JP2007285402A - Fastening member and anticorrosive structure of joining part including this fastening member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and inexpensive fastening member and an anticorrosive structure of a joining part including this fastening member, anticorrosive over a long period, and capable of preventing even clearance corrosion. <P>SOLUTION: This anticorrosive structure of the fastening member is composed of a bolt fastened to a fastening object member, a nut threadedly engaged with a screw part of the bolt, a washer fitted between the fastening object member and a head part of the bolt, and a washer fitted to the screw part of the bolt between the fastening object member and the nut. The anticorrosive structure of the fastening member is adopted for fitting an anticorrosive ring composed of a ring-shaped anticorrosive material having the current flowing anodic action and a resin ring arranged on its outer periphery, to a side peripheral surface of the washer fitted to the screw part of the bolt between the fastening object member and the nut, by threadedly engaging a nut-shaped anticorrosive material having the current flowing anodic action with the outside of the nut threadedly engaged with the screw part of the bolt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fastening member and an anticorrosion structure for a joint including the fastening member.

  A variety of joining methods are employed in structures such as bridges and buildings. Among them, the joining with bolts and nuts is often used because it does not require special equipment such as welding or advanced technology. However, these corrosion preventions are a problem in corrosive atmospheres in which dry and wet conditions are repeated.

  Conventionally, the anticorrosion of the fastening member has mainly been painting with a rust-proof paint. The anticorrosion performance by painting is intended to block water, oxygen, etc., which are corrosive factors, and it is necessary that a complete painting be present.

  However, the anticorrosion of the fastening member by this coating cannot form a sufficient coating film, and therefore, anticorrosion over a long period of time cannot be expected. In other words, bolt heads and nuts tend to have thin coatings because they have corners and bends, and bolts and nuts have a thick film thickness because it is necessary to ensure screw accuracy. I couldn't. Furthermore, there is a drawback that the coating film is peeled off or damaged when tightening.

  In order to avoid such corrosion, stainless steel fastening members (bolts and nuts) are used instead of steel fastening members (bolts and nuts). In this case, the above problem is solved, but a crevice corrosion problem occurs. Generally, the fastening member is exposed on the surface, and a gap is formed between the member to be fastened and the bolt or the mounting surface and the washer. When moisture enters the gap, it becomes difficult to discharge, and the gap portion has a potential higher than that of other portions. It becomes base and crevice corrosion occurs.

  In order to prevent such corrosion of the fastening member, the fastening member is covered with a protective cap made of aluminum or polyethylene, and further, a solventless epoxy resin paint or a polysulfide resin caulking material is used as an anticorrosive material. It has also been proposed to fill. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 50-14966) discloses that when a bolt portion and a nut portion are subjected to anticorrosion coating, the bolt portion and the nut portion are covered with a hollow outer casing, It is described that an adhesive filler is filled in advance in the outer casing. Further, in Patent Document 2 (Japanese Patent Laid-Open No. 2-138488), the projecting portion from the bolt and / or nut structure is capable of seeing through the inside and covering the projecting portion, and has an inlet and an outlet. Corrosion prevention of bolts and nuts comprising a step of covering with a flame retardant protective cap, a step of injecting and filling an anticorrosive material into the protective cap, and a step of curing the anticorrosive material filled in the protective cap A method is described.

  However, as shown in Patent Document 1, when a protective cap is simply used, moisture remains in the protective cap, or water or moisture enters from the outside, and bolts, nuts, etc. are rusted. May occur and corrosion cannot be prevented.

  In addition, as shown in Patent Documents 1 and 2, when a protective cap is filled with an anticorrosive material, the anticorrosive material is destroyed when the structure is regularly inspected and repaired, and the protective cap is destroyed. It was not practical because it had to be removed and took a lot of work.

  As another proposal, there is a structure in which a screwing member formed of a metal material having a corrosion potential lower than that of an iron-based material is screwed into a double nut shape outside the nut. For example, in Patent Document 3 (Japanese Patent No. 2644591), a screw that is screwed into a double nut shape outside a nut of a bolt / nut and a screw portion of the bolt and is electrically connected to the bolt / nut in a screwed state. There is described an electrochemical anti-corrosion member made of a metal material which is composed of a joint member and in which the screw member has a lower corrosion potential than the material constituting the bolt and nut. Patent Document 4 (Japanese Patent Publication No. 39-4218) describes an anticorrosion device for a cast iron pipe joint bolt in which a tightening nut mounting portion is provided with a zinc nut in addition to a tightening nut.

  However, as shown in Patent Documents 3 and 4, only with a double nut-like screwed structure, there is an anticorrosive effect on the fastening member (structure) and the bolt, and the gap formed between the fastening member and the washer. Insufficient and sometimes corroded by the ingress of moisture.

  In addition, although anticorrosion methods using paints using hot dip galvanizing, electroaluminum plating or various zinc-based and aluminum-based powders have been proposed, all have only a short-term anticorrosive effect.

  Thus, conventionally, corrosion prevention is possible for a long period of time, crevice corrosion can be prevented, and a simple fastening member corrosion prevention method or corrosion prevention structure has not been obtained.

Japanese Patent Laid-Open No. 50-14966 JP-A-2-138488 Japanese Patent No. 2644591 Japanese Examined Patent Publication No. 39-4218

  Accordingly, an object of the present invention is to provide a simple and inexpensive fastening member that can prevent corrosion over a long period of time and prevent crevice corrosion, and a corrosion preventing structure for a joint including the fastening member.

  As a result of the study, the inventors of the present invention screwed a nut-shaped anticorrosive material having an galvanic anode action on the outer side of the nut screwed to the screw portion of the bolt, and the screw portion of the bolt between the fastened member and the nut. By fitting an anticorrosion ring composed of a ring-shaped anticorrosive material having an galvanic anode action and a resin ring provided on the outer periphery thereof on the side peripheral surface of the washer fitted to the washer, or the side periphery of the washer A protective cap having a plurality of holes on a nut-side fastening member including a nut-like anticorrosive and a ring-shaped anticorrosive that is fitted with a ring-shaped anticorrosive on the surface and arranged on a side peripheral surface of the ring-shaped anticorrosive The inventors have found that the above object can be achieved by coating, and have reached the present invention.

  That is, the present invention relates to a bolt fastened to a member to be fastened, a nut screwed into a threaded portion of the bolt, a washer fitted between the fastened member and the head of the bolt, and the fastened An anti-corrosion structure for a fastening member comprising a member and a washer fitted to a screw portion of the bolt between the nut and having an galvanic anode action outside the nut screwed to the screw portion of the bolt A nut-shaped anticorrosive material is screwed together, and a ring-shaped anticorrosive material having an galvanostatic action and an outer periphery thereof are formed on the side peripheral surface of a washer fitted to the screw portion of the bolt between the fastened member and the nut. An anti-corrosion structure for a fastening member formed by fitting an anti-corrosion ring comprising a provided resin ring is provided.

  The present invention also provides a bolt fastened to a fastened member, a nut screwed into a threaded portion of the bolt, a washer fitted between the fastened member and the head of the bolt, and the fastened An anti-corrosion structure for a fastening member comprising a member and a washer fitted to a screw portion of the bolt between the nut and having an galvanic anode action outside the nut screwed to the screw portion of the bolt A nut-shaped anticorrosive material is screwed together, and a ring-shaped anticorrosive material having an galvanic anode action is fitted to the side peripheral surface of the washer fitted to the screw portion of the bolt between the fastened member and the nut. And the fastening member which is arranged on the side peripheral surface of the ring-shaped anticorrosive material and covers the nut-like anticorrosive material and the nut-side fastening member including the ring-shaped anticorrosive material with a protective cap having a plurality of holes with a gap An anticorrosion structure is provided.

  In the anticorrosion structure for a fastening member according to the present invention, a ring-shaped anticorrosive material having an galvanostatic action and an outer periphery thereof are provided on a side peripheral surface of a washer fitted between the fastened member and the head of the bolt. It is desirable that an anticorrosion ring comprising a resin ring is fitted.

  In the anticorrosion structure for a fastening member according to the present invention, the nut-like anticorrosive material and the ring-shaped anticorrosive material are preferably selected from a single metal of zinc, aluminum or magnesium or a metal alloy thereof.

  In the anticorrosion structure for the fastening member according to the present invention, it is preferable that the resin ring of the anticorrosion ring is provided so as to cover an upper portion of the ring-shaped anticorrosion material.

  In addition, the present invention is a fastening member formed by fastening a plurality of fastening members having the above-described anticorrosion structure to a fastened member, and pasting zinc sheets on both surfaces of the fastened member positioned between the fastened fastening members. The anticorrosion structure of the junction part containing is provided.

  In the anticorrosion structure for the joint portion including the fastening member according to the present invention, the fastened member is a joint portion obtained by joining a connecting plate to both surfaces of the beam member.

  The anticorrosion structure of the fastening member and the joint including the fastening member according to the present invention can prevent corrosion of the fastening member over a long period of time, and includes not only a nut-like anticorrosive material but also a ring-like anticorrosive material and a resin ring. Since the anticorrosion ring or the ring-shaped anticorrosion material and the protective cap are used, crevice corrosion can be prevented, and the structure is simple and inexpensive.

  In addition, since the resin ring is formed on the outer periphery of the ring-shaped anticorrosive material, the elution site of the ring-shaped anticorrosive material is regulated, so that a gap can be prevented over a long period of time, and the structure is inexpensive with a simple structure.

  Furthermore, when the fastening member is covered with a gap with a protective cap having a plurality of holes, the protective cap can be easily removed when maintenance of the fastening member is performed. In addition, since the ring-shaped anticorrosive material is provided inside the protective cap, the anticorrosive effect can be exhibited by positively utilizing the moisture that enters from the plurality of holes.

Hereinafter, the best mode for carrying out the present invention will be described in detail.
FIG. 1 is a schematic cross-sectional view showing an embodiment of a corrosion prevention structure for a fastening member according to the present invention.

  In FIG. 1, the fastening member includes a bolt 1, a nut 2 screwed into a screw portion 1 a of the bolt, a fastening member 4, a washer 3 a fitted between the head 1 b of the bolt, and the fastening member 4. And a washer 3b fitted to the threaded portion 1b of the bolt between the nuts 2 to fasten the member 4 to be fastened. For the washers 3a and 3b, it is preferable to use two washers, a plain washer and a spring washer, to prevent loosening. Such a fastening member is generally used for a joint portion.

  In the anticorrosion structure for a fastening member according to the present invention, a nut-like anticorrosive material 5 having an galvanic anode function is screwed onto the outside of a nut 2 screwed to a screw portion 1a of a bolt. A perspective view of the nut-like anticorrosive material 5 is shown in FIG. The nut-like anticorrosive 5 has a galvanic anodic action and is preferably selected from zinc, aluminum or magnesium simple metal or a metal alloy thereof.

  In the anticorrosion structure for a fastening member according to the present invention, the nut-like anticorrosive material 5 alone is a gap formed between the fastened member (structure) 4 and the bolt 1 and the fastened member (structure) 4 and the washer 3b. On the other hand, since the anticorrosion effect is insufficient, as shown in FIG. 1, the galvanic anode action is applied to the side peripheral surface of the washer 3 b fitted to the screw portion 1 a of the bolt between the fastened member 4 and the nut 2. The anticorrosion ring 8 which consists of the ring-shaped anticorrosion material 6 which has this, and the resin-made rings 7 provided in the outer periphery is fitted.

  FIG. 3 shows a perspective view of the anticorrosion ring 8. The anticorrosion ring 8 is formed from the ring-shaped anticorrosive material 6 and the resin ring 7 provided on the outer periphery thereof as described above. The ring-shaped anticorrosive material 6 has a galvanic anodic action like the nut-shaped anticorrosive material 5 and is preferably selected from zinc, aluminum or magnesium metal alone or a metal alloy thereof. The resin ring 7 is formed of a thermoplastic plastic having impact strength such as polyacetal resin, polycarbonate, polyamide resin, ABS resin.

  As shown in FIG. 1, the resin ring 7 of the anticorrosion ring 8 is preferably provided so as to cover the upper part of the ring-shaped anticorrosive material 6. By using such an anticorrosion ring 8, the elution site of the ring-shaped anticorrosion material 6 can be regulated, and it can be pushed in with a tool such as a spectacle wrench and fitted to the side peripheral surface of the washer 3b.

  In FIG. 1, a ring-shaped anticorrosive material 6 having an galvanostatic action and a resin ring provided on the outer periphery of the washer 3a fitted between the fastened member 4 and the bolt head 1b. The anticorrosion ring 8 consisting of 7 is fitted, thereby preventing crevice corrosion formed between the fastened member (structure) 4 and the bolt 1 and between the fastened member (structure) 4 and the washer 3a. The ring-shaped anticorrosive material 6 and the resin ring 7 are the same as described above. Moreover, it is desirable that the resin ring 7 of the anticorrosion ring 8 is provided so as to cover the upper part of the ring-shaped anticorrosion material 6 as described above. In the present invention, the installation of the anticorrosion ring 8 composed of the ring-shaped anticorrosion material 6 and the resin ring 7 fitted to the side peripheral surface of the washer 3a is not necessarily essential and is optional.

  FIG. 4: is a schematic sectional drawing which shows other embodiment which is the anticorrosion structure of the fastening member which concerns on this invention. In FIG. 4, a fastening member similar to that in FIG. 1 is used, but the fastening member on the bolt head 1b side is omitted, and only the fastening member on the nut 2 side is shown.

  Also in FIG. 4, a nut-like anticorrosive material 5 having an galvanostatic action is screwed onto the outside of the nut 2 screwed to the screw portion 1 a of the bolt. The nut-like anticorrosive material 5 is made of the same material as described above.

  In FIG. 4, together with the nut-shaped anticorrosive material 5, a ring-shaped anticorrosive material 6 having an galvanostatic action on the side peripheral surface of a washer 3 b fitted to the screw portion 1 a of the bolt between the fastened member 4 and the nut 2. Are mated. The ring-shaped anticorrosive material 6 is made of the same material as described above. In this case, a resin ring as shown in FIG. 1 is not necessary.

  Further, in FIG. 4, the protective cap 9 is disposed on the side peripheral surface of the ring-shaped anticorrosive material 6, and the nut-side fastening member including the nut-shaped anticorrosive material 5 and the ring-shaped anticorrosive material 6 is covered with a gap. The protective cap 9 has a plurality of holes 10.

  FIG. 5 shows a perspective view of the protective cap 9 having a plurality of holes 10. By using such a protective cap 9, maintenance of the fastening member is facilitated, and the removed protective cap can be reused. Moreover, the anti-corrosion effect can be exhibited using the moisture which permeates through the plurality of holes 10. The protective cap 9 is formed from a thermoplastic having impact strength such as polyacetal resin, polycarbonate, polyamide resin, ABS resin, or rubber having rebound resilience and weather resistance such as chloroprene rubber, ethylene propylene rubber, urethane rubber or the like. .

  In FIG. 4, as described above, the fastening member on the bolt head side is omitted, but as shown in FIG. 1, the fastening member 4 is fitted between the bolt head 1 b. An anticorrosion ring 8 comprising a ring-shaped anticorrosive material 6 having an galvanostatic action and a resin ring 7 provided on the outer periphery thereof may be fitted to the side peripheral surface of the washer 3a.

  FIG. 6 is a cross-sectional view of the anticorrosion structure of the joint including the fastening member according to the present invention. In FIG. 6, a plurality of fastening members having the above anticorrosion structure according to the present invention are fastened to a fastened member (joint portion) 4, and a fastened member (joint portion) 4 located between the fastened fastening members. The zinc sheet 11 is stuck on both sides. The fastened member (joint portion) 4 is obtained by joining the connecting plate 13 to both sides of the beam member 12.

The joined members (joint portions) are joined by joining connecting plates to both front and back sides of the beam member and fastening them with bolts and nuts. The anticorrosion structure of the joint including such a fastening member is constructed as follows.
(1) A hole for inserting the anticorrosion ring into a zinc sheet having a conductive adhesive layer on one side is opened at a predetermined position.
(2) About the connecting plate, remove rust with a wire brush etc., and remove dust, water, etc.
(3) A nut-shaped anticorrosive material is screwed onto the outside of the nut.
(4) Position the anticorrosion ring so that it can be fitted to the washer, and press it strongly with a tool such as a spectacle wrench.
(5) Affix the zinc sheet to the connecting plate.

  According to the above-described anticorrosion structure of the fastening member according to the present invention, as a result of the salt spray test for three months, rust is observed when any of soft steel, hot dip galvanized soft steel and stainless steel is used as a bolt, nut and washer. The metal potential between the fastened member and the washer was −0.8 to −0.9V. On the other hand, without using the anti-corrosion structure of the fastening member according to the present invention, those using mild steel as bolts, nuts, and washers are completely red rusted, and hot galvanized as bolts, nuts, and washers. In the case of using the mild steel, red rust occurred locally. Further, without using the anticorrosion structure of the fastening member according to the present invention, when the stainless steel was used as the bolt, nut and washer, significant crevice corrosion occurred between the fastened member and the bolt and the fastened member and the washer.

  The anti-corrosion structure of the fastening member according to the present invention and the coupling portion including the fastening member enables anti-corrosion of the fastening member over a long period of time, and includes not only a nut-like anti-corrosive material but also a ring-like anti-corrosive material and a resin ring. Since the anticorrosion ring or the ring-shaped anticorrosion material and the protective cap are used, crevice corrosion can be prevented, and the structure is simple and inexpensive. Therefore, the anticorrosion structure of the fastening member according to the present invention and the joint portion including the fastening member is preferably used as an anticorrosion structure for a fastening member used in a structure such as a bridge or a building.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a corrosion prevention structure for a fastening member according to the present invention. FIG. 2 is a perspective view of a nut-like anticorrosive material used in the present invention. FIG. 3 is a perspective view of the anticorrosion ring used in the present invention. FIG. 4: is a schematic sectional drawing which shows other embodiment which is the anticorrosion structure of the fastening member which concerns on this invention. FIG. 5 is a perspective view of a protective cap used in the present invention. FIG. 6 is a cross-sectional view of the anticorrosion structure of the joint including the fastening member according to the present invention.

Explanation of symbols

1: Bolt 1a: Screw portion 1b: Bolt head 2: Nut 3a, 3b: Washer 4: Fastened member 5: Nut-shaped anticorrosive 6: Ring-shaped anticorrosive 7: Resin ring 8: Anticorrosion ring 9 : Protection cap 10: Hole 11: Zinc sheet 12: Girder 13: Connecting plate

Claims (7)

A bolt fastened to the fastened member, a nut screwed into a threaded portion of the bolt, a washer fitted between the fastened member and the head of the bolt, and between the fastened member and the nut An anti-corrosion structure for a fastening member comprising a washer fitted to a screw portion of the bolt, wherein a nut-like anti-corrosion material having an galvanic anode action is screwed to the outside of the nut screwed to the screw portion of the bolt. And a ring-shaped anticorrosive material having an galvanic anode action on the side peripheral surface of the washer fitted to the threaded portion of the bolt between the fastened member and the nut, and a resin ring provided on the outer periphery thereof An anticorrosion structure for a fastening member formed by fitting an anticorrosion ring comprising A bolt fastened to the fastened member, a nut screwed into a threaded portion of the bolt, a washer fitted between the fastened member and the head of the bolt, and between the fastened member and the nut An anti-corrosion structure for a fastening member comprising a washer fitted to a screw portion of the bolt, wherein a nut-like anti-corrosion material having an galvanic anode action is screwed to the outside of the nut screwed to the screw portion of the bolt. A ring-shaped anticorrosive material having an galvanic anode action is fitted on the side peripheral surface of the washer fitted to the threaded portion of the bolt between the fastened member and the nut, and the ring-shaped anticorrosive An anti-corrosion structure for a fastening member, which is arranged on a side peripheral surface of the food and is formed by covering the nut-side fastening member including the nut-shaped anti-corrosive material and the ring-shaped anti-corrosive material with a protective cap having a plurality of holes. An anticorrosion ring comprising a ring-shaped anticorrosive material having an galvanic anode action and a resin ring provided on the outer periphery thereof is fitted on the side peripheral surface of the washer fitted between the fastening member and the head of the bolt. The anticorrosion structure according to claim 1 or 2, which is combined. The anticorrosion structure for a fastening member according to claim 1, 2 or 3, wherein the nut-shaped anticorrosive material and the ring-shaped anticorrosive material are selected from a single metal of zinc, aluminum or magnesium or a metal alloy thereof. 5. The anticorrosion structure for a fastening member according to claim 1, wherein the anticorrosion ring is provided so that the resin ring covers an upper portion of the ring-shaped anticorrosion material. A plurality of fastening members having the anticorrosion structure according to any one of claims 1 to 5 are fastened to the fastened member, and zinc sheets are pasted on both surfaces of the fastened member positioned between the fastened fastening members. An anticorrosion structure for a joint including a fastening member. The anticorrosion structure for a joint portion including the fastening member according to claim 6, wherein the member to be fastened is a joint portion in which a connecting plate is joined to both sides of the beam member.

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