JPH0392511A - Valve drive for engine - Google Patents

Abstract

PURPOSE:To restrict the wear of a cam and a lifter and reduce their sizes by forming a follower portion of a lifter in sliding contact with the cam in a spherical shape, and forming the cam surface in sliding contact with the lifter of the cam with an arcuate curvature. CONSTITUTION:At the time of engine operation, a lifter 3 in sliding contact with a cam surface 8, following the rotation of a cam shaft 11, reciprocates within a fitting hole 5, while compressing a valve spring 6 and allowing it to expand, to drive a valve 1 to be opened and closed. If the amount of lift of the valve 1 is increased here, the travel amount during which the cam surface 8 of a cam 2 is in contact with the follower portion 7 of the lifter 3 increases, necessitating an increase in the diameter of the lifter 3 accordingly. However, since the follower portion 7 is formed with a spherically curved surface, the diameter of the lifter necessary for securing a specified travel amount need not be increased. Because the cam surface 8 is recessed with an arcuate cross section to secure a specified contact width L, contact surface pressure is reduced.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、エンジンの動弁装置の改良に関する．（従米
の技術およびその課題） 吸徘式バルブをカムにより直接的に開閉駆動する直動式
動弁Ｖｃ置は、中間部品が少ないため、バルブの開閉に
狂いが少なく、高速化が容易である。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvement of a valve train for an engine. (Junior's technology and its issues) The direct-acting valve Vc system, in which the suction valve is opened and closed directly by a cam, has fewer intermediate parts, so there is less error in opening and closing the valve, and it is easy to increase speed. .

この種の動弁装置として、例えば弟３図に示すように、
バルブ２１とカム２２の間１こリ７夕２３が介装され、
カム２２の動きを直接的にバルブ２１に伝えるものがあ
る。As this type of valve train, for example, as shown in Fig. 3,
A valve 23 is interposed between the valve 21 and the cam 22,
There is one that directly transmits the movement of the cam 22 to the valve 21.

この場合、バルブの揚程量を大きくすると、カム２２が
リフタ２３に摺接するトラベル量が大きくなり、リフタ
２３の径を拡大する心要が生じるため、シリングヘッド
上の限られたスペースによって十分なバルブの揚程量を
確保できないという制幕勺があった。In this case, if the lift amount of the valve is increased, the amount of travel in which the cam 22 slides into contact with the lifter 23 will increase, and the diameter of the lifter 23 will need to be expanded. There were concerns that it would not be possible to secure a lift of 1.

また、弟４図に示すように、リ７夕２４の頂面２５を球
状に湾曲させると、上記ＩＳ３図の例に比べてリ７夕２
５の径を小さくすることができるが、この場合、カム２
７とリフタ２４が互いに点接触となるため、接触面圧が
高くなり、摩耗量が増大するという問題点が生じた。Also, as shown in Fig. 4, if the top surface 25 of the Ri 7 bar 24 is curved into a spherical shape, the Ri 7 bar 2
The diameter of cam 5 can be made smaller, but in this case, the diameter of cam 2 can be made smaller.
Since the lifter 7 and the lifter 24 are in point contact with each other, a problem arises in that the contact surface pressure increases and the amount of wear increases.

本発明は、こうした従米の問題点を解決することを目的
とする。The present invention aims to solve these problems.

（問題点を解決するための手段） 上記目的を達或するため本発明では、カムに摺接して往
復移動するリフタを介してバルブを闇閉駆動するエンジ
ンの動弁装置において、前記リフタの前記カムに摺接す
る７才ロワ部を球面状に湾曲させるとともに、カムのリ
フタに摺接するカム面を７才ロワ部に沿って円弧状に湾
曲する断面を持つ溝状に形成した。(Means for Solving the Problems) In order to achieve the above object, the present invention provides a valve operating system for an engine that drives a valve in a closed manner via a lifter that slides on a cam and moves back and forth. The 7-year-old lower part that comes into sliding contact with the cam is curved into a spherical shape, and the cam surface that comes into sliding contact with the lifter of the cam is formed into a groove shape having a cross section that curves in an arc shape along the 7-year-old lower part.

（作用） リ７夕のフォロワ部を球面状に湾曲させることにより、
所定のトラベル量を確保するのにリフタの径を比較的に
小さくすることが可能となり、パルブ追従性を高められ
るとともに、動弁系の設計自由度をひろげることができ
る． カム面の断面を７オロ７部に沿って円弧状に湾曲させた
ため、カムとリフタが互いに線状に摺接するので、両者
の接触面圧を低減し、潤滑油面を維持して摩耗を抑制す
ることができる．（実施例） 以下、本発明の実施例を添付図面に基づいて説明する． 第１図，第２図に示すように、パルブ１とカム２の間に
はリフタ３が介装され、バルブ１はリフタ３を介してパ
ルブスプリング６の弾性復元力によりカム２に押し付け
られる。(Function) By curving the follower part of the controller into a spherical shape,
It is possible to make the diameter of the lifter relatively small in order to secure a predetermined amount of travel, improving the valve tracking ability and increasing the degree of freedom in designing the valve train. Since the cross section of the cam surface is curved into an arc along the 7th part, the cam and lifter make linear sliding contact with each other, reducing the contact pressure between the two and maintaining the lubricating oil level to suppress wear. can do. (Example) Hereinafter, an example of the present invention will be described based on the attached drawings. As shown in FIGS. 1 and 2, a lifter 3 is interposed between the valve 1 and the cam 2, and the valve 1 is pressed against the cam 2 via the lifter 3 by the elastic restoring force of the valve spring 6.

リフタ３はシリングへッド４の嵌合穴５に摺動自在に嵌
合する円筒部９と、この円筒部９の頂部にカム２に摺接
する７才ロワ部７が一体形成され、７才ロワ部７の内側
に突出する中央突起１０にバルブ１のステム頂部が当接
している。The lifter 3 is integrally formed with a cylindrical portion 9 that is slidably fitted into the fitting hole 5 of the sling head 4, and a 7-year lower portion 7 that is in sliding contact with the cam 2 on the top of the cylindrical portion 9. The top of the stem of the valve 1 is in contact with a central protrusion 10 that projects inwardly of the lower portion 7.

＋７　７夕３のフォロワ部７はカム２に向けて球面状に
湾曲して突出する． カム２はエンジンに同期して回転するカムシャ７ト１１
に一体形成され、その回転中心からの距離が所定のブａ
７イールで変化するカム面８を有し、カムシャフト１１
の回転に伴いカム面８に摺接するリフタ３をバルブスプ
リング６に抗して押し込み、パルプ１を開弁させる。The follower part 7 of +7 7 3 protrudes in a spherical curve toward the cam 2. Cam 2 is a camshaft 11 that rotates in synchronization with the engine.
The distance from the center of rotation is a predetermined distance from the center of rotation.
The camshaft 11 has a cam surface 8 that changes with 7 eels.
As the valve rotates, the lifter 3 slidingly in contact with the cam surface 8 is pushed against the valve spring 6 to open the pulp 1.

リフタ３の７才ロワ部７はカム２に向けて球面状に所定
の曲率で湾曲して突出する一方、カム２はリフタ３の径
にほぼ等しい幅を有し、そのカム面８は全周に渡って溝
状に窪んで形成される。The 7-year-old lower portion 7 of the lifter 3 protrudes spherically with a predetermined curvature toward the cam 2, while the cam 2 has a width approximately equal to the diameter of the lifter 3, and its cam surface 8 extends around the entire circumference. It is formed in a groove-like depression across the area.

カム面８の断面は上記球面状フォロワ部７とほぼ同一曲
率半径で円弧状に湾曲して形成され、７ｔａワ部７に対
して所定の接触巾Ｌを確保する．次に作用について説明
する。The cross section of the cam surface 8 is curved into an arc with substantially the same radius of curvature as the spherical follower section 7, and ensures a predetermined contact width L with respect to the spherical follower section 7. Next, the effect will be explained.

エンジン運転時、カムシャフト１１の回転に伴いカム面
８に摺接するリフタ３はパルプスプリング６を伸縮させ
なから嵌合穴５内で往復運動し、パルブ１をＷ４閉作動
させる。During engine operation, as the camshaft 11 rotates, the lifter 3 that slides against the cam surface 8 reciprocates within the fitting hole 5 without expanding or contracting the pulp spring 6, thereby operating the valve 1 to close W4.

バルブ１の揚程量を大さくすると、＋７　７夕３の７ｔ
ロワ部７に対してカム２のカム面８が摺接するトラベル
量が大きくなり、これに対応してリフタ３の径を大きく
する必要がある． ところが、リフタ３のフォロワ部７を球面状に湾曲させ
たため、平面状の７才ロワ部を有する従未のリフタに比
べて同じトラベル量を確保するのに必要なリフタの径を
縮小できる．その結果として、＋７　７夕３を小型化し
て、その軽量化によりパルプ追従性を高められるととも
に、１気筒当たり複数の吸徘スパルプを備える工冫クン
においでも、シリングへッド４上のスペースによる制約
を少なくして、動弁系の設計自由度をひろげられる．カ
ム面８は断面円弧状に窪み、フォロワ部７に？って所定
の接触巾Ｌを確保することにより、両者の接触面圧を低
減し、潤滑油膜の形或が有利となるので、カム面７およ
び７才０７部７の摩耗を抑制できる。If you increase the head of valve 1, +7 7t of 7t3
The amount of travel of the cam surface 8 of the cam 2 in sliding contact with the lower portion 7 increases, and the diameter of the lifter 3 needs to be increased accordingly. However, since the follower section 7 of the lifter 3 is curved into a spherical shape, the diameter of the lifter required to secure the same amount of travel can be reduced compared to conventional lifters that have a flat 7-year-old lower section. As a result, the +7 7-3 has been made smaller and lighter, which improves its ability to follow pulp, and even in Kojikun, which has multiple suctioned pulps per cylinder, the space above the shilling head 4 has been reduced. By reducing constraints, you can increase the degree of freedom in designing the valve train. The cam surface 8 is recessed with an arcuate cross section and is attached to the follower section 7? By ensuring a predetermined contact width L, the contact surface pressure between the two is reduced, and the shape of the lubricating oil film becomes advantageous, so that wear of the cam surface 7 and the 7-year-old part 7 can be suppressed.

また、７才ロワ部７を球面状に湾曲させることにより、
リフタ３が嵌合穴５内で回転しても、バルブ１のリフト
特性に影響がない。これに対して、７才ロワ部を例えば
円柱状に湾曲させた場合は、リフタの回り止めをする機
構を設ける必要■が有り、構造の複雑化を招くのである
。In addition, by curving the 7-year-old lower part 7 into a spherical shape,
Even if the lifter 3 rotates within the fitting hole 5, the lift characteristics of the valve 1 are not affected. On the other hand, if the 7-year-old lower portion is curved into a cylindrical shape, for example, it is necessary to provide a mechanism to prevent the lifter from rotating, which leads to a complicated structure.

（発明の効果） 以上の通り本発明によれば、カムに摺接して往復移動す
るリフタを介してバルブをｒＷＩ閉駆動するエンジンの
動弁装置において、＋７７夕のカムに摺接する７才ロワ
部を球面状に湾曲させるとともに、カムのりフタに摺接
するカム面を７ｔロワ部に沿って円弧状に湾曲する断面
を持つ溝状に形成したため、カムおよびリ７夕の摩耗を
Ｆｒｊ　ｉｌＪ　Ｌて酊久性を改！でき、リフタを小型
化して、エンジンの高速化を有利にするとともに、シリ
ングへ・冫ド上のスベースによる制約が多い多弁式エン
ジンにおいでも動ｔ＋系の設計自由度をひろげることが
できる。(Effects of the Invention) As described above, according to the present invention, in an engine valve operating system that drives a valve to RWI close via a lifter that slides in sliding contact with a cam and moves back and forth, the 7-year-old lower portion slides in sliding contact with a cam of +77 mm. The cam surface is curved into a spherical shape, and the cam surface that slides into contact with the cam lid is formed into a groove shape with a cross section that curves in an arc along the 7t lower part, reducing wear on the cam and the rear 7t. Change durability! This makes it possible to miniaturize the lifter, making it advantageous to increase the speed of the engine, and to expand the degree of freedom in designing the dynamic t+ system even in multi-valve engines, which are often restricted by the silling and the above-mentioned bases.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の実施例を示す側面図、第２図は同図Ａ
　　Ａ線に沿う横断面図である。第３図，弟４図はそれ
ぞれ従来例を示す横断面図である。 １・・・バノレブ、２・・・カム、３・・・リフタ、７
・・・７才ロワ部、８・・・カム面。 第 １−−バノレ７゛７−フ珂ロフ部 ２・−カム　　８〜一一力Ｋ茄 ３−−−リフタ 第２図 第 ３ 汐 ］ 第 ４ 図 ？ ■一＝コ トラ ：′ｌレ１』 Σ啓覧Fig. 1 is a side view showing an embodiment of the present invention, and Fig. 2 is a side view showing an embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along line A. Figures 3 and 4 are cross-sectional views showing conventional examples, respectively. 1...Vanorev, 2...Cam, 3...Lifter, 7
...7 year old lower part, 8... cam side. 1st--Banore 7゛7-Fukurofu part 2--Cam 8~11 force K 3---Lifter Fig. 2 Fig. 3] Fig. 4? ■One = Kotora:'lre1'' ΣKeiran

Claims (1)

【特許請求の範囲】[Claims] カムに摺接して往復移動するリフタを介してバルブを開
閉駆動するエンジンの動弁装置において、前記リフタの
前記カムに摺接するフォロワ部を球面状に湾曲して突出
させるとともに、カムのリフタに摺接するカム面をフォ
ロワ部に沿って円弧状に湾曲する断面を持つ溝状に形成
したことを特徴とするエンジンの動弁装置。In an engine valve train that opens and closes a valve through a lifter that slides in contact with a cam and moves back and forth, the follower part of the lifter that slides in contact with the cam is curved into a spherical shape and protrudes, and the follower part of the lifter that slides in contact with the cam is curved and protrudes. A valve train for an engine, characterized in that a contacting cam surface is formed in a groove shape with a cross section curved in an arc shape along a follower part.