JP2014070699A - Oil leakage prevention washer, oil leakage prevention structure and oil leakage prevention method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil leakage from a flange part used in electric equipment, especially oil leakage from a bolt nut for fastening a flange.SOLUTION: An oil leakage prevention washer includes: first and second flanges 102FL and 102FR; a bolt 12 inserted into a bolt hole 102h of the flanges from the first flange side; a nut 106 screwed into the bolt from the second flange side; a liquid leakage prevention washer 14 that includes first and second grooves 14and 14provided respectively between the bolt and the first flange and between the second flange and the nut and filled with a liquid gasket 22; a liquid leakage prevention nut 16 having a cap bolt 21 closing a through hole 18e filled with the liquid gasket, and screwed into the bolt from outside the nut.

Description

  The present invention relates to a liquid leakage prevention washer, a liquid leakage prevention nut, a liquid leakage prevention structure, and a liquid leakage prevention method suitable for oil leakage prevention from electric power equipment using high-pressure insulating oil such as an oil-filled transformer or oil breaker. .

  In substations and the like of electric power companies, power equipment (hereinafter also referred to as oil-filled power equipment or equipment) filled with high-pressure insulating oil (hereinafter also referred to as insulating oil) such as an oil breaker or oil-filled transformer. Used. The insulating oil filled in the oil-filled power device is circulated using an insulating oil pipe (hereinafter also simply referred to as a pipe) for cooling and electrical insulation of the equipment.

  In general, a flange tightened with a bolt and nut is used to connect two insulating oil pipes. In this case, in order to prevent oil leakage from the flange portion, a gasket such as NBR (nitrile rubber) is interposed between the contact surfaces of the two flanges. However, the gasket may deteriorate due to heat generation of the device, a temperature change ranging from −20 ° C. to + 30 ° C. in the device installation environment, and oil leakage may occur from the flange portion. Here, the flange portion is a concept including a flange and a bolt and nut for fastening the flange. Hereinafter, the flange portion is also referred to as a fastening structure.

  Of course, oil leakage can be stopped by replacing the deteriorated gasket with a new one. However, since it is necessary to remove the pipes once to replace the gasket, the power equipment must be stopped during the replacement work. Therefore, conventionally, a technique for stopping oil leakage from the flange portion in a state where the device is operated has been proposed (see, for example, Patent Documents 1 to 3).

  Patent Document 1 discloses a technology for stopping oil leakage by covering the entire flange portion where oil leakage has occurred with multiple thin films, and applying and curing a caulking agent on the film. Yes.

  Patent Document 2 discloses a technique for stopping oil leakage through a screw groove of a bolt and nut by interposing a rubber nut formed with a female screw between a bolt and a nut and a flange seating surface. Yes.

  Patent Document 3 discloses a technique in which a bolt is inserted into a bolt hole of a flange filled with a filler and tightened with a nut in order to stop oil leakage from the bolt and nut for fastening the flange.

JP 2011-163400 A JP 2003-139290 A Utility Model Registration No. 3077863

  However, in the technique disclosed in Patent Document 1, since the flange portion is covered with the caulking agent together with the bolt and nut, the bolt and nut cannot be operated after the construction.

  In the technique disclosed in Patent Document 2, a thick elastic body (rubber nut) is interposed in a bolt and nut used for fastening a flange in order to stop oil leakage. Therefore, when an external force is applied from the radial direction (lateral direction) of the pipe, the pipe is likely to be bent at the flange portion, which may cause undesired deformation, displacement, and the like.

  Further, with the technique disclosed in Patent Document 3, it is not possible to stop oil leakage through the gap between the inner wall surface of the bolt hole and the filler.

  The present invention has been made under the technical background as described above. Accordingly, an object of the present invention is to provide a liquid leakage prevention washer, a liquid leakage prevention nut suitable for use in preventing oil leakage from a flange portion of a pipe used in electric power equipment, particularly oil leakage from a bolt and nut that fastens the flange, An object of the present invention is to provide a liquid leakage prevention structure and a liquid leakage prevention method.

  As a result of intensive studies, the inventor has come up with the idea that the above-described object can be achieved by using a liquid leakage prevention washer and a liquid leakage prevention nut, which are washers and nuts having a devised structure together with a liquid gasket. Accordingly, the liquid leakage prevention washer of the present invention includes a washer body that is a parallel plate having planar first and second surfaces, and a washer hole that penetrates the washer body. An annular first groove surrounding the washer hole is provided on the first surface side, and an annular second groove surrounding the washer hole is provided on the second surface side.

  In addition, the liquid leakage prevention nut of the present invention includes a substantially regular hexagonal column prevention nut body having a substantially cylindrical screw hole with a female thread at the center, and a through hole extending to the screw hole on the side surface of the prevention nut body. It has.

  The liquid leakage prevention structure of the present invention includes a first flange and a second flange fastened to the first flange. Moreover, the bolt inserted from both the bolt holes of the first and second flanges from the first flange side, and a nut screwed from the second flange side to the shaft portion of this bolt are provided. Furthermore, between the bolt and the first flange, the first surface is opposed to the first flange side, the above-described liquid leakage prevention washer, and the nut and the second flange between the second flange side and the second flange side. And another liquid leakage prevention washer arranged with one surface facing each other.

  Furthermore, the liquid leakage prevention method of the present invention is performed in the following order using the first and second liquid leakage prevention washers that are the above-described liquid leakage prevention washers and the above-described liquid leakage prevention nut.

  First, the first and second grooves of the first and second liquid leakage prevention washers are filled with a liquid gasket without any gaps. Then, through both the bolt holes of the first and second flanges, a bolt inserted through the first liquid leakage prevention washer with the first surface facing the first flange side is inserted from the first flange side. Similarly, a nut is screwed onto the shaft portion of the bolt protruding from the second flange, with the second liquid leakage prevention washer facing the first surface on the second flange side, and the first and second 2Fasten the flange.

  Subsequently, a liquid leakage prevention nut is fastened to the shaft portion of the bolt protruding from the nut, and a liquid gasket is injected into the through hole of the liquid leakage prevention nut, and then the cap bolt is screwed into the through hole.

  The present invention is configured as described above. Therefore, it is possible to effectively prevent oil leakage from the flange portion used in the power equipment, particularly oil leakage from the bolt and nut that fastens the flange.

(A) is an end view showing two flanges fastened using a conventional technique together with fastening parts, and (B) is an end face showing an enlarged area around a dotted line in (A). FIG. (A) is an end view showing two flanges fastened using the present invention together with a liquid leakage prevention component, and (B) is an enlarged view of the area surrounded by the dotted line in (A). It is an end view. (A) is a perspective view schematically showing the structure of a liquid leakage prevention washer, (B) is a front view of the liquid leakage prevention washer, and (C) is a side view of the liquid leakage prevention washer. . (A) is a schematic diagram for explaining the arrangement condition of the first groove provided in the liquid leakage prevention washer, and (B) is a schematic diagram for explanation of the arrangement condition of the second groove provided in the liquid leakage prevention washer. is there. It is the cutting | disconnection end elevation which cut | disconnected the liquid leak prevention washer of the modification along the diameter. (A) is a schematic diagram which shows the 1st aspect of arrangement | positioning of the auxiliary | assistant prevention washer in a special flange part, (B) is a schematic diagram which shows the 2nd aspect of arrangement | positioning of an auxiliary | assistant prevention washer. It is a schematic diagram which shows the 3rd aspect of arrangement | positioning of an auxiliary | assistant prevention washer. (A) is a perspective view schematically showing the structure of a liquid leakage prevention nut together with a cap bolt, and (B) is a front view schematically showing the structure of the liquid leakage prevention nut together with a cap bolt. C) is a side view schematically showing the structure of a liquid leakage prevention nut and a reinforcing nut together with a cap bolt. It is a schematic diagram which shows roughly the structure of the liquid-leakage prevention structure in the state where the set screw was used. (A)-(C) are the schematic diagrams of the liquid-leakage prevention structure which shows each process step of the liquid-leakage prevention method. (A)-(C) are the cut end views used for description of the subprocess of the process shown in FIG.10 (C), and are taken along the PP line of FIG.10 (C). (A)-(C) are the cut | disconnected end elevations used for description of the subprocess following FIG.11 (C), and are taken along the PP line of FIG.10 (C). FIG. 13C is a cut end view for explaining the sub-process following FIG. 12C, taken along the line QQ in FIG. 10C.

  Embodiments of the present invention will be described below with reference to the drawings. In each figure, the shape, size, and arrangement relationship of each component are schematically shown to such an extent that the present invention can be understood. Moreover, although the preferable structural example of this invention is demonstrated hereafter, the material of each component, a numerical condition, etc. are only a suitable example. Therefore, the present invention is not limited to the following embodiments. Moreover, in each figure, the same code | symbol is attached | subjected to a common component and the overlapping description may be abbreviate | omitted. In addition, reference numerals of components that have a clear correspondence with other drawings may be omitted.

(Summary of Invention)
First, a liquid leakage prevention washer, a liquid leakage prevention nut, a liquid leakage prevention structure, and a liquid leakage prevention method according to the present invention will be schematically described with reference to FIGS. FIG. 1A is an end view showing two flanges fastened using a conventional technique together with fastening parts. FIG. 1B is an enlarged end view showing the vicinity of the area surrounded by the dotted line in FIG. FIG. 2A is an end view showing two flanges fastened using the present invention together with a liquid leakage prevention component. FIG. 2B is an end view showing an enlarged view of the vicinity of the region surrounded by the dotted line in FIG.

<Oil leakage>
First, with reference to FIG. 1 (A) and (B), the conventional fastening structure and the oil leakage through the fastening structure will be described.

  First, a direction used in the following description is defined with reference to FIG. The direction is determined based on the bolt 12 shown in FIG. That is, the direction in which the bolt 12 advances when the head 12a of the bolt 12 that is a right screw is rotated in the clockwise direction is referred to as an axial direction Ax1. A direction perpendicular to the axial direction Ax1 is referred to as a radial direction Ax2. Furthermore, the rotation direction (clockwise direction) of the head 12a when the bolt 12 is advanced in the axial direction Ax1 is referred to as a circumferential direction Ax3.

  As shown in FIG. 1A, the fastening structure 200 includes a fastening part 100 and two flanges 102FL and 102FR. Hereinafter, the flanges 102FL and 102FR may be collectively referred to as “flange 102F”. Both pipes 102 </ b> L and 102 </ b> R provided with both flanges 102 </ b> FL and 102 </ b> FR are cylindrical pipes for circulating insulating oil Oil, and are fastened to each other by a fastening structure 200. Hereinafter, the pipes 102L and 102R may be collectively referred to as “pipe 102”.

  The flange 102FL is an annular parallel plate integrally formed at the end of the pipe 102L. The flange 102FL is formed with bolt holes that are through holes extending in the axial direction Ax1 of the pipe 102L at equal angular intervals along the circumferential direction Ax3 of the ring. The flange 102FR has the same shape as the flange 102FL, and is provided at the end of the pipe 102R so as to face the flange 102FL. And the bolt hole is formed in the flange 102FR similarly to the flange 102FL. Further, a gasket 108 made of, for example, NBR rubber is provided on the joint surface between the flanges 102FL and 102FR in order to prevent oil leakage.

  Both flanges 102FL and 102FR are arranged with their bolt holes aligned. Both the flanges 102FL and 102FR are fastened by the fastening part 100 provided in these bolt holes. FIG. 1A shows one of the bolt holes 102hL and 102hR. Hereinafter, the bolt holes 102hL and 102hR may be collectively referred to as “bolt holes 102h”.

  The bolt hole 102h is a cylindrical through hole through which the shaft portion 12b of the bolt 12 is inserted. The inner wall surface 102hS of the bolt hole 102h is formed in a smooth curved surface. The bolt hole 102h is formed to have a diameter larger than the diameter of the bolt shaft portion 12b.

  The fastening component 100 includes a bolt 12, two washers 104 </ b> L and 104 </ b> R, and a nut 106. A normal spring washer (not shown) is provided between the nut 106 and the washer 104R.

  The bolt 12 includes a head portion 12a and a shaft portion 12b formed integrally with the head portion 12a and having a male screw on a side surface. The head portion 12a is a substantially regular hexagonal column, and the side surface of the regular hexagonal column is sandwiched by a tool such as a wrench to rotate the shaft portion 12b.

  The nut 106 is a substantially regular hexagonal column, and is provided with a screw hole in which an internal thread is formed so as to penetrate the upper surface and the lower surface. The male screw of the shaft portion 12b of the bolt 12 is screwed into this screw hole. The two flanges 102FL and 102FR are fastened by screwing and tightening the nut 106 and the bolt 12.

  The washer 104L is disposed between the head 12a of the bolt 12 and the flange 102FL. The washer 104R is disposed between the nut 106 and the flange 102FR. Hereinafter, the washers 104L and 104R may be collectively referred to as “washer 104”.

  The washer 104L is an annular parallel plate interposed between the head 12a of the bolt 12 and the seating surface of the flange 102FL. The washer 104L has a shaft part 12b inserted through a circular washer hole in the center, and is compressed between the head part 12a and the seating surface of the flange 102FL, thereby preventing the bolt 12 and the nut 106 from loosening. .

  The washer 104R is configured in the same manner as the washer 104L, and is interposed between the nut 106 and the seating surface of the flange 102FR. The washer 104R is compressed between the nut 106 and the seating surface of the flange 102FR, thereby preventing the bolt 12 and the nut 106 from loosening.

<Oil leakage>
Next, with reference to FIGS. 1A and 1B, the oil leakage from the fastening component 100 used for the flange 102F will be described. As shown in FIG. 1 (A), when the gasket 108 deteriorates, the insulating oil Oil circulating through the pipe 102 starts to leak from a slight gap on the joint surface of the flange 102F (indicated by an arrow A in FIG. 1 (A)). Hereinafter, it is also simply referred to as oil leakage A). This oil leakage A is a capillary generated by the pressure generated by the dead weight of the insulating oil Oil, the pressure applied to the insulating oil Oil in order to circulate the pipe 102 (hereinafter also referred to as operating pressure), and the gap between the joint surfaces of the flange 102F. Caused by the phenomenon.

  The oil leakage A eventually reaches the bolt hole 102h of the flange 102F and branches in three directions at the bolt hole 102h (indicated by arrows B, C, and K in FIGS. 1A and 1B). Also referred to as oils B, C and K).

  The branched first oil leakage C travels in the oil leakage path 2 in the direction toward the nut 106 along the axial direction Ax1 (FIG. 1B). Here, the oil leakage path 2 is a space between the inner wall surface 102hRS of the bolt hole 102hR and the thread of the shaft portion 12b, and a space between the inner wall surface 104RS of the washer hole and the thread of the shaft portion 12b. Respectively.

  A part of the oil leakage C leaks to the outside through the joint surface between the flange 102FR and the washer 104R due to the above-described operating pressure and capillary action (indicated by an arrow E1 in FIGS. 1A and 1B). Hereinafter, it is also simply referred to as oil leakage E1). Similarly, it leaks to the outside through the joint surface between the washer 104R and the bolt 106 (indicated by an arrow E2 in FIGS. 1A and 1B, hereinafter also simply referred to as oil leakage E2).

  Further, the remaining portion of the oil leakage C proceeds in the oil leakage path 4 toward the tip of the shaft portion 12b (indicated by an arrow F in FIGS. 1A and 1B). Also referred to as oil F). Here, the oil leakage path 4 is a gap between the surface of the thread of the shaft portion 12 b and the surface of the thread groove of the nut 106. The oil leakage path 4 extends spirally toward the tip of the shaft portion 12b. The oil leakage F leaks to the outside from the end face of the nut 106 (indicated by an arrow G in FIG. 1A, hereinafter also simply referred to as oil leakage G).

  The second oil leak B branched to the head 12a side of the bolt 12 through the bolt hole 102h proceeds in the direction toward the head 12a of the bolt 12 via the oil leak path 2 described above. A part of the oil leakage B leaks to the outside through the joint surface between the flange 102FL and the washer 104L (indicated by an arrow J1 in FIG. 1A, hereinafter also simply referred to as oil leakage J1). Similarly, it leaks to the outside through the joint surface between the washer 104L and the head portion 12a (indicated by an arrow J2 in FIG. 1A, hereinafter also simply referred to as oil leakage J2).

  Further, the third oil leak K leaks out from the joint surface of the flange 102F.

<Liquid leakage prevention structure>
Next, the present invention will be schematically described with reference to FIGS. 2 (A) and 2 (B). The liquid leakage prevention structure 20 of the present invention is different from the fastening structure 200 in that the liquid leakage prevention component 10 is used instead of the fastening component 100 described above. Hereinafter, the liquid leakage prevention structure 20 and the liquid leakage prevention component 10 are also referred to as “blocking structure 20” and “blocking component 10”, respectively.

  The blocking component 10 is configured in the same manner as the fastening component 100 except that the liquid leakage blocking washers 14L and 14R are used instead of the washers 104L and 104R and the liquid leakage blocking nut 16 is used. The liquid leakage prevention washers 14L and 14R are also simply referred to as prevention washers 14L and 14R, and both 14L and 14R may be collectively referred to as prevention washers 14. Further, the liquid leakage prevention nut 16 may be simply referred to as a prevention nut 16.

Blocking washer 14 includes first and second grooves 14 ₁ and 14 _2, except with a liquid gasket 22 (in the figure indicated by hatching.) Is configured similarly to the washer 104. The blocking nut 16 is configured in the same manner as the nut 106 except that the blocking nut 16 includes a through hole 18e, a cap bolt 21, and a liquid gasket 22. These differences will be described later.

  The blocking washer 14 and the blocking nut 16 are preferably configured to prevent oil leakage. As a result, by using the blocking structure 20 of the present invention, oil leakage J1, J2, E1, E2, F, and G from the flange 102F is blocked (indicated by arrows marked with “x” in the figure). ). Note that oil leakage K from the joint surface of the flange 102F may be prevented by a conventionally known method.

  Moreover, the blocking structure 20 of the present invention is not limited to the connection portion of the pipe, and can be applied to oil leakage prevention at various connection portions using flanges. For example, the present invention can be applied to oil leakage prevention or the like at a connection portion between a flange provided in an insulating oil tank and a flange of a pipe connected to the tank. Moreover, the blocking structure 20 of the present invention can be applied to a flange with a stud bolt welded to the device main body, a flange with a standing bolt, or the like.

(Liquid gasket)
First, the liquid gasket 22 commonly used for the blocking washer 14 and the blocking nut 16 will be described in detail. Although details will be described later, the liquid gasket 22 is filled in the first and second grooves 14 ₁ and 14 ₂ of the blocking washer 14, and is pressure injected into the through hole 18e of the blocking nut 16, to prevent oil leakage gasket Function as.

  The liquid gasket 22 is in a liquid state having viscosity and fluidity before curing, but changes to an elastic solid state after curing, and functions as a gasket that prevents leakage of fluid such as liquid or gas. The liquid gasket 22 having such a property can infiltrate following a complicated shape or a narrow gap, so that leakage of fluid from a place where a normal solid gasket (for example, an O-ring or the like) cannot cope is prevented. can do.

  Various materials having the above-mentioned properties can be selected for the liquid gasket 22, but in this example (product surface: “860 Modal Polymer Gasket” manufactured by AW CHESTERTON COMPANY (USA)) 860 gasket). The 860 gasket changes from a liquid state to a gel state 3 to 4 hours after application, and completely changes to an elastic solid state after about 24 hours. Moreover, since the heat resistance of the gasket formed after hardening is -51 degreeC-+260 degreeC, it can fully endure the temperature change of an apparatus installation environment.

(Blocking washer)
Next, the blocking washer 14 will be described in detail with reference to FIGS. 3A is a perspective view schematically showing the structure of the blocking washer, FIG. 3B is a front view of the blocking washer, and FIG. 3C is a side view of the blocking washer. . 4A is a schematic diagram for explaining the arrangement condition of the first groove provided in the blocking washer, and FIG. 4B is a schematic diagram for explaining the arrangement condition of the second groove provided in the blocking washer. is there. FIG. 5 is a cut end view of the modified blocking washer cut along the diameter.

<Structure>
As discussed above, blocking the washer 14, except that it includes a first groove 14 ₁ and the second groove 14 ₂ liquid gasket 22 is filled, it is formed similarly to the washer 104.

  Referring to FIG. 3A, the blocking washer 14 includes a washer body 14H and a washer hole 14c. The washer body 14H is an annular parallel flat plate, and includes flat first and second surfaces 14a and 14b facing each other. The washer hole 14c is a circular opening having a common center with the washer body 14H, and penetrates the washer body 14H in the axial direction Ax1. In this example, the blocking washer 14 is preferably made of a metal excellent in rust prevention, and in this example, brass is used as the material.

Then, on the first surface 14a side facing the flange 102F, we have a common center with washer body 14H, the first groove 14 ₁ of the annular surrounding the washer hole 14c is provided. Similarly, the second surface 14b side opposite to the first surface 14a has a common center with washer body 14H, is provided with a second groove 14 ₂ annular surrounding the washer hole 14c. In this example, than the first groove 14 ₁ of the diameter direction of the second groove 14 _second diameter smaller.

In the state assembled to the blocking structure 10, the first and second grooves 14 ₁ and 14 ₂ are filled with a liquid gasket 22 that is elastic and solid after curing.

The blocking washer 14 has a diameter regardless of whether it is located on the head 12a side of the bolt 12 (14L: FIG. 2A) or on the nut 106 side (14R: FIG. 2A). big first surface 14a of the first groove 14 ₁ is provided is positioned to face the flange 102F side. Therefore, the second face 14b of the second groove 14 ₂ is provided, the head 12a side of the bolt 12, or are disposed facing the nut 106 side.

Here, with reference to FIG. 3 (B) and (C), the dimension of each part of the blocking washer 14 is defined. First diameter of the blocking washer 14 and _{D 5,} the diameter of the washer hole 14c and _{D 3.} The thickness of the blocking washer 14 measured along the axial direction Ax1 is H. Further, the groove width measured along the first and second grooves 14 ₁ and 14 ₂ in the radial Ax2 and is W, a groove depth measured along the axial direction Ax1 and D. The first groove 14 ₁ of the inner diameter, i.e., the diameter of the circle formed of the first groove 14 ₁ of the inner contour line and _{R 1.} The outer diameter of the second groove 14 _2, i.e., the diameter of the circle formed of the second grooves 14 _{and second} outer contour line and _{R 2.} The distance between the outer edge of the first groove 14 ₁ of the outer contour line and the washer body 14H (width) and _{L 1.} Similarly, the distance between the contour of the second groove 14 _second inner contour and the washer hole 14c (width) and _{L 2.}

In this example, the case where the first and second grooves 14 ₁ and 14 ₂ are circular rings having a common center with the washer body 14 H has been described. However, ₂ the first and second grooves 14 ₁ and 14, according to the dimensions conditions described later, if the annular groove surrounding seamlessly washer hole 14c, is not limited to an annular shape.

In this example, the first groove 14 _first diameter has been described is larger than the second groove 14 _2. However, the first and second grooves 14 ₁ and 14 ₂ of the diameter washers hole 14c, by the dimensions of the bolt hole 102h and the shaft portion 12b, may be determined suitable value independently for each.

In this example, the first and second grooves 14 ₁ and 14 ₂ of the cross-sectional shape, and the manufacturing is easy rectangular. However, the cross section of the groove may be semicircular as long as a sufficient amount of the liquid gasket 22 can be filled to prevent oil leakage.

<Dimensional conditions of first and second grooves>
Subsequently, mainly with reference to FIGS. 4 (A) and (B), first and second grooves 14 ₁ and 14 ₂ of the blocking washer 14 Dimension conditions described to be satisfied. 4A and 4B are schematic views for explaining the arrangement conditions of the first and second grooves 14 ₁ and 14 ₂ , respectively. The head portion 12 a and the shaft portion 12 b of the bolt 12, and the blocking washer 14 are illustrated. FIG. 4 is an enlarged end view of the main part in the vicinity of the engaging part of the flange 102FL.

First, referring to FIGS. 4A and 4B, the dimensions of each part of the bolt 12 and the bolt hole 102hL are defined. Respect bolt 12, the width across flats of the head 12a and _{D 4.} Here, the two surface width D _4, the distance between the mutually parallel two sides of the head 12a. Further, the diameter of the shaft portion 12b and _{D 2.} Further, the diameter of the bolt holes 102hL the shaft portion 12b is inserted and _{D 1.}

<About the inner diameter of the first groove: FIG. 4A>
First, conditions that the inner diameter R ₁ of the first groove 14 ₁ should satisfy will be described. Figure 4 (A), the magnitude relation between the diameter _{D 1} of the diameter _{D 2} and bolt holes 102hL of the shaft portion 12b of the bolt _12, since it is D 1> _{D 2,} the shaft portion 12b in the bolt hole 102hL When inserted, a maximum of (D ₁ -D ₂ ) play occurs. Hereinafter, this play (D ₁ -D ₂ ) is also referred to as a first maximum play.

The first groove 14 _1, between the blocking washer 14 and the flange 102F for not causing leakage oil to a path, it is necessary to place not exposed to the bolt holes 102hL flange 102F. That is, as shown in the following formula (1), the distance ((R ₁ -D ₃ ) / 2) from the edge of the washer hole 14 c to the inner contour line of the first groove 14 ₁ X is larger than the first maximum play. There is a need to.

_{(R 1 -D 3) / 2} > (D 1 -D 2) ··· (1)
When the formula (1) is modified, the following formula (2) is obtained.

R ₁ > D ₃ +2 (D ₁ −D ₂ ) (2)
Equation (2), the diameter _{R 1} of the first groove 14 ₁ of the inner contour, the diameter _{D 3} of the washer hole 14c, is greater than twice the sum of the first maximum play _(D 1 -D ₂₎ Indicates that it is necessary.

The first groove 14 ₁ of the outer diameter, i.e. the diameter of the first groove 14 ₁ of the outer contour line _(R 1 + 2W) is the diameter _{D 5} required is less than the blocking washer 14. From this condition, the first groove 14 ₁ of the groove width W is required to be a length that satisfies _{W <(D 5 -R 1)} / 2.

<About the outer diameter of the second groove: FIG. 4B>
Subsequently, the outer diameter _{R 2} of the second groove 14 ₂ is the condition will be described to be satisfied. As shown in FIG. 4 (B), the diameter _{D 2} of the shaft portion 12b, the magnitude relation of the diameter _{D 3} of the washer hole _14c, so is D 3> _{D 2,} when inserting the blocking washer 14 to the shaft portion 12b , A maximum of (D ₃ -D ₂ ) play occurs. It will hereinafter be referred to this play _(D 3 -D ₂₎ both second maximum play.

Second groove 14 _2, in order not to cause leakage oil to a path between the bolt 12 and the blocking washer 14, is required to be arranged not exposed from the head 12a of the bolt 12 (or nut 106). That is, as in the following equation (3), the distance D ₆ including a second maximum play between the shaft portion 12b and the outer contour of the second groove 14 2 _Y, the shortest distance between the side surface of the shaft portion 12b and the bolt 12 It is necessary to make it smaller than ((D ₄ -D ₂ ) / 2).

D ₆ <(D ₄ -D ₂ ) / 2 (3)
_{D 6 = (D 3 -D 2} ) + (R 2 -D 3) / 2 ··· (3 ')
Here, one item (D ₃ -D ₂ ) of D ₆ in the formula (3 ′) is the second maximum play, and two items (R ₂ -D ₃ ) / 2 are the values of the washer hole 14 c of the blocking washer 14. This is the distance from the outer edge to the outer contour line of the second groove 14 ₂ Y.

  When Expression (3) is transformed using Expression (3 '), the following Expression (4) is obtained.

R ₂ <D ₄ − (D ₃ −D ₂ ) (4)
Equation (4), the diameter _{R 2} of the second groove 14 _{and second} outer contour line, from the two-surface width _{D 4} of the head 12a, smaller than the value obtained by subtracting the second largest play _(D 3 -D ₂₎ Shows that you need to.

The second grooves 14 _{and second} inner diameter, i.e. the diameter of the second groove 14 _second inner contour _(R 2 -2w) is a diameter _{D 3} must be larger than the washer hole 14c. From this condition, the groove width W of the second groove 14 ₂ is required to be a length that satisfies _{W <(R 2 -D 3)} / 2.

<Other dimensions>
The thickness H of the washer body 14H is preferably set to a thickness that can prevent loosening of the bolt 12 and the nut 106, and is about 3 mm in this example. Also, considering the first and second grooves 14 ₁ and 14 _2, etc., the thickness of the thinnest portion of the washer body 14H is preferably not less than 0.5 mm. By setting the dimension of the thinnest portion of the blocking washer 14 in this way, even if the blocking washer 14 is accidentally dropped or bumped, the mechanical strength sufficient to prevent bending at the thinnest portion can be obtained. In this example, since the groove depth D of the _first and _second grooves 141 and 142 is about 0.5 mm as will be described later, the thickness of the washer body 14H at the thinnest portion is about 2.5 mm. is there.

The width _{L 2} of the contour line of width _{L 1,} and the second groove 14 ₂ and the washer hole 14c of the outer edge of the first groove 14 ₁ and the washer body is preferably set to about 0.5mm or more, respectively. By setting the widths L ₁ and L ₂ within this range, a sufficient thickness H and widths L ₁ and L ₂ are provided between the first and second grooves 14 ₁ and 14 ₂ and the edge of the blocking washer 14. A washer body 14H can be provided. As a result, similarly to the above, the first and second modifications of the grooves 14 ₁ and 14 ₂ can be prevented when falling or bumped.

The groove width W and the depth D of the first and second grooves 14 ₁ and 14 ₂ are determined primarily, the mechanical strength of the blocking washer 14, and, in consideration of workability in applying the liquid gasket 22 Is done. In particular, the groove width W needs to further satisfy the above-described two conditions, W <(D ₅ −R ₁ ) / 2 and W <(R ₂ −D ₃ ) / 2.

If the groove depth D and the groove width W are too small, it is not preferable because when the liquid gasket 22 is applied to the first and second grooves 14 ₁ and 14 ₂ , bubbles are easily mixed into the groove. On the other hand, if the groove depth D and the groove width W are too large, the mechanical strength and oil leakage prevention capability of the prevention washer 14 are lowered, which is not preferable. In consideration of the above, in this example, is common to ₂ first and second grooves 14 ₁ and 14, the groove width W of about 1.3 mm, was about 0.5mm groove depth D.

The outer diameter _{D 5} and the diameter _{D 3} of the washer hole 14c of the blocking washer 14 is used to power equipment, be determined so nominal diameter to fit the bolt 12 and the bolt holes 102hL according to JIS standard of M6~M48 Good.

Outer diameter _{D 5} and diameter _{D 3} of the washer hole 14c of the stop washer 14 thus designed does not necessarily conform to JIS standards. This is the result of optimizing the blocking washer 14 to prevent oil leakage. That is, the first and second grooves 14 ₁ and 14 ₂ according to formula (1) and (3), because provided the best position.

  When the blocking washer 14 is used when the flange 102F is fastened, it is preferable to align the blocking washers 14 with the three nominal diameters of the bolt hole 102hL and the bolt 12 according to JIS standards. Thereby, oil leakage can be effectively prevented.

<Effect>
By using the blocking washer 14 of the present invention together with the liquid gasket 22, oil leaks J1, J2, E1, and E2 having a path as a joint surface between the blocking washer 14 and another member (see FIGS. 2A and 2B). ) Can be stopped reliably. The inventor tried to prevent oil leakage using a normal flat washer (for example, washer 104) coated with the liquid gasket 22 on both sides. However, even if the liquid gasket 22 was applied, the oil leakage could not be stopped with the normal flat washer.

<Modification 1>
Next, a modified example of the blocking washer 14 will be described with reference to FIG. FIG. 5 is an end view of a modified blocking washer 14 ′ (hereinafter also referred to as modified 14 ′) cut along the diameter.

Modification 14 ', the first surface 14a side, the second auxiliary grooves 14 ₂ which is the second groove 14 ₂ and symmetrically formed across the washer body 14'H' comprises a, the second surface 14b side, that it comprises a first auxiliary grooves 14 1 _'formed in the first groove 14 ₁ and symmetrically across the washer body 14'H is different from the blocking washer 14. That is, modification 14 'each of the both surfaces of the first and second surfaces 14a and 14b, as it were, provided with two grooves 14 ₁ and 14 ₂ of.

As shown in FIG. 2 (A), prevents the washer 14, the first groove 14 ₁ of the first surface 14a having a toward the flange 102F side, the second groove 14 ₂ bolts 12 or nuts 106 a second surface 14b having It was necessary to assemble to the side. That is, the blocking washer 14 had the correct “direction” when assembled to the liquid leakage blocking structure 20.

In contrast, blocking washer 14 variant 'are both surfaces of the first and second surfaces 14a and 14b, as it were provided with first and second grooves 14 ₁ and 14 _2. As a result, the modified example 14 ′ can be assembled to the liquid leakage prevention structure 20 without minding the orientation of the first and second surfaces 14a and 14b. As a result, by using the modified washer 14 ′, the workability during assembly of the liquid leakage preventing structure 20 is improved.

  In the modification 14 ', the case where the first and second surfaces 14a and 14b each include two grooves has been described. However, the number of grooves provided in the first and second surfaces 14a and 14b is such that a sufficient amount of the liquid gasket 22 can be held to prevent oil leakage, and the mechanical strength of the blocking washer 14 is sufficiently maintained. 3 or more may be sufficient.

  For some reason, when a normal flat washer, for example, a washer 104, is used in addition to the liquid leakage prevention structure 20, it is necessary to prevent oil leakage through a joint surface between the washer 104 and another member. There is. For this purpose, it is preferable to add two additional blocking washers 14 and sandwich this washer 104 from both sides. Thereby, the oil leak originating in the added washer 104 can be prevented.

<Modification 2>
Next, referring to FIGS. 6 and 7, a blocking washer is used with a special flange portion 102F ′ (hereinafter also referred to as “special flange portion 102F ′”) in which the nominal diameters of the bolt hole 102hL ′ and the bolt 12 are not equal. The auxiliary blocking washer (hereinafter also simply referred to as “auxiliary washer”) 15 used together with 14 will be described. 6A is a schematic diagram showing a first mode of arrangement of the auxiliary washer 15 in the special flange portion 102F ′, and FIG. 6B is a schematic diagram showing a second mode of arrangement of the auxiliary washer 15. FIG. 7 is a schematic diagram showing a third mode of arrangement of the auxiliary washer 15.

  The auxiliary washer 15 is disposed between the blocking washer 14 and the flange portion 102F 'when the nominal diameter of the bolt hole 102hL' is larger than that of the bolt 12, and cooperates with the blocking washer 14 to prevent oil leakage.

Such a flange portion 102F ′ is used, for example, as a transformer switching valve mounting flange of a transformer. In this transformer switching valve mounting flange, a bolt 12 (D ₂ = 16 mm) having a nominal diameter of M16 is inserted into a JIS class 3 bolt hole 102hL ′ (D ₁ = 24 mm) having a nominal diameter of M20, and the flange is fastened. Hereinafter, the bolt hole 102hL ′ used for the transformer switching valve mounting flange is also referred to as “large-diameter bolt hole 102hL ′”.

In the special flange portion 102F ′ described above, the M16 blocking washer 14 having the same nominal diameter as that of the bolt cannot be used alone. The dimensions of the blocking washer 14 of M16 are, for example, R ₁ = 23.4 mm, D ₃ = 16.4 mm, and D ₅ = 27 mm, and the first groove 14 is inserted into the large-diameter bolt hole 102hL ′ having a diameter D ₁ (24 mm). _{This is because 1} is completely exposed.

Therefore, in such a case, the auxiliary washer 15 is interposed between the blocking washer 14 and the special flange portion 102F ′ so as to absorb the difference in size between the two. Auxiliary washer 15, except that only the grooves 15 ₁ in the first surface 15a is provided, are substantially the same structure as blocking washer 14.

  Hereinafter, the design conditions of the auxiliary washer 15 will be described with reference to FIGS. 6 and 7. The auxiliary washer 15 needs to satisfy the following three conditions.

(Condition 1) The first groove 14 ₁ of the blocking washer 14 cooperating, not exposed to the washer hole 15c of the auxiliary washer 15.
(Condition 2) grooves 15 ₁ is not exposed to large diameter bolt hole 102hL '.
(Condition 3) grooves 15 ₁ does not protrude from the end surface 102F'a special flange portion 102F '.

Before describing these conditions, first, referring to FIG. 6A, the dimensions of the auxiliary washer 15 and the special flange portion 102F ′ are defined. In the auxiliary washer 15, the diameter of the washer hole 15c and _{d 3.} Further, the diameter of the circle formed by the groove 15 ₁ of the inner contour line is referred to as the inner diameter r _in. Similarly, it refers to the diameter of the circle formed of the groove 15 ₁ of the outer contour line and an outer diameter r _out.

Also, 'with respect to the large-diameter bolt hole 102HL' special flange portion 102F and the shortest distance to the outer edge of the end face 102F'a of the flange and _{D 7.}

  Next, the above (Condition 1) to (Condition 3) will be described. In the following description, the auxiliary washer 15 and the blocking washer 14 of M16, which is equal to the nominal diameter of the bolt 12, are used.

Referring to FIG. 6 (A), the To determine the diameter d ₃ of the washer hole 15c so as to satisfy the condition 1 can be be seen that the use of the equation (2) above. That is, the bolt holes 102HL (FIG 4 (A) refer) in the expression for the first groove 14 ₁ is not exposed condition (2), the following equation obtained by replacing the diameter _{D 1} to diameter _{d 3} of the washer hole 15c (5) Can be established.
d ₃ <(R ₁ + 2D ₂ -D ₃ ) / 2 (5)
Substituting the above-mentioned dimension of the blocking washer 14 having a nominal diameter of M16 into the equation (5), a result of d ₃ <19.5 mm is obtained. Here, d ₃ = 19 mm is set because it is necessary to ensure sufficient play between the auxiliary washer 15 and the bolt 12.

Also with reference to FIG. 6 (A), the described arrangement of the grooves 15 ₁ to satisfy the condition 2. FIG. 6A shows a first mode when the groove 15 ₁ X is closest to the large-diameter bolt hole 102hL ′. Condition 2 are the same as the conditions described previously, the first groove 14 ₁ of the blocking washer 14 meet. Therefore, the inner diameter _{r in} the grooves 15 ₁ may be determined in accordance with the above equation (2). That is, it can be obtained from the following formula (6) obtained by modifying the formula (2).

r _in > d ₃ +2 (D ₁ −D ₂ ) (6)
Substituting d ₃ = 19 mm, D ₁ = 24 mm, and D ₂ = 16 mm into Equation (6), results _in r _in > 35 mm.

Subsequently, Condition 3 will be described with reference to FIG. FIG. 6B shows a second mode when the groove 15 ₁ X is closest to the end face 102F′a of the flange 102F ′. In the second aspect, to satisfy the condition 3, it is necessary to satisfy the following formula (7).

D ₇ > (r _out −d ₃ ) / 2 + d ₃ −D ₂ (7)
In the formula _{(7), (r out -d} 3) / 2 is the distance from the outer edge of the washer hole 15c to the outer contour of the groove 15 _1. D ₃ -D ₂ is “play” derived from the difference in diameter between the shaft portion 12 b and the washer hole 15 c.

  When the equation (7) is modified, the following equation (8) is obtained.

r _out <2D ₇ + 2D ₂ −d ₃ (8)
Outer diameter _{r out} of the groove 15 ₁ may be determined so as to satisfy the equation (8).
Substituting d ₃ = 19 mm and D ₂ = 16 mm into the equation (8) and assuming D ₇ = 15 mm, the result r _out <43 mm is obtained.

To summarize the results of the conditions 2 and 3, when the distance _{D 7} to the flange end face 102F'a is 15 mm, the grooves 15 _{1, r in} the 35mm or more, _{and, r out} is provided to fit in the range of 43mm And good.

Figure 7 is 'a distance _{D 7} between the flange end face 102F'a' large diameter bolt holes 102hL shows a design method of the groove 15 ₁ of smaller than _{D 7.} In FIG. 7, suppose that D ₇ ′ is 8 mm, which is smaller than D ₇ (15 mm). In this case, the result of r _out <29 mm is obtained from the above-described equation (8). However, the result of “r _out <29 mm” contradicts r _in > 35 mm obtained from the equation (6). That is, if the 'distance _{D 7} between the flange end face 102F'a' large diameter bolt holes 102hL small, the auxiliary washer 15, the provision of the grooves 15 ₁ which satisfies both the equation (6) and (8) May be difficult.

More specifically, when the width of the groove 15 _1, measured along the radial direction is W _1, if the hold is the following formula (9) or (10), and the above-mentioned formula (6) and (8) It is necessary to determine r _in and r _out under different conditions.

D ₇ − {(r _in −d ₃ ) / 2 + W ₁ + d ₃ −D ₂ } <0 (9)
D ₇ − {(r _in + d ₃ ) / 2 + W ₁ −D ₂ } <0 (10)
(R _in −d ₃ ) / 2 + W _{1 in the} braces of the formula (9) can be transformed to (r _in + 2W ₁ −d ₃ ) / 2 = (r _out −d ₃ ) / 2. That is, referring to FIG. 7, these terms in the braces is the distance between the outer edge of the groove 15 ₁ of the outer contour line and the washer hole 15c. Further, d ₃ -D ₂ in the braces is the maximum value of play derived from the difference in diameter between the shaft portion 12b and the washer hole 15c (FIG. 6B). Expression (10) is simply a modification of Expression (9).

In other words, the formula (9), when is closest Equation (6) and the groove 15 ₁ of the design according to (8) to the flange end face 102F'a, shows that the difference between the two distances is negative . This is because when the formula (9) or the (10) holds means that the grooves 15 ₁ from the flange end face 102F'a, exposed.

More specifically, as an example when D ₇ is sufficiently large, the above-mentioned D ₇ = 15 mm, r _in = 35 mm, d ₃ = 19 mm, W ₁ = 1.3 mm, and D ₂ = Calculate by substituting 16 mm. At this time, Expression (10) becomes “15 − {(35 + 19) /2+1.3−16} = 15−12.3 = 2.7 (≧ 0)”. That is, when _{D 7} is 15mm It can be seen that the grooves 15 ₁ can be designed based on equation (6) and (8). On the other hand, when D ₇ ′ = 8 mm, the expression (10) becomes “8 − {(35 + 19) /2+1.3−16} = 8−12.3 = −4.3 (<0)”. in the design based on equation (6) and (8), it can be seen that the grooves 15 ₁ is exposed from the flange end face 102F'a.

In this case, as shown in FIG. 7, the auxiliary washer 15 is artificially arranged close to the large-diameter bolt hole 102hL ′ side. By arranging the auxiliary washer 15 in this way, the above-described conditions 2 and 3 can be relaxed. That is, the dimensional condition to be satisfied by r _in and r _out can be relaxed. Hereinafter, this point will be described in detail.

First, in determining the dimensional condition of r _out (condition 3), r _out is set so as to satisfy the following expression (11) in which (d ₃ -D ₂ ) in the above expression (7) is 0 (zero). Just decide.

D ₇ > (r _out −d ₃ ) / 2 (11)
When the equation (11) is modified, the following equation (12) is obtained.

r _out <2D ₇ + d ₃ (12)
Substituting D ₇ = 8 mm and d ₃ = 19 mm into equation (12), the result r _out <35 mm is obtained.

_Next, a description will be given of the size conditions of _{r in} (condition 2). Comparing FIG. 7 and FIG. 6A, when the bolt 12 and the auxiliary washer 15 are arranged as shown in FIG. 7, the groove 15 ₁ Y has a larger diameter bolt hole 102hL ′ than the groove 15 ₁ X. To approach. Therefore, in this arrangement, the dimensional condition for preventing the groove 15 ₁ Y from being exposed to the large-diameter bolt hole 102hL ′ gives the condition 2 described above. Referring to FIG. 7, this condition is given by the following equation (13).

(R _in -d ₃ ) / 2> (D ₁ -d ₃ ) (13)
In the equation (13), (r _in −d ₃ ) / 2 on the left side represents the distance from the outer edge of the washer hole 15c to the grooves 15 ₁ X and 15 ₁ Y. As shown in FIG. 7, (D ₁ -d ₃ ) on the right side is the maximum width of the auxiliary washer 15 exposed in the large-diameter bolt hole 102hL ′.

  When the equation (13) is transformed, the following equation (14) is obtained.

r _in > 2D ₁ -d ₃ (14)
Substituting D ₁ = 24 mm and d ₃ = 19 mm into equation (14), the result r _in > 29 mm is obtained.

In summary, if the _{D 7} '= 8 mm, the grooves 15 _1, r in> 29 mm, and _may it can be seen that by providing a range of r out <35 mm. Thus, _'when the small auxiliary washer 15 large diameter bolt hole 102HL' distance D ₇ By lapping the side, it is possible to dimension condition is relaxed providing grooves 15 _1.

As shown in FIGS. 6 and 7, the grooves 15 _1, the liquid gasket 22 is filled is brought into contact with the end face of the flange 102F is disposed an auxiliary blocking washer 15, the second surface 15b of the groove 15 ₁ is not provided It is brought into contact with the first groove 14 ₁ of the blocking washer 14 liquid gasket 22 is filled. Thereby, both washers 14 and 15 can prevent oil leakage from the contact surface between the auxiliary washer 15 and the flange 102F and oil leakage from the contact surfaces of both washers 14 and 15.

(Blocking nut)
Next, the blocking nut 16 will be described in detail with reference to FIG. FIG. 8A is a perspective view schematically showing the structure of the blocking nut together with the cap bolt, and FIG. 8B is a front view schematically showing the structure of the blocking nut together with the cap bolt. 8 (C) is a side view schematically showing the structure of the blocking nut and the reinforcing nut together with the cap bolt.

Blocking nut 16 includes a blocking nut body 18 of a substantially regular hexagonal prism with a screw hole 18d of the generally cylindrical female threaded centered, formed on each side _18c 1, 18c _2, and 18c ₃ for blocking the nut body 18 The first, second and third through holes 18e ₁ , 18e ₂ and 18e ₃ reaching the screw hole 18d, and cap bolts 21 ₁ , 21 ₂ and 21 ₃ are provided. Further, the blocking nut 16 includes a liquid gasket 22 (FIG. 2A) that is pressure-injected into the first, second, and third through holes 18e ₁ , 18e _2, and 18e ₃ .

The first, second and third through holes 18e ₁ , 18e ₂ and 18e ₃ are provided at an angular interval of 120 ° in the circumferential direction Ax3. That is, the first, second and third through holes 18e ₁ , 18e ₂ and 18e ₃ are provided on the _three side surfaces 18c ₁ , 18c ₂ and 18c ₃ of the blocking nut body 18, respectively. That is, the first, second, and third through holes 18 e ₁ , 18 e _2, and 18 e ₃ are provided on every other six side surfaces of the blocking nut body 18. Hereinafter, the three through holes 18e ₁ , 18e ₂ and 18e ₃ may be collectively referred to as a through hole 18e. The three side surfaces 18c ₁ , 18c ₂ and 18c ₃ may be collectively referred to as the side surface 18c.

  The through hole 18e is formed so as to be perpendicular to the side surface 18c and have the shortest distance from the screw hole 18d. A female screw is formed on the inner wall surface of the through hole 18e. Referring to FIG. 8C, the through hole 18e is formed on the side surface 18c on the rear side of the blocking nut body 18 in the axial direction Ax1. That is, the through hole 18e is formed on the nut 106 side of the side surface 18c with respect to the axial direction Ax1.

The cap bolts 21 ₁ , 21 _2, and 21 ₃ are formed with male screws that are screwed into the first, second, and third through holes 18 e ₁ , 18 e _2, and 18 e ₃ , respectively. Hereinafter, the three cap bolts 21 ₁ , 21 _2, and 21 ₃ may be collectively referred to as the cap bolt 21. The length of the threaded portion of the cap bolt 21 is equal to or longer than the entire length of the through hole 18e. That is, the tip end portion of the cap bolt 21 reaches the shaft portion 12 b of the bolt 12 in a completely screwed state.

As will be described in detail later, when the blocking nut 16 is assembled to the liquid leakage blocking structure 20, the blocking nut body 18 is screwed onto the shaft portion 12b so as to press the nut 106 from the opposite side of the axial direction Ax1. Go. In this state, the liquid gasket 22 is pressure-injected into the first, second, and third through holes 18e ₁ , 18e _2, and 18e ₃ , and the cap bolt 21 is screwed into the through hole 18e that is filled with the liquid gasket 22. As a result, an injection pressure is further applied to the liquid gasket 22 in the through hole 18e, and the liquid gasket 22 penetrates into the gap between the female screw of the blocking nut body 18 and the nut 106 and the male screw of the bolt 12. As a result, as shown in FIG. 2B, the oil leakage path 4 between the female screw of the nut 106 and the male screw of the bolt 12 is blocked by the liquid gasket 22. This prevents oil leaks F and G.

  The diameter of the through hole 18e is preferably set according to the size of the blocking nut body 18 and the amount of the liquid gasket 22 required for preventing oil leakage. When there are three through holes 18e, for example, it is preferable to use a through hole 18e with a nominal diameter of M4 for the blocking nut body 18 with nominal diameters of M8 and M10. Moreover, it is preferable to use the through-hole 18e whose nominal diameter is M5 for the blocking nut main body 18 whose nominal diameter is M12, M16, and M20.

  In this way, by using the blocking nut 16, the oil leaks F and G flowing through the oil leakage path 4 can be blocked. Further, by tightening the nut 106 from the outside with the blocking nut 16 to form a so-called double nut, loosening of the nut 106 can be suppressed without using the spring washer described above.

  In this example, the case of three through holes 18e has been described. However, the number of the through holes 18e is not limited to three as long as the amount of the liquid gasket 22 necessary for blocking the oil leakage path 4 can be secured. For example, two or four or more may be used. However, when there are two through holes, the diameter of the through hole is increased or the inside of the through hole is directed toward the screw hole 18d in order to secure the amount of liquid gasket 22 necessary for oil leakage prevention. It is preferable to take measures such as widening in a conical shape. The two through holes are preferably provided in the blocking nut 16 at intervals of 180 ° in the circumferential direction. That is, it is preferable to provide a through hole on each of the two side surfaces of the blocking nut 16 that face each other in parallel.

<Effect>
By using the blocking nut 16 of the present invention, it is possible to reliably block the oil leaks F and G in which the gap between the thread of the shaft portion 12b and the thread groove of the nut 106 and the blocking nut 16 is the oil leakage path 4. it can. The inventor tried to prevent oil leakage by using a nut 106 in which the liquid gasket 22 was applied to the entire thread groove. However, even if the liquid gasket 22 was applied, the oil leakage could not be stopped with the nut 106 alone.

  Note that oil leakage can be prevented even if the blocking nut 16 in which the liquid gasket 22 is pressure-injected is used alone without using the nut 106. However, since the mechanical strength of the blocking nut 16 is weaker than that of the nut 106 as much as the through hole 18e is formed, when the blocking nut 16 is used alone, a device for increasing the strength of the entire flange 102F is required. .

  For example, the thin reinforcing nut 17 shown in FIG. 8C is screwed into the shaft portion 12b from the outside of the blocking nut 16, so that the blocking nut 16 and the reinforcing nut 17 constitute a double nut. May be. The reinforcing nut 17 only needs to compensate for the fastening force between the blocking nut 16 and the bolt 12 that has been lowered due to the formation of the through hole 18e. Accordingly, the thickness, which is the length of the reinforcing nut 17 along the axial direction Ax1, may be equal to or greater than the diameter of the through hole 18e, in this example, 5 mm or more.

  The double nut of the blocking nut 16 and the reinforcing nut 17 exhibits a practically sufficient fastening force with the bolt 12. Further, since the reinforcing nut 17 is thin, the reinforcing nut 17 can be used in a narrow interval where the normal nut 106 cannot be installed.

  Further, for example, the number of bolt holes 102h provided in the flange 102F may be increased as compared with the case of the nut 106, or the diameter of the bolt nut used for fastening the flange 102F may be increased as compared with the case of the nut 106. .

<Set screw>
Next, the set screw 24 which is an optional element of the blocking nut 16 will be described with reference to FIG. FIG. 9 is a schematic view schematically showing the structure of the liquid leakage prevention structure 20 in a state where the set screw 24 is used. As shown in FIG. 9, the set screw 24 is a screw without a head that is screwed into the screw hole 18d of the blocking nut body 18 from the opposite side in the axial direction Ax1. The set screw 24 is, for example, a JIS standard “set screw with a hexagonal hole”, and is tightened by fitting and rotating a hexagon wrench in a hexagonal columnar hole at the end.

  The set screw 24 is used when the shaft portion 12b of the bolt 12 is too short and the blocking nut body 18 cannot be sufficiently screwed to the shaft portion 12b. In this case, since the shaft portion 12b cannot be screwed into the screw hole 18d sufficiently, the through hole 18e of the blocking nut body 18 may be exposed to the screw hole 18d without being blocked by the shaft portion 12b. In such a state, the liquid gasket 22 injected into the through hole 18e almost flows out from the opening of the screw hole 18d. Therefore, as shown in FIG. 9, the set screw 24 is used as a “plug” and is screwed into the blocking nut body 18 to prevent the liquid gasket 22 from flowing out. As a result, the liquid gasket 22 injected into the through-hole 18e functions effectively for preventing oil leakage without flowing out.

  It is preferable to wind a sealing tetrafluoroethylene resin green tape (Teflon (registered trademark) tape) around the thread of the set screw 24 and then screw it into the screw hole 18d. Thereby, the clearance gap between the threaded portion of the male screw and the female screw is closed, and leakage of the liquid gasket 22 from the screw hole 18d can be prevented more effectively.

(effect)
Then, the effect which the liquid leakage prevention structure 20 of this invention has is demonstrated.

  By using the liquid leakage prevention structure 20 of the present invention, not only a small amount of oil droplets dripping intermittently from bolts and nuts, but also a large amount of leakage of insulating oil flowing in the form of threads is prevented. Can do.

  Further, by using the liquid leakage prevention structure 20 of the present invention, it is possible to prevent the recurrence of oil leakage over a long period of time. Specifically, the liquid leakage prevention structure 20 continues to prevent oil leakage generated in power equipment placed in an environment where the annual temperature difference is about 50 ° C. for about 5 years until now. .

(Liquid leakage prevention method)
Subsequently, the liquid leakage prevention method of the present invention will be described with reference to FIGS. FIGS. 10A to 10C are schematic views in the vicinity of the liquid leakage prevention structure showing the process steps of the liquid leakage prevention method. 11 (A) to 11 (C) are cut end views for explaining sub-steps included in the step shown in FIG. 10 (C), and are taken along the line P-P in FIG. 10 (C). Is. FIGS. 12A to 12C are cut end views for explaining the sub-process following FIG. 11C, and are taken along the line P-P in FIG. FIG. 13 is a cut end view for explaining the sub-process following FIG. 12C, and is taken along the line QQ in FIG. 10C.

  The liquid leakage prevention method of the present invention is used to prevent oil leakage from the existing bolts 12 and nuts 106 of the fastening structure 200 (FIG. 1A), and includes first to fifth steps. Hereinafter, each step will be described. In the following description, the pipe 102L is referred to as a “first pipe”, and the pipe 102R is referred to as a “second pipe”. Similarly, the flange 102FL is referred to as a “first flange”, and the flange 102FR is referred to as a “second flange”. Further, the liquid leakage prevention washer 14L is referred to as “first liquid leakage prevention washer (also referred to as“ first prevention washer ”)”, and the liquid leakage prevention washer 14R is also referred to as “second liquid leakage prevention washer (“ second prevention washer ”). Respectively).

<Preparation process>
First, the preparation process is performed. First, the set of existing bolts 12 and the existing nuts 106 in which oil leakage has occurred are removed according to a conventional method, and the vicinity of the oil leakage occurrence site is cleaned. That is, using a grinder or a release agent, the coating film of the flange 102F is removed to expose the bare metal. Next, degreasing is performed by wiping the vicinity of the location where the oil leak occurred with a cloth soaked in a solvent such as acetone to remove oil on the metal surface. By degreasing, the adhesiveness of the liquid gasket 22 mentioned later improves.

<First to third steps: FIGS. 10A and 10B>
Then, the 1st and 2nd process demonstrated with reference to FIG. 10 (A) and (B) is performed. First, as the first step, the liquid gasket 22 is applied to the entire surfaces of the first and second surfaces 14a and 14b of the first and second blocking washers 14L and 14R prepared in advance, and the first and second the grooves 14 ₁ and 14 ₂ no gap filling. Incidentally, when the coating, a sufficient amount of the liquid gasket 22, the bubbles in the grooves 14 ₁ and 14 ₂ are careful not to introduce.

  Subsequently, the second step is performed. That is, the first blocking washer 14L is inserted through the shaft portion 12b so that the second surface 14b faces the head portion 12a of the bolt 12. Then, the shaft portion 12b in a state where the first blocking washer 14L is inserted is inserted into the bolt hole 102h from the first flange 102FL side. As a result, the first blocking washer 14L has the first surface 14a facing the first flange 102FL, the second surface 14b facing the head 12a, and the shaft 12b between the head 12a and the first flange 102FL. Be placed.

  Subsequently, the third step is performed. That is, the second blocking washer 14R with the first surface 14a facing the second flange 102FR side is inserted into the shaft portion 12b of the bolt 12 protruding from the second flange 102FR. As described above, the liquid gasket 22 is applied to the second blocking washer 14R. Then, as shown in FIG. 10A, the nut 106 is screwed onto the shaft portion 12b in the state where the second blocking washer 14R is inserted from the opposite side of the axial direction Ax1. As a result, as shown in FIG. 10B, the first and second flanges 102FL and 102FR are fastened by the bolt 12, the first and second blocking washers 14L and 14R, and the nut 106.

By using this way the first and second blocking washer 14L and 14R filled with liquid gasket 22 to the first and second grooves 14 ₁ and 14 _2, the leakage oil through a washer 104L and 104R shown in FIG. 1 (A) Is blocked. That is, oil leakage J1 and E1 through the joint surface between the washers 104L and 104R and the flange 102F, oil leakage J2 through the joint surface between the washer 104L and the head 12a of the bolt 12, and the washer 104R and the nut 106 Oil leakage E2 through the joint surface is prevented.

<The 4th process: Drawing 10 (B)>
Subsequently, in the fourth step, as shown in FIG. 10B, the blocking nut body 18 of the blocking nut 16 is fastened to the shaft portion 12 b of the bolt 12 protruding from the nut 106.

<5th process: FIG.10 (C)>
Subsequently, in the fifth step, as shown in FIG. 10C, the liquid gasket 22 is pressure injected into the through hole 18e of the blocking nut body 18, and the cap bolt 21 is screwed into the through hole 18e. Here, “pressure injection” refers to infiltrating the liquid gasket 22 into the through-hole 18e and the oil leakage path 4 (FIG. 1B) by applying a pressure against viscosity.

  In the fifth step, the liquid gasket 22 filled in the through hole 18e is press-fitted into the screw gap between the nut 106 and the blocking nut 16 and the shaft portion 12b by the pressure generated when the cap bolt 21 is screwed. , Block the oil leakage path 4. As a result, the oil leaks F and G shown in FIG.

  In addition, when the oil leak has arisen from the group of the some volt | bolt 12 and nut 106 of the structure 200 for fastening, the above process is repeated and oil leak is prevented.

<Detailed description of the fifth step>
Next, the above-described fifth step will be described in more detail with reference to FIGS. In this section, when the above-described blocking nut 16 having the first, second and third through holes 18e ₁ , 18e ₂ and 18e ₃ provided at intervals of 120 ° is used as the liquid leakage blocking nut. Is illustrated.

  Further, hatched arrows 22A to 22L used in FIGS. 11 to 13 indicate the flowing liquid gasket 22 together with the flow direction.

  The fifth step includes first to fourth substeps. Hereinafter, each sub-process will be described.

<First sub-step: FIGS. 11A and 11B>
As shown in FIG. 11A, in the first sub-step, the liquid gasket 22 is pressure-injected into the first through hole 18e ₁ as shown by the arrow 22A. At this time, the liquid gasket 22 is not cured and is a viscous liquid.

By injecting pressure, the liquid gasket 22 flows through the path 4 as shown by arrows 22B and 22C against the leakage pressure of the leakage oil F flowing through the leakage path 4 (FIG. 1B). Outflow from the second and third through holes 18e ₂ and 18e ₃ as indicated by arrows 22D and 22E, respectively.

  More specifically, the liquid gasket 22B flows along the oil leakage path 4B, and the liquid gasket 22C flows along the oil leakage path 4C. As a result, the liquid gasket 22 is injected into the oil leakage paths 4B and 4C by the first sub-process.

As shown in FIG. 11 (B), if the outflow of the liquid gasket 22 is confirmed from the _second and third through holes 18e ₂ and 18e ₃ , the first through hole 18e ₁ is filled with the liquid gasket 22. screwed lightly cap bolt 21 _1. This corresponds to the "stopper" in the first through-hole 18e _1, to prevent leakage of liquid gasket 22 from the first through-hole 18e _1.

In order to inject pressure into the liquid gasket 22 injected into the first through hole 18e ₁ at a pressure exceeding the leakage pressure of the oil leakage F, for example, a syringe 40 is used. The syringe 40 is particularly suitable for a volume of 2.5 mL. If the inner diameter of the syringe 40 is too large, the pressure required for injection cannot be obtained.

<Second sub-step: FIGS. 11C and 12A>
As shown in FIG. 11 (C), in the second sub-step, the second through hole 18e _2, a syringe 40, a liquid gasket 22 to the pressure injected as indicated by the arrow 22H. Thus, the liquid gasket 22I and 22F, the flow towards the leakage oil passage 4B, the 4C and 4F to the third through-hole 18e _3.

Thus, as shown by arrow 22F, the liquid gasket 22, flows against the oil leakage paths 4F to leakage pressure of leakage oil F, flows out from the third through hole 18e _3. As a result, the total through-hole _18e 1, 18e connecting the _two, and 18e ₃ leaked oil path 4B, the liquid gasket 22 is injected into 4F and 4C.

As shown in FIG. 12 (A), if the outflow of the liquid gasket 22 from the third through-hole 18e ₃ is confirmed, while satisfying the liquid gasket 22 to the second through hole 18e _2, the cap bolts 21 ₂ Screw lightly. As a result, the second through hole 18e ₂ is “plugged”.

<Third sub-step: FIGS. 12A and 12B>
As shown in FIG. 12 (A), in the third sub-step, a syringe 40, to the third through-hole 18e ₃ is full, the liquid gasket 22 to the pressure injected as indicated by the arrow 22J.

Then, as shown in FIG. 12 (B), the third through-hole 18e ₃ is if was filled with the liquid gasket 22J, screwed lightly cap bolt 21 ₃ to the third through-hole 18e _3.

<Fourth sub-step: FIGS. 12C and 13>
In the fourth sub-process, the three cap bolts 21 ₁ , 21 ₂ and 21 ₃ are evenly tightened to fill the interiors of the first, second and third through holes 18e ₁ , 18e ₂ and 18e _3. The injection pressure exceeding the syringe 40 is applied to 22.

As a result, the liquid gaskets 22A, 22H, and 22J inside the through holes 18e ₁ , 18e _2, and 18e ₃ are injected along the axial direction Ax1 along the screw grooves. As a result, as shown in FIG. 13, the oil leakage path 4 (see FIG. 2B) at the interval between the screw engaging portions of the nut 106 and the shaft portion 12 b beyond the nut body 18 is blocked by the liquid gasket 22. . As a result, the oil leakage path 4 is blocked by the liquid gaskets 22K and 22L by the liquid gaskets 22A, 22H and 22J (see FIG. 12B), and the oil leakages F and G are prevented.

  In this liquid leakage prevention method, the example in which each liquid leakage prevention component is provided in place of the existing bolt and the existing nut in which oil leakage has occurred has been described, but the present invention is not limited to this. Instead of existing bolts and existing nuts where no oil leakage has occurred, each liquid leakage prevention component may be provided in advance. Moreover, when attaching a new flange, you may provide each liquid leak prevention component.

In this example, the case where the liquid leakage prevention nut 16 having the _three through holes 18e ₁ , 18e ₂ and 18e ₃ is used has been described. However, even with the blocking nut 16 having two through holes, oil leakage can be blocked in the same manner as described above. That is, after filling the liquid gasket 22 into one through hole by pressure, the cap bolt is lightly screwed. Next, after the liquid gasket 22 is pressure-injected until the other through hole is filled, the cap bolt is screwed and finally both cap bolts are tightened to infiltrate the liquid gasket 22 to the oil leakage path 4.

  In all the above explanations, the case where the liquid leakage prevention washer, the liquid leakage prevention nut, the liquid leakage prevention structure, and the liquid leakage prevention method of the present invention are applied to “oil” as a fluid is exemplified. However, the present invention can be suitably used for preventing leakage from a flange of a liquid such as an organic solvent or an aqueous solution in addition to oil leakage.

2,4 Oil leakage path 10 Liquid leakage prevention component (prevention component)
12 Bolt 12a Head 12b Shaft part 14, 14 'Liquid leak prevention washer (prevention washer)
14L Liquid Leakage Prevention Washer (First Liquid Leakage Prevention Washer)
14R Liquid leakage prevention washer (second liquid leakage prevention washer)
14H, 14'H washer body 14a, 15a first face 14b, 15b second surface 14c washer hole 14 ₁ first groove 14 ₁ 'the first auxiliary grooves 14 ₂ second groove 14 _2' the second auxiliary grooves 15 aid blocking washer 15 ₁ , 15 ₁ X, 15 ₁ Y Groove 16 Liquid leakage prevention nut (blocking nut)
17 reinforcing nut 18 prevents the nut body _{18c, 18c 1, 18c 2,} 18c 3 side 18d threaded holes _{18e, 18e 1, 18e 2,} 18e 3 through holes 20 leakage preventing structure (blocking structure)
21, 21 ₁ , 21 ₂ , 21 ₃ cap bolt 22 liquid gasket 24 set screw 40 syringe 100 fastening part 102 pipe 102L pipe (first pipe)
102R piping (second piping)
102F Flange 102FL Flange (first flange)
102FR flange (second flange)
102h, 102hL, 102hR, 102hL 'Bolt hole 102hRS, 104RS Inner wall surface 104, 104L, 104R Washer 106 Nut 108 Gasket 200 Fastening structure

The present invention relates to an oil leakage prevention washer , an oil leakage prevention structure, and an oil leakage prevention method suitable for oil leakage prevention from electric power equipment using high-pressure insulating oil such as an oil-filled transformer and an oil circuit breaker.

The present invention has been made under the technical background as described above. Accordingly, an object of the present invention is to provide an oil leakage prevention washer and an oil leakage prevention structure suitable for use in preventing oil leakage from a flange portion of a pipe used in electric power equipment, particularly oil leakage from a bolt and nut that fastens the flange. And providing an oil leakage prevention method.

Inventors, a result of intensive studies, the oil leakage preventing washers are washers that devising a structure by using together with liquid gasket, and conceived to achieve the above object. Accordingly, the oil leakage prevention washer of the present invention includes a washer body which is a parallel plate having first and second planar surfaces, and a washer hole penetrating the washer body. An annular first groove surrounding the washer hole is provided on the first surface side, and an annular second groove surrounding the washer hole is provided on the second surface side.

The oil leakage prevention nut includes a substantially regular hexagonal prevention nut body having a substantially cylindrical screw hole with a female thread at the center, and a through hole reaching the screw hole on the side surface of the prevention nut body. Yes.

The oil leakage prevention structure according to the present invention includes a first flange and a second flange fastened to the first flange. Moreover, the bolt inserted from both the bolt holes of the first and second flanges from the first flange side, and a nut screwed from the second flange side to the shaft portion of this bolt are provided. Furthermore, between the bolt and the first flange, the oil leakage prevention washer, which is disposed with the first surface facing the first flange side, between the nut and the second flange, the second flange side is the second flange side. And another oil leakage prevention washer arranged with one surface facing each other.

Further, oil leakage preventing method of the invention uses a first and second oil leakage preventing washer is oil leakage preventing washer described above, the oil leakage preventing nut described above is carried out in the following order.

First , first and second oil leakage prevention washers are prepared by filling the first and second grooves with a liquid gasket without any gaps. And the bolt which penetrated the 1st oil leak prevention washer which turned the 1st surface to the 1st flange side is penetrated from both the 1st flange side through the bolt hole of the 1st and 2nd flange. Similarly, a nut is screwed onto the shaft portion of the bolt protruding from the second flange, with the second oil leakage prevention washer facing the first surface facing the second flange side, and the first and first 2Fasten the flange.

Subsequently, an oil leakage prevention nut is fastened to the shaft portion of the bolt protruding from the nut, and a liquid gasket is injected into the through hole of the oil leakage prevention nut, and then the cap bolt is screwed into the through hole.

The liquid gasket 22 can be selected from various materials having properties described above, in this example, (trade name: "860 mall double Polymer gasket" A.W.CHESTERTON COMPANY (USA)) (hereinafter , Also simply referred to as 860 gasket). The 860 gasket changes from a liquid state to a gel state 3 to 4 hours after application, and completely changes to an elastic solid state after about 24 hours. Moreover, since the heat resistance of the gasket formed after hardening is -51 degreeC-+260 degreeC, it can fully endure the temperature change of an apparatus installation environment.

Claims (21)

A washer body that is a parallel plate having first and second planar surfaces, and a washer hole penetrating the washer body,
The first surface side is provided with an annular first groove surrounding the washer hole, and the second surface side is provided with an annular second groove surrounding the washer hole. Blocking washer. When two nuts are fastened by fastening nuts to bolts that are inserted through the bolt holes of the two flanges, between one flange and the bolt and between the other flange and the nut. Used between
The diameter of the bolt holes and D _1, the diameter of the shank of the bolt and D _2, the diameter of the washer hole and D _3, the width across flats of the head of the bolt and D _4, the first groove when the diameter of the inner contour line and R _1, the diameter of the outer contour of the second groove and R _2,
The liquid leakage prevention washer according to claim 1, wherein the R ₁ satisfies the following formula (a), and the R ₂ satisfies the following formula (b).
R ₁ > D ₃ +2 (D ₁ −D ₂ ) (a)
_{R 2 <D 4 - (D} 3 -D 2) ··· (b)   The liquid leakage prevention washer according to claim 1 or 2, wherein the washer body is made of metal. When viewed from a direction perpendicular to the first surface, the first groove is provided at a position surrounding the second groove;
A second auxiliary groove formed symmetrically with the second groove across the washer body is provided on the first surface side, and symmetrical with the first groove across the washer body on the second surface side. The liquid leakage prevention washer according to any one of claims 1 to 3, further comprising a first auxiliary groove that is formed automatically.   The liquid leakage prevention washer according to any one of claims 1 to 4, wherein a thickness of the thinnest portion of the washer body measured in a direction perpendicular to the first surface is 0.5 mm or more.   The distance between the outer contour line of the first groove and the outer edge of the washer body, and the distance between the inner contour line of the second groove and the outer edge of the washer hole are 0.5 mm or more, respectively. The liquid leak prevention washer according to any one of claims 1 to 5.   A liquid gasket filled in the first groove and applied on the first surface, and a liquid gasket filled in the second groove and applied on the second surface. The liquid leakage prevention washer according to any one of claims 1 to 6, further comprising: When the diameter of the washer body and the D _5, the formula R ₁ obtained from (a) is, if the D ₅ or more, between the flange and the washer body, the diameter of the body is the D ₅ or more, the diameter of the washer hole further provided an auxiliary blocking washer d _3,
Wherein the auxiliary blocking washer, the contact surface between the flange, the has been a groove surrounding the washer hole of the auxiliary blocking washer provided, the diameter of the inner contour of the groove and r _in, and an outer the diameter of the contour line and r _out, when the distance between the end face of the said bolt hole flange and D _7, wherein d ₃ satisfies the following formula (c), wherein r _in satisfies the following formula (d) is and leakage preventing washer according to any one of claims 2-7, wherein r _out is characterized by satisfying the following formula (e).
d ₃ <(R ₁ + 2D ₂ −D ₃ ) / 2 (c)
r _in > d ₃ +2 (D ₁ −D ₂ ) (d)
r _out <2D ₇ + 2D ₂ −d ₃ (e) In the auxiliary blocking washer, D ₇ − {(r _in + d ₃ ) / 2 + W ₁ −D ₂ } <0 is satisfied, where W ₁ is the width of the groove measured along the radial direction of the washer body. The liquid leakage prevention washer according to claim 8, wherein the r _in satisfies the following formula (f) and the r _out satisfies the following formula (g).
r _in > 2D ₁ -d ₃ (f)
r _out <2D ₇ + d ₃ (g)   A liquid leak comprising: a substantially regular hexagonal blocking nut body having a substantially cylindrical screw hole with a female thread at the center; and a through hole reaching the screw hole on a side surface of the blocking nut body Blocking nut.   The liquid leakage prevention nut according to claim 10, wherein the prevention nut body includes two or more of the through holes.   12. The liquid leakage prevention nut according to claim 10, wherein a female screw is formed in the through hole, and a cap bolt that is screwed into the through hole is provided.   The liquid leakage prevention nut according to any one of claims 10 to 12, further comprising a set screw that is screwed into the prevention nut main body.   14. The liquid according to claim 13, further comprising an unbaked tape for sealing tetrafluoroethylene resin interposed between a screw thread of the set screw and a screw hole of the blocking nut main body. Leak prevention nut. The screw hole and the female nut provided in the screw hole are equal to the blocking nut body, have a thickness equal to or larger than the diameter of the through hole, and are a reinforcing nut screwed into the bolt together with the blocking nut body. Further comprising
The liquid leakage prevention nut according to any one of claims 10 to 14, wherein the reinforcing nut is fastened to the prevention nut main body from the side opposite to the part to be fastened.   The three through holes are provided at intervals of 120 ° in the circumferential direction, and each of the three through holes is a first, second, and third through hole. Liquid leakage prevention nut.   The liquid leakage prevention nut according to any one of claims 10 to 16, further comprising a liquid gasket pressure-injected into the through hole. A first flange and a second flange fastened to the first flange;
Bolts inserted from the first flange side into both bolt holes of the first and second flanges;
A nut screwed to the bolt shaft from the second flange side;
The liquid leakage prevention nut according to any one of claims 10 to 17, which is screwed into the bolt shaft from the outside of the nut from the second flange side.
A first liquid leakage prevention washer provided between the bolt and the first flange;
A second liquid leakage prevention washer provided between the nut and the second flange,
Each of the first and second liquid leakage prevention washers is a liquid leakage prevention washer according to any one of claims 1 to 9,
The first liquid leakage prevention washer is disposed with the first surface facing the first flange side, and the second liquid leakage prevention washer has the first surface opposed to the second flange side. A liquid leakage prevention structure characterized in that the liquid leakage prevention structure is arranged. In preventing the liquid leakage from the bolt and nut in the first and second flanges fastened with the bolt and nut,
Using the first and second liquid leakage prevention washers that are the liquid leakage prevention washers according to any one of claims 1 to 9, and the liquid leakage prevention nut according to any one of claims 10 to 15,
A first step of filling the first and second grooves of the first and second liquid leakage prevention washers with the liquid gasket without gaps;
A bolt in which the first liquid leakage prevention washer with the first surface facing the first flange is inserted into both bolt holes of the first and second flanges from the first flange side. Process,
A nut is screwed onto the shaft portion of the bolt protruding from the second flange, with the second liquid leakage prevention washer with the first surface facing the second flange side, A third step of fastening the first and second flanges;
A fourth step of fastening the liquid leakage prevention nut to the shaft portion of the bolt protruding from the nut;
A liquid leakage prevention method comprising: a fifth step of pressure-injecting the liquid gasket into the through hole of the liquid leakage prevention nut and screwing the cap bolt into the through hole. In preventing the liquid leakage from the bolt and nut in the first and second flanges fastened with the bolt and nut,
The first and second liquid leakage prevention washers that are the liquid leakage prevention washers according to any one of claims 1 to 9, and the liquid leakage prevention nut according to claim 16,
A first step of filling the first and second grooves of the first and second liquid leakage prevention washers with the liquid gasket without gaps;
A bolt in which the first liquid leakage prevention washer with the first surface facing the first flange is inserted into both bolt holes of the first and second flanges from the first flange side. Process,
A nut is screwed onto the shaft portion of the bolt protruding from the second flange, with the second liquid leakage prevention washer with the first surface facing the second flange side, A third step of fastening the first and second flanges;
A fourth step of fastening the liquid leakage prevention nut to the shaft portion of the bolt protruding from the nut;
A fifth step of screwing the cap bolt into the first, second and third through holes of the liquid leakage prevention nut into which the liquid gasket has been pressure-injected,
A first sub-process in which the liquid gasket is injected into the first through-hole until the fifth step flows out of the second and third through-holes, and then the cap bolt is screwed into the first through-hole. ,
A second sub-step of injecting the liquid gasket into the second through-hole until it flows out of the third through-hole, and then screwing the cap bolt into the second through-hole;
A third sub-step of filling the third through hole with the liquid gasket and screwing the cap bolt into the third through hole;
Cap bolts screwed into the first, second and third through-holes are evenly tightened, and the liquid gasket is made up of a male screw of the shaft portion and a female screw of the nut and the liquid leakage prevention nut. A liquid leakage prevention method comprising: a fourth sub-process for injecting into the gap. When the first and second flanges are fastened by existing bolts and existing nuts and liquid leakage occurs from at least one set of the existing bolts and existing nuts, the first and second flanges are performed before the first step. Including a preparation step of removing the set of the existing bolt and the existing nut in which liquid leakage has occurred,
21. The liquid leakage prevention method according to claim 19 or 20, wherein the steps from the preparation step to the fifth step are performed on all the existing bolts and existing nuts in which liquid leakage has occurred. .