JPH09203347A - Cylinder-head cover structure - Google Patents
Cylinder-head cover structureInfo
- Publication number
- JPH09203347A JPH09203347A JP1062396A JP1062396A JPH09203347A JP H09203347 A JPH09203347 A JP H09203347A JP 1062396 A JP1062396 A JP 1062396A JP 1062396 A JP1062396 A JP 1062396A JP H09203347 A JPH09203347 A JP H09203347A
- Authority
- JP
- Japan
- Prior art keywords
- head cover
- covering member
- blow
- gas passage
- valve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F7/00—Casings, e.g. crankcases or frames
- F02F7/006—Camshaft or pushrod housings
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】 この発明は、動弁機構の保
護機能とブローバイガス還元機能を兼ね備えた内燃エン
ジンンのヘッドカバー構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head cover structure for an internal combustion engine that has both a valve mechanism protection function and a blowby gas reduction function.
【０００２】[0002]
【従来の技術】 従来提案されているヘッドカバー構造
としては、特開昭６１−２７７８１４号公報等に記載さ
れているようなものがある（図１３，図１４参照のこ
と）。これらのヘッドカバー構造においては、ヘッドカ
バー下面と動弁機構を収めた動弁室上方の略全面を覆う
遮蔽板との間にブローバイガス通路が形成され、動弁機
構の保護機能とブローバイガス還元機能を兼ね備える構
造となっている。また、近年エンジン本体の剛性向上の
ため、オイルパンやヘッドカバーをアルミダイキャスト
等の高剛性部材で構成する例も増えてきている。2. Description of the Related Art Conventionally proposed head cover structures include those described in JP-A-61-277814 (see FIGS. 13 and 14). In these head cover structures, a blow-by gas passage is formed between the lower surface of the head cover and a shielding plate that covers substantially the entire upper surface of the valve operating chamber that houses the valve operating mechanism, and provides a protective function for the valve operating mechanism and a blow-by gas reducing function. It has a structure that combines it. Further, in recent years, in order to improve the rigidity of the engine body, an example in which the oil pan and the head cover are made of a highly rigid member such as aluminum die cast is increasing.
【０００３】[0003]
【発明が解決しようとする課題】 しかしながら、上記
従来例のヘッドカバーを高剛性化する場合、剛性向上の
結果ヘッドカバーの膜１次共振周波数が１ＫＨｚを越え
る高い周波数に出現する様になり、エンジン放射騒音を
悪化させるという問題が発生するようになった。本発明
は、このような従来の技術が有する未解決の課題に着目
してなされたものであって、エンジン本体の剛性確保と
ヘッドカバー表面からの放射騒音の低減を両立させるヘ
ッドカバー構造を提供することを目的とする。However, when the head cover of the above-mentioned conventional example is made to have high rigidity, as a result of the improvement in rigidity, the membrane primary resonance frequency of the head cover appears at a high frequency exceeding 1 KHz, and engine radiation noise is generated. The problem of getting worse has come to occur. The present invention has been made in view of the above-mentioned unsolved problems of the conventional technique, and provides a head cover structure that ensures both the rigidity of the engine body and the reduction of radiated noise from the surface of the head cover. With the goal.
【０００４】[0004]
【課題を解決するための手段】 上記目的を達成するた
めに、請求項１記載の発明は、バルブ、カムシャフト、
ロッカーアーム等から構成される動弁機構の保護機能と
ブローバイガス還元機能を兼ね備えた内燃エンジンのヘ
ッドカバーにおいて、前記ヘッドカバーは高剛性部材で
構成されると共に、前記ヘッドカバー天面にブローバイ
ガス通路を付設し、前記ブローバイガス通路を低剛性の
被覆部材で被覆することとした。また、請求項２記載の
発明では、請求項１記載の発明において、前記ヘッドカ
バー縦断面形状が略Ｈ型形状であり、該ヘッドカバー天
面に形成された凹部を低剛性の被覆部材で被覆すること
により、ブローバイガス通路を形成することとした。請
求項３記載の発明は、請求項１または２記載の発明にお
いて、前記ヘッドカバーと前記被覆部材との結合部が前
記被覆部材の低次膜振動モードの腹位置に位置すること
とした。請求項４記載の発明は、請求項１または２記載
の発明において、前記ヘッドカバー天面と前記被覆部材
との間に設けられ、ブローバイガス通路を形成する仕切
り板が前記被覆部材の低次膜振動モードの腹位置に位置
することとした。請求項５記載の発明は、請求項１また
は２記載の発明において、前期被覆部材の長手方向に隣
接してＰＣＶバルブが設けられ、前記被覆部材と前記Ｐ
ＣＶバルブカバーの材質及び板厚がほぼ同等であり、前
記被覆部材の縦横寸法が前記ＰＣＶバルブカバー直径の
略整数倍になっていることとした。In order to achieve the above object, the invention according to claim 1 provides a valve, a camshaft, and
In a head cover of an internal combustion engine having both a function of protecting a valve mechanism including a rocker arm and a function of returning blow-by gas, the head cover is made of a highly rigid member, and a blow-by gas passage is attached to the top surface of the head cover. The blow-by gas passage is covered with a low-rigidity covering member. According to a second aspect of the present invention, in the first aspect of the present invention, the vertical shape of the head cover is substantially H-shaped, and the recess formed in the top surface of the head cover is covered with a low-rigidity covering member. Therefore, the blow-by gas passage is formed. According to a third aspect of the present invention, in the first or second aspect of the invention, the joint portion between the head cover and the covering member is located at the antinode position of the covering member in the low order membrane vibration mode. The invention according to claim 4 is the invention according to claim 1 or 2, wherein a partition plate which is provided between the top surface of the head cover and the covering member and which forms a blow-by gas passage is a low-order film vibration of the covering member. It was decided to be located at the belly position of the mode. The invention according to claim 5 is the invention according to claim 1 or 2, wherein a PCV valve is provided adjacent to the covering member in the longitudinal direction, and the covering member and the P
The material and the plate thickness of the CV valve cover are almost the same, and the vertical and horizontal dimensions of the covering member are substantially integral multiples of the diameter of the PCV valve cover.
【０００５】[0005]
【作用】 請求項１記載の発明にあっては、バルブ、カ
ムシャフト、ロッカーアーム等から構成される動弁機構
の保護機能とブローバイガス還元機能を兼ね備えた内燃
エンジンのヘッドカバーにおいて、前記ヘッドカバーは
高剛性部材で構成されると共に、前記ヘッドカバー天面
にブローバイガス通路を付設し、前記ブローバイガス通
路を低剛性の被覆部材で被覆することにより、ヘッドカ
バー本体の剛性を保ちつつ、ヘッドカバー表面の膜一次
共振周波数を低下させ騒音の放射効率を低下させるもの
とした。請求項２記載の発明にあっては、請求項１記載
の発明において、前記ヘッドカバー縦断面形状が略Ｈ型
形状であり、該ヘッドカバー天面に形成された凹部を低
剛性の被覆部材で被覆してブローバイガス通路を形成す
ることにより、請求項１記載の作用に加えてヘッドカバ
ー側壁の膜振動及び口開き振動を抑制するものとした。
請求項３記載の発明にあっては、請求項１または２記載
の発明において、前記ヘッドカバーと前記被覆部材との
結合部が前記被覆部材の低次膜振動モードの腹位置に位
置することにより、請求項１記載の作用に加えて発音効
率の高い低次の膜振動モードの発生を抑制するものとし
た。請求項４記載の発明にあっては、請求項１または２
記載の発明において、前記ヘッドカバー天面と前記被覆
部材との間に設けられ、ブローバイガス通路を形成する
仕切り板が前記被覆部材の低次膜振動モードの腹位置に
位置することにより、請求項１記載の作用に加えて発音
効率の高い低次の膜振動モードの発生を抑制するものと
した。請求項５記載の発明にあっては、請求項１または
２記載の発明において、前期被覆部材の長手方向に隣接
してＰＣＶバルブが設けられ、前記被覆部材と前記ＰＣ
Ｖバルブカバーの材質及び板厚がほぼ同等であり、前記
被覆部材の縦横寸法が前記ＰＣＶバルブカバー直径の略
整数倍になっていることにより、請求項１記載の作用に
加えて、前記被覆部材端部の膜振動モードと前記ＰＣＶ
バルブカバーの膜振動モードを略位相に発生させるもの
とした。According to the first aspect of the invention, in the head cover of the internal combustion engine having both the protection function of the valve operating mechanism including the valve, the camshaft, the rocker arm, etc. and the blow-by gas returning function, the head cover is high. In addition to being composed of a rigid member, a blow-by gas passage is attached to the top surface of the head cover, and the blow-by gas passage is covered with a low-rigidity covering member to maintain the rigidity of the head cover main body while maintaining the film primary resonance of the head cover surface. The frequency is lowered and the radiation efficiency of noise is lowered. According to a second aspect of the present invention, in the first aspect of the present invention, the head cover has a vertical cross-sectional shape that is substantially H-shaped, and the recess formed in the top surface of the head cover is covered with a low-rigidity covering member. By forming the blow-by gas passage by the above, the film vibration and the mouth opening vibration of the side wall of the head cover are suppressed in addition to the effect of the first aspect.
In the invention according to claim 3, in the invention according to claim 1 or 2, since the coupling portion between the head cover and the covering member is located at the antinode position of the lower order membrane vibration mode of the covering member, In addition to the operation described in claim 1, the generation of a low-order membrane vibration mode having high sound generation efficiency is suppressed. In the invention of claim 4, claim 1 or 2
In the invention described above, the partition plate that is provided between the top surface of the head cover and the covering member and forms a blow-by gas passage is located at the antinode position of the covering member in the low-order film vibration mode. In addition to the effects described above, the generation of low-order membrane vibration modes with high sound production efficiency is suppressed. According to a fifth aspect of the present invention, in the first or second aspect of the present invention, a PCV valve is provided adjacent to the covering member in the longitudinal direction, and the covering member and the PC are provided.
The V-valve cover is made of substantially the same material and has the same thickness, and the vertical and horizontal dimensions of the covering member are substantially integral multiples of the diameter of the PCV valve cover. Membrane vibration mode at the end and the PCV
The membrane vibration mode of the valve cover is set to be generated substantially in phase.
【０００６】[0006]
【発明の実施の形態】 以下、本発明の実施の形態を図
面に基づいて説明する。まず、本発明の第１実施の形態
を図１〜図８について説明する。図１は第１実施の形態
によるヘッドカバー構造の平面図を表すもので、その構
造はアルミダイキャスト等の高剛性部材で構成される略
Ｈ型の縦断面形状を有するヘッドカバー１とその天面の
凹部をガスケット２を介して被覆するバッフルプレート
（被覆部材）３と、バッフルプレート３とヘッドカバー
１を係合するネジ４と、ヘッドカバー１側面の穴から圧
入され、クランクケースからのブローバイガスを導くブ
ローバイガスホースとヘッドカバー天面凹部の空間を接
続するパイプ５と、ブローバイガスの通過を制御するＰ
ＣＶバルブ６と、ＰＣＶバルブ６から出たガスを吸気側
まで導くホース７から構成される。ヘッドカバー１の天
面凹部内にはリブ８が一体成形されており、ブローバス
ガイの迂回路を形成する仕切り板の役割を果たしてい
る。ヘッドカバー１はボルト９によりヘッド１１（図２
参照）に固定される。バッフルプレート３は例えば耐熱
性樹脂または薄手の鋼板といった低剛性の部材で構成さ
れるものとする。図２は図１のＡ−Ａ断面を表示したも
のである。ヘッドカバー１の天面がカム１２、カムキャ
ップ１３等の動弁機構とブローバイガス通路を隔てる遮
蔽板の役割を果たしていることがわかる。なお、図１，
２ではブローバイガスから分離したオイルをヘッド内に
戻すための通路等は省略されている。また、図中１０は
オイルキャップである。Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a plan view of a head cover structure according to the first embodiment. The structure is a head cover 1 having a substantially H-shaped vertical cross-sectional shape composed of a high-rigidity member such as aluminum die-cast and its top surface. A baffle plate (covering member) 3 that covers the concave portion via a gasket 2, a screw 4 that engages the baffle plate 3 and the head cover 1, and a blow-by gas that is press-fitted from a hole on the side surface of the head cover 1 and guides blow-by gas from the crankcase. A pipe 5 that connects the gas hose and the space of the head cover top recess, and P that controls the passage of blow-by gas.
It is composed of a CV valve 6 and a hose 7 that guides the gas discharged from the PCV valve 6 to the intake side. A rib 8 is integrally formed in the top surface recess of the head cover 1 and plays a role of a partition plate forming a bypass of the blow bus guy. The head cover 1 is attached to the head 11 (see FIG.
Reference). The baffle plate 3 is made of a low-rigidity member such as heat resistant resin or a thin steel plate. FIG. 2 shows the AA cross section of FIG. It can be seen that the top surface of the head cover 1 plays a role of a shielding plate that separates the valve mechanism such as the cam 12 and the cam cap 13 from the blow-by gas passage. Note that FIG.
In FIG. 2, a passage for returning the oil separated from the blow-by gas into the head is omitted. Further, reference numeral 10 in the drawing is an oil cap.
【０００７】ヘッドカバー１表面からの音の放射は長方
形板の共振による音の放射として近似的にモデル化でき
る。２辺の長さが１ｘ，１ｙで４辺を単純支持された長
方形板に振動を加えると、ある振動周波数において板上
に低在波が発生し、板の振動振幅が局所的に大きくなる
共振現象が発生する。板の縦弾性係数をＥ、ポアソン比
をν、板厚をｈ、板の密度をρとすると、その共振周波
数は次式で表される（１）； ｆ＝（π／２）［Ｅｈ2 ／１２（１−ν2 ）ρ］1/2 ・［（ｍ／１ｘ）2 ＋（ｎ／１ｙ）2 ］ …（１） （１）式でｍ，ｎは正の整数で、板上に振動の腹が１ｘ
方向にｍ個、１ｙ方向にｎ個できることを示す。ｍ＝ｎ
＝１の場合、板の振動モードは図３に示すように板中心
が腹となる膜１次の振動モードとなる。ここで長方形が
無限平板の中に単純支持されており長方形板の片側から
放射される音のみを評価すると仮定すると、膜１次の振
動モードをしている長方形板は近似的にmonopole（湧
点）音源とみなされ、その放射パワーＷｍは次式であら
わされる（２）； Ｗｍ＝（ρａｃｋ2 ／４π）Ａ2 ｕ2 …（２） （２）式中ρａは空気密度、ｃは空気中の音速、ｋは波
数（＝２πｆ／ｃ）、Ａは音源表面積、ｕは音減速度
（ｒｍｓ値）を表す。次に高次の振動モードにおける音
の放射を考える。図４は例としてｍ＝４、ｎ＝３の場合
の長方形板の振動モードを示すもので、１ｘ方向に４等
分、１ｙ方向に３等分された小区画単位で振動し、かつ
各区画は隣接する区画に対して逆位相に振動するモード
となる。この場合、長方形板は図５に示すように４つの
monopole音源，８つのdipole音源、６つのquadrupole音
源の集合とみなされる。dipole、quadrupole音源の放射
パワーＷｄ、Ｗｑはそれぞれ Ｗｄ＝（１／３）（ｋｄ）2 Ｗｍ …（３） ｄはdipoleの振動波長 Ｗｑ＝（１／１５）（ｋｄｘ）2 （ｋｄｙ）2 Ｗｍ …（４） ｄｘ，ｄｙはquadrupole音源のｘ，ｙ方向の振動波長 となり、音源の振動波長が空気中の音の波長に比べて小
さい場合は両音源の放射パワーは同じ大きさのmonopole
音源に比べて非常に小さくなる。従って長方形板の放射
効率は膜一次共振の場合が最も大きく、高次の振動モー
ドになるにつれてその効率は小さくなることがわかる。
以上のことから、長方形板の剛性を低下させ膜振動１次
の共振周波数を下げてやると、それ以降の周波数領域で
は膜振動モードは放射効率の低い膜振動モードとなり、
放射騒音が低減できることがわかる。これがヘッド表面
を低剛性の部材で被覆することによる放射騒音低減のメ
カニズムである。The sound radiation from the surface of the head cover 1 can be approximately modeled as the sound radiation due to the resonance of the rectangular plate. When vibration is applied to a rectangular plate whose two sides are 1x and 1y and whose four sides are simply supported, a standing wave is generated on the plate at a certain vibration frequency and the vibration amplitude of the plate locally increases. The phenomenon occurs. When the longitudinal elastic modulus of the plate is E, the Poisson's ratio is ν, the plate thickness is h, and the plate density is ρ, its resonance frequency is expressed by the following equation (1); f = (π / 2) [Eh 2 / 12 (1-ν 2 ) ρ] 1/2 · [(m / 1x) 2 + (n / 1y) 2 ] ... (1) In the formula (1), m and n are positive integers, and Vibration belly is 1x
It is shown that m pieces can be formed in the direction and n pieces can be formed in the 1y direction. m = n
When = 1, the vibration mode of the plate is the first-order vibration mode of the film whose plate center is the antinode as shown in FIG. Assuming that the rectangle is simply supported in an infinite flat plate and only the sound radiated from one side of the rectangular plate is evaluated, the rectangular plate with the first-order vibration mode of the membrane is approximately a monopole (spring point). ) It is regarded as a sound source, and its radiation power Wm is expressed by the following equation (2); Wm = (ρack 2 / 4π) A 2 u 2 (2) (2) In the equation, ρa is the air density and c is in the air. , K is the wave number (= 2πf / c), A is the sound source surface area, and u is the sound deceleration (rms value). Next, consider radiation of sound in higher-order vibration modes. FIG. 4 shows a vibration mode of a rectangular plate in the case of m = 4 and n = 3 as an example. The vibration mode is divided into 4 equal parts in 1x direction and 3 equal parts in 1y direction, and Becomes a mode of vibrating in an opposite phase with respect to an adjacent section. In this case, the rectangular plate has four
It is regarded as a set of monopole sound source, 8 dipole sound sources, and 6 quadrupole sound sources. Radiation powers Wd and Wq of the dipole and quadrupole sound sources are Wd = (1/3) (kd) 2 Wm ... (3) d is the vibration wavelength of the dipole Wq = (1/15) (kdx) 2 (kdy) 2 Wm (4) dx and dy are vibration wavelengths in the x and y directions of the quadrupole sound source. If the vibration wavelength of the sound source is smaller than the wavelength of sound in the air, the radiated power of both sound sources is the same magnitude.
Very small compared to the sound source. Therefore, it can be seen that the radiation efficiency of the rectangular plate is greatest in the case of the film primary resonance, and becomes smaller as the vibration mode becomes higher.
From the above, when the rigidity of the rectangular plate is reduced to lower the resonance frequency of the first-order membrane vibration, the membrane vibration mode becomes a membrane vibration mode with low radiation efficiency in the frequency range thereafter.
It can be seen that the radiated noise can be reduced. This is a mechanism for reducing radiated noise by coating the head surface with a low-rigidity member.
【０００８】図６〜図８は従来のヘッドカバーと本発明
によるヘッドカバー１との振動モード及び放射騒音レベ
ルの比較を表すものである。従来の高剛性ヘッドカバー
においては１〜２ｋＨｚの高周波帯域において図６に示
すような放射効率の高い膜１次の振動モードが発生して
いたが、本発明によるヘッドカバー１においては１〜２
ｋＨｚの高周波帯域における振動モードは図７に示すよ
うに放射効率の低い高次の膜振動モードとなる。そのた
め、高周波帯域における放射騒音は図８に示すとおり、
本発明によるヘッドカバー１のほうが低減されることが
わかる。本発明によるヘッドカバー１においては、膜１
次の振動モードが数百Ｈｚの低周波数側にシフトするた
め、その領域における放射騒音は従来品に対して悪化し
ているが、その領域は１ｋＨｚ以降の高周波数領域に対
して聴感上の感度が相対的に低い領域でもあり、放射騒
音全体に与える影響は小さくなっている。FIGS. 6 to 8 show comparisons of vibration modes and radiated noise levels between the conventional head cover and the head cover 1 according to the present invention. In the conventional high-rigidity head cover, the first-order vibration mode of the film having high radiation efficiency as shown in FIG. 6 occurs in the high frequency band of 1-2 kHz, but in the head cover 1 according to the present invention, 1-2
The vibration mode in the high frequency band of kHz is a high-order film vibration mode with low radiation efficiency as shown in FIG. Therefore, the radiated noise in the high frequency band is as shown in FIG.
It can be seen that the head cover 1 according to the invention is reduced. In the head cover 1 according to the invention, the membrane 1
Since the next vibration mode shifts to the low frequency side of several hundred Hz, the radiated noise in that region is worse than the conventional product, but that region is audible to the high frequency region after 1 kHz. Is also a relatively low region, and its effect on the radiated noise as a whole is small.
【０００９】第１実施の形態では従来ヘッドカバー１内
部にあったバッフルプレート３を天面に配置した構造を
取るため、従来に比べて部品点数を増やすことなく騒音
低減が達成できブローバイガス通路の気密性保持も容易
となる。また、ヘッドカバー１の縦断面形状がＨ型であ
ることから側壁中央に桁が入った構造となるため、側壁
の１次の膜振動モードが抑えられると共に、従来ヘッド
カバーの膜振動を励起する一因となっていた側壁の口開
き振動モードも抑制され、騒音低減効果をより高めてい
る。In the first embodiment, the structure in which the baffle plate 3 inside the conventional head cover 1 is arranged on the top surface is adopted, so that noise reduction can be achieved without increasing the number of parts as compared with the conventional case, and the air-tightness of the blow-by gas passage is achieved. It becomes easy to maintain sex. Further, since the head cover 1 has an H-shaped vertical cross-section, it has a structure in which a girder is inserted in the center of the side wall, so that the first-order film vibration mode of the side wall is suppressed and it is a factor that excites the film vibration of the conventional head cover. The opening vibration mode of the side wall, which had become the above, is also suppressed, and the noise reduction effect is further enhanced.
【００１０】次に本発明の第２実施の形態を図９〜１０
について説明する。図９は図１と同様にヘッドカバー構
造の平面図を示すものである。第２実施の形態の構成は
第１実施の形態とほぼ同一であるが、リブ８ａの位置が
バッフルプレート３のほぼ長手方向中央に移動し、その
リブ８ａの中、バッフルプレート３のほぼ中心位置にヘ
ッドカバー１とバッフルプレート３をネジ４で結合する
ボス２１を設け、リブ８ｂをリブ８ａより左側のバッフ
ルプレート３のほぼ中央に設けている。このような構造
にすることにより、バッフルプレート３の膜１次共振は
その腹位置にリブ８ａ及びボス２１があるため振動が抑
制され、膜２次共振（図１０参照）はその腹位置にリブ
８ｂがあるため振動が抑制される。その結果、発音効率
の高い膜振動１次、２次の振動が抑制され、膜振動１
次、２次共振の発生する周波数領域における騒音の悪化
代を抑えることができる。ただし、このようなリブ８
ａ，８ｂ、ボス２１によるバッフルプレート３の補強は
結果として（１）式の１ｘ、１ｙの値を小さくし膜振動
の共振周波数の上昇をもたらす恐れもあるので、バッフ
ルプレート３の縦弾性係数をより低めに設定したり、板
密度を大きくするといったことも合わせて実施したほう
が良い。図９でリブ８ａの位置がバッフルプレート３の
長手方向中央よりやや左に寄っているのは、ＰＣＶバル
ブ６がある影響で、膜１次共振の腹位置が図６にも示す
ようにやや左位置によるためである。Next, a second embodiment of the present invention will be described with reference to FIGS.
Will be described. FIG. 9 shows a plan view of the head cover structure as in FIG. The structure of the second embodiment is almost the same as that of the first embodiment, but the position of the rib 8a is moved to the approximate center of the baffle plate 3 in the longitudinal direction, and the central position of the baffle plate 3 is in the rib 8a. A boss 21 for connecting the head cover 1 and the baffle plate 3 with a screw 4 is provided, and a rib 8b is provided substantially in the center of the baffle plate 3 on the left side of the rib 8a. With such a structure, the vibration of the membrane primary resonance of the baffle plate 3 is suppressed because the rib 8a and the boss 21 are present at the antinode position, and the membrane secondary resonance (see FIG. 10) is ribbed at the antinode position. Since there is 8b, vibration is suppressed. As a result, the first and second vibrations of the film vibration with high sound generation efficiency are suppressed, and the film vibration 1
It is possible to suppress an increase in noise in the frequency range where secondary and secondary resonance occur. However, such rib 8
Since the reinforcement of the baffle plate 3 by the a, 8b and the boss 21 may result in a decrease in the values of 1x and 1y in the equation (1) and an increase in the resonance frequency of the membrane vibration, the longitudinal elastic coefficient of the baffle plate 3 is changed. It is better to set it lower or increase the plate density. In FIG. 9, the position of the rib 8a is located slightly left of the longitudinal center of the baffle plate 3 because of the influence of the PCV valve 6, and the antinode position of the membrane primary resonance is slightly left as shown in FIG. This is because it depends on the position.
【００１１】次に本発明の第３実施の形態を図１１〜１
２について説明する。図１１は図１と同様にヘッドカバ
ー構造の平面図を示すものである。第３実施の形態の構
成も第１実施の形態とほぼ同一であるが、バッフルプレ
ート３の大きさがヘッドカバー１の天面のほぼ半分とな
り、バッフルプレート３の長手方向に隣接してＰＣＶバ
ルブ６が配置される構造となっている。バッフルプレー
ト３の大きさは縦寸法がＰＣＶバルブカバー直径と略同
じで横寸法がＰＣＶバルブカバー直径の約５倍で、材質
及び板厚は両者とも同一である。このような構造にする
ことにより、図１２に示すように略同一周波数において
ＰＣＶバルブカバーの膜１次共振とバッフルプレート３
の高次膜共振が同時に発生する様になる。バッフルプレ
ート３とＰＣＶバルブ６はブローバイガス通路として連
通しているため、内部の空気圧変動を最小にするために
バッフルプレート３右端の膜振動とＰＣＶバルブカバー
の膜振動は略逆相となる。そのためバッフルプレート３
右端で発生する放射音とＰＣＶバルブカバーの放射音は
互いを打ち消すように作用し、結果としてＰＣＶバルブ
カバーからの放射音が低減される。Next, a third embodiment of the present invention will be described with reference to FIGS.
2 will be described. FIG. 11 shows a plan view of the head cover structure as in FIG. The configuration of the third embodiment is also substantially the same as that of the first embodiment, but the size of the baffle plate 3 is almost half of the top surface of the head cover 1, and the PCV valve 6 is adjacent to the baffle plate 3 in the longitudinal direction. Has a structure that is arranged. The size of the baffle plate 3 is approximately the same as the diameter of the PCV valve cover in the vertical dimension, and is approximately 5 times the diameter of the PCV valve cover in the lateral dimension, and the material and the plate thickness of both are the same. With such a structure, as shown in FIG. 12, the primary resonance of the membrane of the PCV valve cover and the baffle plate 3 at approximately the same frequency.
The higher-layer resonances of are simultaneously generated. Since the baffle plate 3 and the PCV valve 6 communicate with each other as a blow-by gas passage, the membrane vibration of the right end of the baffle plate 3 and the membrane vibration of the PCV valve cover are in substantially opposite phases in order to minimize the fluctuation of the internal air pressure. Therefore baffle plate 3
The radiated sound generated at the right end and the radiated sound of the PCV valve cover act to cancel each other, and as a result, the radiated sound from the PCV valve cover is reduced.
【００１２】[0012]
【発明の効果】 以上説明してきたように、請求項１に
関わるヘッドカバー構造によれば、バルブ、カムシャフ
ト、ロッカーアーム等から構成される動弁機構の保護機
能とブローバイガス還元機能を兼ね備えた内燃エンジン
のヘッドカバーにおいて、前記ヘッドカバーは高剛性部
材で構成されると共に、前記ヘッドカバー天面にブロー
バイガス通路を付設し、前記ブローバイガス通路を低剛
性の被覆部材で被覆する構成としたので、ヘッドカバー
の剛性を保ちつつヘッドカバー表面の膜一次共振周波数
低下により騒音の放射効率を低下させ、剛性確保と騒音
低減の両方の効果が得られる。また、請求項２に関わる
ヘッドカバー構造によれば、請求項１記載の発明におい
て、前記ヘッドカバー縦断面形状が略Ｈ型形状であり、
該ヘッドカバー天面に形成された凹部を低剛性の被覆部
材で被覆して、ブローバイガス通路を形成することによ
り、請求項１記載の作用に加えてヘッドカバー側壁の膜
振動及び口開き振動を抑制し、騒音低減効果をより高め
る効果が得られる。請求項３に関わるヘッドカバー構造
によれば、請求項１または２記載の発明において、前記
ヘッドカバーと前記被覆部材との結合部が前記被覆部材
の低次膜振動モードの腹位置に位置する構成としたの
で、請求項１記載の効果に加えて発音効率の高い低次の
膜振動モードの発生を抑制して騒音放射効率を更に低減
し、騒音をより低く抑えるという効果が得られる。請求
項４に関わるヘッドカバー構造によれば、請求項１また
は２記載の発明において、前記ヘッドカバー天面と前記
被覆部材との間に設けられ、ブローバイガス通路を形成
する仕切り板が前記被覆部材の低次膜振動モードの腹位
置に位置する構成としたので、前項と同様に、請求項１
記載の効果に加えて発音効率の高い低次の膜振動モード
の発生を抑制して騒音放射効率を更に低減し、騒音をよ
り低く抑えるという効果が得られる。請求項５に関わる
ヘッドカバー構造によれば、請求項１または２記載の発
明において、前期被覆部材の長手方向に隣接してＰＣＶ
バルブが設けられ、前記被覆部材と前記ＰＣＶバルブが
バーの材質及び板厚がほぼ同等であり、前記被覆部材の
縦横寸法が前記ＰＣＶバルブカバー直径の略整数倍にな
っていることにより、請求項１記載の効果に加えて、前
記被覆部材端部の膜振動モードと前記ＰＣＶバルブカバ
ーの膜振動モードを略位相に発生させることによりＰＣ
Ｖバルブカバーの放射騒音を低減するという効果が得ら
れる。As described above, according to the head cover structure of the first aspect, the internal combustion engine having both the protective function of the valve mechanism including the valve, the camshaft, the rocker arm, and the blow-by gas reducing function. In the engine head cover, the head cover is composed of a high-rigidity member, a blow-by gas passage is attached to the top surface of the head cover, and the blow-by gas passage is covered with a low-rigidity covering member. While maintaining the above, the primary resonance frequency of the film on the surface of the head cover is reduced to reduce the radiation efficiency of noise, and both the effects of securing rigidity and reducing noise are obtained. Further, according to the head cover structure relating to claim 2, in the invention according to claim 1, the head cover longitudinal cross-sectional shape is substantially H-shaped,
The recess formed on the top surface of the head cover is covered with a low-rigidity covering member to form a blow-by gas passage, thereby suppressing film vibration and opening vibration on the side wall of the head cover in addition to the function of claim 1. The effect of further increasing the noise reduction effect can be obtained. According to the head cover structure relating to claim 3, in the invention according to claim 1 or 2, the joint portion between the head cover and the covering member is located at an antinode position of the covering member in the low order membrane vibration mode. Therefore, in addition to the effect described in the first aspect, it is possible to obtain the effect of suppressing the generation of the low-order membrane vibration mode having a high sounding efficiency, further reducing the noise radiation efficiency, and further suppressing the noise. According to the head cover structure relating to claim 4, in the invention according to claim 1 or 2, the partition plate which is provided between the top surface of the head cover and the covering member and which forms a blow-by gas passage is a low member of the covering member. Since the structure is located at the antinode position of the next membrane vibration mode, the same as in the preceding paragraph,
In addition to the effects described above, it is possible to obtain the effect of suppressing the generation of a low-order membrane vibration mode having high sound emission efficiency, further reducing the noise radiation efficiency, and further suppressing the noise. According to the head cover structure according to claim 5, in the invention according to claim 1 or 2, the PCV is adjacent to the covering member in the longitudinal direction.
A valve is provided, the material of the bar and the plate thickness of the covering member and the PCV valve are substantially equal, and the vertical and horizontal dimensions of the covering member are substantially integral multiples of the PCV valve cover diameter. In addition to the effect described in 1, the PCV by generating the film vibration mode of the end portion of the covering member and the film vibration mode of the PCV valve cover in substantially phase
The effect of reducing the radiated noise of the V valve cover is obtained.
【図１】本発明第１実施の形態におけるヘッドカバー構
造の平面図である。FIG. 1 is a plan view of a head cover structure according to a first embodiment of the present invention.
【図２】第１実施の形態におけるヘッドカバー構造の縦
断面図である。FIG. 2 is a vertical cross-sectional view of the head cover structure according to the first embodiment.
【図３】長方形板の１次の膜振動モードを示す図であ
る。FIG. 3 is a diagram showing a first-order membrane vibration mode of a rectangular plate.
【図４】長方形板の高次の膜振動モード（ｍ＝３，ｎ＝
２）を示す図である。FIG. 4 shows higher-order membrane vibration modes of a rectangular plate (m = 3, n =
It is a figure which shows 2).
【図５】図４の膜振動モードを各種音源の集合体と近似
した図である。FIG. 5 is a diagram in which the membrane vibration mode of FIG. 4 is approximated to an aggregate of various sound sources.
【図６】従来のヘッドカバー表面の１次膜振動モードを
示す図である。FIG. 6 is a diagram showing a primary film vibration mode of a conventional head cover surface.
【図７】図６とほぼ同じ周波数帯域における第１実施の
形態のヘッドカバー表面の膜振動モードを示す図であ
る。FIG. 7 is a diagram showing a film vibration mode of the head cover surface of the first embodiment in substantially the same frequency band as FIG.
【図８】第１実施の形態の騒音低減効果を表す図であ
る。FIG. 8 is a diagram showing a noise reduction effect of the first embodiment.
【図９】本発明第２実施の形態におけるヘッドカバー構
造の平面図である。FIG. 9 is a plan view of a head cover structure according to a second embodiment of the present invention.
【図１０】第２実施の形態におけるヘッドカバー表面の
２次の膜振動モードを示す図である。FIG. 10 is a diagram showing a secondary film vibration mode on the surface of a head cover in the second embodiment.
【図１１】本発明第３実施の形態におけるヘッドカバー
構造の平面図である。FIG. 11 is a plan view of a head cover structure according to a third embodiment of the present invention.
【図１２】第３実施の形態におけるＰＣＶバルブカバー
膜１次共振時の被覆部材表面の膜振動モードを示す図で
ある。FIG. 12 is a diagram showing a film vibration mode of a surface of a covering member at the time of primary resonance of a PCV valve cover film in the third embodiment.
【図１３】従来技術を示す構造図である。FIG. 13 is a structural diagram showing a conventional technique.
【図１４】従来技術を示す構造図である。FIG. 14 is a structural diagram showing a conventional technique.
１ ヘッドカバー ２ ガスケット ３ バッフルプレート（被覆部材） ４ ネジ ５ パイプ ６ ＰＣＶバルブ ７ ホース ８ リブ ８ａ リブ ８ｂ リブ ９ ボルト １０ オイルキャップ １１ ヘッド １２ カム １３ カムキャップ ２１ ボス 1 Head Cover 2 Gasket 3 Baffle Plate (Coating Member) 4 Screw 5 Pipe 6 PCV Valve 7 Hose 8 Rib 8a Rib 8b Rib 9 Bolt 10 Oil Cap 11 Head 12 Cam 13 Cam Cap 21 Boss
Claims (5)
等から構成される動弁機構の保護機能とブローバイガス
還元機能を兼ね備えた内燃エンジンのヘッドカバーにお
いて、前記ヘッドカバーは高剛性部材で構成されると共
に、前記ヘッドカバー天面にブローバイガス通路を付設
し、前記ブローバイガス通路を低剛性の被覆部材で被覆
したことを特徴とするヘッドカバー構造。1. A head cover of an internal combustion engine, which has a function of protecting a valve mechanism including a valve, a camshaft, a rocker arm, and the like, and a function of returning blow-by gas, wherein the head cover is made of a highly rigid member, and A blow-by gas passage is attached to the top surface of the head cover, and the blow-by gas passage is covered with a low-rigidity covering member.
状であり、該ヘッドカバー天面に形成された凹部を低剛
性の被覆部材で被覆することにより、ブローバイガス通
路を形成することを特徴とする請求項１記載のヘッドカ
バー構造。2. The blow-by gas passage is formed by forming the vertical cross section of the head cover into a substantially H shape, and by covering the recess formed on the top surface of the head cover with a low-rigidity covering member. The head cover structure according to claim 1.
合部が前記被覆部材の低次膜振動モードの腹位置に位置
することを特徴とする請求項１または２記載のヘッドカ
バー構造。3. The head cover structure according to claim 1, wherein a joint portion between the head cover and the covering member is located at an antinode position of the covering member in a low order film vibration mode.
の間に設けられ、ブローバイガス通路を形成する仕切り
板が前記被覆部材の低次膜振動モードの腹位置に位置す
ることを特徴とする請求項１または２記載のヘッドカバ
ー構造。4. A partition plate, which is provided between the top surface of the head cover and the covering member and forms a blow-by gas passage, is located at an antinode position of the covering member in a low-order film vibration mode. Item 3. The head cover structure according to item 1 or 2.
Ｖバルブが設けられ、前記被覆部材と前記ＰＣＶバルブ
カバーの材質及び板厚がほぼ同等であり、前記被覆部材
の縦横寸法が前記ＰＣＶバルブカバー直径の略整数倍に
なっていることを特徴とする請求項１また２記載のヘッ
ドカバー構造。5. A PC adjacent to the covering member in the longitudinal direction.
A V-valve is provided, the cover member and the PCV valve cover are substantially the same in material and plate thickness, and the vertical and horizontal dimensions of the cover member are substantially integral multiples of the PCV valve cover diameter. The head cover structure according to claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1062396A JPH09203347A (en) | 1996-01-25 | 1996-01-25 | Cylinder-head cover structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1062396A JPH09203347A (en) | 1996-01-25 | 1996-01-25 | Cylinder-head cover structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09203347A true JPH09203347A (en) | 1997-08-05 |
Family
ID=11755357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1062396A Pending JPH09203347A (en) | 1996-01-25 | 1996-01-25 | Cylinder-head cover structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09203347A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6520134B1 (en) * | 2001-10-11 | 2003-02-18 | Dana Corporation | Screen printable foam coating for sealing and vibration isolation of cam cover baffles |
| FR2934013A1 (en) * | 2008-07-16 | 2010-01-22 | Mann & Hummel Gmbh | Noise attenuating method for e.g. air filter box, of motor vehicle, involves adding auxiliary wall to portion of surface of main wall for covering surface while forming space between walls to obtain double wall for sound insulation |
| JP2011207099A (en) * | 2010-03-30 | 2011-10-20 | Aisin Keikinzoku Co Ltd | Caulking structure |
| WO2016006361A1 (en) * | 2014-07-10 | 2016-01-14 | 日産自動車株式会社 | Electronic-component-accommodating structure |
-
1996
- 1996-01-25 JP JP1062396A patent/JPH09203347A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6520134B1 (en) * | 2001-10-11 | 2003-02-18 | Dana Corporation | Screen printable foam coating for sealing and vibration isolation of cam cover baffles |
| FR2934013A1 (en) * | 2008-07-16 | 2010-01-22 | Mann & Hummel Gmbh | Noise attenuating method for e.g. air filter box, of motor vehicle, involves adding auxiliary wall to portion of surface of main wall for covering surface while forming space between walls to obtain double wall for sound insulation |
| JP2011207099A (en) * | 2010-03-30 | 2011-10-20 | Aisin Keikinzoku Co Ltd | Caulking structure |
| WO2016006361A1 (en) * | 2014-07-10 | 2016-01-14 | 日産自動車株式会社 | Electronic-component-accommodating structure |
| JPWO2016006361A1 (en) * | 2014-07-10 | 2017-05-25 | 日産自動車株式会社 | Electronic component housing structure |
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