M260296 捌、新型說明： 【新型所屬之技術領域】 本創作係關於擊打高爾夫球用的高爾夫球桿的桿頭，特 別是高爾夫球鐵桿頭。詳細地說，本創作係關於包括有從 後面凹陷的凹處（容腔）的桿頭主體，和設在此一凹處的 F R P體的高爾夫球鐵桿頭。 【先前技術】 習知之高爾夫球鐵桿頭僅用不銹鋼、鑄鐵等金屬材料來 構成，但是近年來在桿頭主體的背後側配置 F R P (纖維強 化合成樹脂）材料的高爾夫球鐵桿頭也在市場上開始銷售。 例如，在日本專利特開昭6 2 — 9 7 5 7 0號公報中，記載了 在擊球面的背面側附著CFRP (碳纖維強化合成樹脂）層而 提高擊球感的高爾夫球鐵桿頭。 此外，在日本專利特開昭6 3 — 1 9 1 6 9號公報中，記載了 把此一 C F R P層附著於擊球面的背面側，且以合成樹脂製背 襯構件覆蓋該C F R P層。在此一特開昭6 3 — 1 9 1 6 9號公報的 圖5中，記載了容腔的入口部分也以背襯構件封閉並使F R P 構件成為中空結構的高爾夫球鐵桿頭。 圖4係日本專利特開昭6 3 — 1 9 1 6 9號公報之圖5。此一 高爾夫球鐵桿頭的桿頭主體1在擊球面部2的背後側有凹 部4，並從底面部3的後緣豎立設置豎起部8。 在凹部4的内表面上以緊密接觸狀態添加設置纖維強化 構件5。纖維強化構件5為中空殼結構。再者，在同號公 報中如何把此一中空殼結構的纖維強化構件5配置、形成 5 312/發明說明書(補件)/93-08/93208604 M260296 於凹部4内。在凹部4中填充合成樹脂材料，以覆蓋擋住 此一纖維強化構件5的方式通過施行硬化處理形成背襯構 件6 (同號公報第5頁左上欄至左下攔）。 (專利文獻）日本專利特 (專利文獻） 日本專利特 【新型内容】 (新型所欲解決之問題） 圖4中所示的日本專利特 主體中，凹部4的角部是銳 1與纖維強化構件5之間容 空隙，則在擊打高爾夫球的 擊打感變差。 (解決問題之手段） 本創作的目的在於提供一 主體的貼合性優良的高爾夫 本創作的高爾夫球鐵桿頭 處的桿頭主體’和設在該凹 頭，其特徵在於，該凹處有 頭主體的後面下垂連接於該 空形狀，且重疊於該凹處的 處的入口部分，該内面與周 由彎曲面構成。 在本創作的高爾夫球鐵桿 叉角部為彎曲面，故可以防 開昭6 2 - 9 7 5 7 0號公報 開昭6 3 - 1 9 1 6 9號公報 開昭6 3 — 1 9 1 6 9號公報的桿頭 角。在這種角部，在桿頭主體 易產生空隙。如果存在著這種 擊球時產生不規則的振動等而 種配置於凹處的FRP體與桿頭 球鐵桿頭。 ，是具有在面部的背後設有凹 處的 FRP體的高爾夫球鐵桿 沿著該面部的内面，和從該桿 内面的周壁面，該FRP體為中 内面和周壁面，同時封閉該凹 壁面的交叉角部的整體或大半 頭中，因為内面與周壁面的交 止在此一交叉角部處在FRP體 312/發明說明書(補件)/93-08/93208604 6 M260296 與桿頭主體之間產生空隙。 FRP體最好是含有碳纖維、玻璃纖維等長纖維而成的UD 預浸潰材，或上述纖維的布的預浸潰材多張疊層，緊密接 觸於桿頭主體地形成。 特別是，在凹處内吹塑成形而形成該FRP體，藉此幾乎 完全消除凹處與周壁面之間的空隙。在此一場合，使把凹 處的入口部分成為越接近桿頭主體的該入口部分開口面積 越慢慢縮小的形狀，藉此可以消除凹處的入口緣部與 F R P 體之間的空隙。 在本創作中，也可以在凹處的内面，或凹處内的下部和 後部設有高比重樹脂層。通過設置此一高比重樹脂層，擊 球時的振動吸收特性提高。此外，可以加深重心使擊球穩 定化。進而還可以由高比重樹脂層進行高爾夫球鐵桿頭的 重量調整。 【實施方式】 以下，參照附圖就本創作的實施形態進行說明。圖1是 根據實施形態的高爾夫球鐵桿頭的正視圖，圖2、3是沿圖 1的I I — I I，I I I — I I I線之剖視圖。 此一高爾夫球鐵桿頭的桿頭主體 1 0 有擊球用的面部 1 1，及連接於此一面部1 1的下緣2底部1 2。在此一底部 1 2上固定著配重件1 3。在桿頭主體1 0的插口部1 4中裝設 桿軸（未圖示）。 此一桿頭主體 10由不銹鋼等金屬製成。再者，也可以 使面部1 1鈦、鈦合金等，而其他部分為不銹鋼等。 7 312/發明說明書(補件)/93-08/93208604 M260296 桿頭主體10有從後面凹陷的凹處20。此一凹處20的内 面21由與面部11的前表面平行的平面組成，面部11成為 大致均一厚度的板狀。凹處2 0的周壁面從桿頭主體1 0的 後面下垂連接於該内面2 1，由底側的周壁面2 2、上緣側的 周壁面2 3、突出側的周壁面2 4和跟側的周壁面2 5組成。 這些周壁面22〜25與内面21的交叉角部，除了底部12 的台座部1 2 a附近，全都成為平滑地凹入彎曲的彎曲面。 為了在此一交叉角部在桿頭主體10與FRP體16之間不產 生間隙，此一彎曲面的曲率半徑最好是1 . 5〜8 0 m m，特別 是2〜6 0 mm 〇 凹處 2 0的入口側（桿頭主體 1 0的後面側），成為越接 近桿頭主體 10的後面開口面積越慢慢減小地收窄的形 狀。再者，如圖2中所示，凹處20的入口側的緣部的壁厚， 朝該入口的中心側慢慢減少，該緣部的斷面形狀如圖2成 為銳角形狀。 在此一内面2 1上貼著高比重樹脂層1 5。此一高比重樹 脂層1 5最好是由配有鎢或鎢合金等比重1 0以上的高比重 金屬粉末的環氧樹脂、尼龍、聚酯、聚氨酯、A B S、熱塑性 彈性體等樹脂材料來構成。此一高比重樹脂層1 5的比重最 好是10〜17,特別是10〜14左右，厚度最好是0.4〜1.2mm 左右。高比重樹脂層1 5雖然最好是設置於内面2 1的大致 全體上，但是可以以包括内面21的中心附近並覆蓋内面面 積的5 0 %以上特別是6 0 %以上的方式設置。再者，在本實 施形態中，高比重樹脂層1 5設置成其周緣還多少搭在周壁 8 312/發明說明書(補件)/93-08/93208604 M260296 面22〜25上。 通過設置此一高比重樹脂層 1 5 可以吸收擊球時的振 動，同時高爾夫球鐵桿頭的重量調整變得容易。 為了在底部1 2上設置裝設配重件1 3的螺紋孔1 3 a，桿 頭主體 1 0的突出·跟方向的中央附近成為厚壁而形成台 座部1 2 a。螺紋孔1 3 a係以上下方向貫通該台座部1 2 a地 設置。但是，配重件1 3也可以不是旋入，而是通過焊接等 固定於桿頭主體1 0。 沿著凹處2 0的内表面設有F R P體1 6。此一 F R P體1 6為 覆蓋高比重樹脂層15，並且覆蓋周壁面22〜25，進而，封 閉凹處2 0的入口部分的中空殼形狀。在桿頭主體1 0的後 表面，此一 FRP體16成為與該桿頭主體後表面大致同一平 面狀。 此一 FRP體16在凹處20内吹塑成形。為要進行此一吹 塑成形，首先，在安裝配重件13前的桿頭主體10的凹處 2 0内插入高比重樹脂層1 5的片狀的坯料，使之重合於内 面2 1。此一片狀的坯料雖然也可以是單張物，但是最好是 多張疊層薄膜狀物。此一多張疊層薄膜狀物容易柔軟地變 形，容易沿著凹處20的内表面。 接著，把FRP體1 6的坯料插入凹處20内。此一 FRP體 1 6的坯料，具有稍小於凹處2 0的中空殼形狀，重疊配置 於高比重樹脂層1 5的坯料與周壁面2 2。在此一 F R P坯料 内配置尼龍等的袋。 F R P體1 6的坯料由未硬化的纖維強化合成樹脂製成。作 9 312/發明說明書(補件)/93-08/93208604 M260296 為此一纖維雖然最好是碳纖維，但是不限於此。再者，關 於構成F R P體1 6的後表面的部分，最好是在最外層配置碳 纖維布等織物，使在F R P體1 6的後表面上顯現出網目狀。 在此一 FRP體的坯料的内部，如前所述配置著由尼龍等 製成的袋。在此一袋和F R P體的坯料上，在重合於螺紋孔 1 3 a的位置上設有開口。 把F R P體1 6的坯料插入凹處2 0内後，把高爾夫球鐵桿 頭1 0裝設於吹塑成形用的金屬模，透過螺紋孔1 3 a把空氣 等氣體供給到F RP體的坯料内的袋内使袋膨脹。藉此，高 比重樹脂層1 5的坯料被推靠於内面2 1，並且F RP體1 6的 坯料緊密接觸於高比重樹脂層1 5的坯料、周壁面2 2〜2 5 和金屬模内表面。接著，加熱金屬模使各述料硬化。然後， 進行脫模。脫模後，經由螺紋孔1 3 a拉掉袋體，接著把配 重件1 3旋入螺紋孔1 3 a。 通過此一吹塑成形可以製造高比重樹脂層 1 5和F R P體 16在内面21與周壁面22〜25的交叉角部緊密接觸的高爾 夫球鐵桿頭。再者，在本實施形態中，由於凹處2 0的入口 側成為收窄的形狀，所以F R P體1 6亦緊密接觸於凹處的入 口緣部内表面。而且，F R P體1 6中向桿頭主體1 0的後表 面露出的部分與桿頭主體的後表面平滑地同一平面狀連 圖5A〜圖5C是根據在内面21上設置肋片30的實施形 態的高爾夫球桿頭的構成圖，圖5 A是正視圖，圖5 B、5 C 是沿圖5 A的B — B線、C - C線之剖視圖。 10 312/發明說明書(補件)/93-08/93208604 M260296 在本實施形態中，設有在上下方向上延長的三條肋片 3 0。各肋片從上緣側的周壁面2 3延長到底側的周壁面2 2。 藉由設置此一肋片3 0，可以提高高爾夫球桿頭的擊打感。 再者，在内面21上，在肋片3 0、3 0間存在著高比重樹 脂層1 5與F R P體1 6。肋片3 0不被高比重樹脂層1 5和F R P 體16的任何一方覆蓋。圖5A〜圖5C的高爾夫球鐵桿頭的 其他構成與前述實施形態相同，同一元件符號表示同一部 分。 圖6是根據把高比重樹脂層1 5設在凹處2 0的下部和後 部的實施形態的高爾夫球鐵桿頭的剖視圖。 此一高比重樹脂層1 5從上側的周壁面2 3的後部到F R P 體1 6的後面下部配料。在内面2 1上不設置高比重樹脂層。 此一 FRP體16由外層16a與内層16b的兩層組成。高 比重樹脂層1 5以夾在該外層1 6 a與内層1 6 b之間的狀態配 置，成為埋設於F R P體1 6内的狀態。 此一高爾夫球鐵桿頭的其他構成與圖 1〜4的實施形態 相同，同一元件符號表示同一部分。 藉由此高爾夫球鐵桿頭，由於重心既深且低，因此，在 擊球安定的同時，球亦變得容易向上。 上述實施形態是本創作之一例，本創作也可以採用圖示 以外的形態。例如，在本創作中，也可以省略配重件1 3。 此外，也可以在FRP體16的内表面上貼著吸收振動用的橡 膠、樹脂、彈性體等的彈性體或衝擊吸收體。 在有肋片的圖5A〜圖5C的態樣中也是，也可以把高比 11 312/發明說明書(補件)/93-08/93208604 M260296 重樹脂層1 5設在凹處2 0的下後部。 (實施例） (實施例1、2 ) 在圖 1〜4中所示的高爾夫球桿頭中，把上側的周壁面 2 3與内面2 1的交叉角部的曲率半徑設為2 m m，把底側周 壁面 22與内面 21的交叉角部的曲率半徑取為 50或 70 mm。FRP體1 6由疊層兩層用彈性率2 4 t / mm2的碳纖維的 UD預浸潰材與一層用該碳纖維的布預浸潰材的三層而形 成。 結果，任意一種高爾夫球桿頭都擊打感良好。 (實施例3、4 ) 製作省略了在實施例1、2中高比重樹脂層1 5而其他為 相同的構成之高爾夫球桿頭。這些高爾夫球桿頭也是擊打 感良好。 (實施例5 ) 製作如圖5 A〜圖5 C所示設有肋片3 0而其他與實施例1 為相同構成之高爾夫球桿頭。再者，肋片的突出·跟方向 的寬度為2 mm，離内面21的高度為2 mm。 此一高爾夫球桿頭擊打感極其良好。 (實施例6 ) 製作如圖6所示把高比重樹脂層配置於底側的後部而其 他為與實施例1相同構成之高爾夫球桿頭。再者，省略沿 著内面的高比重樹脂層。此一高爾夫球桿頭，擊打感良好， 並且飛行距離穩定。 12 312/發明說明書(補件)/93-08/93208604 M260296 【圖式簡單說明】 圖1是根據實施形態的高爾夫球鐵桿頭的正視圖。 圖2是沿圖1的I I _ I I線之剖視圖。 圖3是沿圖1的I I I 一 I I I線之剖視圖。 圖4是習知高爾夫球鐵桿頭的剖視圖。 圖5A、5B、5C是表示另一個實施形態的構成圖。 圖6是表示又另一個實施形態的剖視圖。 (元件符號說明） 1 桿頭主體 2 面部 3 底部 4 凹部 5 纖維強化構件 6 背襯構件 8 豎起部 10 桿頭主體 11 面部 12 底部 12a 台座部 13 配重件 13a 螺紋孔 14 插口部 15 高比重樹脂層 1 6 F R P 體 13 312/發明說明書(補件)/93-08/93208604 M260296 16a 外層 16b 内層 2 0 凹處 2 1 内面 2 2 底側周壁面 23 上緣側周壁面 2 4 突出側周壁面 2 5 跟側周壁面 3 0 肋片 14 3丨2/發明說明書(補件)/93-08/93208604M260296 新型 Description of the new type: [Technical field to which the new type belongs] This creation is about the head of a golf club for hitting a golf ball, especially a golf iron head. In detail, this creation relates to a golf club head including a head (cavity) recessed from the back, and an F R P body provided in the recess. [Prior art] Conventional golf iron heads are made of only metal materials such as stainless steel and cast iron, but in recent years, golf iron heads equipped with FRP (fiber-reinforced synthetic resin) materials have been installed on the back of the head body. Sales. For example, Japanese Patent Laid-Open No. Sho 6 2-97 5 7 0 describes a golf iron head in which a CFRP (carbon fiber reinforced synthetic resin) layer is attached to the back side of the ball striking surface to improve the feel of the ball. In addition, Japanese Patent Laid-Open No. S63-1191-69 describes that this C F R P layer is attached to the back side of the ball striking surface, and the C F R P layer is covered with a synthetic resin backing member. In Fig. 5 of this Japanese Patent Application Laid-Open No. 6 3-1 9 1 6 9, it is described that the entrance portion of the cavity is also closed with a backing member and the F R P member is a golf iron head having a hollow structure. FIG. 4 is FIG. 5 of Japanese Patent Laid-Open No. Sho 6 3-1 9 1 6 9. The head body 1 of this golf iron head has a recessed portion 4 on the back side of the hitting surface portion 2, and a raised portion 8 is erected from the rear edge of the bottom surface portion 3. A fiber-reinforced member 5 is added to the inner surface of the recess 4 in a close contact state. The fiber-reinforced member 5 has a hollow shell structure. Furthermore, how to arrange and form the fiber-reinforced member 5 of this hollow shell structure in the same publication No. 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 in the recess 4. The recessed portion 4 is filled with a synthetic resin material, and a backing member 6 is formed by performing a hardening process so as to cover and block this fiber-reinforced member 5 (the upper left column to the lower left column on page 5 of the same publication). (Patent Document) Japanese Patent (Patent Document) Japanese Patent [New Content] (New type of problem to be solved) In the main body of Japanese Patent Special shown in Fig. 4, the corners of the recess 4 are sharp 1 and the fiber-reinforced member If the clearance is between 5, the hitting feeling when hitting the golf ball becomes worse. (Means for Solving the Problem) The purpose of this creation is to provide a golf body with excellent fit of the main body. The head body of the golf iron head of this creation is provided with the concave head, and the concave portion has a head. The rear surface of the main body is droopingly connected to the entrance portion of the hollow shape and overlapping the recess, and the inner surface and the periphery are formed by curved surfaces. The prong corners of the golf irons created in this work have curved surfaces, so they can be prevented from JP 6 2-9 7 5 7 0 JP 6 3-1 9 1 6 9 JP 6 6-1 9 1 6 Head angle of Bulletin 9. At such a corner, a gap is easily generated in the head body. If there is such an irregular vibration when hitting the ball, the FRP body and the club head which are arranged in the recess are placed. Is a golf iron with a FRP body provided with a recess on the back of the face along the inner surface of the face, and a peripheral wall surface from the inner surface of the shaft, the FRP body is a middle inner surface and a peripheral wall surface, and simultaneously closes the concave wall In the whole or most of the intersection corners, the intersection between the inner surface and the peripheral wall surface is at this intersection corner between FRP body 312 / Invention Manual (Supplement) / 93-08 / 93208604 6 M260296 and the head body Create voids. The FRP body is preferably formed of a UD prepreg made of long fibers such as carbon fibers and glass fibers, or a plurality of prepregs of a cloth made of the above-mentioned fibers, which are closely contacted with the head body. In particular, the FRP body is formed by blow molding in the recess, thereby almost completely eliminating the gap between the recess and the peripheral wall surface. In this case, the gap between the entrance edge of the recess and the F R P body can be eliminated by making the entrance portion of the recess into a shape that gradually decreases as the opening area of the entrance portion approaches the head body. In this creation, it is also possible to provide a high specific gravity resin layer on the inner surface of the recess, or on the lower and rear portions of the recess. By providing such a high specific gravity resin layer, the vibration absorption characteristics at the time of hitting the ball are improved. In addition, the center of gravity can be deepened to stabilize the shot. Furthermore, the weight of the golf iron head can be adjusted from the high specific gravity resin layer. [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view of a golf iron head according to an embodiment, and Figs. 2 and 3 are cross-sectional views taken along lines I I-I I and I I I-I I I in Fig. 1. The head main body 1 0 of this golf iron head has a face 11 for hitting, and a lower edge 2 bottom 12 connected to the face 1 1. A weight 1 3 is fixed to the bottom 1 2. A shaft (not shown) is installed in the socket portion 14 of the head body 10. This head body 10 is made of metal such as stainless steel. Further, the surface portion 11 may be made of titanium, titanium alloy, or the like, and the other portions may be made of stainless steel or the like. 7 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 The head body 10 has a recess 20 recessed from the rear. The inner surface 21 of this recess 20 is composed of a plane parallel to the front surface of the face portion 11, and the face portion 11 has a plate shape having a substantially uniform thickness. The peripheral wall surface of the recess 20 is connected to the inner surface 21 from the back of the head main body 10 by the peripheral wall surface 2 on the bottom side 2, the peripheral wall surface 2 on the upper edge side 3, the peripheral wall surface 2 4 on the protruding side, and the heel The peripheral wall surface on the side is composed of 2 5. The intersections of these peripheral wall surfaces 22 to 25 and the inner surface 21 are curved surfaces that are smoothly concavely curved except for the vicinity of the pedestal portion 12 a of the bottom portion 12. In order to prevent a gap between the head body 10 and the FRP body 16 at this crossing corner, the curvature radius of this curved surface is preferably 1.5 to 80 mm, especially 2 to 60 mm. The entrance side of 20 (the rear side of the head body 10) has a shape that gradually decreases as the opening area of the rear side of the head body 10 decreases. Further, as shown in FIG. 2, the wall thickness of the edge portion on the entrance side of the recess 20 gradually decreases toward the center side of the entrance, and the cross-sectional shape of the edge portion is an acute angle shape as shown in FIG. On this inner surface 21, a high specific gravity resin layer 15 is attached. The high specific gravity resin layer 15 is preferably made of resin materials such as epoxy resin, nylon, polyester, polyurethane, ABS, thermoplastic elastomer and the like, which are provided with high specific gravity metal powder such as tungsten or tungsten alloy. . The specific gravity of the high specific gravity resin layer 15 is preferably 10 to 17, especially about 10 to 14, and the thickness is preferably about 0.4 to 1.2 mm. Although the high specific gravity resin layer 15 is preferably provided on substantially the entire inner surface 21, it may be provided so as to include 50% or more of the inner surface area near the center of the inner surface 21, particularly 60% or more. Furthermore, in this embodiment, the high-specific gravity resin layer 15 is provided so that its peripheral edge rests on the peripheral wall 8 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 surface 22-25. By providing such a high specific gravity resin layer 1 5, it is possible to absorb the vibration at the time of hitting the ball, and at the same time, the weight adjustment of the golf iron head becomes easy. In order to provide a threaded hole 13a for mounting a weight 13 in the bottom 12, the center of the head main body 10 in the protruding and heeling direction is thickened to form a base portion 12a. The screw holes 1 3 a are provided through the base portion 1 2 a in the up-down direction. However, the weights 13 may not be screwed in, but may be fixed to the head body 10 by welding or the like. An F R P body 16 is provided along the inner surface of the recess 20. This F R P body 16 has a hollow shell shape that covers the high specific gravity resin layer 15 and covers the peripheral wall surfaces 22 to 25, and further, seals the entrance portion of the recess 20. On the rear surface of the head body 10, this FRP body 16 has a substantially flat shape similar to the rear surface of the head body. This FRP body 16 is blow-molded in the recess 20. In order to perform this blow molding, first, a sheet-shaped blank of the high specific gravity resin layer 15 is inserted into the recess 20 of the head main body 10 before the weight member 13 is mounted so as to overlap the inner surface 21. Although this one-piece blank may be a single piece, it is preferably a multi-layer laminated film. The plurality of laminated film-like objects are easily deformed softly and easily follow the inner surface of the recess 20. Next, the blank of the FRP body 16 is inserted into the recess 20. The blank of this FRP body 16 has a hollow shell shape slightly smaller than the recess 20, and the blank and the peripheral wall surface 22 are arranged on the high specific gravity resin layer 15 in an overlapping manner. A bag such as nylon is arranged in this F R P blank. The blank of the F R P body 16 is made of an unhardened fiber-reinforced synthetic resin. Operation 9 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 Although this fiber is preferably a carbon fiber, it is not limited to this. In addition, as for the portion constituting the rear surface of the F R P body 16, it is preferable to arrange a fabric such as a carbon fiber cloth on the outermost layer so that a mesh shape appears on the rear surface of the F R P body 16. Inside the blank of this FRP body, a bag made of nylon or the like is arranged as described above. An opening is provided in the bag and the blank of the F R P body at positions overlapping with the screw holes 1 a. After inserting the blank of the FRP body 16 into the recess 20, the golf iron head 10 is installed in a metal mold for blow molding, and gas such as air is supplied to the blank of the F RP body through the threaded hole 1 3a. The inner bag swells the bag. Thereby, the blank of the high specific gravity resin layer 15 is pushed against the inner surface 21, and the blank of the F RP body 16 is in close contact with the blank of the high specific gravity resin layer 15, the peripheral wall surface 2 2 to 2 5 and the mold. surface. Next, each mold is hardened by heating the mold. Then, demolding is performed. After demoulding, pull the bag body through the threaded hole 1 3 a, and then screw the weight 13 into the threaded hole 1 3 a. By this blow molding, a high specific gravity resin layer 15 and the F R P body 16 can be manufactured into a golf club head in which the inner corner 21 and the crossing corners of the peripheral wall surfaces 22 to 25 are in close contact. Furthermore, in this embodiment, since the entrance side of the recess 20 has a narrowed shape, the F R P body 16 also comes into close contact with the inner surface of the entrance edge portion of the recess. In addition, the portion of the FRP body 16 exposed to the rear surface of the head body 10 is smoothly in the same plane as the rear surface of the head body. FIG. 5A to FIG. 5C show an embodiment in which ribs 30 are provided on the inner surface 21. 5A is a front view of the golf club head, and FIGS. 5B and 5C are cross-sectional views taken along lines B-B and C-C of FIG. 5A. 10 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 In this embodiment, three ribs 30 extending in the vertical direction are provided. Each rib extends from the peripheral wall surface 23 on the upper edge side to the peripheral wall surface 22 on the bottom side. By providing such a rib 30, it is possible to improve the hitting feeling of the golf club head. Further, on the inner surface 21, a high specific gravity resin layer 15 and an F R P body 16 exist between the ribs 30 and 30. The ribs 30 are not covered with either the high specific gravity resin layer 15 or the F R P body 16. The other structures of the golf iron head of Figs. 5A to 5C are the same as those of the previous embodiment, and the same reference numerals denote the same portions. Fig. 6 is a sectional view of a golf iron head according to an embodiment in which a high specific gravity resin layer 15 is provided in the lower portion and the rear portion of the recess 20. This high specific gravity resin layer 15 is compounded from the rear part of the upper peripheral wall surface 23 to the lower part of the rear face of the F R P body 16. No high specific gravity resin layer is provided on the inner surface 21. This FRP body 16 is composed of two layers, an outer layer 16a and an inner layer 16b. The high specific gravity resin layer 15 is arranged in a state sandwiched between the outer layer 16 a and the inner layer 16 b, and is in a state of being buried in the F R P body 16. The other structures of this golf iron head are the same as those of the embodiment shown in Figs. 1 to 4, and the same reference numerals denote the same parts. With this golf iron head, since the center of gravity is deep and low, the ball becomes easy to go up while the ball is stable. The above-mentioned embodiment is an example of this creation, and this creation may also take a form other than the illustration. For example, in this creation, the weights 1 3 can also be omitted. Alternatively, an elastic body such as rubber, resin, or elastomer for absorbing vibration or an impact absorber may be attached to the inner surface of the FRP body 16. 5A to 5C with ribs, the aspect ratio 11 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 heavy resin layer 15 can also be set below the recess 20 rear. (Examples) (Examples 1 and 2) In the golf club head shown in Figs. 1 to 4, the radius of curvature of the intersection corner of the upper peripheral wall surface 23 and the inner surface 21 is set to 2 mm, and The radius of curvature of the corner of the intersection between the bottom-side peripheral wall surface 22 and the inner surface 21 is 50 or 70 mm. The FRP body 16 is formed by stacking two layers of a UD prepreg made of carbon fiber with an elastic modulus of 24 t / mm2 and a layer of prepreg made of the carbon fiber cloth. As a result, any golf club head has a good hitting feeling. (Examples 3 and 4) Golf club heads in which the high specific gravity resin layer 15 in Examples 1 and 2 were omitted and the other structures were the same were produced. These golf club heads also have a good hitting feel. (Embodiment 5) A golf club head provided with ribs 30 as shown in FIGS. 5A to 5C and having the same structure as in Embodiment 1 was manufactured. The width of the ribs in the protruding and heel directions is 2 mm, and the height from the inner surface 21 is 2 mm. This golf club head hits extremely well. (Example 6) As shown in FIG. 6, a golf club head with a high specific gravity resin layer disposed at the rear portion of the bottom side and having the same structure as in Example 1 was produced. The high specific gravity resin layer along the inner surface is omitted. This golf club head has a good hitting feeling and a stable flying distance. 12 312 / Invention Specification (Supplement) / 93-08 / 93208604 M260296 [Brief Description of Drawings] FIG. 1 is a front view of a golf iron head according to an embodiment. FIG. 2 is a cross-sectional view taken along the line I I _ I I in FIG. 1. FIG. 3 is a cross-sectional view taken along the line I I I-I I I in FIG. 1. Fig. 4 is a sectional view of a conventional golf iron head. 5A, 5B, and 5C are configuration diagrams showing another embodiment. Fig. 6 is a sectional view showing still another embodiment. (Description of component symbols) 1 Head body 2 Face 3 Bottom 4 Recess 5 Fiber-reinforced member 6 Backing member 8 Rising part 10 Head body 11 Face 12 Bottom 12a Pedestal portion 13 Counterweight 13a Threaded hole 14 Socket portion 15 High Specific gravity resin layer 1 6 FRP body 13 312 / Instruction manual (Supplement) / 93-08 / 93208604 M260296 16a Outer layer 16b Inner layer 2 0 Recess 2 2 Inner surface 2 2 Bottom side peripheral wall surface 23 Upper edge side peripheral wall surface 2 4 Protruding side Peripheral wall surface 2 5 Heel side peripheral wall surface 3 0 Ribs 14 3 丨 2 / Invention Manual (Supplement) / 93-08 / 93208604