JP2555411B2 - Valve train for internal combustion engine - Google Patents
Valve train for internal combustion engineInfo
- Publication number
- JP2555411B2 JP2555411B2 JP63081602A JP8160288A JP2555411B2 JP 2555411 B2 JP2555411 B2 JP 2555411B2 JP 63081602 A JP63081602 A JP 63081602A JP 8160288 A JP8160288 A JP 8160288A JP 2555411 B2 JP2555411 B2 JP 2555411B2
- Authority
- JP
- Japan
- Prior art keywords
- valve
- slope
- cam
- engine
- hydraulic tappet
- 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.)
- Expired - Lifetime
Links
Landscapes
- Valve-Gear Or Valve Arrangements (AREA)
Description
【発明の詳細な説明】 A.発明の目的 （１） 産業上の利用分野 本発明は、機関弁を閉弁方向へ付勢する弁ばねと、機
関弁を開弁させるリフト部及び機関弁の閉弁を許容する
ベース部を有するカムと、このカムから機関弁に至る力
の伝達系に介装されて弁頭間隙を排除する油圧タペット
とを備えた内燃機関の動弁装置の改良に関する。DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a valve spring for urging an engine valve in a valve closing direction, a lift portion for opening the engine valve, and an engine valve. The present invention relates to an improvement in a valve operating system of an internal combustion engine including a cam having a base portion that allows valve closing and a hydraulic tappet that eliminates a valve head clearance by being interposed in a force transmission system from the cam to an engine valve.
（２） 従来の技術 従来、かかる動弁装置において、カム軸の芯振れや撓
みに起因するカムの振動により機関弁に閉弁不良を惹起
するのを防止するために、カムのベース部に閉弁点から
開弁点（即ちリフト部の開弁緩衝曲線の開始点）に向っ
て下り勾配をつけると共に、それらの二点間の落差を油
圧タペットの遊びに相当するリフト量またはそれよりや
ゝ小さいリフト量に設定して、機関弁の開弁時期を狂わ
せることなく、ベース部のリフト方向の振れをベース部
の下り勾配と相殺させるようにすることが知られている
（特開昭59−43911号公報参照）。(2) Related Art Conventionally, in such a valve operating device, in order to prevent the valve failure of the engine valve from being caused by the vibration of the cam due to the center runout or bending of the cam shaft, the valve is closed at the base portion of the cam. A downward slope is provided from the valve point toward the valve opening point (that is, the starting point of the valve opening cushioning curve of the lift portion), and the head difference between these two points is the lift amount equivalent to the play of the hydraulic tappet or slightly more than that. It is known that a small lift amount is set so as to offset the swing in the lift direction of the base portion with the downward gradient of the base portion without disturbing the opening timing of the engine valve (Japanese Patent Laid-Open No. 59-59). See 43911 bulletin).
（３） 発明が解決しようとする課題 上記のようにカムのベース部に閉弁点から開弁点に向
って直線的に下り勾配をつけるものでは、その下り勾配
が比較的緩やかになるため、機関弁の閉弁直後にベース
部にリフト方向の大きな振れが起こったときには、これ
を上記下り勾配で相殺することが困難である。殊に、ベ
ース部の大きな振れは機関弁の閉弁直後に発生し易い。(3) Problems to be Solved by the Invention As described above, in the case where the base portion of the cam is provided with a straight downward gradient from the valve closing point to the valve opening point, the downward gradient becomes relatively gentle. When a large swing in the lift direction occurs in the base immediately after the engine valve is closed, it is difficult to offset this with the above-described downward slope. In particular, a large swing of the base portion is likely to occur immediately after the engine valve is closed.
本発明は、かかる事情に鑑みてなされたもので、機関
弁の閉弁直後、カムのベース部にリフト方向の大きな振
れが生じても、その振れの影響を機関弁に及ぼさないよ
うにした内燃機関の動弁装置を提供することを目的とす
る。The present invention has been made in view of the above circumstances. Even if a large swing in the lift direction occurs in the base portion of the cam immediately after the engine valve is closed, the internal combustion engine is configured so as not to exert the influence of the swing on the engine valve. It is an object to provide a valve operating system for an engine.
B.発明の構成 （１） 課題を解決するための手段 上記目的を達成するために、本発明は、機関弁を閉弁
方向へ付勢する弁ばねと、機関弁を開弁させるリフト部
及び機関弁の閉弁を許容するベース部を有するカムと、
フリーボール型のチェック弁を有して、カムから機関弁
に至る力の伝達系に介装される弁頭間隙排除用の油圧タ
ペットとを備えた、内燃機関の動弁装置であって、カム
のベース部に、閉弁点から所定の中間点に向って下る下
り勾配部と、前記中間点以降からリフト部の開弁緩衝曲
線の開始点に向って上る上り勾配部とを設けると共に、
その上り勾配部の勾配を、リフト部が作動する前にチェ
ック弁が閉弁しないよう該リフト部の開弁緩衝曲線の勾
配より緩くしたことを特徴とする。B. Configuration of the Invention (1) Means for Solving the Problems To achieve the above object, the present invention provides a valve spring for urging an engine valve in a valve closing direction, a lift portion for opening the engine valve, and A cam having a base portion that allows closing of the engine valve,
A valve operating system for an internal combustion engine, comprising a free-ball type check valve, and a hydraulic tappet for eliminating a valve head clearance, which is interposed in a force transmission system from a cam to an engine valve, the cam comprising: In the base portion of the, with a downward slope portion that goes down from the valve closing point toward a predetermined intermediate point, and an upward slope portion that goes up from the intermediate point and thereafter toward the starting point of the valve opening cushioning curve of the lift portion,
It is characterized in that the gradient of the ascending gradient portion is made gentler than the gradient of the valve opening buffer curve of the lift portion so that the check valve does not close before the lift portion operates.
尚、下り勾配部の終点と上り勾配部の始点とは互いに
一致させてもよく、また相互間に適当な距離を置いても
よい。It should be noted that the end point of the descending slope portion and the start point of the ascending slope portion may coincide with each other, or may have an appropriate distance therebetween.
また本発明は、上記特徴に加えて、下り勾配部の油圧
タペットの伸縮量に換算した高低差をＡ、上り勾配部の
油圧タペットの伸縮量に換算した高低差をＢ、油圧タペ
ットの遊びをL0としたとき、 L0≧Ａ≧Ｂ 上式が成立するようにＡ及びＢを設定したことを特徴
とする。Further, in addition to the above characteristics, the present invention is such that the height difference converted into the expansion / contraction amount of the hydraulic tappet in the downward slope portion is A, the height difference converted into the expansion / contraction amount of the hydraulic tappet in the upward slope portion B, and the play of the hydraulic tappet is When L 0 , L 0 ≧ A ≧ B is characterized in that A and B are set so that the above equation is satisfied.
（２） 作用 第１の特徴によれば、前記従来例の如くカムのベース
部が全長に亘り下り勾配とされる構造のものと比較し
て、特にベース部前半の下り勾配部にはそのベース部後
半部の上り勾配部の存在に基づいて大なる下り勾配をつ
けることができるから、機関弁の閉弁直後に生じるベー
ス部の大なるリフト方向の振れでも上記下り勾配部の勾
配によって相殺することができ、また相殺しきれない振
れは油圧タペットの遊びによって吸収される。(2) Operation According to the first feature, compared to the structure in which the base portion of the cam has a downward slope over the entire length as in the above-described conventional example, the base is particularly formed in the downward slope portion in the first half of the base portion. Since a large downward slope can be provided based on the existence of an upward slope portion in the latter half of the engine part, even a large lift direction swing of the base portion that occurs immediately after closing the engine valve is offset by the slope of the downward slope portion. Any runout that can and cannot be offset is absorbed by the play of the hydraulic tappet.
また、このようにベース部前半の下り勾配部の勾配を
大きくするためにベース部後半に上り勾配部を特設して
も、その上り勾配部の勾配は、リフト部が作動する前に
油圧タペットのフリーボール型チェック弁が開弁しない
よう該リフト部の開弁緩衝曲線の勾配よりも緩く設定さ
れるから、この上り勾配部により油圧タペットが踏張機
能を発揮して機関弁を開弁させてしまうことを確実に回
避でき、従って上り勾配部の特設によるも機関弁の開弁
時期が早まることはない。In addition, even if an upslope part is specially provided in the latter half of the base part in order to increase the slope of the downslope part in the first half of the base part, the slope of the upslope part of the upslope part of the hydraulic tappet before the lift part operates. Since the freeball type check valve is set to be gentler than the gradient of the valve opening buffer curve of the lift portion so that the lift valve portion does not open, the hydraulic tappet exerts a stepping function to open the engine valve. It is possible to surely avoid such a situation, and therefore, even if the upslope portion is specially provided, the opening timing of the engine valve will not be advanced.
また特に第２の特徴によれば、ベース部後半の上り勾
配による油圧タペットの作動をより確実に防止すること
ができると共に、カムのリフト部の開弁緩衝曲線を、開
弁点及びリフト部のリフト量を変えることなく自由に選
定することができる。Further, in particular, according to the second feature, the operation of the hydraulic tappet due to the upward slope in the latter half of the base portion can be more reliably prevented, and the valve opening buffer curve of the lift portion of the cam can be changed to the valve opening point and the lift portion. It can be freely selected without changing the lift amount.
（３） 実施例 以下、図面により本発明の実施例について説明する。(3) Examples Hereinafter, examples of the present invention will be described with reference to the drawings.
先ず本発明の第１実施例を示す第１図において、内燃
機関のシリンダヘッド１には燃焼室２と、この燃焼室２
に開口するポート３とが形成されており、そのポートは
吸，排気弁等の機関弁４により開閉される。First, referring to FIG. 1 showing a first embodiment of the present invention, a combustion chamber 2 is provided in a cylinder head 1 of an internal combustion engine, and the combustion chamber 2
And a port 3 that is open to the outside are formed, and the port is opened and closed by an engine valve 4 such as an intake and exhaust valve.
機関弁４はシリンダヘッド１にバルブガイド５を介し
て昇降自在に支承され、本発明による動弁装置６により
開閉駆動される。The engine valve 4 is supported by the cylinder head 1 via a valve guide 5 so as to be able to move up and down, and is opened and closed by a valve operating device 6 according to the present invention.
動弁装置６は、機関弁４の頭部に固着されたリテーナ
4aとシリンダヘッド１との間に縮設されて機関弁４を閉
じ方向に付勢する弁ばね７と、シリンダヘッド１の支持
孔８に装着される油圧タペット９と、この油圧タペット
９に揺動自在に支承されて先端部を機関弁４の頭部に係
合させるカムフォロア10と、シリンダヘッド１に支承さ
れて図示しないクランク軸より回転駆動され、カムフォ
ロア10の上側に形成されたスリッパ面10aにカムＣを係
合させるカム軸11とより構成される。The valve gear 6 is a retainer fixed to the head of the engine valve 4.
A valve spring 7 that is compressed between the cylinder head 1 and the cylinder head 1 and urges the engine valve 4 in the closing direction, a hydraulic tappet 9 that is mounted in the support hole 8 of the cylinder head 1, and a swinging motion of the hydraulic tappet 9. A cam follower 10 that is movably supported and has its tip end engaged with the head portion of the engine valve 4, and a slipper surface 10a formed on the upper side of the cam follower 10 that is supported by the cylinder head 1 and is rotationally driven by a crank shaft (not shown). And a cam shaft 11 for engaging the cam C.
上記カムＣは、第１図及び第２図に示すように、機関
弁４を開弁させるリフト部Clと、同弁４の閉弁を許容す
るベース部Cbとを有し、両部Cl,Cbの境界点の一方が閉
弁点P1、他方が開弁点P2となる。ベース部Cbは、閉弁点
P1から所定の中間点P3に向って下る下り勾配部b1と、中
間点P3から、閉弁点P2（即ちリフト部Clの開弁緩衝曲線
の開始点）に向って上る上り勾配部b2とから構成され、
この上り勾配部b2の上り勾配は、前記リフト部Clの開弁
緩衝曲線の上り勾配よりも緩く設定される。As shown in FIGS. 1 and 2, the cam C has a lift portion Cl for opening the engine valve 4 and a base portion Cb for allowing the valve 4 to be closed. One of the boundary points of Cb is the valve closing point P 1 and the other is the valve opening point P 2 . Base part Cb is the valve closing point
A down slope portion b 1 descending towards the P 1 to a predetermined intermediate point P 3, rise from the intermediate point P 3, towards the closed point P 2 (i.e. starting point of the opening cushioning curved lift portion Cl) upstream Composed of a gradient part b 2 and
The upslope of the upslope part b 2 is set to be gentler than the upslope of the valve opening buffer curve of the lift part Cl.
次に第３図により前記油圧タペット９について説明す
る。油圧タペット９は、有底のシリンダ20と、このシリ
ンダ20のシリンダ孔20aに摺動自在に嵌合してその内部
に油圧室21を画成するプランジャ22とを主たる構成要素
としており、シリンダ20が前記支持孔８に嵌着される。
プランジャ22はその外端の球状端部22aをカムフォロア1
0基端部の球状凹部10bに係合させる。Next, the hydraulic tappet 9 will be described with reference to FIG. The hydraulic tappet 9 has a bottomed cylinder 20 and a plunger 22 slidably fitted in a cylinder hole 20a of the cylinder 20 and defining a hydraulic chamber 21 therein, as main constituent elements. Are fitted into the support holes 8.
The plunger 22 has a spherical end 22a at the outer end thereof which is a cam follower 1
0 It is engaged with the spherical recess 10b at the base end.
プランジャ22には油溜室23と、この油溜室23を前記油
圧室21に連通する弁孔24とが設けられており、油溜室23
は、プランジャ22の側壁の油孔25、シリンダ20及びプラ
ンジャ22の摺動面間の環状油路27及びシリンダ20の側壁
の油孔26を介して、シリンダヘッド１に穿設された給油
路32に連通し、この給油路32を図示しない油ポンプの吐
出口に連なる。したがって機関の運転中、油溜室23は油
ポンプから送られる油によって常に満たされる。The plunger 22 is provided with an oil reservoir chamber 23 and a valve hole 24 that connects the oil reservoir chamber 23 to the hydraulic chamber 21.
Is an oil supply passage 32 formed in the cylinder head 1 through an oil hole 25 in the side wall of the plunger 22, an annular oil passage 27 between the sliding surfaces of the cylinder 20 and the plunger 22, and an oil hole 26 in the side wall of the cylinder 20. The oil supply passage 32 is connected to the discharge port of an oil pump (not shown). Therefore, during operation of the engine, the oil sump 23 is constantly filled with oil sent from the oil pump.
プランジャ22の下端にはハット形のバルブケージ28の
フランジ部28aが嵌合され、そしてかしめリング33によ
り固着される。このバルブケージ28には、それに開閉ス
トロークを規定されつゝ前記弁孔24を開閉するフリーボ
ール型のチェック弁29が収容される。即ち、チェック弁
29は閉弁方向にばね付勢されてはおらず、油圧室21の昇
圧にのみ依存して弁孔24を閉じるようになっている。A flange portion 28a of a hat-shaped valve cage 28 is fitted to the lower end of the plunger 22 and fixed by a caulking ring 33. The valve cage 28 accommodates a free-ball type check valve 29 that opens and closes the valve hole 24 with an opening / closing stroke defined therein. That is, the check valve
The valve 29 is not spring-biased in the valve closing direction, and the valve hole 24 is closed only by increasing the pressure in the hydraulic chamber 21.
更に油圧室21にはプランジャ22をシリンダ20の上方へ
突出させるように付勢する伸長ばね31が収容される。Further, the hydraulic chamber 21 accommodates an extension spring 31 that urges the plunger 22 to project above the cylinder 20.
而して、カムＣの回転に伴いリフト部Clがカムフォロ
ア10のスリッパ面10aに押圧力を加えると、油圧タペッ
ト９では、プランジャ22が油圧室21側へ押圧されるの
で、油圧室21が昇圧し始め、該室21から弁孔24を通して
油溜室23へ少量の油が流出することによりプランジャ22
が初期沈みを起こした後、チェック弁29が弁孔24を閉じ
て油圧室21の油圧を保持し、続いて油圧室21の油中に混
在する気泡の圧縮等に起因してプランジャ22が弾性沈み
を起こした後、油圧室21の油圧が急上昇し、その油圧に
よりプランジャ22が踏張力が発揮する結果、カムフォロ
ア10は、プランジャ22の球状端部22aを支点として、リ
フト部Clにより下方へ揺動され、弁ばね７の力に抗して
機関弁４を開く。When the lift portion Cl applies a pressing force to the slipper surface 10a of the cam follower 10 with the rotation of the cam C, the plunger 22 of the hydraulic tappet 9 is pressed toward the hydraulic chamber 21 side. And a small amount of oil flows out of the chamber 21 through the valve hole 24 into the oil reservoir chamber 23.
After the initial sinking, the check valve 29 closes the valve hole 24 to maintain the hydraulic pressure in the hydraulic chamber 21, and subsequently the plunger 22 is elasticized due to the compression of bubbles mixed in the oil in the hydraulic chamber 21. After the sinking, the hydraulic pressure in the hydraulic chamber 21 suddenly rises, and as a result, the pedal tension is exerted on the plunger 22.As a result, the cam follower 10 swings downward by the lift Cl with the spherical end 22a of the plunger 22 as the fulcrum. The engine valve 4 is opened against the force of the valve spring 7.
機関弁４の開弁中、油圧室21の高圧の油がシリンダ20
及びプランジャ22の摺動間隙へ僅かに漏洩するため、プ
ランジャ22はリーク沈みを起こす。While the engine valve 4 is open, high pressure oil in the hydraulic chamber 21
Also, the plunger 22 slightly leaks to the sliding gap of the plunger 22, so that the plunger 22 leaks and sinks.
次に、カムＣのベース部Cbがカムフォロア10に到来す
ると、弁ばね７が機関弁４をカムフォロア10と共に押上
げて閉弁位置に戻す。他方、油圧タペット９では伸長ば
ね31がプランジャ22を伸長復帰させてカムフォロア10の
スリッパ面10aをカム11aに当接させ、これによって弁頭
間隙を排除する。Next, when the base portion Cb of the cam C reaches the cam follower 10, the valve spring 7 pushes up the engine valve 4 together with the cam follower 10 to return it to the closed position. On the other hand, in the hydraulic tappet 9, the extension spring 31 extends and returns the plunger 22 to bring the slipper surface 10a of the cam follower 10 into contact with the cam 11a, thereby eliminating the valve head gap.
そして、伸長ばね31のプランジャ22に対する伸長作用
により油圧室21が減圧すれば、チェック弁29が開弁する
ので、油溜室23の油が弁孔24を通して油圧室21に供給さ
れ、油圧室21からの油の流出分が補充される。When the expansion chamber 31 expands the plunger 22 to reduce the pressure in the hydraulic chamber 21, the check valve 29 opens, so that the oil in the oil reservoir 23 is supplied to the hydraulic chamber 21 through the valve hole 24. The oil spill from the tank is replenished.
こゝで、 としたとき、前記カムＣのベース部Cbにおける下り勾配
部b1の油圧タペット９の伸縮量に換算した高低差Ａ、上
り勾配部b2の油圧タペット９の伸縮量に換算した高低差
Ｂは次式が成立するように設定される。Here, Then, the height difference A converted to the expansion / contraction amount of the hydraulic tappet 9 of the downward slope part b 1 and the height difference B converted to the expansion / contraction amount of the hydraulic tappet 9 of the upward slope part b 2 in the base part Cb of the cam C are It is set so that the following equation holds.
L0＝l1A+l1B＋Ｌ≧Ａ≧Ｂ 次にこの実施例の作用について説明する。L 0 = l 1A + l 1B + L ≧ A ≧ B Next, the operation of this embodiment will be described.
第４図はカムＣの回転に伴う油圧タペット９及び機関
弁４の各変位を示すもので、同図において、点ａでリフ
ト部Clの作動によりプランジャ22が沈みを始め、点ｂで
チェック弁29が閉じ、点ｂ−ｃ間で油圧タペット９に弾
性沈みを生じ、点ｄで機関弁４の開弁が開始され、点ｅ
で機関弁４の閉弁（弁座に着座）し、点ｆ−ｇ間で前記
弾性沈みの反発力によりプランジャ22が伸び、点ｈでプ
ランジャ22が弁頭間隙を排除すべく完全復帰する。FIG. 4 shows each displacement of the hydraulic tappet 9 and the engine valve 4 due to the rotation of the cam C. In FIG. 4, the plunger 22 starts to sink due to the operation of the lift Cl at the point a, and the check valve at the point b. 29 is closed, the hydraulic tappet 9 is elastically sunk between the points bc, the opening of the engine valve 4 is started at the point d, and the point e
At this point, the engine valve 4 is closed (seated on the valve seat), the plunger 22 extends due to the repulsive force of the elastic depression between points f and g, and at point h the plunger 22 completely returns to eliminate the valve head clearance.
点ｈを過ぎると、点ｉに達するまでプランジャ22はチ
ェック弁29を開いたまゝカムＣのベース部Cbにおける下
り勾配部b1に沿って伸びて行く。特に、その下り勾配部
b1は閉弁点P1からベース部Cbの中間点P3に下っているの
で、ベース部の全長に亘って下る従来のものに比し、そ
の勾配は急であり、したがって機関弁４の閉弁直後にカ
ムｃがリフト方へ大きく振れても、その振れは下り勾配
部b1の大なる下り勾配によって相殺され、油圧タペット
９のチェック弁29の閉弁を防止し得る。その結果、機関
弁４は無用な開弁力を全く受けず、正常な閉弁状態を維
持することができる。After the point h, the plunger 22 extends along the descending slope portion b 1 of the base portion Cb of the cam C with the check valve 29 opened until the point i is reached. Especially, the downhill part
Since b 1 descends from the valve closing point P 1 to the midpoint P 3 of the base portion Cb, the slope is steeper than that of the conventional one that descends over the entire length of the base portion, and therefore the engine valve 4 Even if the cam c swings greatly toward the lift immediately after the valve is closed, the swing is offset by the large downward gradient of the downward gradient part b 1 , and the check valve 29 of the hydraulic tappet 9 can be prevented from closing. As a result, the engine valve 4 receives no unnecessary valve opening force and can maintain a normal valve closed state.
この場合、カムＣの振れが下り勾配部b1の勾配で相殺
しきれない程大であれば、残余の振れは油圧タペット９
自体の遊びL0によって吸収される。In this case, if the shake of the cam C is so large that it cannot be canceled by the slope of the downward slope part b 1 , the remaining shake will be the hydraulic tappet 9
It is absorbed by its own play L 0 .
また特に油圧タペット９が、フリーボール型のチェッ
ク弁29を有する自由チェック弁型に構成されている関係
で、その遊びL0は、初期沈み量l1A＋弾性沈み量l1B＋リ
ーク沈み量Ｌとなり、就中、L1Aは、油圧タペット９の
チェック弁29の開閉ストロークの選定により自由に大き
く設定できるから、チェック弁29の閉じ後の油圧タペッ
ト９の踏張機能を何等損じることなく遊びL0を大きく取
ることが可能であり、これによって油圧タペット９の吸
振幅を増大させ、カムＣの残余の振れを確実に吸収する
ことができる。Further, in particular, since the hydraulic tappet 9 is configured as a free check valve type having the free ball type check valve 29, the play L 0 is the initial sink amount l 1A + elastic sink amount l 1B + leak sink amount L. In particular, L 1A can be freely set to a large value by selecting the opening / closing stroke of the check valve 29 of the hydraulic tappet 9, so that the play L 1A can be played without damaging the stepping function of the hydraulic tappet 9 after the check valve 29 is closed. It is possible to take a large value of 0 , whereby the suction amplitude of the hydraulic tappet 9 can be increased, and the residual shake of the cam C can be reliably absorbed.
点ｉを過ぎると、再び点ａに達するまでプランジャ22
はカムＣのベース部Cbにおける上り勾配部b2に沿って沈
んでいくが、この上り勾配部b2の勾配はリフト部Clの開
弁緩衝曲線の勾配よりも緩くなっているから、この間の
プランジャ22の沈み速度は遅く、チェック弁29の閉弁を
もたらすには至らず、従ってこの間で油圧タペット９が
踏張機能を発揮して機関弁４を開弁させるようなことは
ない。After passing point i, the plunger 22 is reached until point a is reached again.
Of the cam C sinks along the ascending slope portion b 2 of the base portion Cb of the cam C, but the slope of the ascending slope portion b 2 is less than the slope of the valve opening buffer curve of the lift portion Cl, so that the interval between The sinking speed of the plunger 22 is slow, and the check valve 29 is not closed. Therefore, the hydraulic tappet 9 does not exert the stepping function and open the engine valve 4 during this period.
第５図及び第６図は本発明の第２及び第３実施例を示
すもので、第２実施例は、ベース部Cbにおける下り勾配
部b1の高低差Ａと上り勾配部b2の高低差Ｂとを等しく設
定した点を除けば第１実施例と同様構成であり、第３実
施例は、ベース部Cbにおける下り勾配部b1の勾配を上り
勾配部b2の勾配よりも大とした点を除けば第１実施例と
同様構成である。FIGS. 5 and 6 show the second and third embodiments of the present invention. In the second embodiment, the height difference A of the descending slope portion b 1 and the height of the ascending slope portion b 2 in the base portion Cb are shown. The structure is the same as that of the first embodiment except that the difference B is set to be the same. In the third embodiment, the slope of the downward slope portion b 1 in the base portion Cb is set larger than the slope of the upward slope portion b 2. The configuration is the same as that of the first embodiment except the above point.
また第７図は本発明の第４実施例を示すもので、油圧
タペット９を、固定のロッカ軸35に枢支されるカムフォ
ロア10の揺動端部に装着して、その先端を機関弁４頭部
に当接させた点を除けば第１実施例と同様構成であり、
図中、第１実施例と対応する部分には同一符号を付す。Further, FIG. 7 shows a fourth embodiment of the present invention, in which a hydraulic tappet 9 is attached to the swing end of a cam follower 10 pivotally supported by a fixed rocker shaft 35, and the tip thereof is attached to the engine valve 4 It has the same configuration as that of the first embodiment except that it is brought into contact with the head,
In the figure, parts corresponding to those in the first embodiment are designated by the same reference numerals.
C.発明の効果 以上のように本発明の第１の特徴によれば、カムのベ
ース部に、閉弁点から所定の中間点に向って下る下り勾
配部と、前記中間点以降からリフト部の開弁緩衝曲線の
開始点に向って上る上り勾配部とを設けたので、従来例
の如くカムのベース部が全長に亘り下り勾配とされる構
造のものと比較して、特にベース部前半の下り勾配部に
は大なる下り勾配をつけることができ、従って、油圧タ
ペットの吸振機能と相俟って、機関弁閉じ直後のベース
部の大なる振れを効果的に吸収することができる。また
このようにベース部前半の下り勾配部の勾配を大きくす
るためにベース部後半に上り勾配部を特設しても、その
上り勾配部の勾配は、リフト部が作動する前に油圧タペ
ットのフリーボール型チェック弁が閉弁しないよう該リ
フト部の開弁緩衝曲線の勾配よりも緩く設定されるの
で、この上り勾配部により油圧タペットが踏張機能を発
揮して機関弁を早めに開弁させてしまうことを確実に回
避することができ、以上の結果、機関弁の閉弁領域では
正常な閉弁状態を維持することができる。C. Effects of the Invention As described above, according to the first feature of the present invention, the base portion of the cam has a descending slope portion that descends from the valve closing point toward a predetermined intermediate point, and the lift portion from the intermediate point and thereafter. Since the upslope part that rises toward the start point of the valve opening cushioning curve is provided, compared with the conventional structure in which the base part of the cam has a downslope over the entire length, especially in the first half of the base part. A large downward slope can be added to the downward slope portion, and therefore, in combination with the vibration absorbing function of the hydraulic tappet, a large shake of the base portion immediately after the engine valve is closed can be effectively absorbed. In addition, even if an upslope part is specially provided in the latter half of the base part in order to increase the slope of the downslope part in the first half of the base part as described above, the slope of the upslope part will be free before the lift part operates. Since the ball-type check valve is set to be gentler than the gradient of the valve opening buffer curve of the lift part so that it will not close, the hydraulic tappet exerts a stepping function by this rising slope part and opens the engine valve early. As a result, it is possible to reliably prevent the engine from being closed, and as a result, it is possible to maintain a normal valve closed state in the valve closed region of the engine valve.
また油圧タペットが、フリーボール型チェック弁を有
する自由チェック弁型に構成されている関係で、その油
圧タペットの遊びは、フリーボール型チェック弁の開閉
ストロークの選定により自由に大きく設定できるから、
チェック弁の閉じ後の油圧タペットの踏張機能を何等損
じることなく遊びを大きく取ることが可能であり、これ
によって油圧タペットの吸振幅を増大させ、カムの残余
の振れを確実に吸収することができる。In addition, since the hydraulic tappet is configured as a free check valve type having a freeball type check valve, the play of the hydraulic tappet can be freely set large by selecting the opening / closing stroke of the freeball type check valve.
After the check valve is closed, a large amount of play can be taken without impairing the stepping function of the hydraulic tappet, which can increase the absorption amplitude of the hydraulic tappet and reliably absorb the residual runout of the cam. it can.
また本発明の第２の特徴によれば、ベース部後半の上
り勾配部による油圧タペットの作動をより確実に防止す
ることができ、その上カムの開弁点及びリフト部のリフ
ト量を変えずともリフト部の開弁緩衝曲線の選定を自由
に行うことができ、設計の自由度が大幅に増大する。Further, according to the second feature of the present invention, the operation of the hydraulic tappet by the ascending slope portion in the latter half of the base portion can be more reliably prevented, and the valve opening point of the upper cam and the lift amount of the lift portion are not changed. In both cases, it is possible to freely select the valve opening cushioning curve of the lift portion, which greatly increases the degree of freedom in design.
第１図ないし第４図は本発明の第１実施例を示すもの
で、第１図は全体図、第２図はカムのプロフィル展開
図、第３図は油圧タペットの縦断面図、第４図はカムの
回転に伴う油圧タペット及び機関弁の変位特性線図、第
５図及び第６図は本発明の第２及び第３実施例を示すカ
ムのプロフィル展開図、第７図は本発明の第４実施例を
示す、第１図に対応した全体図である。 Ｃ……カム、Cl……リフト部、Cb……ベース部、P1……
閉弁点、P2……開弁点、b1……下り勾配部、b2……上り
勾配部、４……機関弁、６……動弁装置、９……油圧タ
ペット、10……カムフォロア、11……カム軸、20……シ
リンダ、21……油圧室、22……プランジャ、23……油溜
室、28……バルブケージ、29……チェック弁、31……伸
長ばね1 to 4 show a first embodiment of the present invention. FIG. 1 is a general view, FIG. 2 is a profile development view of a cam, and FIG. 3 is a vertical sectional view of a hydraulic tappet. The figures are displacement characteristic diagrams of the hydraulic tappet and the engine valve due to the rotation of the cam, FIGS. 5 and 6 are cam profile development diagrams showing the second and third embodiments of the present invention, and FIG. 7 is the present invention. FIG. 7 is an overall view corresponding to FIG. 1 showing a fourth embodiment of FIG. C …… Cam, Cl …… Lift section, Cb …… Base section, P 1 ……
Valve closing point, P 2 ...... Opening point, b 1 ...... Downward slope part, b 2 ...... Upward slope part, 4 …… Engine valve, 6 …… Valve device, 9 …… Hydraulic tappet, 10 …… Cam follower, 11 …… Cam shaft, 20 …… Cylinder, 21 …… Hydraulic chamber, 22 …… Plunger, 23 …… Oil reservoir, 28 …… Valve cage, 29 …… Check valve, 31 …… Extension spring
───────────────────────────────────────────────────── フロントページの続き (72)発明者 福尾 幸一 埼玉県和光市中央１丁目４番１号 株式 会社本田技術研究所内 (56)参考文献 特開 昭59−43911（ＪＰ，Ａ) 特開 昭61−49112（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Fukuo 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Inside the Honda R & D Co., Ltd. (56) Reference JP-A-59-43911 (JP, A) JP-A-SHO 61-49112 (JP, A)
Claims (2)
（７）と、機関弁（４）を開弁させるリフト部（Cl）及
び機関弁（４）の閉弁を許容するベース部（Cb）を有す
るカム（Ｃ）と、フリーボール型のチェック弁（29）を
有して、カム（Ｃ）から機関弁（４）に至る力の伝達系
に介装される弁頭間隙排除用の油圧タペット（９）とを
備えた、内燃機関の動弁装置であって、 カム（Ｃ）のベース部（Cb）に、閉弁点（P1）から所定
の中間点（P3）に向って下る下り勾配部（b1）と、前記
中間点（P3）以降からリフト部（Cl）の開弁緩衝曲線の
開始点（P2）に向って上る上り勾配部（b2）とを設ける
と共に、その上り勾配部（b2）の勾配を、リフト部（C
l）が作動する前にチェック弁（29）が閉弁しないよう
該リフト部（Cl）の開弁緩衝曲線の勾配より緩くしたこ
とを特徴とする、内燃機関の動弁装置。1. A valve spring (7) for urging the engine valve (4) in a closing direction, a lift portion (Cl) for opening the engine valve (4) and closing of the engine valve (4) are allowed. A valve having a cam (C) having a base portion (Cb) and a free ball type check valve (29), which is interposed in a force transmission system from the cam (C) to the engine valve (4). A valve operating system for an internal combustion engine, comprising: a hydraulic tappet (9) for eliminating head gap, wherein a predetermined intermediate point (from a valve closing point (P 1 ) to a base portion (Cb) of a cam (C) ( P 3 down slope portion descending toward the) and (b 1), the intermediate point (P 3) the starting point (rising slope portion amounting toward the P 2) of the opening cushioning curved lift portion (Cl) from the following ( b 2 ) and the slope of the ascending slope part (b 2 ) is changed to the lift part (C
A valve operating device for an internal combustion engine, wherein the check valve (29) is made gentler than the gradient of the valve opening cushioning curve of the lift portion (Cl) so that the check valve (29) does not close before the operation of l).
（b1）の油圧タペット（９）の伸縮量に換算した高低差
をＡ、上り勾配部（b2）の油圧タペット（９）の伸縮量
に換算した高低差をＢ、油圧タペット（９）の遊びをL0
としたとき、 L0≧Ａ≧Ｂ 上式が成立するようにＡ及びＢを設定したことを特徴と
する、内燃機関の動弁装置。2. A those paragraph wherein, a height difference in terms of expansion and contraction amount of the hydraulic tappet (9) with a descending slope portion (b 1) A, the up slope of (b 2) of the hydraulic tappet (9) The height difference converted to the amount of expansion and contraction is B, and the play of the hydraulic tappet (9) is L 0.
In this case, L 0 ≧ A ≧ B, A and B are set so that the above equation is satisfied.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63081602A JP2555411B2 (en) | 1988-04-01 | 1988-04-01 | Valve train for internal combustion engine |
| US07/317,771 US4942854A (en) | 1988-03-03 | 1989-03-02 | Valve operating device for use in internal combustion engine |
| CA000592597A CA1326183C (en) | 1988-03-03 | 1989-03-02 | Valve operating device for use in internal combustion engine |
| EP89302186A EP0332359B1 (en) | 1988-03-03 | 1989-03-03 | Valve operating device for use in internal combustion engine |
| AU30986/89A AU607382B2 (en) | 1988-03-03 | 1989-03-03 | Valve operating device for use in internal combustion engine |
| DE89302186T DE68911173T2 (en) | 1988-03-03 | 1989-03-03 | Valve control device for internal combustion engines. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63081602A JP2555411B2 (en) | 1988-04-01 | 1988-04-01 | Valve train for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01253511A JPH01253511A (en) | 1989-10-09 |
| JP2555411B2 true JP2555411B2 (en) | 1996-11-20 |
Family
ID=13750866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63081602A Expired - Lifetime JP2555411B2 (en) | 1988-03-03 | 1988-04-01 | Valve train for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2555411B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5614305B2 (en) * | 2011-01-25 | 2014-10-29 | トヨタ自動車株式会社 | Variable valve operating apparatus and internal combustion engine provided with the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5943911A (en) * | 1982-09-03 | 1984-03-12 | Toyota Motor Corp | Cam of internal-combustion engine |
| JPS6149112A (en) * | 1984-08-17 | 1986-03-11 | Fuji Heavy Ind Ltd | Valve moving mechanism of engine |
-
1988
- 1988-04-01 JP JP63081602A patent/JP2555411B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01253511A (en) | 1989-10-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0717765Y2 (en) | Hydraulic hydraulic lash adjuster device | |
| JPS5943911A (en) | Cam of internal-combustion engine | |
| JP2555411B2 (en) | Valve train for internal combustion engine | |
| JPH089963B2 (en) | Valve train for internal combustion engine | |
| JPS622244Y2 (en) | ||
| JPH057451Y2 (en) | ||
| JPH0816441B2 (en) | Valve train for internal combustion engine | |
| JPH01301905A (en) | Valve system for internal combustion engine | |
| JP2007211615A (en) | Valve system for internal combustion engine | |
| JPS6111408A (en) | Forced driven valve device of engine | |
| JPS5910329Y2 (en) | Sealed valve gap automatic adjustment device | |
| US11391224B2 (en) | Compression-release type engine brake | |
| JPS647201Y2 (en) | ||
| JPH0625524B2 (en) | Valve drive for internal combustion engine | |
| JPS6327048Y2 (en) | ||
| JPS61286509A (en) | Hydraulic tappet for internal-combustion engine | |
| JPS6235841Y2 (en) | ||
| JPS633365Y2 (en) | ||
| JP2563796Y2 (en) | Hydraulic valve gear for internal combustion engine | |
| JPS6029614Y2 (en) | Oil tappet oil leakage prevention device | |
| JPS6291612A (en) | Hydraulic tappet for internal combustion engine | |
| JPS5910326Y2 (en) | Lush adjuster support mechanism | |
| JP2528009Y2 (en) | Hydraulic lash adjuster for internal combustion engine | |
| JPH0518215A (en) | Ship shaped rocker arm type valve system of overhead valve engine | |
| JPH0223217A (en) | Hydraulic rush adjustor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20070905 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080905 Year of fee payment: 12 |
|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080905 Year of fee payment: 12 |