JP3739506B2

JP3739506B2 - Joining structure of wood structure material for building and joining method thereof

Info

Publication number: JP3739506B2
Application number: JP31010696A
Authority: JP
Inventors: 二郎梅津; 秀三鈴木; 通友鈴木
Original assignee: 株式会社平安コーポレーション
Priority date: 1996-11-06
Filing date: 1996-11-06
Publication date: 2006-01-25
Anticipated expiration: 2016-11-06
Also published as: JPH10140669A

Description

【０００１】
【産業上の利用分野】
本発明は、建築構造材の木質接合方法及び建築構造材の蟻継構造に関する。更に詳しくは、工場で前もってプレカットする木質建築構造材の蟻継ぎ構造に関する。
【０００２】
【従来技術】
わが国において、木造住宅は独特の風合いを持つため、その人気は根強いものがある。住宅として建築物にした場合、多数の構造材を使用してその強度を担保しなければならない。そのための伝統的な加工方法は、大工が下小屋で多数の構造材を一つ一つ板図をもとに墨付けし加工する方法であった。このような加工方法は、当然に大変な手間がかかる。このような低能率な加工方法を改めて高能率に木工機械で一挙に行うための加工方法として、プレカット方式が知られている。
【０００３】
このプレカット方式はいわゆる工場生産方式あり、前もって工場で構造材の継ぎ手、仕口等を木材専用の仕口加工盤等を使って加工しておくものである。このための接合部の構造も種々に知られ、たとえば、実公昭５８−１５２５号、実公昭６１−２３１３０号、実公昭６１−４０９号などで提案されている。このようなプレカット方式は、人手と技能者不足の解消、加工精度の向上、品質の向上、工期の短縮、コストダウン等の多くのメリットをもたらした。
【０００４】
一方、日本の慣行上建築現場での建前は、普通大安吉日に行うことが圧倒的に多い。そのため、この建前は必ずしも常に天候的に恵まれた良い日とは限らず、雨の日、風の日、雪の日等に行わなければならないときがある。このような場合、プレカットされた構造材の仕口が雨等により水に触れると膨潤して微妙な変形を起こすことがある。特に梅雨時には構造材が水分をたくさん吸う時期に当たるので、変形によるトラブルが極めて多い。
【０００５】
木材の方向によるこの膨潤と収縮割合は、接線方向が最大であり、半径方向がこれにつぎ、繊維方向に最も小さく、その比は大体１０：５：１〜０．５とされている。具体的にいうと、例えば仕口の接合構造を取り上げて見ると、従来、２つの構造材の仕口を蟻継ぎ接合する場合、各々構造材の蟻ほぞや蟻ほぞ穴の各部の寸法、特に蟻ほぞの側面の傾斜と蟻ほぞ穴の側面の傾斜の角度は一致されている。この組立は工場にて両者が正確にはまり込むようにプレカットしてあるものの、前述のような理由で狂い易かった。特に、蟻ほぞ穴側の前記理由による膨潤と収縮が大きく、はまり込みを困難にしている。
【０００６】
特に蟻ほぞの側面と蟻ほぞ穴の側面との面合わせが上手くいかないことが多い。結果的にははめ込みが正確にできなくなるのである。そのため、多くは現場でその場合わせの手直し加工を応急的に行い対応している。例えば、蟻ほぞの側面か蟻ほぞ穴の側面の何れか一方が大きくなっている方を削る等の処理である。結局このようなことをすると、接合面のはめ込みが甘くなり棟上げ後に各仕口の接合部にガタがきたりすることもあった。このような難点を少しでも解決するために、蟻ほぞの側面と蟻ほぞ穴の側面との嵌め合い部に僅かのオーバーラップ量を工場生産時に設けておき、組立時圧入作業が容易でありかつ強度低下を起こさない蟻溝構造を先に提案した。
【０００７】
しかしこのような提案は本質的な解決でなく、対症療法的解決であり、多少緩めに蟻溝接合しても本来的に強度がより優れ且つ工場生産能率を高めることができる構造及びその接合方法の提案が望まれている。
【０００８】
【発明が解決しようとする課題】
本発明は、上記問題の解決を意図したものであり、次のような目的を達成する。
【０００９】
本発明の目的は、強度がより優れた建築用木質構造材の木質接合部の接合構造及び木質接合部の加工方法を提供することにある。
【００１０】
本発明の他の目的は、工場生産能率を高めることができる建築用木質構造材の木質接合部の接合構造及び木質接合部の加工方法を提供することにある。
【００１１】
【課題を解決するための手段】
本発明は、前記課題を解決するために次のような手段を採る。
【００１２】
本発明１の建築用木質構造材の木質接合部の接合構造は、蟻継ぎ接合される２つの建築用木質構造材（１，２）の木質接合部の構造であり、前記木質構造材の一方（１）は腰掛部（１ｂ）と前記腰掛部（１ｂ）から突出する蟻ほぞ部（１ａ）とを備え、前記木質構造材の他方（２）は腰掛穴部（２ｂ）と前記腰掛穴部（２ｂ）から掘り下げられた蟻ほぞ穴部（２ａ）とを備え、前記腰掛部（１ｂ）は前記腰掛穴部（２ｂ）の腰掛穴面（１１）に突き合わせられるＵ字状の腰掛面（３）を有し、前記蟻ほぞ部（１ａ）は前記蟻ほぞ穴部（２ａ）の蟻ほぞ穴面（７）に突き合わせられるＵ字状の蟻ほぞ面（５）を有し、前記腰掛面（３）の下端と前記蟻ほぞ面（５）の下端とが共通線又は共通面を実質的に形成し、前記腰掛穴部（２ｂ）は前記腰掛部（１ｂ）の前記腰掛面（３）に突き合わせられるＵ字状の前記腰掛穴面（１１）を有し、前記蟻ほぞ穴部（２ａ）は前記蟻ほぞ部（１ａ）の前記蟻ほぞ面（５）に突き合わせられるＵ字状の前記蟻ほぞ穴面（７）を有し、前記腰掛穴面（１１）の下端と前記蟻ほぞ穴面（７）の下端とが共通線又は共通面を実質的に形成することを特徴とする。
【００１３】
本発明２の建築用木質構造材の木質接合部の接合構造は、前記本発明１の木質構造材の木質接合部の接合構造であり、前記腰掛面（３）と基準面とがなす角度をαで表し前記蟻ほぞ面（５）と前記基準面とがなす角度をβで表すと、実質的に、α＝β、かつ、前記腰掛穴面（１１）と基準面とがなす角度は前記αであることを特徴とする。
【００１４】
本発明３の建築用木質構造材の木質接合部の加工方法は、一方（１）が腰掛部（１ｂ）と前記腰掛部（１ｂ）から突出する蟻ほぞ部（１ａ）とを備え、他方（２）が腰掛穴部（２ｂ）と前記腰掛穴部（２ｂ）から掘り下げられた蟻ほぞ穴部（２ａ）とを備え、前記腰掛部（１ｂ）及び蟻ほぞ部（１ａ）はそれぞれにＵ字状の腰掛面（３）及び蟻ほぞ面（５）を有し、前記腰掛穴部（２ｂ）及び蟻ほぞ穴部（２ａ）はそれぞれにＵ字状の腰掛穴面（１１）及び蟻ほぞ穴面（７）を有する蟻継ぎ接合される２つの建築用木質構造材（１，２）の木質接合部の加工方法であり、円錐形状の切削刃で先に蟻ほぞ面（５）を形成し、円錐形状の切削刃で腰掛面（３）を切削することにより、前記ほぞ面（５）の下端に重ねて前記腰掛面（３）を形成し、円錐形状の切削刃で先に前記蟻ほぞ穴面（７）を形成し、円錐形状の切削刃で前記腰掛穴面（１１）を切削することにより、前記蟻ほぞ穴面（７）の下端に重ねて前記腰掛穴面（１１）を形成することを特徴とする。
【００１５】
本発明の建築用木質構造材の木質接合部の構造は、腰掛部と蟻ほぞ部とが実質的に一体物として構造体を構成し、腰掛穴部と蟻ほぞ穴部とが実質的に一体穴として構造体を構成する。このような一体化構造により強度が増大する。
【００１６】
【発明の実施の形態】
図１（ａ），（ｂ）は、本発明の建築用木質構造材の木質接合構造、すなわちいわゆる仕口の腰掛蟻継ぎ接合の構造を示している。同図１（ａ）及び図２，３，４は、男木側木質構造材１の接合構造を示し、図１（ｂ）及び図５，６，７は、女木側木質構造材２の接合構造を示している。両木質構造材１，２は、直交する向きに接合され、断面はそれぞれに正方形又は長方形である。
【００１７】
構造材１，２は、例えば、梁桁、胴差し、土台、通し柱、化粧柱、小屋束等として用いられる。男木側木質構造材１は一端側の下部側が切削され、男木側木質構造材１には木質接合部が形成されている。木質接合部は、基準面Ｓから垂直方向に立ち上がっている。基準面Ｓは男木側木質構造材１の一端部の端面を形成している。
【００１８】
木質接合部は、腰掛部１ｂと蟻ほぞ部１ａとから構成されている。腰掛部１ｂは、Ｕ字形に連続する周面として腰掛面３を有している。腰掛面３と基準面Ｓとが成す角度は鋭角であり、この鋭角をαで表す。この角度αは、腰掛面３のどの位置でも一定である。腰掛部１ｂは、腰掛部端面１２を有する。腰掛部端面１２は基準面Ｓに平行である。腰掛面３は左右の平面部３ａと左右の平面部３ａを連続に滑らかに接続する円錐面部分３ｂとから形成されている。
【００１９】
蟻ほぞ部１ａは、腰掛部端面１２から垂直方向に立ち上がってＵ字形に連続する周面として蟻ほぞ面５を有している。蟻ほぞ面５と腰掛部端面１２とが成す角度は鋭角であり、この鋭角をβで表す。この角度βは、蟻ほぞ面５のどの位置でも一定である。特に、角度αと角度βとの間に、次式の関係を与える。α＝β。
【００２０】
蟻ほぞ部１ａは、蟻ほぞ部端面１３を有する。蟻ほぞ部端面１３は基準面Ｓに平行である。蟻ほぞ面５は左右の平面部５ａを連続に滑らかに接続する円錐面部分５ｂとから形成されている。
【００２１】
女木側木質構造材２は一端側の上部側が切削され、女木側木質構造材２には木質接合部が形成されている。木質接合部は、基準面Ｓから垂直方向に孔掘りされている。基準面Ｓは女木側木質構造材２の正面を形成している。木質接合部は、腰掛穴部２ｂと蟻ほぞ穴部２ａとから構成されている。図６に示すように、腰掛穴部２ｂは、Ｕ字形に連続する周面として腰掛穴面１１を有している。腰掛穴面１１と基準面Ｓとが成す角度は鋭角である。腰掛穴面１１は左右の平面部１１ａと左右の平面部１１を連続に滑らかに接続する円錐面部分１１ｂとから形成されている。腰掛穴部２ｂは、腰掛穴部端面１５を有する。腰掛穴部端面１５は基準面Ｓに平行である。腰掛穴部端面１５と腰掛穴面１１が成す角度は鋭角であり、この鋭角はαである。
【００２２】
蟻ほぞ穴部２ａは、腰掛穴部端面１５から垂直方向に掘り下げられ、Ｕ字形に連続する周面として蟻ほぞ穴面７を有している。蟻ほぞ穴面７と腰掛穴部端面１５とが成す角度は鋭角である。この鋭角は、βである。この角度βは、蟻ほぞ穴面７のいたるところで一定である。特に、角度αと角度βとの間に、次式の関係を与える。α＝β。
【００２３】
蟻ほぞ穴部２ａは、蟻ほぞ穴部端面１４を有する。蟻ほぞ穴部端面１４は基準面Ｓに平行である。従って、蟻ほぞ穴部端面１４と蟻ほぞ穴面７が成す角度も角度βである。蟻ほぞ穴面７は左右の平面部７ａと左右の平面部７ａを連続に滑らかに接続する円錐面部分７ｂとから形成されている。
【００２４】
図４に示すように、腰掛部１ｂが腰掛穴部２ｂの腰掛穴面１１ｂに突き合わせられる腰掛面３ｂと、蟻ほぞ部１ａが蟻ほぞ穴部２ａの蟻ほぞ穴面７ｂに突き合わせられる蟻ほぞ面５ｂとは、突き合わせ部で共通線Ｌ′又は共通面を実質的に形成している。即ち、円錐面部分５ｂと円錐面部分３ｂは、一部領域で共通線Ｌ又は組立時に実質的に共通円錐面Ｌを共有する。角度αと角度βは厳密に等しくなくてよく、接合時に実質的に等しくなればよい。
【００２５】
図７に示すように、腰掛穴部２ｂが腰掛部１ｂの腰掛面３ｂに突き合わせられる腰掛穴面１１ｂと蟻ほぞ穴部２ａが蟻ほぞ部１ａの蟻ほぞ面５に突き合わせられる蟻ほぞ穴面７ｂとは、突き合わせ部で共通線又は共通面を実質的に形成している。即ち、円錐面部分１１ｂと円錐面部分７ｂは、一部領域で共通線又は組立時に実質的に共通円錐面を共有する。
【００２６】
角度αと角度βは厳密に等しくなくてよく、接合時に実質的に等しくなればよい。このような技術的意味で、角度αと角度βは、実質的に等しい。なお、角度αと角度βは、それぞれにあらゆるところで等しくなくてよいが、切削刃物として回転刃を用いるので結果的に角度αも角度βもあらゆるところで等しくなる。
【００２７】
図８は、男木側木質構造材１と女木側木質構造材２とが接合されて組み立てられた組立時の状態を示している。組み立てられた後は、互いに干渉する部分を押しつぶすので、角度αと角度βは、互いに等しくなっている。図４に示す共通線の近傍領域では円錐面部分３ｂと円錐面部分５ｂは連続した面を形成し、また、図７に示す共通線の近傍領域では円錐面部分７ｂと円錐面部１１ｂは連続した面を形成し、それぞれに連続する両面が互いに接触して１つの大きい接触面を形成する。
【００２８】
このように接触しあう男木側木質構造材１と女木側木質構造材２の木質接合は、男木側木質構造材１において蟻ほぞ部１ａと腰掛部１ｂとが一体化された蟻溝接合部を構成し、また、女木側木質構造材２において蟻ほぞ穴部２ａと腰掛穴部２ｂとが一体化された蟻溝接合部を構成するので、接合部の断面積が大きい。このように大きい断面積の男木側木質構造材１と女木側木質構造材２の接合は、大きい強度を示す。この強度の向上は、男木側木質構造材１と女木側木質構造材２の直線方向の押し合いに関しても、男木側木質構造材１と女木側木質構造材２の回転方向のねじれに対しても示されている。
【００２９】
図１に示す男木側木質構造材１及び女木側木質構造材２の加工方法は、次のように行われる。まず、男木側木質構造材１の元の材料の端面側に蟻ほぞ面５が、円錐形状の回転刃物による切削加工により、Ｕ字状に形成される。この場合、腰掛部端面１２が形成される。
【００３０】
次に、腰掛部端面１２を端面とする男木側木質構造材１の端面側に腰掛面３が、円錐形状の回転刃物による切削加工により、Ｕ字状に形成される。このような２工程で用いられる回転刃物としては同一の大きさの円錐状刃物が用いられる。その結果、αとβが等しくなる。
【００３１】
腰掛面３を形成する場合、腰掛面３を形成する刃物が、蟻ほぞ面５の一部（Ｕ字部の底部即ち折り返し部）を僅かに切削するか蟻ほぞ面５の一部に接触するようにする。このような加工方法により、腰掛面３と蟻ほぞ面５の一部は共通の面に形成される。腰掛穴面１１を形成する場合、蟻ほぞ穴面７を形成する刃物が、腰掛穴面１１の一部（Ｕ字部の底部即ち折り返し部）を僅かに切削するか腰掛穴面１１の一部に接触するようにする。このような加工方法により、蟻ほぞ穴面７と腰掛穴面１１の一部は共通の面に形成される。
【００３２】
図８に示す嵌合状態で、蟻ほぞ部端面１３と蟻ほぞ穴部端面１４は平行であり、腰掛部端面１２と腰掛穴部端面１５は平行である。図８では、α＝βになっているが、組立前にはα＝βである必要はない。組立前の蟻ほぞ面５と組立前の蟻ほぞ穴面７とが緩衝しあい、組立後に蟻ほぞ面５と蟻ほぞ穴面７との部分が共通面を形成するように設計されている。蟻ほぞ部端面１３と蟻ほぞ穴部端面１４との間及び腰掛部端面１２と腰掛穴部端面１５との間には通常、クリアランスが与えられている。
【００３３】
（実験データ）
図１７は、従来型と本発明型とを比較実験するためのの形状及び寸法仕様を示している。従来型であるタイプ１と本発明型のタイプ２，３の３タイプで比較する。比較実験で使用する供試材は、比重０．５２、含水率１１〜１４、平均年輪幅４．１ｍｍのベイマツである。以下、前記角度αを蟻角という。
【００３４】
図１７は、３タイプの仕口形状を示す。従来型の男木側木質構造材１及び本発明型の男木側木質構造材１の諸元ａ，ｂ，ｃ，ｄ，ｅ，ｆ，ｇ，ｈ，ｉを図９として示す図表に示している。従来型は、腰掛面と蟻ほぞ面とが共通線又は共通面を有さない。タイプ２，３は、本発明であり腰掛面３と蟻ほぞ面５とは共通線を有している。タイプ１は蟻角が１８度で変化しないが、タイプ２，３は蟻角が１８度、２５度の２つの角度で変化させた。１８度は従来から賞用されている角度であるが、２５度は推奨できる角度である（特開平６−１０４１８号参照）。
【００３５】
強度試験は、せん断、引っ張り及び曲げの３試験である。テンシロン試験機で加力した。加重はロードセルで測定し、変位は電気式変位計で測定した。変位は、男木側木質構造材１と女木側木質構造材２の相対変位である。仕口形状が強度性能に及ぼす影響を吟味するために、蟻角を１８度、図９中に示す長さＨを１５ｍｍに固定し、仕口形状の諸元をパラメータとする比較実験（実験１という）を行った。他方、蟻角及びありせい（長さｉ）が強度性能に及ぼす影響を吟味するために、タイプ２で仕口形状を固定し、蟻角及び長さＨをパラメータとし、蟻角を１８度と２５で変化させ、長さＨを５ｍｍ、１０ｍｍ、１５ｍｍで変化させた比較実験（実験２という）を行った。
【００３６】
せん断試験は、Ｈ型に構成した試験体に鋼板を介して仕口部に鉛直荷重を作用させせん断力が働くようにした。荷重は、クロスヘッドスピード０．５ｍｍ／ｍｉｎで加力した。引っ張り試験は、Ｔ型に構成した試験体に男木側木質構造材１の軸方向に荷重がかかるようにした。荷重は、クロスヘッドスピード０．５ｍｍ／ｍｉｎで加力した。曲げ試験は、Ｔ型に構成した試験体（女木側木質構造材２）を固定し男木側木質構造材１にクロスヘッドスピード０．５ｍｍ／ｍｉｎで加力した。
【００３７】
（実験結果）
せん断試験−実験１
図１０（ａ），（ｂ），（ｃ）は、実験１のせん断試験の結果を示している。剛性、最大荷重、ねばりに関しては、タイプ１とタイプ２に差異はないが、タイプ３は剛性、最大荷重について他のタイプよりやや劣る。
【００３８】
せん断試験−実験２
図１１（ａ），（ｂ），（ｃ）は、実験２のせん断試験の結果を示している。長さＨを変化させても剛性、最大荷重の点で差異は見られないが、ねばりはＨ＝１０ｍｍでもっとも大きいことがわかる。なお、この場合、Ｈ＝５ｍｍで男木側木質構造材１が、Ｈ＝１０ｍｍで男木側木質構造材１とともに女木側木質構造材２が、Ｈ＝１５ｍｍで女木側木質構造材２が破壊された。
【００３９】
せん断試験−実験３
図１２（ａ），（ｂ），（ｃ）は、実験１の引っ張り試験の結果を示している。剛性に関しては、タイプ２は、タイプ１、タイプ３より著しく大きく定量的には概ね２倍程度とみなせるが、最大荷重については若干大きい程度である。
【００４０】
図１３（ａ），（ｂ），（ｃ）は、実験２の引っ張り試験の結果を示している。Ｈが大きくなるほど剛性、最大荷重は増加する傾向にある。また、蟻角２５度は蟻角１８度より剛性、最大荷重がすぐれている。この結果は、前回の報告に示す研究結果に符号する。
【００４１】
図１４（ａ），（ｂ），（ｃ）は、実験１の曲げ試験の結果を示す。タイプ２，３は、タイプ１より回転剛性、最大モーメントが大きく、特にタイプ２の回転剛性は、タイプ１より１．４倍大きい。これらの傾向は、前記引っ張り試験の場合と同様である。一方、ねばりではタイプ２はタイプ１より大きく、この傾向は前記引っ張り試験の結果と異なる。
【００４２】
図１５（ａ），（ｂ），（ｃ）は、実験２の曲げ試験の結果を示す。回転剛性と最大モーメントでは、いずれのＨの長さに対しても２５度の方が１８度よりすぐれている。また、同一の蟻角においてはＨが大きくなるほど回転剛性、最大モーメントがともに増加傾向にある。
【００４３】
以上の実験結果から、タイプ２，３は、強度性能がすぐれており、機械加工能率上有利である。
【００４４】
【その他の実施例】
本発明は前記実施形態に限られず発明の本質を逸脱しない範囲で他の種々の変形が可能なことは言うまでもない。例えば、図１６（ａ），（ｂ）に示すように、腰掛面３と腰掛部端面１２との角度及び腰掛穴面１１と腰掛穴部端面１５との角度が直角である場合にも適用できる。
【００４５】
【発明の効果】
本発明の建築構造材における木質接合方法及びその構造によると、強度性能が優れているし、先に蟻ほぞ面５を切削して後で腰掛面３を切削することにより、共通線を容易に作り出せるから、加工能率がよい。
【図面の簡単な説明】
【図１】図１は、本発明の構造材１，２の蟻ほぞ及び蟻ほぞ穴の立体分解図であり、図１（ａ）は男木側木質構造材１の斜軸投影図、図１（ｂ）は女木側木質構造材２の斜軸投影図である。
【図２】図２は、男木側木質構造材１の正面図である。
【図３】図３は、図２の平面図である。
【図４】図４は、図２の側面図である。
【図５】図５は、女木側木質構造材２の正面図である。
【図６】図６は、図５の平面図である。
【図７】図７は、図５の側面断面図である。
【図８】図８は、男木側木質構造材１と女木側木質構造材２の組立状態を示す平面図である。
【図９】図９は、実験タイプの諸元表である。
【図１０】図１０（ａ），（ｂ），（ｃ）はグラフであり、図１０（ａ）は各タイプについて変位と荷重の関係を示し、図１０（ｂ）は各タイプの最大荷重を示し、図１０１０（ｃ）は各タイプについて形状とねばりの関係を示す。
【図１１】図１１（ａ），（ｂ），（ｃ）はグラフであり、図１１（ａ）は各タイプについて変位と荷重の関係を示し、図１１（ｂ）は各タイプ最大荷重を示し、図１１R>１（ｃ）は各タイプについて形状とねばりの関係を示す。
【図１２】図１２（ａ），（ｂ），（ｃ）はグラフであり、図１２（ａ）は各タイプについて変位と荷重の関係を示し、図１２（ｂ）は各タイプの最大荷重を示し、図１２１２（ｃ）は各タイプについて形状とねばりの関係を示す。
【図１３】図１３（ａ），（ｂ），（ｃ）はグラフであり、図１３（ａ）は各タイプについて変位と荷重の関係を示し、図１３（ｂ）は各タイプについて最大荷重と長さＨとの関係を示し、図１３（ｃ）は各タイプについてねばりと長さＨとの関係を示している。
【図１４】図１４（ａ），（ｂ），（ｃ）はグラフであり、図１４（ａ）は各タイプについて回転角とモーメントの関係を示し、図１４（ｂ）は各タイプの最大モーメントを示し、図１４（ｃ）は各タイプのねばりを示す。
【図１５】図１５（ａ），（ｂ），（ｃ）はグラフであり、図１５（ａ）は各タイプについて回転角とモーメントの関係を示し、図１５（ｂ）は各タイプの最大モーメントを示し、図１５（ｃ）は各タイプのねばりを示す。
【図１６】図１６（ａ），（ｂ）は、他の実施形態を示す斜軸投影図であり、図１６（ａ）は男木側木質構造材１の斜軸投影図、図１６（ｂ）は女木側木質構造材２の斜軸投影図である。
【図１７】図１７は、従来タイプと本発明タイプとの形状比較を示す図表である。
【符号の説明】
１…木質構造材
１ａ…蟻ほぞ部
１ｂ…腰掛部
２…木質構造材
２ａ…腰掛穴部
２ｂ…蟻ほぞ穴部
３…腰掛面
５…蟻ほぞ面
７…蟻ほぞ穴面
１１…腰掛穴面[0001]
[Industrial application fields]
The present invention relates to a method for joining wood of a building structure material and a dovetail structure of the building structure material. More specifically, the present invention relates to a dovetail structure of a wooden building structure material precut at a factory in advance.
[0002]
[Prior art]
In Japan, wooden houses have a unique texture, so their popularity is strong. When a building is constructed as a house, its strength must be secured by using a large number of structural materials. The traditional processing method for this purpose was a method in which a carpenter painted and processed a number of structural materials one by one on the basis of a plan view in a lower hut. Such a processing method naturally takes a lot of labor. A pre-cut method is known as a processing method for performing such a low-efficiency processing method once again at a high efficiency with a woodworking machine.
[0003]
This pre-cut method is a so-called factory production method, in which the joints and joints of structural materials are processed in advance at the factory using a joint processing machine dedicated to wood. Various joint structures for this purpose are also known, for example, proposed in Japanese Utility Model Publication Nos. 58-1525, 61-23130, and 61-409. Such a pre-cut method has brought many merits such as elimination of shortage of manpower and technicians, improvement of processing accuracy, improvement of quality, shortening of construction period, and cost reduction.
[0004]
On the other hand, it is overwhelmingly often performed on the days of Daianichi on the construction site in Japan. For this reason, this building is not always a good day blessed with the weather, but may have to be done on a rainy day, a windy day, a snowy day, etc. In such a case, when the joint of the pre-cut structural material comes into contact with water due to rain or the like, it may swell and cause subtle deformation. Especially during the rainy season, it is time for the structural material to absorb a lot of water, so there are many troubles due to deformation.
[0005]
This swelling and shrinkage ratio depending on the direction of wood is greatest in the tangential direction, followed by the radial direction and smallest in the fiber direction, and the ratio is approximately 10: 5: 1 to 0.5. Specifically, for example, taking the joint connection structure of the joint, when connecting joints of two structural members in the past, the dimensions of each part of the ant tenon and ant mortise of the structural member, The angle of the side of the ant tenon and the side of the side of the ant tenon are the same. Although this assembly was pre-cut at the factory so that the two could fit correctly, it was easy to go wrong for the reasons described above. In particular, swelling and shrinkage due to the above reason on the ant mortise side are large, making it difficult to fit.
[0006]
In particular, the alignment between the ant tenon side and the ant tenon side often fails. As a result, the fitting cannot be performed accurately. For this reason, in many cases, emergency repairs are made on the spot to cope with the problem. For example, it is a process of scraping the larger one of the side surface of the ant tenon or the side surface of the ant tenon hole. Eventually, when this was done, the fitting of the joint surface became sweet and the joints of each joint could become loose after the building was built. In order to solve these difficulties, a small amount of overlap is provided at the time of factory production at the fitting part between the side of the ant tenon and the side of the ant mortise hole, and the press-fitting work during assembly is easy. A dovetail structure that does not cause a decrease in strength was proposed previously.
[0007]
However, such a proposal is not an essential solution, but a symptomatic solution, and a structure that is inherently superior in strength and can improve factory production efficiency even if the dovetail joint is somewhat loosened and a joining method thereof The proposal of is desired.
[0008]
[Problems to be solved by the invention]
The present invention is intended to solve the above problems and achieves the following objects.
[0009]
An object of the present invention is to provide a joint structure of a wood joint portion of a wooden structure material for building having higher strength and a processing method of the wood joint portion.
[0010]
Another object of the present invention is to provide a joint structure for a wood joint portion of a wooden structure material for construction and a method for processing the wood joint portion, which can increase the factory production efficiency.
[0011]
[Means for Solving the Problems]
The present invention adopts the following means in order to solve the above problems.
[0012]
The joint structure of the wood joint portion of the wood structure material of the present invention 1 is a structure of the wood joint portion of two building wood structure materials (1, 2) to be joined by dovetail joining, and one of the wood structure materials (1) includes a seat (1b) and an ant tenon (1a) protruding from the seat (1b), and the other (2) of the wooden structure material is a seat hole (2b) and the seat hole A dent mortise portion (2a) dug down from (2b), and the seat portion (1b) is a U-shaped seat surface (3) abutted against the seat hole surface (11) of the seat hole portion (2b) ) , And the ant tenon portion (1a) has a U-shaped ant tenon surface (5) abutted against the ant tenon hole surface (7) of the ant tenon hole portion (2a) , and the seat surface ( and lower ends of said dovetail surface 3) (5) substantially form a common line or a common plane, wherein the seat hole (2b) is the waist A section (1b) of the seat surface (3) in the U-shape for abutting the seat bore surface (11), said dovetail faces of the dovetail mortise portion (2a) said dovetail portion (1a) (5) It has a U-shaped mortise surface (7) to be abutted to (5), the lower end of the seat hole surface (11) and the lower end of the ant mortise surface (7) have a common line or a common surface It is characterized by forming substantially.
[0013]
The joining structure of the wood joint portion of the wood structure material for construction of the present invention 2 is the joint structure of the wood joint portion of the wood structure material of the present invention 1 and has an angle formed by the seating surface (3) and the reference surface. When the angle between the ant tenon surface (5) and the reference surface is expressed by α and β is expressed by β, the angle between the seat hole surface (11) and the reference surface is substantially α = β. It is characterized by α.
[0014]
In the method of processing a wood joint portion of a wood structure material for construction of the present invention 3, one (1) includes a seat portion (1b) and an ant tenon portion (1a) protruding from the seat portion (1b), and the other ( 2) includes a seat hole portion (2b) and an ant mortise portion (2a) dug down from the seat hole portion (2b), and the seat portion (1b) and the ant tenon portion (1a) are each U-shaped. A seat-like surface (3) and an ant tenon surface (5), and the seat-hole portion (2b) and the ant-morte portion (2a) are respectively U-shaped seat-hole surface (11) and ant-morte hole This is a method for processing the wood joints of two wood structures for construction (1, 2) to be jointed with dovetails having a surface (7). The dovetail surface (5) is formed first with a conical cutting blade. By cutting the seating surface (3) with a conical cutting blade, the seating surface (3) is formed on the lower end of the tenon surface (5), The dovetail surface (7) is first formed with a conical cutting blade, and the seat hole surface (11) is cut with a conical cutting blade, so that the dovetail surface (7) has a lower end. The seat hole surface (11) is formed by overlapping.
[0015]
The structure of the wood joint portion of the wood structure material for building of the present invention is that the seat portion and the ant tenon portion constitute a structure as a substantially integrated body, and the seat hole portion and the ant tenon portion are substantially integrated. The structure is configured as a hole. Such an integrated structure increases the strength.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
1 (a) and 1 (b) show a wood joint structure of a wood structure material for construction of the present invention, that is, a so-called joint seat dovetail joint structure. 1 (a) and FIGS. 2, 3, and 4 show the joining structure of the male-side wooden structural member 1, and FIGS. 1 (b) and 5, 6, and 7 show the female-side wooden structural member 2. FIG. The joining structure is shown. Both wooden structural materials 1 and 2 are joined in a direction orthogonal to each other, and their cross sections are square or rectangular, respectively.
[0017]
The structural materials 1 and 2 are used as, for example, a beam girder, a girder, a base, a through column, a decorative column, a shed bundle, and the like. The lower side of the one end side of the male side wooden structure material 1 is cut, and the male side wooden structure material 1 is formed with a wooden joint. The wood joint is rising from the reference plane S in the vertical direction. The reference surface S forms an end surface of one end portion of the male side wood structure material 1.
[0018]
The wood joint is composed of a seat portion 1b and an ant tenon portion 1a. The seat portion 1b has a seat surface 3 as a circumferential surface continuous in a U shape. The angle formed between the seating surface 3 and the reference surface S is an acute angle, and this acute angle is represented by α. This angle α is constant at any position on the seating surface 3. The seat portion 1b has a seat portion end surface 12. The seat portion end surface 12 is parallel to the reference surface S. The seating surface 3 is formed of a left and right flat surface portion 3a and a conical surface portion 3b that connects the left and right flat surface portions 3a continuously and smoothly.
[0019]
The ant tenon portion 1a has an ant tenon surface 5 as a circumferential surface that rises in the vertical direction from the seat end surface 12 and continues in a U-shape. The angle formed between the ant tenon surface 5 and the seat end surface 12 is an acute angle, and this acute angle is represented by β. This angle β is constant at any position on the ant tenon surface 5. In particular, the relationship of the following equation is given between the angle α and the angle β. α = β.
[0020]
The ant tenon portion 1 a has an ant tenon end surface 13. The ant tenon end face 13 is parallel to the reference plane S. The ant tenon surface 5 is formed of a conical surface portion 5b that connects the left and right flat portions 5a continuously and smoothly.
[0021]
The upper side of one end side of the female tree side wooden structure material 2 is cut, and a wooden joint portion is formed on the female tree side wooden structure material 2. The wood joint is dug in the vertical direction from the reference plane S. The reference plane S forms the front of the female tree side wooden structure material 2. The wood joint is composed of a seat hole 2b and an ant mortise 2a. As shown in FIG. 6, the seating hole portion 2 b has a seating hole surface 11 as a circumferential surface continuous in a U shape. The angle formed between the seat hole surface 11 and the reference surface S is an acute angle. The seat hole surface 11 is formed of a left and right plane portion 11a and a conical surface portion 11b that connects the left and right plane portions 11 continuously and smoothly. The seat hole 2 b has a seat hole end face 15. The seat hole end face 15 is parallel to the reference plane S. The angle formed between the seat hole end face 15 and the seat hole surface 11 is an acute angle, and this acute angle is α.
[0022]
The ant mortise part 2a is dug down in the vertical direction from the end face 15 of the seating hole part and has an ant mortise face 7 as a U-shaped continuous surface. The angle formed between the ant mortise surface 7 and the seat hole end surface 15 is an acute angle. This acute angle is β. This angle β is constant throughout the ant mortise surface 7. In particular, the relationship of the following equation is given between the angle α and the angle β. α = β.
[0023]
The ant mortise part 2 a has an ant mortise part end face 14. The ant mortise end face 14 is parallel to the reference plane S. Therefore, the angle formed between the ant mortise end face 14 and the ant mortise surface 7 is also the angle β. The ant mortise surface 7 is formed of a left and right flat surface portion 7a and a conical surface portion 7b that connects the left and right flat surface portions 7a smoothly and continuously.
[0024]
As shown in FIG. 4, a seat surface 3b in which the seat portion 1b is abutted against the seat hole surface 11b of the seat hole portion 2b, and an ant tenon surface in which the ant tenon portion 1a is abutted against the ant tenon surface 7b of the ant mortise portion 2a. 5b substantially forms a common line L ′ or a common surface at the butted portion. That is, the conical surface portion 5b and the conical surface portion 3b share the common line L or the common conical surface L substantially at the time of assembly in a partial region. The angle α and the angle β do not have to be exactly equal and need only be substantially equal at the time of joining.
[0025]
As shown in FIG. 7, a seat hole surface 11b in which the seat hole portion 2b is abutted against the seat surface 3b of the seat portion 1b and an ant tenon surface 7b in which the ant tenon portion 2a is abutted against the ant tenon surface 5 of the ant tenon portion 1a. And substantially form a common line or a common surface at the butted portion. In other words, the conical surface portion 11b and the conical surface portion 7b share a common line or a common conical surface substantially at the time of assembly in a partial region.
[0026]
The angle α and the angle β do not have to be exactly equal and need only be substantially equal at the time of joining. In this technical sense, the angle α and the angle β are substantially equal. Note that the angle α and the angle β may not be equal everywhere, but since a rotary blade is used as a cutting blade, the angle α and the angle β are equal everywhere.
[0027]
FIG. 8 shows a state at the time of assembling in which the male-side wooden structural member 1 and the female-side wooden structural member 2 are joined and assembled. After being assembled, the portions that interfere with each other are crushed, so that the angle α and the angle β are equal to each other. 4, the conical surface portion 3b and the conical surface portion 5b form a continuous surface, and the conical surface portion 7b and the conical surface portion 11b are continuous in the region near the common line shown in FIG. Forming a large contact surface with each successive two surfaces contacting each other.
[0028]
The wood joint of the male side wooden structure material 1 and the female side wooden structure material 2 that are in contact with each other in this manner is the dovetail groove in which the ant tenon portion 1a and the seat portion 1b are integrated in the male side wooden structure material 1. Since the joint part is formed and the dovetail joint part in which the ant mortise hole part 2a and the seat hole part 2b are integrated in the female tree side wooden structure material 2, a cross-sectional area of the joint part is large. The joint between the male-side wooden structural member 1 and the female-side wooden structural member 2 having such a large cross-sectional area exhibits a high strength. This improvement in strength is due to the twist in the rotational direction of the male-side wooden structural material 1 and the female-side wooden structural material 2 with respect to the pushing of the male-side wooden structural material 1 and the female-side wooden structural material 2 in the linear direction. Also shown against.
[0029]
The processing method of the male side wooden structure material 1 and the female side wooden structure material 2 shown in FIG. 1 is performed as follows. First, an ant tenon surface 5 is formed in a U-shape by cutting with a conical rotating blade on the end surface side of the original material of the male side wooden structure material 1. In this case, the seat part end face 12 is formed.
[0030]
Next, the seating surface 3 is formed in a U-shape by cutting with a conical rotating blade on the end surface side of the male side wood structure material 1 having the seating portion end surface 12 as an end surface. As the rotary blade used in such two steps, a conical blade having the same size is used. As a result, α and β are equal.
[0031]
When the seat surface 3 is formed, the blade forming the seat surface 3 slightly cuts a part of the ant tenon surface 5 (the bottom portion of the U-shaped portion, that is, the folded portion) or contacts a part of the ant tenon surface 5. Like that. By such a processing method, a part of the seating surface 3 and the ant tenon surface 5 is formed on a common surface. When forming the seat hole surface 11, the blade forming the dovetail surface 7 slightly cuts a part of the seat hole surface 11 (the bottom portion of the U-shaped portion, that is, the folded portion) or a part of the seat hole surface 11. To touch. By such a processing method, a part of the ant mortise surface 7 and the seat hole surface 11 is formed on a common surface.
[0032]
In the fitted state shown in FIG. 8, the dovetail end surface 13 and the dovetail end surface 14 are parallel, and the seat end surface 12 and the seat hole end surface 15 are parallel. In FIG. 8, α = β, but it is not necessary that α = β before assembly. The ant tenon surface 5 before assembly and the ant tenon hole surface 7 before assembly cushion each other, and the parts of the ant tenon surface 5 and the ant tenon hole surface 7 form a common surface after assembly. Clearance is normally provided between the ant tenon end surface 13 and the ant tenon hole end surface 14 and between the seat part end surface 12 and the seat hole part end surface 15.
[0033]
(Experimental data)
FIG. 17 shows the shape and dimensional specifications for a comparative experiment between the conventional type and the present invention type. Comparison is made between the conventional type 1 and the type 2 and type 3 of the present invention. The test material used in the comparative experiment is a bay pine having a specific gravity of 0.52, a moisture content of 11 to 14, and an average annual ring width of 4.1 mm. Hereinafter, the angle α is referred to as an ant angle.
[0034]
FIG. 17 shows three types of joint shapes. Specifications a, b, c, d, e, f, g, h, and i of the conventional male-side wooden structural material 1 and the inventive male-side wooden structural material 1 are shown in FIG. ing. In the conventional type, the seating surface and the ant tenon surface do not have a common line or a common surface. Types 2 and 3 are the present invention, and the seating surface 3 and the ant tenon surface 5 have a common line. Type 1 has an ant angle of 18 degrees and does not change, while types 2 and 3 have an ant angle of 18 degrees and 25 degrees. Although 18 degrees is an angle that has been conventionally used for prizes, 25 degrees is an angle that can be recommended (see Japanese Patent Laid-Open No. 6-10418).
[0035]
The strength test is three tests of shearing, pulling and bending. Force was applied with a Tensilon testing machine. The load was measured with a load cell, and the displacement was measured with an electric displacement meter. The displacement is a relative displacement between the male-side wooden structure material 1 and the female-side wooden structure material 2. In order to examine the influence of the shape of the joint on strength performance, a comparative experiment (Experiment 1) was conducted with the dovetail angle fixed at 18 degrees, the length H shown in FIG. Called). On the other hand, in order to examine the effect of the ant angle and the arsenal (length i) on the strength performance, the joint shape is fixed with type 2, the ant angle and the length H are parameters, and the ant angle is 18 degrees. A comparative experiment (referred to as Experiment 2) was performed in which the length H was changed at 25 mm, 10 mm, and 15 mm.
[0036]
In the shear test, a vertical load was applied to the joint portion of the test piece configured in the H shape via a steel plate so that a shear force was applied. The load was applied at a crosshead speed of 0.5 mm / min. In the tensile test, a load was applied to the test piece configured in the T shape in the axial direction of the male side wooden structure material 1. The load was applied at a crosshead speed of 0.5 mm / min. In the bending test, a T-shaped specimen (Wooden-side wooden structural material 2) was fixed and applied to the male-side wooden structural material 1 at a crosshead speed of 0.5 mm / min.
[0037]
(Experimental result)
Shear test-Experiment 1
10A, 10B, and 10C show the results of the shear test in Experiment 1. FIG. There is no difference between Type 1 and Type 2 regarding rigidity, maximum load, and stickiness, but Type 3 is slightly inferior to other types in terms of rigidity and maximum load.
[0038]
Shear test-Experiment 2
11A, 11B, and 11C show the results of the shear test in Experiment 2. FIG. Even when the length H is changed, no difference is seen in terms of rigidity and maximum load, but the stickiness is the largest at H = 10 mm. In this case, when H = 5 mm, the male-side wooden structural material 1 is H = 10 mm, and the female-side wooden structural material 2 together with the male-side wooden structural material 1 is H = 15 mm. Was destroyed.
[0039]
Shear test-Experiment 3
FIGS. 12A, 12B, and 12C show the results of the tensile test of Experiment 1. FIG. Regarding rigidity, Type 2 is significantly larger than Type 1 and Type 3 and can be regarded as about twice as large quantitatively, but the maximum load is slightly larger.
[0040]
13A, 13B, and 13C show the results of the tensile test of Experiment 2. FIG. As H becomes larger, the rigidity and the maximum load tend to increase. Also, the ant angle of 25 degrees is more rigid and has a maximum load than the ant angle of 18 degrees. This result is in line with the study results shown in the previous report.
[0041]
14A, 14B, and 14C show the results of the bending test of Experiment 1. FIG. Types 2 and 3 have greater rotational rigidity and maximum moment than Type 1, and Type 2 has 1.4 times greater rotational rigidity than Type 1. These tendencies are the same as in the case of the tensile test. On the other hand, in the stickiness, type 2 is larger than type 1, and this tendency is different from the result of the tensile test.
[0042]
15A, 15B, and 15C show the results of the bending test of Experiment 2. FIG. In rotational rigidity and maximum moment, 25 degrees is better than 18 degrees for any length of H. Further, at the same dovetail angle, both the rotational rigidity and the maximum moment tend to increase as H increases.
[0043]
From the above experimental results, types 2 and 3 have excellent strength performance and are advantageous in terms of machining efficiency.
[0044]
[Other examples]
It goes without saying that the present invention is not limited to the above-described embodiment, and various other modifications are possible without departing from the essence of the invention. For example, as shown in FIGS. 16A and 16B, the present invention can also be applied when the angle between the seating surface 3 and the seating portion end surface 12 and the angle between the seating hole surface 11 and the seating hole end surface 15 are right angles. .
[0045]
【The invention's effect】
According to the wood joining method and the structure thereof in the building structure material of the present invention, the strength performance is excellent, and the common line can be easily formed by cutting the ant tenon surface 5 first and then the seating surface 3 later. Since it can be created, the processing efficiency is good.
[Brief description of the drawings]
FIG. 1 is a three-dimensional exploded view of ant tenons and ant mortises of structural materials 1 and 2 according to the present invention, and FIG. 1 (b) is an oblique axis projection view of the female-side wooden structure material 2. FIG.
FIG. 2 is a front view of a male-side wooden structure material 1;
FIG. 3 is a plan view of FIG. 2;
FIG. 4 is a side view of FIG. 2;
FIG. 5 is a front view of a female tree side wooden structure material 2;
FIG. 6 is a plan view of FIG. 5;
FIG. 7 is a side cross-sectional view of FIG.
FIG. 8 is a plan view showing an assembled state of the male-side wooden structural member 1 and the female-side wooden structural member 2;
FIG. 9 is an experimental type specification table;
10 (a), (b), and (c) are graphs, FIG. 10 (a) shows the relationship between displacement and load for each type, and FIG. 10 (b) shows the maximum load for each type. FIG. 1010 (c) shows the relationship between shape and stickiness for each type.
11 (a), (b), and (c) are graphs, FIG. 11 (a) shows the relationship between displacement and load for each type, and FIG. 11 (b) shows the maximum load for each type. 11R> 1 (c) shows the relationship between shape and stickiness for each type.
12 (a), (b), and (c) are graphs, FIG. 12 (a) shows the relationship between displacement and load for each type, and FIG. 12 (b) shows the maximum load for each type. FIG. 1212 (c) shows the relationship between shape and stickiness for each type.
13 (a), (b), and (c) are graphs, FIG. 13 (a) shows the relationship between displacement and load for each type, and FIG. 13 (b) shows the maximum load for each type. FIG. 13C shows the relationship between stickiness and length H for each type.
14 (a), (b), and (c) are graphs, FIG. 14 (a) shows the relationship between the rotation angle and moment for each type, and FIG. 14 (b) shows the maximum of each type. FIG. 14 (c) shows each type of stickiness.
15 (a), (b) and (c) are graphs, FIG. 15 (a) shows the relationship between the rotation angle and moment for each type, and FIG. 15 (b) shows the maximum of each type. FIG. 15 (c) shows each type of stickiness.
16 (a) and 16 (b) are oblique axis projection views showing another embodiment, and FIG. 16 (a) is an oblique axis projection view of the male-side wooden structure material 1, FIG. b) is an oblique axis projection view of the female-side wooden structure material 2;
FIG. 17 is a chart showing a shape comparison between the conventional type and the present invention type.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wood structure material 1a ... Ant tenon part 1b ... Seat part 2 ... Wooden structure material 2a ... Seat hole part 2b ... Ant tenon hole part 3 ... Seat surface 5 ... Ant tenon surface 7 ... Ant tenon surface 11 ... Seat hole surface

Claims

It is the structure of the wood joint of two building wood structures (1, 2) to be joined
One (1) of the wooden structure material comprises a seat part (1b) and an ant tenon part (1a) protruding from the seat part (1b),
The other (2) of the wooden structure material includes a seat hole (2b) and an ant mortise (2a) dug down from the seat hole (2b).
The seat portion (1b) has a U-shaped seat surface (3) that is abutted against the seat hole surface (11) of the seat hole portion (2b) ,
The ant tenon portion (1a) has a U-shaped ant tenon surface (5) that is abutted against the ant tenon hole surface (7) of the ant tenon hole portion (2a);
The lower end of the seating surface (3) and the lower end of the ant tenon surface (5) substantially form a common line or a common surface;
The seat hole (2b) has the seat surface (3) to the butt is U-shaped said seat bore surface of the seat portion (1b) (11),
The dovetail tenon hole (2a) has the dovetail surface (5) to the butt is U-shaped said dovetail mortise surface (7) of the dovetail portion (1a),
The joint structure of the wood joint portion of the wood structure material for building , wherein the lower end of the seat hole surface (11) and the lower end of the dovetail surface (7) substantially form a common line or a common surface .

It is the joint structure of the wood joint portion of the wood structure material for building of claim 1,
When the angle formed between the seating surface (3) and the reference surface is represented by α and the angle formed between the dovetail surface (5) and the reference surface is represented by β, substantially α = β and the seating surface The angle formed by the hole surface (11) and the reference surface is α.

One (1) includes a seat (1b) and a dovetail (1a) projecting from the seat (1b), and the other (2) includes a seat hole (2b) and a seat hole (2b). With ant mortise (2a) dug down,
The seat portion (1b) and the ant tenon portion (1a) each have a U-shaped seat surface (3) and an ant tenon surface (5), and the seat hole portion (2b) and the ant tenon portion (2a) ) Is a method for processing wood joints of two wood structures for construction (1,2) which are jointed with ant joints each having a U-shaped seat hole surface (11) and ant mortise surface (7) ,
The dovetail surface (5) is first formed with a conical cutting blade, and the seating surface (3) is cut with the conical cutting blade, thereby overlapping the lower end of the tenon surface (5) with the seating surface ( 3)
The dovetail surface (7) is first formed with a conical cutting blade, and the seat hole surface (11) is cut with a conical cutting blade, so that the dovetail surface (7) has a lower end. A method for processing a wood joint portion of a wood structure material for building, wherein the seat hole surface (11) is formed by overlapping.