JP2015034541A

JP2015034541A - Cast molding

Info

Publication number: JP2015034541A
Application number: JP2013167054A
Authority: JP
Inventors: 光裕岩佐; Mitsuhiro Iwasa; 健一首藤; Kenichi Shudo; 明桜井; Akira Sakurai; 浩信及川; Hironobu Oikawa; 賢一片平; Kenichi Katahira; 大高城; Dai Takagi
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2013-08-09
Filing date: 2013-08-09
Publication date: 2015-02-19
Anticipated expiration: 2033-08-09
Also published as: JP5770794B2

Abstract

PROBLEM TO BE SOLVED: To eliminate an anxiety that a casting defect is generated in the vicinity of a bulged part, in a cast molding whose hollow part is partitioned by a partitioning wall part, and in which the bulged part is protrusively formed at an upper end face of a sidewall part.SOLUTION: In a cylinder head 50 being a cast molding, there is formed a hollow part 64 which is formed of a first long sidewall part 54, a second long sidewall part 56, a first short sidewall part 58 and a second short sidewall part 60. The hollow part 64 is partitioned by a first short partitioning wall part 66a to a fourth short partitioning wall part 66d, and a long partitioning wall part 68. Furthermore, a first bulged part 84a to an eleventh bulged part 84k are protrusively formed at upper end faces of the first long sidewall part 54 and the second long sidewall part 56. In an intersection between the long sidewall part and the short partitioning wall part, or the short sidewall part, a first triangular columnar protrusion 88a to a sixth triangular columnar protrusion 88f are formed at places approximating the second bulged part 84b, the third bulged part 84c, the fifth bulged part 84e to the seventh bulged part 84g, and the tenth bulged part 84j.

Description

本発明は、鋳造成形品に関し、一層詳細には、中空内部が区画壁部で仕切られることによって複数個の内室が形成された鋳造成形品に関する。 The present invention relates to a cast molded product, and more particularly, to a cast molded product in which a plurality of inner chambers are formed by partitioning a hollow interior with a partition wall portion.

自動車に搭載される内燃機関は、シリンダブロックと、図５に示されるシリンダヘッド１０とを有する。これらはいずれも鋳造加工装置によって作製される鋳造成形品であり、例えば、アルミニウム合金の溶湯から得られる。 An internal combustion engine mounted on an automobile has a cylinder block and a cylinder head 10 shown in FIG. These are all cast products produced by a casting apparatus, and are obtained from, for example, a molten aluminum alloy.

この中のシリンダヘッド１０は、平面視で略長方形形状をなす中空体である。すなわち、シリンダヘッド１０は、底壁部１２と、該底壁部１２から略垂直に立ち上がった長側壁部１４ａ、１４ｂ及び短側壁部１６ａ、１６ｂとを有する。そして、長側壁部１４ａ、１４ｂ及び短側壁部１６ａ、１６ｂの内方には、これら長側壁部１４ａ、１４ｂ及び短側壁部１６ａ、１６ｂに囲繞されることによって中空内部１８が形成されている。 The cylinder head 10 is a hollow body having a substantially rectangular shape in plan view. That is, the cylinder head 10 includes a bottom wall portion 12, and long side wall portions 14 a and 14 b and short side wall portions 16 a and 16 b that rise substantially vertically from the bottom wall portion 12. A hollow interior 18 is formed inside the long side wall portions 14a and 14b and the short side wall portions 16a and 16b by being surrounded by the long side wall portions 14a and 14b and the short side wall portions 16a and 16b.

なお、底壁部１２の外面は、シリンダブロックに臨むガスケット面となる。ガスケット面には、図６に示すように、鋳造加工装置に形成された湯道等に残留した溶湯が固化した方案部１９が一体的に連なる。 Note that the outer surface of the bottom wall portion 12 is a gasket surface facing the cylinder block. As shown in FIG. 6, a design portion 19 in which the molten metal remaining in the runner formed in the casting apparatus is solidified is integrally connected to the gasket surface.

長側壁部１４ａ、１４ｂ同士の間には、短側壁部１６ａ、１６ｂの延在方向（矢印Ｘ方向）に平行な短区画壁部２０ａ〜２０ｄが複数個橋架される。さらに、短区画壁部２０ａ〜２０ｄ同士の間には、長側壁部１４ａ、１４ｂの延在方向（矢印Ｙ方向）に平行な長区画壁部２２が設けられる。 Between the long side wall portions 14a and 14b, a plurality of short partition wall portions 20a to 20d parallel to the extending direction of the short side wall portions 16a and 16b (arrow X direction) are bridged. Furthermore, between the short partition wall parts 20a-20d, the long partition wall part 22 parallel to the extending direction (arrow Y direction) of the long side wall parts 14a and 14b is provided.

近年における自動車構成部品の軽量化への要請から、長側壁部１４ａ、１４ｂの厚みは可及的に小さく設定される。そこで、長側壁部１４ａ、１４ｂの外面には、長側壁部１４ａ、１４ｂの剛性を向上させるための複数個のリブ２４が設けられる。特許文献１に示されるように、リブ２４は、中空内部１８の深さ方向、すなわち、図６における上下方向（矢印Ｚ方向）に沿って延在する。場合によっては、ポート２６に近接する側が逆Ｖ字状となるように分岐することもある。 Due to the recent demand for weight reduction of automobile components, the thickness of the long side wall portions 14a and 14b is set as small as possible. Therefore, a plurality of ribs 24 for improving the rigidity of the long side wall portions 14a and 14b are provided on the outer surfaces of the long side wall portions 14a and 14b. As shown in Patent Document 1, the rib 24 extends along the depth direction of the hollow interior 18, that is, the vertical direction (arrow Z direction) in FIG. In some cases, the side close to the port 26 may be branched so as to have an inverted V shape.

長側壁部１４ａ、１４ｂの上端面には、中空内部１８を閉塞するヘッドケースを締め付ける締め付けボルト用のボルト受部２８が矢印Ｘ方向に沿って突出形成される。前記複数個のリブ２４の各々は、ボルト受部２８の各々に連なる。 On the upper end surfaces of the long side wall portions 14a and 14b, bolt receiving portions 28 for fastening bolts for tightening the head case closing the hollow interior 18 are formed protruding along the arrow X direction. Each of the plurality of ribs 24 is connected to each of the bolt receiving portions 28.

特開２０１３−５２４１５号公報JP2013-52415A

上記したシリンダヘッド１０は、低圧鋳造によって作製される。この低圧鋳造において、湯口近傍の溶湯が先に凝固してしまうと、溶湯をキャビティに導入することが困難となる。このことから諒解されるように、湯口からの押し湯効果を維持するには、キャビティに充填された溶湯を、湯口から最も離間した部分から湯口に向かって凝固させる（いわゆる指向性凝固）ことが望ましい。 The cylinder head 10 described above is manufactured by low pressure casting. In this low pressure casting, if the molten metal near the gate is first solidified, it becomes difficult to introduce the molten metal into the cavity. As can be understood from this, in order to maintain the effect of the hot water from the gate, the molten metal filled in the cavity is solidified from the portion farthest from the gate toward the gate (so-called directional solidification). desirable.

ここで、長側壁部１４ａ、１４ｂにおいて、上記したボルト受部２８が設けられた部位は、ボルト受部２８の突出量分だけ、ボルト受部２８が設けられていない部位に比して肉厚である。このため、ボルト受部２８の突出量が特に大きい場合、他の部位に比して凝固速度が小さくなる、いわゆる凝固遅れが生じる懸念がある。 Here, in the long side wall portions 14a and 14b, the portion where the bolt receiving portion 28 is provided is thicker than the portion where the bolt receiving portion 28 is not provided by the protrusion amount of the bolt receiving portion 28. It is. For this reason, when the protrusion amount of the bolt receiving portion 28 is particularly large, there is a concern that a so-called solidification delay may occur, in which the solidification rate becomes smaller than that of other portions.

一般に、液相（溶湯）から固相（鋳造成形品）への相変化が起こるときには、体積収縮を伴う。従って、凝固遅れが生じた部位は、引け巣等の鋳造欠陥の一因となる。 Generally, when a phase change from a liquid phase (molten metal) to a solid phase (cast product) occurs, volume shrinkage is accompanied. Therefore, the site where the solidification delay occurs contributes to casting defects such as shrinkage cavities.

以上のように、内室が形成されるとともに、ボルト受部２８等の外方に向かって突出した膨出部を有する鋳造成形品を作製するに際しては、前記膨出部に鋳造欠陥が発生し易いという不具合が指摘されている。 As described above, when producing a cast product having an inner chamber and a bulging portion protruding outward such as the bolt receiving portion 28, a casting defect occurs in the bulging portion. It has been pointed out that it is easy.

本発明は上記した問題を解決するためになされたもので、膨出部が設けられて肉厚となった部位での凝固遅れが回避され、このために該部位で鋳造欠陥が発生する懸念が払拭された鋳造成形品を提供することを目的とする。 The present invention has been made in order to solve the above-described problems, and avoids a solidification delay in a portion where the bulging portion is provided and becomes thick, and there is a concern that a casting defect may occur in the portion. An object is to provide a cast product that has been wiped away.

前記の目的を達成するために、本発明は、底壁部と、前記底壁部から立ち上がった側壁部とを有し、前記側壁部に囲繞されることで中空内部が形成された鋳造成形品であって、
前記側壁部の対向部位同士に橋架され、前記中空内部を複数個の内室に区分する区画壁部と、
前記側壁部の上端面に、前記中空内部の深さ方向に対して直交する方向に突出形成された複数個の膨出部と、
前記側壁部の外面に突出形成され、且つ該中空内部の深さ方向に沿って延在して前記複数個の膨出部の各々に連なる複数個のリブと、
を備え、
前記膨出部の中の少なくとも１個は、前記区画壁部の橋架方向に対して平行に突出し、且つ前記区画壁部から離間した位置に配設され、
前記側壁部と前記区画壁部との複数個の交差部の中、少なくとも、前記区画壁部から離間した位置に配設された前記膨出部に近接する交差部に、前記側壁部と前記区画壁部に橋架された部位を一辺とし、且つ前記中空内部の深さ方向に沿って延在する平面視で三角形状の三角柱状突部が設けられていることを特徴とする。 In order to achieve the above object, the present invention provides a cast molded article having a bottom wall portion and a side wall portion rising from the bottom wall portion, and having a hollow interior formed by being surrounded by the side wall portion. Because
A partition wall portion that is bridged between opposing portions of the side wall portion and divides the hollow interior into a plurality of inner chambers;
A plurality of bulging portions formed on the upper end surface of the side wall portion so as to protrude in a direction perpendicular to the depth direction of the hollow interior;
A plurality of ribs formed on the outer surface of the side wall portion and extending along the depth direction of the hollow interior and continuing to each of the plurality of bulging portions;
With
At least one of the bulges protrudes in parallel to the bridge direction of the partition wall and is disposed at a position spaced from the partition wall,
Among the plurality of intersecting portions of the side wall portion and the partition wall portion, at least at the intersecting portion adjacent to the bulging portion disposed at a position separated from the partition wall portion, the side wall portion and the partition A portion bridged by the wall portion is provided as one side, and a triangular prism-shaped protrusion portion having a triangular shape in a plan view extending along the depth direction of the hollow interior is provided.

このような構成においては、鋳造成形品を鋳造加工にて作製する際、膨出部と区画壁部ないし側壁部との間で三角柱状突部を介して熱が伝達される。従って、湯口からの距離が大きな膨出部の温度は、指向性凝固により区画壁部ないし側壁部の温度よりも低くなる。 In such a configuration, when a cast product is produced by casting, heat is transmitted between the bulging portion and the partition wall portion or the side wall portion via the triangular columnar projection. Therefore, the temperature of the bulging portion having a large distance from the gate becomes lower than the temperature of the partition wall portion or the side wall portion due to directional solidification.

その結果として、膨出部に、周囲の温度よりも高温の箇所、すなわち、いわゆる熱溜まりが発生することを抑制することができる。結局、膨出部に凝固遅れが生じることが回避され、これにより、膨出部の近傍に引け巣等の鋳造欠陥が発生することを防止することができる。 As a result, it is possible to suppress the occurrence of a portion having a temperature higher than the ambient temperature, that is, a so-called heat pool, in the bulging portion. Eventually, the occurrence of a solidification delay in the bulging portion is avoided, thereby preventing the occurrence of casting defects such as shrinkage cavities in the vicinity of the bulging portion.

前記側壁部と前記区画壁部とが直交する鋳造成形品では、前記三角柱状突部は、前記側壁部と前記区画壁部に橋架された部位によって形成される一辺を斜辺、前記側壁部の内面の一部を底辺とする直角三角形をなす。この場合、前記斜辺と前記底辺との交差角度は２０°〜３０°の範囲内であることが好ましい。２０°未満では、鋳造加工時、キャビティの三角柱状突部を形成する部分に溶湯が回り込むことが容易でなくなる。また、３０°を超えると、内室に収容する機構が、三角柱状突部に干渉し易くなる。 In the cast molded product in which the side wall portion and the partition wall portion are orthogonal to each other, the triangular prism-shaped protrusion has a hypotenuse on one side formed by the portion bridged by the side wall portion and the partition wall portion, and the inner surface of the side wall portion It forms a right triangle with a part of. In this case, the crossing angle between the oblique side and the bottom side is preferably within a range of 20 ° to 30 °. If it is less than 20 °, it is not easy for the molten metal to enter the portion of the cavity where the triangular columnar protrusion is formed during casting. If the angle exceeds 30 °, the mechanism accommodated in the inner chamber easily interferes with the triangular prism-shaped protrusion.

また、前記膨出部が平面視で円弧状に湾曲した形状をなすときには、前記三角柱状突部の、前記側壁部と前記区画壁部に橋架された部位は、前記膨出部の仮想内接円の直径と、前記側壁部の内面側とが直交する箇所を起点として前記区画壁部に向かうことが好ましい。これにより、鋳造成形品に求められる機能と品質を両立させることが容易となる。 Further, when the bulging portion has a shape curved in an arc shape in a plan view, a portion of the triangular columnar projection bridged by the side wall portion and the partition wall portion is a virtual inscribed portion of the bulging portion. It is preferable that the circle diameter and the inner surface side of the side wall portion are directed to the partition wall portion from a starting point. Thereby, it becomes easy to achieve both the function and quality required for a cast product.

さらに、前記膨出部に連なる前記複数個のリブの中の少なくとも１つが、前記膨出部から離間するに従って拡開することが好ましい。例えば、前記底壁部が湯口に近接する側であると、鋳造加工時、リブの拡開した端部には溶湯が近接することになる。このため、膨出部側が低温、リブの拡開した端部が高温となるような熱勾配が生じる。従って、膨出部が先に凝固し始める指向性凝固が生じ易くなる。 Furthermore, it is preferable that at least one of the plurality of ribs connected to the bulging portion expands as the distance from the bulging portion increases. For example, when the bottom wall portion is on the side close to the pouring gate, the molten metal comes close to the end portion where the rib is expanded during casting. For this reason, a thermal gradient is generated such that the bulging portion side is at a low temperature and the end portion where the rib is expanded is at a high temperature. Therefore, directional solidification tends to occur in which the bulging portion starts to solidify first.

内室の寸法や形状によっては、三角柱状突部を設けると、該内室に収容する機器が三角柱状突部に干渉することがある。このような内室には三角柱状突部を設けず、該内室の外面に形成するリブを上記した形状とすればよい。換言すれば、前記膨出部から離間するに従って拡開するように延在するリブは、三角柱状突部が設けられていない内室の近傍に配設された膨出部に連設すればよい。これにより、三角柱状突部が存在しない内室の近傍に設けられた膨出であっても、上記の通り、指向性凝固が生じ易くなる。 Depending on the dimensions and shape of the inner chamber, when a triangular prism-shaped protrusion is provided, the device accommodated in the inner chamber may interfere with the triangular prism-shaped protrusion. Such an inner chamber is not provided with a triangular prism-shaped protrusion, and the rib formed on the outer surface of the inner chamber may have the shape described above. In other words, the rib extending so as to expand as it is separated from the bulging portion may be provided continuously with the bulging portion disposed in the vicinity of the inner chamber where the triangular columnar protrusion is not provided. . Thereby, even if it is the bulging provided in the vicinity of the inner chamber where there is no triangular columnar protrusion, directional solidification is likely to occur as described above.

底壁部側に湯口を設けた場合、方案部は、底壁部から突出するように形成される。すなわち、この場合、溶湯は、キャビティの前記リブを形成する部分に溶湯が導入された後、前記膨出部を形成する部分に導入される。このような鋳造成形品であっても、リブよりも先に膨出部で凝固が生じる指向性凝固を確保することができる。 When the gate is provided on the bottom wall side, the design part is formed so as to protrude from the bottom wall part. That is, in this case, the molten metal is introduced into the portion of the cavity where the rib is formed and then introduced into the portion of the cavity where the bulging portion is formed. Even in such a cast product, directional solidification in which solidification occurs at the bulging portion prior to the rib can be ensured.

以上において、鋳造成形品の好適な具体例としては、シリンダヘッドが挙げられる。 In the above, a cylinder head is mentioned as a suitable specific example of the cast product.

本発明によれば、中空内部が区画壁部によって仕切られ、且つ側壁部の上端面に膨出部が突出形成される鋳造成形品において、区画壁部と側壁部の交差部の少なくとも１つに、これら区画壁部と側壁部に橋架された三角柱状突部を設けるようにしている。この三角柱状突部を介して、膨出部と区画壁部、ないし側壁部との間で熱伝達が起こるので、湯口から最も大きく離間した膨出部の温度が、区画壁部ないし側壁部の温度よりも低くなる。 According to the present invention, in a cast molded product in which the hollow interior is partitioned by the partition wall portion and the bulging portion protrudes from the upper end surface of the side wall portion, at least one of the intersecting portions of the partition wall portion and the side wall portion The triangular columnar projections bridged between the partition wall and the side wall are provided. Since heat transfer occurs between the bulging portion and the partition wall portion or the side wall portion through the triangular columnar protrusion, the temperature of the bulging portion that is the largest away from the gate is the temperature of the partition wall portion or the side wall portion. It becomes lower than the temperature.

その結果、膨出部に熱溜まりが発生することを抑制することができる。従って、該膨出部において凝固遅れが発生することが回避される。このため、該膨出部の近傍で鋳造欠陥が発生する懸念を払拭することができる。 As a result, it is possible to suppress the occurrence of heat accumulation in the bulging portion. Therefore, the occurrence of a solidification delay in the bulging portion is avoided. For this reason, the concern that a casting defect occurs in the vicinity of the bulging portion can be eliminated.

本発明の実施の形態に係る鋳造成形品であるシリンダヘッドの全体概略平面図である。1 is an overall schematic plan view of a cylinder head that is a cast product according to an embodiment of the present invention. 図１中のＡ方向矢視側面図である。It is an A direction arrow side view in FIG. 図１中のＢ方向矢視側面図である。It is a B direction arrow side view in FIG. 三角柱状突部の１つである第３三角柱状突部の近傍を拡大した要部拡大平面図である。It is the principal part enlarged plan view which expanded the vicinity of the 3rd triangular prism-shaped protrusion which is one of the triangular prism-shaped protrusions. 従来技術に係るシリンダヘッド（鋳造成形品）の全体概略平面図である。It is the whole general | schematic top view of the cylinder head (casting molded article) which concerns on a prior art. 図５中のＡ方向矢視側面図である。It is an A direction arrow side view in FIG.

以下、本発明に係る鋳造成形品につき好適な実施の形態を挙げ、添付の図面を参照して詳細に説明する。なお、以下の図面におけるＡ方向、Ｘ方向、Ｙ方向及びＺ方向は、図５及び図６中のＡ方向、Ｘ方向、Ｙ方向及びＺ方向に対応する。 DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a cast product according to the present invention will be given and described in detail with reference to the accompanying drawings. In the following drawings, the A direction, the X direction, the Y direction, and the Z direction correspond to the A direction, the X direction, the Y direction, and the Z direction in FIGS. 5 and 6.

図１〜図３は、それぞれ、本実施の形態に係る鋳造成形品としてのシリンダヘッド５０の全体概略平面図、図１中のＡ方向矢視側面図、Ｂ方向矢視側面図である。このシリンダヘッド５０は、底壁部５２と、該底壁部５２から略垂直に立ち上がった第１長側壁部５４、第２長側壁部５６、第１短側壁部５８及び第２短側壁部６０とを有する。シリンダヘッド５０は単一部材であり、従って、底壁部５２と４個の側壁部５４、５６、５８、６０同士が一体的に連なるとともに、側壁部５４、５６、５８、６０の中の互いに交差するもの同士が一体的に連なっていることは勿論である。 1 to 3 are an overall schematic plan view of a cylinder head 50 as a cast product according to the present embodiment, a side view as viewed from the direction A in FIG. 1, and a side view as viewed from the direction B. The cylinder head 50 includes a bottom wall portion 52, a first long side wall portion 54, a second long side wall portion 56, a first short side wall portion 58, and a second short side wall portion 60 that rise substantially vertically from the bottom wall portion 52. And have. The cylinder head 50 is a single member. Therefore, the bottom wall portion 52 and the four side wall portions 54, 56, 58, 60 are integrally connected to each other, and the side walls 54, 56, 58, 60 are mutually connected. Of course, the intersecting objects are connected together.

底壁部５２は、互いに平行な２個の長辺と、該長辺に略直交し且つ互いに平行な２個の短辺とを有する略長方形形状をなす。この底壁部５２の外面は、シリンダブロックに臨むガスケット面となる。 The bottom wall portion 52 has a substantially rectangular shape having two long sides parallel to each other and two short sides substantially orthogonal to the long sides and parallel to each other. The outer surface of the bottom wall portion 52 is a gasket surface facing the cylinder block.

このシリンダヘッド５０は、低圧鋳造によって作製される。この際、溶湯は、キャビティの下方に位置して底壁部５２を形成する部分から導入される。従って、鋳造された直後の底壁部５２には、湯道等に残留した溶湯が固化することで形成された方案部６２（図２及び図３参照）が一体的に連なっている。 The cylinder head 50 is manufactured by low pressure casting. At this time, the molten metal is introduced from a portion located below the cavity and forming the bottom wall portion 52. Therefore, a plan portion 62 (see FIGS. 2 and 3) formed by solidification of the molten metal remaining in the runner or the like is integrally connected to the bottom wall portion 52 immediately after casting.

第１長側壁部５４及び第２長側壁部５６は前記２個の長辺の各々から立ち上がり、一方、第１短側壁部５８及び第２短側壁部６０は前記２個の短辺の各々から立ち上がっている。従って、図１に示すように、第１長側壁部５４と第２長側壁部５６が互いに平行して対向するとともに、第１短側壁部５８と第２短側壁部６０も互いに平行して対向する。 The first long side wall part 54 and the second long side wall part 56 rise from each of the two long sides, while the first short side wall part 58 and the second short side wall part 60 start from each of the two short sides. Standing up. Accordingly, as shown in FIG. 1, the first long side wall portion 54 and the second long side wall portion 56 face each other in parallel, and the first short side wall portion 58 and the second short side wall portion 60 face each other in parallel. To do.

第１長側壁部５４及び第２長側壁部５６は、第１短側壁部５８及び第２短側壁部６０の各々に対して略直交し、このため、シリンダヘッド５０は、平面視で略長方形形状をなす中空体である。すなわち、第１長側壁部５４、第２長側壁部５６、第１短側壁部５８及び第２短側壁部６０の内方には、これら４個の側壁部５４、５６、５８、６０に囲繞されることによって中空内部６４が形成されている。なお、シリンダヘッド５０の開放端である上端は、図示しないヘッドケースによって閉塞される。 The first long side wall part 54 and the second long side wall part 56 are substantially orthogonal to each of the first short side wall part 58 and the second short side wall part 60. Therefore, the cylinder head 50 is substantially rectangular in plan view. It is a hollow body having a shape. That is, the first long side wall portion 54, the second long side wall portion 56, the first short side wall portion 58, and the second short side wall portion 60 are surrounded by the four side wall portions 54, 56, 58, 60. As a result, a hollow interior 64 is formed. The upper end, which is the open end of the cylinder head 50, is closed by a head case (not shown).

第１長側壁部５４と第２長側壁部５６の間には、第１短側壁部５８及び第２短側壁部６０の延在方向（矢印Ｘ方向）に略平行な複数個の短区画壁部、すなわち、第１短区画壁部６６ａ、第２短区画壁部６６ｂ、第３短区画壁部６６ｃ及び第４短区画壁部６６ｄが橋架される。さらに、第１短区画壁部６６ａ〜第４短区画壁部６６ｄの長さ方向略中腹部には、長側壁部５４、５６の延在方向（矢印Ｙ方向）に平行な長区画壁部６８が一体的に連なる。これらの区画壁部６６ａ〜６６ｄ、６８により、中空内部６４に第１内室７０ａ〜第７内室７０ｇが形成される。第１内室７０ａ〜第７内室７０ｇの各々は、燃焼室に連通する吸気ポート７２（図２参照）、排気ポート７４（図３参照）を開閉するためのカムが設けられるカム室である。 Between the 1st long side wall part 54 and the 2nd long side wall part 56, the some short partition wall substantially parallel to the extension direction (arrow X direction) of the 1st short side wall part 58 and the 2nd short side wall part 60 That is, the first short partition wall portion 66a, the second short partition wall portion 66b, the third short partition wall portion 66c, and the fourth short partition wall portion 66d are bridged. Furthermore, a long partition wall portion 68 parallel to the extending direction of the long side wall portions 54 and 56 (in the direction of the arrow Y) is provided at the substantially middle portion in the length direction of the first short partition wall portion 66a to the fourth short partition wall portion 66d. Are linked together. By these partition wall portions 66a to 66d and 68, a first inner chamber 70a to a seventh inner chamber 70g are formed in the hollow interior 64. Each of the first inner chamber 70a to the seventh inner chamber 70g is a cam chamber in which a cam for opening and closing an intake port 72 (see FIG. 2) and an exhaust port 74 (see FIG. 3) communicating with the combustion chamber is provided. .

なお、図１中の下方（第１長側壁部５４側）が吸気側、上方（第２長側壁部５６側）が排気側である。そして、第１短区画壁部６６ａ〜第４短区画壁部６６ｄには、それぞれ、吸気側カムシャフトを支持するための第１ジャーナル部７６、排気側カムシャフトを支持するための第２ジャーナル部７８が形成される。 In FIG. 1, the lower side (first long side wall portion 54 side) is the intake side, and the upper side (second long side wall portion 56 side) is the exhaust side. The first short partition wall portion 66a to the fourth short partition wall portion 66d have a first journal portion 76 for supporting the intake side camshaft and a second journal portion for supporting the exhaust side camshaft, respectively. 78 is formed.

第１ジャーナル部７６、第２ジャーナル部７８は、第２短側壁部６０にも形成される。その一方で、第１短側壁部５８には、矢印Ｚ方向寸法（図２及び図３参照）が小さな段部８０が陥没形成される。 The first journal portion 76 and the second journal portion 78 are also formed on the second short side wall portion 60. On the other hand, a step 80 having a small dimension in the arrow Z direction (see FIGS. 2 and 3) is formed in the first short side wall portion 58 in a recessed manner.

中空内部６４において、吸気側の底部（第１内室７０ａ〜第３内室７０ｃの底部と第４内室７０ｄの吸気側の底部）は、排気側の底部（第４内室７０ｄの排気側の底部と第５内室７０ｅ〜第７内室７０ｇの底部）よりも深い位置に設定されている。このため、第１長側壁部５４の内面側の深さは、第２長側壁部５６の内面側の深さよりも大きくなっている。 In the hollow interior 64, the bottom portions on the intake side (the bottom portions of the first inner chamber 70a to the third inner chamber 70c and the bottom portion on the intake side of the fourth inner chamber 70d) are the bottom portions on the exhaust side (the exhaust side of the fourth inner chamber 70d). And the bottom of the fifth inner chamber 70e to the seventh inner chamber 70g). For this reason, the depth on the inner surface side of the first long side wall portion 54 is larger than the depth on the inner surface side of the second long side wall portion 56.

第１長側壁部５４の外面下方では吸気ポート７２が開口し（図２参照）、第２長側壁部５６の外面下方では排気ポート７４が開口する（図３参照）。また、第１長側壁部５４及び第２長側壁部５６の外面には、該長側壁部５４、５６の剛性を向上させるための複数個のリブが長側壁部５４、５６と一体的に設けられる。 The intake port 72 opens below the outer surface of the first long side wall portion 54 (see FIG. 2), and the exhaust port 74 opens below the outer surface of the second long side wall portion 56 (see FIG. 3). Further, a plurality of ribs for improving the rigidity of the long side wall portions 54, 56 are provided integrally with the long side wall portions 54, 56 on the outer surfaces of the first long side wall portion 54 and the second long side wall portion 56. It is done.

すなわち、先ず、第１長側壁部５４の外面からは、第１リブ８２ａ、第２リブ８２ｂ、第３リブ８２ｃ、第４リブ８２ｄ、第５リブ８２ｅ及び第６リブ８２ｆが突出している。これら第１リブ８２ａ〜第６リブ８２ｆは、吸気ポート７２の上方を起点とし、中空内部６４（ないし第１内室７０ａ〜第７内室７０ｇ）の深さ方向である矢印Ｚ方向に沿って延在する。 That is, first, the first rib 82a, the second rib 82b, the third rib 82c, the fourth rib 82d, the fifth rib 82e, and the sixth rib 82f protrude from the outer surface of the first long side wall portion 54. The first rib 82a to the sixth rib 82f start from above the intake port 72 and extend along the arrow Z direction that is the depth direction of the hollow interior 64 (or the first inner chamber 70a to the seventh inner chamber 70g). Extend.

この中、第１リブ８２ａ、第２リブ８２ｂ、第３リブ８２ｃ及び第５リブ８２ｅは略半円柱体形状をなす。また、第４リブ８２ｄは、図２中の上方から下方に向かうに従って拡開しており、このため、三角形ないし台形に近似される形状である。さらに、第６リブ８２ｆは、略Ｋ字状をなす。 Among these, the 1st rib 82a, the 2nd rib 82b, the 3rd rib 82c, and the 5th rib 82e make a substantially semi-cylindrical body shape. Further, the fourth rib 82d expands from the upper side to the lower side in FIG. 2, and thus has a shape that approximates a triangle or a trapezoid. Further, the sixth rib 82f is substantially K-shaped.

図１及び図２を参照して諒解されるように、第１長側壁部５４の上端面には、複数個の膨出部、すなわち、第１膨出部８４ａ、第２膨出部８４ｂ、第３膨出部８４ｃ、第４膨出部８４ｄ、第５膨出部８４ｅ及び第６膨出部８４ｆが突出形成される。これら第１膨出部８４ａ〜第６膨出部８４ｆは、中空内部６４（ないし第１内室７０ａ〜第７内室７０ｇ）の深さ方向である矢印Ｚ方向に対して直交する方向（矢印Ｘ方向）、換言すれば、第１短区画壁部６６ａ〜第４短区画壁部６６ｄの橋架方向に対して平行に延在する。なお、第１膨出部８４ａ〜第６膨出部８４ｆは、ほとんどが、前記ヘッドケースを締め付ける締め付けボルト用のボルト受部として機能する。 As will be understood with reference to FIGS. 1 and 2, the upper end surface of the first long side wall portion 54 has a plurality of bulging portions, that is, a first bulging portion 84 a, a second bulging portion 84 b, A third bulging portion 84c, a fourth bulging portion 84d, a fifth bulging portion 84e, and a sixth bulging portion 84f are formed to protrude. The first bulging portion 84a to the sixth bulging portion 84f are orthogonal to the arrow Z direction that is the depth direction of the hollow interior 64 (or the first inner chamber 70a to the seventh inner chamber 70g). X direction), in other words, extends in parallel to the bridge direction of the first short partition wall portion 66a to the fourth short partition wall portion 66d. Note that most of the first bulging portion 84a to the sixth bulging portion 84f function as bolt receiving portions for fastening bolts that fasten the head case.

第１膨出部８４ａ〜第６膨出部８４ｆは、第１短区画壁部６６ａ〜第４短区画壁部６６ｄの延在方向（矢印Ｘ方向）の軸線上には位置していない。すなわち、第１膨出部８４ａ〜第６膨出部８４ｆは、第１短区画壁部６６ａ〜第４短区画壁部６６ｄから離間した位置に配設されている。特に、第４膨出部８４ｄは、第１長側壁部５４の、第２内室７０ｂの一辺をなす部位の延在方向（矢印Ｙ方向）の略中腹に位置する。 The first bulge portion 84a to the sixth bulge portion 84f are not located on the axis line in the extending direction (arrow X direction) of the first short partition wall portion 66a to the fourth short partition wall portion 66d. That is, the first bulging portion 84a to the sixth bulging portion 84f are disposed at positions separated from the first short partition wall portion 66a to the fourth short partition wall portion 66d. In particular, the fourth bulging portion 84d is located approximately in the middle of the extending direction (arrow Y direction) of the portion that forms one side of the second inner chamber 70b of the first long side wall portion 54.

さらに、第３膨出部８４ｃ〜第５膨出部８４ｅは、図２に示すように、平面視で円弧状に湾曲した形状をなし、略半円形状に近似し得る。 Further, as shown in FIG. 2, the third bulging portion 84 c to the fifth bulging portion 84 e have a shape curved in an arc shape in a plan view, and can approximate a substantially semicircular shape.

前記第１リブ８２ａは、第１膨出部８４ａに一体的に連なる。同様に、第２リブ８２ｂ〜第６リブ８２ｆの各々は、第２膨出部８４ｂ〜第６膨出部８４ｆに一体的に連なる。第１リブ８２ａ〜第６リブ８２ｆの突出量は、第１膨出部８４ａ〜第６膨出部８４ｆに比して小さく設定される。 The first rib 82a is integrally connected to the first bulging portion 84a. Similarly, each of the second rib 82b to the sixth rib 82f is integrally connected to the second bulge portion 84b to the sixth bulge portion 84f. The protruding amount of the first rib 82a to the sixth rib 82f is set to be smaller than that of the first bulge portion 84a to the sixth bulge portion 84f.

次に、第２長側壁部５６の外面からは、図３に示すように、第７リブ８２ｇ、第８リブ８２ｈ、第９リブ８２ｉ及び第１０リブ８２ｊが突出している。これら第７リブ８２ｇ〜第１０リブ８２ｊは、略半円柱体形状をなし、排気ポート７４の上方を起点として、中空内部６４（ないし第１内室７０ａ〜第７内室７０ｇの深さ方向）である矢印Ｚ方向に沿って延在する。 Next, as shown in FIG. 3, the seventh rib 82g, the eighth rib 82h, the ninth rib 82i, and the tenth rib 82j protrude from the outer surface of the second long side wall portion 56. The seventh rib 82g to the tenth rib 82j have a substantially semi-cylindrical shape, and the hollow interior 64 (or the depth direction of the first inner chamber 70a to the seventh inner chamber 70g) starts from above the exhaust port 74. It extends along the arrow Z direction.

図１及び図３を参照して諒解されるように、第２長側壁部５６の上端面には、中空内部６４（ないし第１内室７０ａ〜第７内室７０ｇ）の深さ方向である矢印Ｚ方向に対して直交する方向（矢印Ｘ方向）に、第７膨出部８４ｇ、第８膨出部８４ｈ、第９膨出部８４ｉ、第１０膨出部８４ｊ及び第１１膨出部８４ｋが突出形成される。これら第７膨出部８４ｇ〜第１１膨出部８４ｋもまた、ほとんどが、前記ヘッドケースを締め付ける締め付けボルト用のボルト受部となる。 As will be understood with reference to FIGS. 1 and 3, the upper end surface of the second long side wall portion 56 is in the depth direction of the hollow interior 64 (or the first inner chamber 70 a to the seventh inner chamber 70 g). In a direction orthogonal to the arrow Z direction (arrow X direction), the seventh bulge portion 84g, the eighth bulge portion 84h, the ninth bulge portion 84i, the tenth bulge portion 84j, and the eleventh bulge portion 84k. Projectingly formed. Most of the seventh bulge portion 84g to the eleventh bulge portion 84k also serve as bolt receiving portions for fastening bolts for tightening the head case.

第９膨出部８４ｉには、第６内室７０ｆ側に半楕円形状に膨出し、且つ第６内室７０ｆの深さ方向（矢印Ｚ方向）に沿って延在する半楕円状柱部８６が一体的に連なる。 The ninth bulging portion 84i swells in a semi-elliptical shape toward the sixth inner chamber 70f, and extends in the depth direction (arrow Z direction) of the sixth inner chamber 70f. Are linked together.

第７膨出部８４ｇ〜第１０膨出部８４ｊは、第１短区画壁部６６ａ〜第４短区画壁部６６ｄの延在方向（矢印Ｘ方向）の軸線上には位置しておらず、結局、第１短区画壁部６６ａ〜第４短区画壁部６６ｄから離間した位置に配設されている。一方、第１１膨出部８４ｋは、第４短区画壁部６６ｄの延在方向の軸線上に配置されている。 The seventh bulge portion 84g to the tenth bulge portion 84j are not located on the axis line in the extending direction (arrow X direction) of the first short partition wall portion 66a to the fourth short partition wall portion 66d, After all, it is disposed at a position separated from the first short partition wall portion 66a to the fourth short partition wall portion 66d. On the other hand, the 11th bulging part 84k is arrange | positioned on the axis line of the extension direction of the 4th short division wall part 66d.

前記第７リブ８２ｇは、第７膨出部８４ｇに一体的に連なる。同様に、第８リブ８２ｈ、第９リブ８２ｉ及び第１０リブ８２ｊは、それぞれ、第８膨出部８４ｈ、第９膨出部８４ｉ、第１１膨出部８４ｋに一体的に連なる。第７リブ８２ｇ〜第１０リブ８２ｊの突出量は、第７膨出部８４ｇ〜第９膨出部８４ｉ、第１１膨出部８４ｋに比して小さく設定される。 The seventh rib 82g is integrally connected to the seventh bulging portion 84g. Similarly, the eighth rib 82h, the ninth rib 82i, and the tenth rib 82j are integrally connected to the eighth bulging portion 84h, the ninth bulging portion 84i, and the eleventh bulging portion 84k, respectively. The amount of protrusion of the seventh rib 82g to the tenth rib 82j is set smaller than that of the seventh bulge portion 84g to the ninth bulge portion 84i and the eleventh bulge portion 84k.

図１に示すように、第１内室７０ａにおいて、第１長側壁部５４と第１短区画部の交差部、及び第１長側壁部５４と第２短区画壁部６６ｂの交差部には、第１三角柱状突部８８ａ、第２三角柱状突部８８ｂがそれぞれ設けられる。第１三角柱状突部８８ａは、平面視で、第１長側壁部５４の内面の一部を底辺、第１長側壁部５４と第１短区画壁部６６ａに橋架された部位を斜辺とし、第１短区画壁部６６ａの内面の一部を残余の一辺（高さ方向の辺）とする直角三角形をなす。 As shown in FIG. 1, in the first inner chamber 70a, the intersection between the first long side wall portion 54 and the first short partition portion, and the intersection portion between the first long side wall portion 54 and the second short partition wall portion 66b are provided. The first triangular prismatic protrusion 88a and the second triangular prismatic protrusion 88b are provided. The first triangular prism-shaped protrusion 88a has, in plan view, a part of the inner surface of the first long side wall part 54 as a bottom side, and a part bridged by the first long side wall part 54 and the first short partition wall part 66a as a hypotenuse, It forms a right triangle with a part of the inner surface of the first short partition wall portion 66a as the remaining one side (side in the height direction).

同様に、第２三角柱状突部８８ｂは、平面視で、第１長側壁部５４の内面の一部を底辺、第１長側壁部５４と第２短区画壁部６６ｂに橋架された部位を斜辺とし、第２短区画壁部６６ｂの内面の一部を残余の一辺（高さ方向の辺）とする直角三角形である。そして、第１三角柱状突部８８ａは第２膨出部８４ｂに近接し、第２三角柱状突部８８ｂは第３膨出部８４ｃに近接する。 Similarly, in the plan view, the second triangular columnar projection 88b has a part of the inner surface of the first long side wall portion 54 as a base and a portion bridged by the first long side wall portion 54 and the second short partition wall portion 66b. It is a right triangle with a hypotenuse and a part of the inner surface of the second short partition wall 66b as one remaining side (side in the height direction). The first triangular prismatic protrusion 88a is close to the second bulging portion 84b, and the second triangular prismatic protrusion 88b is close to the third bulging portion 84c.

また、第３内室７０ｃでは、第１長側壁部５４と第３短区画壁部６６ｃの交差部に第３三角柱状突部８８ｃが設けられている。すなわち、第３三角柱状突部８８ｃは、第５膨出部８４ｅに近接する側の交差部に配設されている。この第３三角柱状突部８８ｃは、平面視で、第１長側壁部５４の内面の一部を底辺、第１長側壁部５４と第３短区画壁部６６ｃに橋架された部位を斜辺、第３短区画壁部６６ｃの内面の一部を高さ方向の辺とする直角三角形である。 In the third inner chamber 70c, a third triangular prism-shaped protrusion 88c is provided at the intersection of the first long side wall 54 and the third short partition wall 66c. That is, the third triangular prism-shaped protrusion 88c is disposed at the intersection on the side close to the fifth bulging portion 84e. In the plan view, the third triangular prism-shaped protrusion 88c has a part of the inner surface of the first long side wall portion 54 as a bottom side, and a portion bridged by the first long side wall portion 54 and the third short partition wall portion 66c as a hypotenuse, It is a right triangle whose side in the height direction is a part of the inner surface of the third short partition wall 66c.

さらに、第４内室７０ｄでは、第１長側壁部５４と第２短側壁部６０の交差部、すなわち、第６膨出部８４ｆに近接する側の交差部に第４三角柱状突部８８ｄが設けられている。該第４三角柱状突部８８ｄは、平面視で、第１長側壁部５４の内面の一部を底辺、第１長側壁部５４と第２短側壁部６０に橋架された部位を斜辺、第２短側壁部６０の内面の一部を高さ方向の辺とする直角三角形をなす。 Further, in the fourth inner chamber 70d, the fourth triangular prism-shaped protrusion 88d is formed at the intersection of the first long side wall 54 and the second short side wall 60, that is, the intersection on the side close to the sixth bulging portion 84f. Is provided. The fourth triangular prism-shaped protrusion 88d has, in plan view, a part of the inner surface of the first long side wall portion 54 as a bottom side, a portion bridged by the first long side wall portion 54 and the second short side wall portion 60 as a hypotenuse, 2 Forms a right triangle having a part of the inner surface of the short side wall 60 as a side in the height direction.

そして、第５内室７０ｅでは、第７膨出部８４ｇに近接する第２長側壁部５６と第１短区画部の交差部に第５三角柱状突部８８ｅが設けられ、第７内室７０ｇでは、第１０膨出部８４ｊに近接する第２長側壁部５６と第３短区画部の交差部に第６三角柱状突部８８ｆが設けられる。第５三角柱状突部８８ｅは、平面視で、第２長側壁部５６の内面の一部を底辺、第２長側壁部５６と第１短区画壁部６６ａに橋架された部位を斜辺、第１短区画壁部６６ａの内面の一部を高さ方向の辺とする直角三角形をなし、一方、第６三角柱状突部８８ｆは、平面視で、第２長側壁部５６の内面の一部を底辺、第２長側壁部５６と第３短区画壁部６６ｃに橋架された部位を斜辺、第３短区画壁部６６ｃの内面の一部を高さ方向の辺とする直角三角形をなす。 In the fifth inner chamber 70e, a fifth triangular columnar protrusion 88e is provided at the intersection of the second long side wall portion 56 and the first short partition portion adjacent to the seventh bulging portion 84g, and the seventh inner chamber 70g. Then, the 6th triangular prism-shaped protrusion 88f is provided in the cross | intersection part of the 2nd long side wall part 56 and the 3rd short division part which adjoins the 10th bulging part 84j. The fifth triangular prism-shaped protrusion 88e has, in plan view, a part of the inner surface of the second long side wall part 56 as a bottom side, a part bridged by the second long side wall part 56 and the first short partition wall part 66a, a hypotenuse, The first triangular partition wall portion 66a forms a right triangle having a part of the inner surface of the short partition wall portion 66a as a side in the height direction, while the sixth triangular columnar projection 88f is a part of the inner surface of the second long side wall portion 56 in plan view. Is a right triangle with the hypotenuse on the part bridged by the second long side wall part 56 and the third short partition wall part 66c, and a part of the inner surface of the third short partition wall part 66c on the side in the height direction.

なお、第４膨出部８４ｄが配設された第２室には、三角柱状突部が設けられていない。すなわち、第４膨出部８４ｄから吸気ポート７２（下方）に向かうに従って拡開する第４リブ８２ｄは、三角柱状突部が設けられていない第２内室７０ｂの外面に設けられている。 In addition, the triangular prismatic protrusion is not provided in the second chamber in which the fourth bulging portion 84d is disposed. That is, the fourth rib 82d that expands from the fourth bulging portion 84d toward the intake port 72 (downward) is provided on the outer surface of the second inner chamber 70b where no triangular columnar protrusion is provided.

以上の第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆは、第１内室７０ａ、第３内室７０ｃ、第４内室７０ｄ、第５内室７０ｅ及び第７内室７０ｇの深さ方向である矢印Ｚ方向（図２及び図３参照）に沿って所定の厚みを有する。このため、第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆは三角柱形状をなす。第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆの厚み方向（矢印Ｚ方向）の寸法は、好ましくは、第１リブ８２ａ〜第１０リブ８２ｊのＺ方向寸法と同程度である。 The first triangular columnar protrusion 88a to the sixth triangular columnar protrusion 88f are the depths of the first inner chamber 70a, the third inner chamber 70c, the fourth inner chamber 70d, the fifth inner chamber 70e, and the seventh inner chamber 70g. It has a predetermined thickness along the arrow Z direction (see FIGS. 2 and 3) which is the vertical direction. Therefore, the first triangular prismatic protrusion 88a to the sixth triangular prismatic protrusion 88f have a triangular prism shape. The dimension in the thickness direction (arrow Z direction) of the first triangular columnar protrusion 88a to the sixth triangular columnar protrusion 88f is preferably about the same as the Z direction dimension of the first rib 82a to the tenth rib 82j.

ここで、第３三角柱状突部８８ｃの近傍を拡大して図４に示す。第５膨出部８４ｅが略半円形状に近似されるため、仮想線で示しているように、第５膨出部８４ｅと第１長側壁部５４内に、第５膨出部８４ｅに内接する仮想内接円Ｃ１を形成することが可能である。 Here, the vicinity of the third triangular prism-shaped protrusion 88c is enlarged and shown in FIG. Since the fifth bulge portion 84e is approximated to a substantially semicircular shape, as shown by the phantom line, the fifth bulge portion 84e and the first long side wall portion 54 are within the fifth bulge portion 84e. It is possible to form a tangential virtual inscribed circle C1.

仮想内接円Ｃ１の直径Ｄ、第１長側壁部５４の内面の位置を示す境界線Ｌは、点Ｐで交わる。第３三角柱状突部８８ｃの斜辺Ｓは、点Ｐ（直径Ｄと境界線Ｌ）を起点とし、第３短区画壁部６６ｃに向かっている。第３三角柱状突部８８ｃにおいて、底辺（境界線Ｌ）と斜辺Ｓとの交差角度は、２０°〜３０°であることが好ましい。 A boundary line L indicating the diameter D of the virtual inscribed circle C1 and the position of the inner surface of the first long side wall 54 intersects at a point P. The hypotenuse S of the third triangular columnar projection 88c starts from the point P (diameter D and boundary line L) and faces the third short partition wall 66c. In the third triangular prism-shaped projection 88c, the intersection angle between the base (boundary line L) and the hypotenuse S is preferably 20 ° to 30 °.

残余の第１三角柱状突部８８ａ、第２三角柱状突部８８ｂ、第４三角柱状突部８８ｄ〜第６三角柱状突部８８ｆも同様に、底辺と斜辺との交差角度を２０°〜３０°に設定することが好ましい。 Similarly, the remaining first triangular prismatic protrusion 88a, second triangular prismatic protrusion 88b, and fourth triangular prismatic protrusion 88d to sixth triangular prismatic protrusion 88f have an angle of intersection between the base and the hypotenuse of 20 ° to 30 °. It is preferable to set to.

本実施の形態に係るシリンダヘッド５０（鋳造成形品）は、基本的には以上のように構成されるものであり、次に、その作用効果について説明する。 The cylinder head 50 (cast product) according to the present embodiment is basically configured as described above. Next, the function and effect will be described.

シリンダヘッド５０は、低圧鋳造によって作製される。その際、鋳造加工装置では、ガスケット面を形成する部分が下方、開放端である上端を形成する部分が上方を向くようにキャビティが形成され、湯口及び湯道を通過した溶湯は、キャビティの下方（ガスケット面側）から導入される。すなわち、第１リブ８２ａ〜第１０リブ８２ｊを形成する部分と、第１膨出部８４ａ〜第１１膨出部８４ｋを形成する部分とでは、第１リブ８２ａ〜第１０リブ８２ｊを形成する部分の方に溶湯が先に導入され、次に、第１膨出部８４ａ〜第１１膨出部８４ｋを形成する部分に溶湯が導入される。以上のようにしてキャビティの全体に溶湯が充填された後、溶湯が凝固を開始する。 The cylinder head 50 is manufactured by low pressure casting. At that time, in the casting processing apparatus, the cavity is formed so that the part forming the gasket surface faces downward and the part forming the upper end which is the open end faces upward, and the molten metal passing through the gate and the runner is It is introduced from (gasket side). That is, in the part forming the first rib 82a to the tenth rib 82j and the part forming the first bulge part 84a to the eleventh bulge part 84k, the part forming the first rib 82a to the tenth rib 82j. On the other hand, the molten metal is introduced first, and then the molten metal is introduced into the portion forming the first bulging portion 84a to the eleventh bulging portion 84k. After the molten metal is filled in the entire cavity as described above, the molten metal starts to solidify.

湯口からの押し湯効果を維持するためには、キャビティに充填された溶湯が、湯口から最も離間した部分から湯口に向かって凝固する（指向性凝固）ことが望ましい。しかしながら、第１膨出部８４ａ〜第８膨出部８４ｈ、第１０膨出部８４ｊ及び第１１膨出部８４ｋは、第１リブ８２ａ〜第１０リブ８２ｊに比して突出量が大きい（換言すれば、肉厚が大きい）。このため、第１膨出部８４ａ〜第８膨出部８４ｈ、第１０膨出部８４ｊ及び第１１膨出部８４ｋの凝固速度が、第１リブ８２ａ〜第１０リブ８２ｊに比して小さくなる懸念がある。 In order to maintain the effect of the hot water from the gate, it is desirable that the molten metal filled in the cavity solidifies from the portion farthest from the gate toward the gate (directional solidification). However, the first bulging portion 84a to the eighth bulging portion 84h, the tenth bulging portion 84j, and the eleventh bulging portion 84k have a larger protruding amount than the first rib 82a to the tenth rib 82j (in other words, If so, the wall thickness is large.) For this reason, the solidification speeds of the first bulge portion 84a to the eighth bulge portion 84h, the tenth bulge portion 84j, and the eleventh bulge portion 84k are smaller than those of the first rib 82a to the tenth rib 82j. There are concerns.

この懸念を払拭するべく、本実施の形態においては、第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆを設けるようにしている。すなわち、溶湯は、キャビティにおける第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆを形成する部分に回り込む。 In order to eliminate this concern, in the present embodiment, the first triangular prismatic protrusion 88a to the sixth triangular prismatic protrusion 88f are provided. That is, the molten metal wraps around the portion of the cavity where the first triangular columnar protrusion 88a to the sixth triangular columnar protrusion 88f are formed.

このため、第１三角柱状突部８８ａが近接する第２膨出部８４ｂと、第１短区画壁部６６ａとの間で、第１三角柱状突部８８ａを介して熱が伝達される。第２三角柱状突部８８ｂが近接する第３膨出部８４ｃと、第２短区画壁部６６ｂとの間でも同様に、第２三角柱状突部８８ｂを介して熱が伝達される。勿論、第５膨出部８４ｅ、第６膨出部８４ｆ、第７膨出部８４ｇ、第１０膨出部８４ｊにおいても同様に、第３三角柱状突部８８ｃ〜第６三角柱状突部８８ｆを介して、第３短区画壁部６６ｃ、第２短側壁部６０、第１短側壁部５８、第３短区画壁部６６ｃとの間で熱伝達が起こる。 For this reason, heat is transmitted through the first triangular prismatic protrusion 88a between the second bulging part 84b adjacent to the first triangular prismatic protrusion 88a and the first short partition wall part 66a. Similarly, heat is transferred between the third bulging portion 84c adjacent to the second triangular prism-shaped projection 88b and the second short partition wall portion 66b via the second triangular prism-shaped projection 88b. Of course, in the fifth bulge portion 84e, the sixth bulge portion 84f, the seventh bulge portion 84g, and the tenth bulge portion 84j, the third triangular columnar protrusion 88c to the sixth triangular columnar protrusion 88f are similarly formed. Thus, heat transfer occurs between the third short partition wall portion 66c, the second short side wall portion 60, the first short side wall portion 58, and the third short partition wall portion 66c.

その結果、第２膨出部８４ｂ、第３膨出部８４ｃ、第５膨出部８４ｅ、第６膨出部８４ｆ、第７膨出部８４ｇ及び第１０膨出部８４ｊの温度は、指向性凝固も相俟って、第１短区画壁部６６ａ、第２短区画壁部６６ｂ、第３短区画壁部６６ｃ、第２短側壁部６０の上端面の温度よりも低くなる。このため、膨出部８４ｂ、８４ｃ、８４ｅ、８４ｆ、８４ｇ、８４ｊに、周囲の温度よりも高温の箇所、すなわち、熱溜まりが発生することが抑制される。以上のような理由から、膨出部８４ｂ、８４ｃ、８４ｅ、８４ｆ、８４ｇ、８４ｊは、第１短区画壁部６６ａ〜第３短区画壁部６６ｃ、第２短側壁部６０の上端面と略同時に凝固し始める。すなわち、膨出部８４ｂ、８４ｃ、８４ｅ、８４ｆ、８４ｇ、８４ｊに凝固遅れが生じることが回避されて指向性凝固が確保される。 As a result, the temperatures of the second bulging portion 84b, the third bulging portion 84c, the fifth bulging portion 84e, the sixth bulging portion 84f, the seventh bulging portion 84g, and the tenth bulging portion 84j are directional. Together with the solidification, the temperature becomes lower than the temperatures of the upper end surfaces of the first short partition wall portion 66a, the second short partition wall portion 66b, the third short partition wall portion 66c, and the second short side wall portion 60. For this reason, it is suppressed that the location where the temperature is higher than the surrounding temperature, that is, a heat pool, is generated in the bulging portions 84b, 84c, 84e, 84f, 84g, and 84j. For the reasons described above, the bulging portions 84b, 84c, 84e, 84f, 84g, and 84j are substantially the same as the upper end surfaces of the first short partition wall portion 66a to the third short partition wall portion 66c and the second short side wall portion 60. At the same time start to solidify. That is, it is avoided that a solidification delay occurs in the bulging portions 84b, 84c, 84e, 84f, 84g, and 84j, and directional solidification is ensured.

なお、第２内室７０ｂに三角柱状突部を設けると、第２内室７０ｂに設けられる機構が該三角柱状突部に干渉することになる。この不具合を回避するべく、第２内室７０ｂには三角柱状突部が設けられていない。 In addition, when the triangular columnar protrusion is provided in the second inner chamber 70b, the mechanism provided in the second inner chamber 70b interferes with the triangular columnar protrusion. In order to avoid this problem, the second inner chamber 70b is not provided with a triangular columnar protrusion.

ここで、第４膨出部８４ｄに連なる第４リブ８２ｄは、吸気ポート７２に向かうにつれて拡開した三角形形状ないし台形形状をなす。すなわち、第４リブ８２ｄの幅方向（矢印Ｙ方向）寸法、ひいては断面積は、湯口に近接する下方で大きくなっている。このため、第４膨出部８４ｄと、第１長側壁部５４の下方との間で、第１長側壁部５４の下方側が高温、第４膨出部８４ｄ側が低温となる熱勾配が生じる。従って、第４膨出部８４ｄが優先的に凝固する。これにより、指向性凝固が確保される。 Here, the fourth rib 82 d connected to the fourth bulging portion 84 d has a triangular shape or a trapezoidal shape that expands toward the intake port 72. That is, the dimension in the width direction (arrow Y direction) of the fourth rib 82d, that is, the cross-sectional area is large in the lower part close to the gate. For this reason, a thermal gradient is generated between the fourth bulging portion 84d and the lower side of the first long side wall portion 54 such that the lower side of the first long side wall portion 54 has a high temperature and the fourth bulging portion 84d side has a low temperature. Accordingly, the fourth bulging portion 84d is preferentially solidified. Thereby, directional solidification is ensured.

第１１膨出部８４ｋは、第４短区画壁部６６ｄの延在方向の軸線上に位置する。このため、第１１膨出部８４ｋと第４短区画壁部６６ｄの間で熱が直接授受される。従って、第１１膨出部８４ｋの近傍に三角柱状突部を設けなくとも、該第１１膨出部８４ｋは第４短区画壁部６６ｄの上端面と略同時に凝固し始める。 The eleventh bulge portion 84k is located on the axis line in the extending direction of the fourth short partition wall portion 66d. For this reason, heat is directly transferred between the eleventh bulging portion 84k and the fourth short partition wall portion 66d. Therefore, even if the triangular columnar protrusion is not provided in the vicinity of the eleventh bulging portion 84k, the eleventh bulging portion 84k begins to solidify substantially simultaneously with the upper end surface of the fourth short partition wall portion 66d.

加えて、第２長側壁部５６の内面側の深さは、第１長側壁部５４の内面側の深さよりも小さい。このため、第２長側壁部５６に設けられる第７膨出部８４ｇ〜第１１膨出部８４ｋでは、凝固遅れが生じ難い。このことも、第７膨出部８４ｇ〜第１１膨出部８４ｋからの指向性凝固に寄与する。従って、三角柱状突部の個数が吸気側（第１長側壁部５４側）に比して少なくとも、特に差し支えはない。 In addition, the depth on the inner surface side of the second long side wall portion 56 is smaller than the depth on the inner surface side of the first long side wall portion 54. For this reason, in the 7th bulge part 84g-11th bulge part 84k provided in the 2nd long side wall part 56, it is hard to produce a solidification delay. This also contributes to directional solidification from the seventh bulge portion 84g to the eleventh bulge portion 84k. Therefore, the number of the triangular prism-shaped protrusions is at least as long as the intake side (first long side wall 54 side).

なお、第１膨出部８４ａは、比較的厚肉の第１短側壁部５８に連なる。このため、第１膨出部８４ａと第１短側壁部５８の間で熱が伝達されるので、第１膨出部８４ａからの指向性凝固が確保される。 The first bulging portion 84a is connected to the relatively thick first short side wall portion 58. For this reason, since heat is transmitted between the first bulging portion 84a and the first short side wall portion 58, directional solidification from the first bulging portion 84a is ensured.

以上のように、本実施の形態では、短区画壁部との間で熱伝達が起こり難く、このために凝固遅れが生じ易い膨出部の近傍に三角柱状突部を設けるようにしている。このため、膨出部と短区画壁部との間で、三角柱状突部を介する熱伝達が起こり易くなる。これにより、該膨出部から、その下方のリブに向かって凝固するような指向性凝固が起こる。 As described above, in the present embodiment, heat transfer is unlikely to occur between the short partition wall portions, and for this reason, the triangular columnar protrusion is provided in the vicinity of the bulging portion where a solidification delay is likely to occur. For this reason, heat transfer via the triangular columnar protrusion is likely to occur between the bulging portion and the short partition wall portion. Thereby, directional solidification that solidifies from the bulging portion toward the rib below the bulging portion occurs.

その結果として、該膨出部において凝固遅れが生じることが回避される。従って、該膨出部の近傍に引け巣等の鋳造欠陥が発生することを防止することができる。すなわち、鋳造欠陥が発生する懸念が払拭される。 As a result, the occurrence of a solidification delay in the bulging portion is avoided. Accordingly, it is possible to prevent the occurrence of casting defects such as shrinkage cavities in the vicinity of the bulging portion. That is, the concern that casting defects will occur is eliminated.

また、第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆにおいて、底辺と斜辺の交差角度を２０°〜３０°とした場合には、キャビティの、第１三角柱状突部８８ａ〜第６三角柱状突部８８ｆを形成するための部分に十分に溶湯が回り込むとともに、第１内室７０ａ、第３内室７０ｃ、第４内室７０ｄ、第５内室７０ｅ及び第６内室７０ｆに収容される機構が干渉することを回避することが容易となるという利点がある。 Further, in the first triangular prismatic protrusion 88a to the sixth triangular prismatic protrusion 88f, when the crossing angle between the base and the hypotenuse is 20 ° to 30 °, the first triangular prismatic protrusion 88a to sixth of the cavity. The molten metal sufficiently wraps around the portion for forming the triangular columnar protrusion 88f, and is accommodated in the first inner chamber 70a, the third inner chamber 70c, the fourth inner chamber 70d, the fifth inner chamber 70e, and the sixth inner chamber 70f. There is an advantage that it is easy to avoid the interference of the mechanism to be performed.

特に、第５膨出部８４ｅの近傍の第３三角形状突部８８ｃでは、斜辺Ｓの起点を、第５膨出部８４ｅの仮想内接円Ｃ１の直径Ｄと、第１長側壁部５４の内面側の境界線Ｌとの交点としている。このような第３三角柱状突部８８ｃを設けることにより、シリンダヘッド５０としての製品機能と、品質との双方を両立させることができる。 In particular, in the third triangular protrusion 88c in the vicinity of the fifth bulging portion 84e, the starting point of the hypotenuse S is set to the diameter D of the virtual inscribed circle C1 of the fifth bulging portion 84e and the first long side wall portion 54. The intersection point with the boundary line L on the inner surface side. By providing such a third triangular prism-shaped protrusion 88c, both the product function as the cylinder head 50 and the quality can be achieved.

本発明は、上記した実施の形態に特に限定されるものではなく、本発明の主旨を逸脱しない範囲で種々の変更が可能である。 The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

例えば、鋳造成形品はシリンダヘッド５０に限定されるものではなく、中空内部６４が区画壁部によって仕切られることで内室が形成され、且つ側壁部の上端面に膨出部が突出形成される形状、すなわち、平面視でいわゆる井桁形状をなすものであればよい。 For example, the cast product is not limited to the cylinder head 50, and the hollow interior 64 is partitioned by the partition wall portion to form the inner chamber, and the bulging portion projects from the upper end surface of the side wall portion. What is necessary is just to make a shape, ie, what is called a cross-beam shape by planar view.

また、重量が過度に大きくならないような場合であれば、第１リブ８２ａ〜第１０リブ８２ｊの全てを、第４リブ８２ｄと同様に三角形形状ないし台形形状とするようにしてもよい。 Further, if the weight does not become excessively large, all of the first rib 82a to the tenth rib 82j may be triangular or trapezoidal like the fourth rib 82d.

さらに、内室に収容される機器に対して干渉が起こらない場合には、三角柱状突部における底辺と斜辺の交差角度を３０°よりも大きくするようにしてもよい。 Furthermore, when no interference occurs with the equipment accommodated in the inner chamber, the angle of intersection of the base and the hypotenuse in the triangular prismatic protrusion may be made larger than 30 °.

内室に収容される機構に対して干渉が起こらず、重量が過度に大きくならないような場合には、第１長側壁部５４又は第２長側壁部５６と、第１短区画壁部６６ａ〜第４短区画壁部６６ｄとの交差部の全てに三角柱状突部を設けてもよいことは勿論である。 When interference does not occur with respect to the mechanism accommodated in the inner chamber and the weight does not become excessively large, the first long side wall part 54 or the second long side wall part 56 and the first short partition wall parts 66a to 66a. Of course, a triangular prism-shaped protrusion may be provided at all of the intersections with the fourth short partition wall 66d.

１０、５０…シリンダヘッド１２、５２…底壁部
１４ａ、１４ｂ、５４、５６…長側壁部
１６ａ、１６ｂ、５８、６０…短側壁部
１８、６４…中空内部１９、６２…方案部
２０ａ〜２０ｄ、６６ａ〜６６ｄ…短区画壁部２２、６８…長区画壁部
２４、８２ａ〜８２ｊ…リブ７０ａ〜７０ｇ…内室
８４ａ〜８４ｋ…膨出部８６…半楕円状柱部
８８ａ〜８８ｆ…三角柱状突部Ｃ１…仮想内接円 DESCRIPTION OF SYMBOLS 10, 50 ... Cylinder head 12, 52 ... Bottom wall part 14a, 14b, 54, 56 ... Long side wall part 16a, 16b, 58, 60 ... Short side wall part 18, 64 ... Hollow inside 19, 62 ... Plan part 20a-20d , 66a to 66d ... short partition wall portions 22, 68 ... long partition wall portions 24, 82a to 82j ... ribs 70a to 70g ... inner chambers 84a to 84k ... bulge portions 86 ... semi-elliptical column portions 88a to 88f ... triangular column shapes Projection C1 ... Virtual inscribed circle

Claims

底壁部と、前記底壁部から立ち上がった側壁部とを有し、前記側壁部に囲繞されることで中空内部が形成された鋳造成形品であって、
前記側壁部の対向部位同士に橋架され、前記中空内部を複数個の内室に区分する区画壁部と、
前記側壁部の上端面に、前記中空内部の深さ方向に対して直交する方向に突出形成された複数個の膨出部と、
前記側壁部の外面に突出形成され、且つ該中空内部の深さ方向に沿って延在して前記複数個の膨出部の各々に連なる複数個のリブと、
を備え、
前記膨出部の中の少なくとも１個は、前記区画壁部の橋架方向に対して平行に突出し、且つ前記区画壁部から離間した位置に配設され、
前記側壁部と前記区画壁部との複数個の交差部の中、少なくとも、前記区画壁部から離間した位置に配設された前記膨出部に近接する交差部に、前記側壁部と前記区画壁部に橋架された部位を一辺とし、且つ前記中空内部の深さ方向に沿って延在する平面視で三角形状の三角柱状突部が設けられていることを特徴とする鋳造成形品。 A cast molded article having a bottom wall part and a side wall part rising from the bottom wall part, wherein a hollow interior is formed by being surrounded by the side wall part,
A partition wall portion that is bridged between opposing portions of the side wall portion and divides the hollow interior into a plurality of inner chambers;
A plurality of bulging portions formed on the upper end surface of the side wall portion so as to protrude in a direction perpendicular to the depth direction of the hollow interior;
A plurality of ribs formed on the outer surface of the side wall portion and extending along the depth direction of the hollow interior and continuing to each of the plurality of bulging portions;
With
At least one of the bulges protrudes in parallel to the bridge direction of the partition wall and is disposed at a position spaced from the partition wall,
Among the plurality of intersecting portions of the side wall portion and the partition wall portion, at least at the intersecting portion adjacent to the bulging portion disposed at a position separated from the partition wall portion, the side wall portion and the partition A cast molded article characterized in that a portion bridged by a wall portion is provided on one side, and a triangular prism-shaped protrusion is formed in a triangular shape in a plan view extending along the depth direction of the hollow interior.

請求項１記載の鋳造成形品において、前記側壁部と前記区画壁部とが直交し、且つ前記三角柱状突部は、前記側壁部と前記区画壁部に橋架された部位によって形成される一辺を斜辺、前記側壁部の内面の一部を底辺とする直角三角形をなし、
前記斜辺と前記底辺との交差角度が２０°〜３０°であることを特徴とする鋳造成形品。 2. The cast molded product according to claim 1, wherein the side wall portion and the partition wall portion are orthogonal to each other, and the triangular columnar protrusion has a side formed by a portion bridged by the side wall portion and the partition wall portion. A hypotenuse, a right triangle with the base of a part of the inner surface of the side wall,
A cast-molded product, wherein an angle of intersection between the oblique side and the bottom side is 20 ° to 30 °.

請求項１又は２記載の鋳造成形品において、前記膨出部が平面視で円弧状に湾曲した形状をなし、前記三角柱状突部の、前記側壁部と前記区画壁部に橋架された部位は、前記膨出部の仮想内接円の直径と、前記側壁部の内面側とが直交する箇所を起点として前記区画壁部に向かうことを特徴とする鋳造成形品。 The cast molded product according to claim 1 or 2, wherein the bulging portion has a shape curved in an arc shape in a plan view, and a portion of the triangular columnar projection portion bridged by the side wall portion and the partition wall portion is A casting product characterized by heading toward the partition wall portion starting from a location where the diameter of the virtual inscribed circle of the bulging portion and the inner surface side of the side wall portion are orthogonal to each other.

請求項１〜３のいずれか１項に記載の鋳造成形品において、前記複数個のリブの中の少なくとも１つが、前記膨出部から離間するに従って拡開するように延在することを特徴とする鋳造成形品。 The cast product according to any one of claims 1 to 3, wherein at least one of the plurality of ribs extends so as to expand as it is separated from the bulging portion. Cast molding product to be.

請求項４記載の鋳造成形品において、前記複数個の内室の中の少なくとも１つには前記三角柱状突部が設けられておらず、
前記膨出部から離間するに従って拡開するように延在する前記リブは、前記三角柱状突部が設けられていない前記内室の近傍に配設された膨出部に連なることを特徴とする鋳造成形品。 In the cast product according to claim 4, at least one of the plurality of inner chambers is not provided with the triangular columnar protrusion,
The rib extending so as to expand as it is separated from the bulging portion is connected to a bulging portion disposed in the vicinity of the inner chamber where the triangular columnar protrusion is not provided. Cast molded product.

請求項１〜５のいずれか１項に記載の鋳造成形品において、前記底壁部から突出した方案部を有することを特徴とする鋳造成形品。 The cast molded product according to any one of claims 1 to 5, further comprising a design portion that protrudes from the bottom wall portion.

請求項１〜６のいずれか１項に記載の鋳造成形品において、シリンダヘッドであることを特徴とする鋳造成形品。 The cast molded article according to any one of claims 1 to 6, wherein the cast molded article is a cylinder head.