 and 220 come into contact with the pressure contact portion 330, the amount of plastic deformation and the line contact timing can be adjusted.

Further, the angle θ1 formed by the first sealing surface 210 and the plane perpendicular to the central axis CL is larger than or equal to the angle θ2 formed by the second sealing surface 230 and the plane perpendicular to the central axis CL. Is formed in. This is because a certain amount of deformation or line contact timing can be adjusted so that the first and second sealing portions maintain the same airtightness.

In one embodiment, the first sealing surface 210 can be tilted at an angle of 5 to 25 degrees with respect to a plane perpendicular to the central axis CL. If the tilted angle θ1 is less than 5 degrees or exceeds 25 degrees, there may be a problem in maintaining the airtightness due to the problem of the amount of plastic deformation or the contact timing of the first sealing portions 210 and 220. ..

Further, in one embodiment, with respect to the axial length L2 of the first sealing portions 210 and 220, the axial length L2 of the first sealing portions 210 and 220 is referred to as the screw portion of the head portion 100. It can be formed so that the dimensionless value of the axial length L2 of the first sealing portions 210 and 220 obtained by dividing by the diameter M is 0.05 to 0.3.

In one embodiment, the diameter d2 of the upper end portion of the first inclined portion 220 is obtained by dividing the diameter d2 of the upper end portion of the first inclined portion 220 by the nominal diameter M of the threaded portion of the head portion 100. The dimensionless value of the diameter d2 of the upper end portion of the first inclined portion 220 can be formed to be 0.16 to 0.98.

Further, in one embodiment, regarding the diameter d1 of the lower end portion of the first inclined portion 220, the corner portion F of the second inclined portion 240 and the second sealing surface 230 and the first inclined portion 220 and the first inclined portion 220. It can be formed so that the angle formed by the virtual line connecting the corners E of the sealing surface 210 and the plane perpendicular to the central axis CL is 30 degrees to 90 degrees. This is because the first and second sealing portions are in simultaneous contact at the same angle as or different from the pressure welding portion 330, or the ratio of the amount of plastic deformation of the first and second sealing portions is set to, for example, 5: 5 or. This is because it can be changed to 6: 4 and 7: 3.

When the first sealing portions 210 and 220 are in pressure contact with the pressure contact portion 330 of the fluid hole 301, at least a part of the first sealing surface 210 and / or the first inclined portion 220 is plastically deformed, so that the first sealing portion 210 and 220 are plastically deformed. It is in surface contact with the pressure contact portion 330.

According to various embodiments, the sealing portion 200 can include a recess 250 formed in a concave shape upward from the central portion of the lower end surface. The hydraulic pressure acting upward pressurizes the inner peripheral surface of the recess 250, so that the first sealing portion and / or the second sealing portion is pressurized outward in the radial direction by such a hydraulic pressure. Therefore, the sealing efficiency of the sealing portion can be increased by the flood control without separately applying a fastening force.

With reference to FIG. 1, in one embodiment, the recess 250 is formed to have a V-shaped cross section, but is not limited thereto. As shown in FIG. 3, it can also be formed into a U-shaped cross section or a hemispherical cross section.

The fluid closing plugs according to the various embodiments of the present invention as described above can be inserted into the fluid holes 301 formed in the hydraulic device 300 to seal the fluid holes 301.

With reference to FIG. 4, the fluid hole 301 can include an inner threaded portion 310 that is screwed to the threaded portion of the head portion 100 of the fluid closing plug. On the inner peripheral surface of the inner threaded portion 310, a female threaded portion corresponding to the threaded portion 110 of the head portion 100 is provided. In one embodiment, with respect to the axial length L3 of the inner threaded portion 310, the inner thread obtained by dividing the axial length L3 of the inner threaded portion 310 by the nominal diameter M of the threaded portion of the head portion 100. The dimensionless value of the axial length L3 of the portion 310 can be formed to be 0.3 to 1.25. This is because when the fluid closing plug is tightened into the fluid hole, it is possible to induce the maintenance of a sufficient fastening force and the prevention of interference between the fastenings.

Further, at the lower end of the inner threaded portion 310, a pressure welding portion 330 formed in an upper wide and lower narrow shape whose diameter becomes smaller toward the lower side is arranged. When the head portion 100 is tightened by the tool, the first sealing portions 210 and 220 and the second sealing portions 230 and 240 of the sealing portion 200 are pressure-welded to the pressure-welding portion 330. By plastically deforming the first sealing portions 210 and 220 and the second sealing portions 230 and 240, respectively, the first sealing portions 210 and 220 and the second sealing portions 230 and 240 can be surface-contacted or line-contacted with at least a part of the pressure-welded portion to provide a sealing effect. .. In one embodiment, the angle formed by the pressure contact portion and the central axis is formed so as to be smaller than or equal to the first inclined portion and the second inclined portion. In one embodiment, the angle θ5 of the inner peripheral surface of the pressure contact portion 330 is formed so as to be inclined by about 25 to 95 degrees with respect to the plane perpendicular to the central axis CL. This is because the first and second sealing portions can be deformed by adjusting the ratio of the amount of plastic deformation and the contact timing as described above.

As described above, the head portion 100 of the fluid closing plug according to various embodiments of the present invention is fastened to the inner threaded portion 310 of the fluid hole 301 by a tool.

By screwing the threaded portion of the head portion 100 with the inner threaded portion 310, the lower end portion of the sealing portion 200 is moved downward. Further, as the tool is tightened, at least a part of the first sealing portions 210 and 220 and the second sealing portions 230 and 240 is pressed against the pressure welding portion 330. When the pressure contact force becomes larger than a certain amount, at least a part of the first sealing portions 210 and 220 and the second sealing portions 230 and 240 undergo plastic deformation, and the plastically deformed portion and the pressure contact portion 330 are included. The side surface is in surface contact.

In the present invention, the first sealing portions 210 and 220 are provided in the portion closest to the fluid, and the sealing can be performed temporarily through the plastic deformation of the first sealing portions 210 and 220. Further, by providing the second sealing portions 230 and 240 on the upper side of the first sealing portions 210 and 220, it is possible to provide a secondary sealing effect through the plastic deformation of the second sealing portions 230 and 240. .. Further, by applying a coating member to the threaded portion 110 of the head portion 100 arranged on the upper side of the sealing portion, the leaked fluid is finally discharged through the first sealing portions 210 and 220 and the second sealing portions 230 and 240. Can be sealed.

Further, in the present invention, by providing the recesses 250 at the lower ends of the first sealing portions 210 and 220, the pressure of the fluid directly pressurizes the inner peripheral surface of the recesses 250, whereby the first sealing A pressing force can be provided radially outward to the portions 210, 220 or the second sealing portions 230, 240.

Further, since the screw portion on which the fastening force acts as the tool is tightened is arranged on the head portion 100, even if the fastening force continues to increase, a tensile force is generated between the head portion 100 and the sealing portion. Since it does not occur, there is no risk of breakage.

That is, not only the torque generated by tightening the tool but also the additional pressing force by the hydraulic pressure is applied to the first and / or the second sealing portion, so that the effect of increasing the sealing effect can be obtained.

Although it has been described above that all the components in the examples of the present invention are combined or operated in combination, the present invention is not limited to the above-mentioned examples. That is, within the scope of the object of the present invention, all the components can be selectively combined with one or more to operate. In addition, the terms "including", "constituting", "having" and the like in the above mean that the component can be inherently contained unless otherwise specified, and do not mean that other components are excluded. , Should be interpreted as being able to further include other components. Unless otherwise stated, all terms, including technical or scientific terms, have the same meaning as would normally be understood by a person of ordinary knowledge in the technical field to which the present invention belongs. Commonly used terms, such as those defined in dictionaries, should be construed as consistent with the contextual meaning of the relevant technology and are ideal or excessive unless explicitly defined in the present invention. Is not interpreted as a formal meaning.

The above is merely an exemplary explanation of the technical idea of the present invention, and any person having ordinary knowledge in the technical field to which the present invention belongs can vary within a range that does not deviate from the essential characteristics of the present invention. Can be modified and modified. Therefore, the examples disclosed in the present invention do not limit the technical idea of the present invention, but are for facilitating understanding, and such examples may limit the scope of the technical idea of the present invention. No. The scope of protection of the present invention should be judged by the scope of the appended claims, and all technical ideas within the equivalent scope should be construed as being included in the scope of the principle of the present invention. be.

100: Head part, 110: Thread part, 150: Tool coupling groove part, 151: Square part, 152: Valley part, 200: Sealing part, 260: Buffer part, 220: First inclined part, 210: First sealing part Surface, 240: Second inclined portion, 230: Second sealing surface, 250: Recessed portion, 300: Hydraulic equipment, 301: Fluid hole, 310: Inner threaded portion, 330: Pressure welding portion

Claims (7)

A fluid blocking plug that is coupled to a fluid hole provided in a hydraulic device.
A head portion having a constant diameter and provided with a threaded portion on the peripheral edge; and a sealing portion extending from the lower end of the head portion and at least partially pressed against the inner peripheral surface of the fluid hole;
It said sealing portion includes a first sealing portion disposed in said head portion coaxially and saw including a second sealing portion disposed between the head portion first sealing portion,
The first sealing portion includes a first inclined portion and a first sealing surface formed so as to form different angles with respect to the central axis of the head portion with reference to the first corner portion. The second sealing portion has a second inclination formed so as to form a different angle with respect to the central axis of the head portion with reference to the second corner portion formed on the upper side of the first corner portion. A fluid closure plug that includes a section and a second sealing surface. It said second sealing surface, the angle formed with respect to a plane perpendicular to the central axis of the head portion, the first sealing surface, the angle is smaller than that formed with respect to a plane perpendicular to the central axis of the head portion The fluid blocking plug according to claim 1, which is equal to or equivalent to. The fluid blocking plug according to claim 1, further comprising a coating member applied to the threaded portion of the head portion. The fluid blocking plug according to claim 1, wherein the sealing portion includes a concave portion formed in a concave shape upward from the central portion of the lower end surface. The head portion includes a tool coupling groove portion and includes a tool coupling groove portion.
The tool coupling groove is formed six corners cross-section in including shape, the six corners each formed with rounded, plug fluid blockage of claim 1. The fluid hole includes an inner threaded portion screwed to the head portion and a pressure contact portion provided at the lower end portion of the inner threaded portion and having an inner peripheral surface having an upper wide and lower narrow shape.
By tightening the head portion along the screw thread provided on the inner thread portion, the first sealing portion and the second sealing portion are pressed against the inner peripheral surface of the pressure welding portion, respectively, and the fluid hole is formed. The fluid closing plug according to claim 1. A sealed structure of a hydraulic device including the fluid blocking plug according to claim 6.
A closed structure for a hydraulic device in which the angle formed by the pressure contact portion and the central axis is smaller than the angle formed by each of the first inclined portion and the second inclined portion and the central axis.

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