JPH0244006Y2 - - Google Patents
Info
- Publication number
- JPH0244006Y2 JPH0244006Y2 JP1984062547U JP6254784U JPH0244006Y2 JP H0244006 Y2 JPH0244006 Y2 JP H0244006Y2 JP 1984062547 U JP1984062547 U JP 1984062547U JP 6254784 U JP6254784 U JP 6254784U JP H0244006 Y2 JPH0244006 Y2 JP H0244006Y2
- Authority
- JP
- Japan
- Prior art keywords
- cam
- camshaft
- auxiliary cam
- auxiliary
- intake 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.)
- Expired
Links
- 230000006835 compression Effects 0.000 claims description 23
- 238000007906 compression Methods 0.000 claims description 23
- 238000002485 combustion reaction Methods 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 2
- 239000007858 starting material Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Landscapes
- Valve Device For Special Equipments (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Description
【考案の詳細な説明】
（産業上の利用分野）
本考案は、始動時にカムシヤフトに設けられた
補助カムの作動によつて吸気弁又は排気弁を圧縮
行程に開閉する内燃機関の減圧装置に関する。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pressure reducing device for an internal combustion engine that opens and closes an intake valve or an exhaust valve during a compression stroke by operating an auxiliary cam provided on a camshaft during startup.
（従来の技術）
エンジン始動時に、シリンダ内の圧縮圧力を軽
減してエンジンの始動性を向上させる減圧装置と
して、例えば、実開昭56−127806号公報のものが
ある。これは、吸気弁又は排気弁を、通常のカム
による正規の開閉動作とは別に、始動時に、圧縮
行程時のある期間のみ開き、所定の回転速度にな
ると弁の開閉は行われない構造である。(Prior Art) For example, there is a pressure reducing device disclosed in Japanese Utility Model Application Publication No. 56-127806, which improves the startability of the engine by reducing the compression pressure in the cylinder when starting the engine. This is a structure in which the intake or exhaust valves are opened for a certain period of time during the compression stroke at startup, in addition to the regular opening and closing operations by normal cams, and the valves are not opened or closed once a predetermined rotational speed is reached. .
（考案が解決しようとする課題）
ところが、この装置では、弁の閉弁時期を遅く
設定すると、エンジン始動時の始動引張力は軽く
なるが、圧縮圧力が不十分で着火が困難になると
いう問題があつた。また、弁の閉弁時期を早く設
定すると、着火性は良くなるが、エンジン始動開
始時のエンジン最高回転速度近傍で、急に始動引
張力が大きくなるという問題があつた。(Problem that the invention aims to solve) However, with this device, if the valve closing timing is set later, the starting pulling force when starting the engine becomes lighter, but the problem is that the compression pressure is insufficient and ignition becomes difficult. It was hot. Further, if the valve closing timing is set earlier, the ignitability improves, but there is a problem in that the starting tensile force suddenly increases near the maximum engine rotational speed at the beginning of engine starting.
本考案はかかる点に鑑み、簡単な構造でかつ確
実な作動でもつて、エンジン始動開始時の減圧を
行つて始動時のロープ引張力を軽減するととも
に、エンジン始動開始時から通常運転時への移行
期においては良好な着火が行われ、通常運転時の
運転性を損なうことなく、総合的な始動性を向上
させるようにした内燃機関の減圧装置を提供する
ことを目的とする。 In view of these points, the present invention has a simple structure and reliable operation, reduces the pressure at the start of the engine to reduce the rope pulling force at the time of starting, and also reduces the pressure during the transition from the start of the engine to normal operation. It is an object of the present invention to provide a pressure reducing device for an internal combustion engine, in which good ignition is performed during the period, and overall startability is improved without impairing drivability during normal operation.
（課題を解決するための手段）
上記目的を達成するため、本考案の解決手段
は、カムシヤフトに設けられ、かつ一側面に該カ
ムシヤフトの軸心に直交する平面に対して傾斜し
た案内斜面が形成され、外周のカム面が吸気弁又
は排気弁へカム力を伝達するカム力伝達部に当接
して該吸気弁又は排気弁を正規の行程で開閉する
主カムを備えるとともに、上記カムシヤフトに上
記主カムの案内斜面と対向して回転可能にかつ摺
動可能に嵌合され、該案内斜面と対向する側の側
面に該カムシヤフトの軸心に直交する平面に対し
て傾斜し該案内斜面に摺接する摺動斜面が形成さ
れ、外周のカム面が上記カム力伝達部に当接して
上記吸気弁又は排気弁を圧縮行程時に開閉する補
助カムを備える。また、該補助カムをその摺動斜
面が上記主カムの案内斜面に当接するように押圧
するスプリングと、上記カムシヤフトに設けられ
該カムシヤフトと一体に回転する支持体とを備え
る。さらに、該支持体に回転可能に枢支され、該
枢支点より一端側に上記補助カムに係合するレバ
ー部を有するとともに他端側に上記カムシヤフト
の回転に伴う遠心力でカムシヤフトの回転中心か
ら遠ざかる方向に回動するウエイト部を有し、始
動時カムシヤフトの回転の上昇に応じて上記補助
カムを該補助カムによる吸気弁又は排気弁の閉弁
時期が早まる方向に回転せしめるとともに補助カ
ムを上記カム力伝達部との当接が解除されるよう
上記摺動斜面の案内斜面に対する回転摺接により
主カムより離反する方向に移動せしめる遠心アー
ムを備える。また、該遠心アームをそのウエイト
部がカムシヤフトの回転中心に近付く方向に付勢
するスプリングを備えたものとする。(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention is provided on a camshaft, and on one side thereof a guide slope is formed which is inclined with respect to a plane orthogonal to the axis of the camshaft. The main cam is provided with a main cam whose outer cam surface contacts a cam force transmitting part that transmits cam force to the intake valve or exhaust valve to open and close the intake valve or exhaust valve in a regular stroke, and the main cam is attached to the camshaft. The cam is rotatably and slidably fitted opposite the guide slope of the cam, and the side surface facing the guide slope is inclined with respect to a plane perpendicular to the axis of the camshaft and slides into contact with the guide slope. The auxiliary cam is provided with a sliding slope and a cam surface on the outer periphery that contacts the cam force transmitting portion to open and close the intake valve or the exhaust valve during the compression stroke. The auxiliary cam also includes a spring that presses the auxiliary cam so that its sliding slope comes into contact with a guide slope of the main cam, and a support that is provided on the camshaft and rotates together with the camshaft. Furthermore, it is rotatably supported by the support body, and has a lever portion that engages with the auxiliary cam on one end side of the pivot point, and a lever portion that engages with the auxiliary cam on the other end side from the center of rotation of the camshaft due to the centrifugal force accompanying the rotation of the camshaft. The auxiliary cam has a weight part that rotates in a direction that moves away, and rotates the auxiliary cam in a direction that accelerates the closing timing of the intake valve or exhaust valve by the auxiliary cam as the rotation of the camshaft increases during startup. A centrifugal arm is provided which is moved in a direction away from the main cam by rotationally sliding contact of the sliding slope with the guide slope so as to release the contact with the cam force transmitting part. Further, the centrifugal arm is provided with a spring that urges the weight portion of the centrifugal arm in a direction toward the center of rotation of the camshaft.
（作用）
このことにより、本考案では、始動時、補助カ
ムによる吸気弁もしくは排気弁の閉弁時期がエン
ジン回転の上昇に伴う遠心力の増大に比例して早
められ、内燃機関の圧縮行程におけるシリンダ内
圧力がスタータによるエンジン回転数の上昇に比
例して高められる。そして、始動後の通常運転時
には補助カムのカム力伝達部との当接が解除され
て該補助カムによる弁の開閉停止が確実に行われ
ることになる。(Function) As a result, in the present invention, at the time of starting, the closing timing of the intake valve or exhaust valve by the auxiliary cam is advanced in proportion to the increase in centrifugal force accompanying the increase in engine speed, and the timing of closing the intake valve or exhaust valve by the auxiliary cam is advanced in proportion to the increase in centrifugal force accompanying the increase in engine rotation. The pressure inside the cylinder is increased in proportion to the increase in engine speed caused by the starter. During normal operation after startup, the auxiliary cam is released from contact with the cam force transmission section, and the auxiliary cam reliably opens and closes the valve.
（実施例）
以下、本考案の実施例につき図面に沿つて説明
する。(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.
第１図及び第２図はカムシヤフトに設けられた
補助カムの動作によつて吸気弁または排気弁を圧
縮行程時に開閉する４サイクルエンジンの減圧装
置を示す。尚、該エンジンは、図示はしないが、
リコイルスタータによつて始動されるものであ
る。 FIGS. 1 and 2 show a pressure reducing device for a four-stroke engine that opens and closes an intake valve or an exhaust valve during a compression stroke by operating an auxiliary cam provided on a camshaft. Although the engine is not shown,
It is started by a recoil starter.
第１図において、１は吸気弁２（第２図）に連
結され該吸気弁２にカム力を伝達するカム力伝達
部としてのタペツト、３はカムシヤフト、４はカ
ムシヤフト３に設けられ吸気弁２を正規の吸気行
程時に開閉するための主カム、５はカムシヤフト
３に設けられた歯車で、主カム４と歯車５とはカ
ムシヤフト３とともに同行回転される。 In FIG. 1, 1 is a tappet connected to an intake valve 2 (FIG. 2) and serves as a cam force transmitting part that transmits cam force to the intake valve 2, 3 is a camshaft, and 4 is a tapered part provided on the camshaft 3 and connected to the intake valve 2. The main cam 5 is a gear provided on the camshaft 3 for opening and closing the main cam 5 during the regular intake stroke, and the main cam 4 and the gear 5 are rotated together with the camshaft 3.
前記主カム４と歯車５との間のカムシヤフト３
に補助カム６が回転可能にかつ摺動可能に嵌合さ
れ、該補助カムと歯車５との間にスプリング７
（第２図）が介在されている。 Camshaft 3 between the main cam 4 and gear 5
An auxiliary cam 6 is rotatably and slidably fitted in the auxiliary cam 6, and a spring 7 is inserted between the auxiliary cam and the gear 5.
(Fig. 2) is interposed.
前記主カム４の前記補助カム６に対向する一側
面は、カムシヤフト３の軸心に直交する平面に対
し若干傾斜した案内斜面４ａに形成され、補助カ
ム６の前記主カム４に対向する一側面は、カムシ
ヤフト３の軸心に直交する平面に対し若干傾斜し
た摺動斜面６ａに形成されている。この補助カム
６の摺動斜面６ａは主カム４の案内斜面４ａに摺
接されている。また、補助カム６はカムシヤフト
３の軸心方向に進退可能に設けられ、該補助カム
６がタペツト１の下方から退出可能に、つまりタ
ペツト１との当接が解除できるようになされてい
る。さらに、補助カム６と主カム４との相対位置
は、エンジン停止時においては、第１図に示すよ
うに、主カム４に対して補助カム６が約90度位相
が遅れるように配されている。 One side of the main cam 4 facing the auxiliary cam 6 is formed into a guide slope 4a slightly inclined with respect to a plane perpendicular to the axis of the camshaft 3; is formed on a sliding slope 6a that is slightly inclined with respect to a plane perpendicular to the axis of the camshaft 3. The sliding slope 6a of the auxiliary cam 6 is in sliding contact with the guide slope 4a of the main cam 4. Further, the auxiliary cam 6 is provided so as to be movable back and forth in the axial direction of the camshaft 3, so that the auxiliary cam 6 can be withdrawn from below the tappet 1, that is, the contact with the tappet 1 can be released. Furthermore, the relative positions of the auxiliary cam 6 and the main cam 4 are arranged such that when the engine is stopped, the auxiliary cam 6 is delayed in phase by about 90 degrees with respect to the main cam 4, as shown in FIG. There is.
遠心アーム１０は、レバー部１０ａとウエイト
部１０ｂとで略く字形に形成されたもので、屈曲
部が支軸８によつて歯車５の側面５ａに枢支され
ている。レバー部１０ａはカムシヤフト３の軸心
方向に突出され、その先端部１０ｃが前記補助カ
ム６の周部に設けられた係合凹部６ｂ内に挿入係
合されている。ウエイト部１０ｂは歯車５の外周
に沿う円弧形状に形成されている。また、遠心ア
ーム１０のレバー部１０ａと歯車５の側面５ａに
設けられた係止軸１１との間にはスプリング１２
が張設されている。このスプリング１２によつ
て、遠心アーム１０のウエイト部１０ｂが常にカ
ムシヤフト３の中心方向に付勢されている。 The centrifugal arm 10 is formed into a substantially dogleg shape with a lever portion 10a and a weight portion 10b, and a bent portion is pivotally supported on the side surface 5a of the gear 5 by a support shaft 8. The lever portion 10a projects in the axial direction of the camshaft 3, and its tip portion 10c is inserted into and engaged with an engagement recess 6b provided on the circumference of the auxiliary cam 6. The weight portion 10b is formed in an arc shape along the outer periphery of the gear 5. Further, a spring 12 is provided between the lever portion 10a of the centrifugal arm 10 and the locking shaft 11 provided on the side surface 5a of the gear 5.
is installed. The weight portion 10b of the centrifugal arm 10 is always urged toward the center of the camshaft 3 by the spring 12.
なお、遠心アーム１０のレバー部１０ａは、歯
車５の側面５ａに設けられた規制ピン１３ａ，１
３ｂで回動範囲が規制されている。図中の記号Ｒ
はカムシヤフト３の回転方向、記号ｔは主カム４
とタペツト１とのクリアランス、記号Ｌはこのク
リアランスｔ分を含んだ主カム４のベースサーク
ルである。 Note that the lever portion 10a of the centrifugal arm 10 is connected to the regulating pins 13a, 1 provided on the side surface 5a of the gear 5.
The rotation range is restricted by 3b. Symbol R in the diagram
is the rotation direction of the camshaft 3, symbol t is the main cam 4
The clearance between the tappet 1 and the tappet 1, symbol L is the base circle of the main cam 4 that includes this clearance t.
次に、上記構成の減圧装置の動作を第３図を参
照して説明する。なお、第３図は圧縮圧力とエン
ジン回転速度との関係を示している。 Next, the operation of the pressure reducing device having the above configuration will be explained with reference to FIG. Note that FIG. 3 shows the relationship between compression pressure and engine rotation speed.
エンジン始動開始時のエンジン回転速度（第３
図において範囲Ａ）では、スプリング１２の付勢
力が遠心アーム１０のウエイト部１０ｂに働く遠
心力に打ち勝ち、補助カム６は、主カム４に対し
て位相が約90度遅れる位置（第１図の位置関係）
を保つて主カム４と同行回転される。したがつ
て、圧縮行程時、補助カム６の作用により、ピス
トン（図示省略）の下死点（圧縮開始点）近傍で
吸気弁２が押し上げられ、上死点（圧縮完了点）
近傍で該吸気弁２が閉じられることになる。この
ピストンが下死点から上死点に移行する間に、シ
リンガ１４（第２図）内の混合ガスが相当量吸気
弁２から抜けるので、圧縮圧力が減少し、エンジ
ン始動開始時のリコイルスタータの始動引張力が
軽くなる。 Engine rotation speed at the start of engine startup (3rd
In range A) in the figure, the biasing force of the spring 12 overcomes the centrifugal force acting on the weight part 10b of the centrifugal arm 10, and the auxiliary cam 6 is at a position where the phase is delayed by about 90 degrees with respect to the main cam 4 (as shown in FIG. positional relationship)
It is rotated together with the main cam 4 while maintaining the main cam 4. Therefore, during the compression stroke, the action of the auxiliary cam 6 pushes up the intake valve 2 near the bottom dead center (compression start point) of the piston (not shown), and the intake valve 2 is pushed up near the bottom dead center (compression completion point) of the piston (not shown).
The intake valve 2 will be closed in the vicinity. While the piston moves from the bottom dead center to the top dead center, a considerable amount of the mixed gas in the syringe 14 (Fig. 2) escapes from the intake valve 2, so the compression pressure decreases and the recoil starter at the start of engine startup. The starting pulling force becomes lighter.
エンジン始動開始時のエンジン回転速度が上昇
（第３図において範囲Ｂ）すると、遠心アーム１
０のウエイト部１０ｂに働く遠心力がスプリング
１２の付勢力に打ち勝ち、遠心アーム１０のウエ
イト部１０ｂがカムシヤフト３の中心から遠ざか
る方向に移動を始める。この遠心アーム１０の移
動に伴つて、補助カム６が主カム４に対して位相
の遅れが少なくなる方向Ｑ（第１図）に変位され
ることになる、したがつて、圧縮行程時、補助カ
ム６の作用による吸気弁２の閉じる時期が、ピス
トン（図示省略）の上死点近傍から下死点側に移
行される。よつて、圧縮行程時に吸気弁から抜け
る混合ガスの量が減少するので、エンジン回転速
度の上昇に伴いシリンダ１４内の圧縮圧力が増加
し、着火に必要な圧縮圧力（第３図において範囲
Ｃ）に近づく。この間、リコイルスタータの始動
抵抗が徐々に増加するが、始動用ロープの引張り
時の勢いがついているので、圧縮圧力が増加して
も、作業者にとつて負担となるものではない。 When the engine speed increases at the start of engine startup (range B in Figure 3), centrifugal arm 1
The centrifugal force acting on the weight portion 10b of the centrifugal arm 10 overcomes the biasing force of the spring 12, and the weight portion 10b of the centrifugal arm 10 begins to move away from the center of the camshaft 3. Along with this movement of the centrifugal arm 10, the auxiliary cam 6 is displaced in the direction Q (Fig. 1) in which the phase delay is reduced relative to the main cam 4. Therefore, during the compression stroke, the auxiliary cam 6 is The timing at which the intake valve 2 closes due to the action of the cam 6 is shifted from near the top dead center of the piston (not shown) to the bottom dead center. Therefore, the amount of mixed gas that escapes from the intake valve during the compression stroke decreases, and as the engine speed increases, the compression pressure within the cylinder 14 increases, increasing the compression pressure required for ignition (range C in Figure 3). approach. During this time, the starting resistance of the recoil starter gradually increases, but since the starting rope has momentum when pulled, even if the compression pressure increases, it will not be a burden to the operator.
エンジン始動開始時のエンジン最高回転速度近
傍もしくはアイドリング時のエンジン回転速度
（第３図において範囲Ｄ）では、補助カム６は、
さらに主カム４に対して位相の遅れが少なくなる
方向Ｑ（第１図）に変位されるとともに、主カム
４とタペツト１との間のクリアランスｔ（第１図）
分を含んだ主カム４のベースサークルＬ（第１図）
内に、補助カム６が納められる。しかも、補助カ
ム６はその摺動斜面６ａの案内斜面４ａに対する
回転摺接によりカムシヤフト３の軸心方向Ｐ（主
カム４より離反する方向）にも移動されるから、
補助カム６がタペツト１の下方から退出される。
したがつて、リシンダ１４内の混合ガスは正規の
圧縮圧力に圧縮され、エンジンが始動されるので
ある。 At near the maximum engine rotation speed at the start of engine startup or at engine rotation speed during idling (range D in FIG. 3), the auxiliary cam 6
Furthermore, it is displaced in the direction Q (Fig. 1) in which the phase delay is reduced relative to the main cam 4, and the clearance t between the main cam 4 and the tappet 1 (Fig. 1).
Base circle L of main cam 4 including minutes (Fig. 1)
The auxiliary cam 6 is housed inside. Furthermore, the auxiliary cam 6 is also moved in the axial direction P of the camshaft 3 (in the direction away from the main cam 4) by the rotational sliding contact of the sliding slope 6a with the guide slope 4a.
The auxiliary cam 6 is withdrawn from below the tapepet 1.
Therefore, the mixed gas in the ricinder 14 is compressed to a normal compression pressure, and the engine is started.
エンジンを停止すると、遠心アーム１０がスプ
リング１２の作用によつてエンジン停止時の位置
（第１図）に復帰し、該遠心アーム１２に連動す
る補助カム６もエンジン停止時の位置（第１図及
び第２図）に回動復帰する。 When the engine is stopped, the centrifugal arm 10 returns to the position when the engine is stopped (Fig. 1) by the action of the spring 12, and the auxiliary cam 6 linked to the centrifugal arm 12 is also moved to the position when the engine is stopped (Fig. 1). and Fig. 2).
なお、第３図において破線で示す直線は、エン
ジンが回転を開始するのとほぼ同時に圧縮圧力が
増加する例を示している。このようにエンジン回
転速度のどの段階で圧縮圧力の増加を開始させる
かは、スプリング１２の付勢力或いはウエイト部
１０ｂの重量を任意に設定することによつて可能
である。 In addition, the straight line shown by the broken line in FIG. 3 shows an example in which the compression pressure increases almost at the same time as the engine starts rotating. In this way, at what stage of the engine rotation speed the compression pressure starts to increase can be determined by arbitrarily setting the biasing force of the spring 12 or the weight of the weight portion 10b.
また、第４図はカム（主カム）と補助カムの位
相関係を示すもので、カムの位相曲線に対する補
助カムの位相曲線が位置Ｅとなる場合が、第３図
における範囲Ａに対応する。カムの位相曲線に対
する補助カムの位相曲線がＳ方向に変位される間
が、第３図における範囲Ｂに対応する。カムの位
相曲線に対する補助カムの位相曲線が位置Ｆとな
る場合が、第３図における範囲Ｄに対応する。 Further, FIG. 4 shows the phase relationship between the cam (main cam) and the auxiliary cam, and the case where the phase curve of the auxiliary cam with respect to the phase curve of the cam is at position E corresponds to range A in FIG. The period during which the phase curve of the auxiliary cam relative to the phase curve of the cam is displaced in the S direction corresponds to range B in FIG. The case where the phase curve of the auxiliary cam with respect to the phase curve of the cam is at position F corresponds to range D in FIG.
ところで、上記動作説明において、エンジン始
動開始時のエンジン最高回転速度近傍もしくはア
イドリング時のエンジン回転速度で、補助カム６
が主カム４のベースサークルＬ内に納まるように
そのタイミング及びカムプロフイルを調整するこ
とは、実際には難しい。このため、前記したエン
ジン回転速度で、補助カム６をタペツト１の下方
から退出させる構造としている。 By the way, in the above explanation of the operation, the auxiliary cam 6
It is actually difficult to adjust the timing and cam profile so that the main cam 4 falls within the base circle L of the main cam 4. For this reason, the structure is such that the auxiliary cam 6 is withdrawn from below the tappet 1 at the engine speed mentioned above.
なお、上記実施例では、補助カム６を用いて吸
気弁２を開閉させる例を説明したが、補助カム６
を排気弁（図示省略）側のカムシヤフトに設けて
排気弁を開閉させる構造であつてもよい。この場
合、補助カムは主カムに対して約180度位相が遅
れるように配置される。 In addition, in the above embodiment, an example was explained in which the intake valve 2 is opened and closed using the auxiliary cam 6, but the auxiliary cam 6
may be provided on a camshaft on the exhaust valve (not shown) side to open and close the exhaust valve. In this case, the auxiliary cam is arranged to be about 180 degrees behind the main cam.
また、遠心アームは上記歯車５の他、カムシヤ
フトに別途支持体を固定し、この支持体に枢支し
てもよい。 Further, in addition to the gear 5 described above, the centrifugal arm may be pivoted to a support body separately fixed to the camshaft.
（考案の効果）
以上説明したように、本考案の内燃機関の減圧
装置は、遠心アームの回動動作によつて補助カム
を回動変位させるとともに主カムより離反移動さ
せるもので、シリンダ内の圧縮圧力をスタータに
よるエンジン回転数の上昇に比例して高めること
ができるので、始動引張力を軽減するとともに良
好な着火を行うことができる。しかも、エンジン
始動後においては、シリンダ内の圧縮圧力を確実
に正規の圧力にして良好な着火性及び運転性を確
保できる。よつて、エンジン始動開始時から通常
運転時への移行期に亘つて、総合的なエンジンの
始動性を向上することができる。尚、本減圧装置
はエレクトリツク・スタータ始動方式のエンジン
にも適用できる。(Effects of the invention) As explained above, the pressure reducing device for an internal combustion engine of the invention rotates and displaces the auxiliary cam and moves it away from the main cam by the rotational action of the centrifugal arm. Since the compression pressure can be increased in proportion to the increase in engine speed due to the starter, the starting pulling force can be reduced and good ignition can be achieved. Furthermore, after the engine is started, the compression pressure in the cylinder can be reliably maintained at the normal pressure to ensure good ignitability and drivability. Therefore, the overall startability of the engine can be improved from the start of engine startup to the transition period to normal operation. Note that this pressure reducing device can also be applied to engines using an electric starter starting method.
図面は本考案の実施例を例示し、第１図は減圧
装置の正面図、第２図は同減圧装置の側面図、第
３図は圧縮圧力とエンジン回転速度との関係を示
す説明図、第４図はカム位相に対する補助カムの
位相の変化を示す曲線図である。
１……タペツト、２……吸気弁、３……カムシ
ヤフト、４……主カム、４ａ……案内斜面、５…
…歯車、６……補助カム、６ａ……摺動斜面、７
……スプリング、８……支軸、１０……遠心アー
ム、１０ａ……レバー部、１０ｂ……ウエイト
部、１２……スプリング。
The drawings illustrate an embodiment of the present invention, and FIG. 1 is a front view of the pressure reducing device, FIG. 2 is a side view of the same pressure reducing device, and FIG. 3 is an explanatory diagram showing the relationship between compression pressure and engine rotation speed. FIG. 4 is a curve diagram showing changes in the phase of the auxiliary cam with respect to the cam phase. 1... Tappet, 2... Intake valve, 3... Camshaft, 4... Main cam, 4a... Guide slope, 5...
...Gear, 6...Auxiliary cam, 6a...Sliding slope, 7
... Spring, 8 ... Support shaft, 10 ... Centrifugal arm, 10a ... Lever section, 10b ... Weight section, 12 ... Spring.
Claims (1)
シヤフトの軸心に直交する平面に対して傾斜した
案内斜面が形成され、外周のカム面が吸気弁又は
排気弁へカム力を伝達するカム力伝達部に当接し
て該吸気弁又は排気弁を正規の行程で開閉する主
カムと、 上記カムシヤフトに上記主カムの案内斜面と対
向して回転可能にかつ摺動可能に嵌合され、該案
内斜面と対向する側の側面に該カムシヤフトの軸
心に直交する平面に対して傾斜し該案内斜面に摺
接する摺動斜面が形成され、外周のカム面が上記
カム力伝達部に当接して上記吸気弁又は排気弁を
圧縮行程時に開閉する補助カムと、 該補助カムをその摺動斜面が上記主カムの案内
斜面に当接するように押圧するスプリングと、 上記カムシヤフトに設けられ該カムシヤフトと
一体に回転する支持体と、 該支持体に回転可能に枢支され、該枢支点より
一端側に上記補助カムに係合するレバー部を有す
るとともに他端側に上記カムシヤフトの回転に伴
う遠心力でカムシヤフトの回転中心から遠ざかる
方向に回動するウエイト部を有し、始動時カムシ
ヤフトの回転の上昇に応じて上記補助カムを該補
助カムによる吸気弁又は排気弁の閉弁時期が早ま
る方向に回転せしめるとともに補助カムを上記カ
ム力伝達部との当接が解除されるよう上記摺動斜
面の案内斜面に対する回転摺接により主カムより
離反する方向に移動せしめる遠心アームと、 該遠心アームをそのウエイト部がカムシヤフト
の回転中心に近付く方向に付勢するスプリング
と、 を備えたことを特徴とする内燃機関の減圧装置。[Claims for Utility Model Registration] A guide slope is provided on the camshaft and is inclined on one side with respect to a plane perpendicular to the axis of the camshaft, and the cam surface on the outer periphery applies cam force to the intake valve or exhaust valve. a main cam that opens and closes the intake valve or exhaust valve in a regular stroke by coming into contact with a cam force transmitting part that transmits a A sliding slope is formed on the side surface facing the guide slope and is inclined with respect to a plane perpendicular to the axis of the camshaft and slides in sliding contact with the guide slope, and the cam surface on the outer periphery is connected to the cam force transmitting portion. an auxiliary cam that contacts the camshaft to open and close the intake valve or exhaust valve during a compression stroke; a spring that presses the auxiliary cam so that its sliding slope contacts the guide slope of the main cam; a support that rotates integrally with the camshaft; a lever that is rotatably supported on the support and that engages with the auxiliary cam at one end of the pivot point; and a lever that engages with the auxiliary cam at the other end; The auxiliary cam has a weight part that rotates in a direction away from the center of rotation of the camshaft due to centrifugal force, and as the rotation of the camshaft increases during startup, the auxiliary cam closes the intake valve or the exhaust valve earlier. a centrifugal arm that rotates the auxiliary cam in a direction and moves the auxiliary cam in a direction away from the main cam by rotating and sliding in contact with the guide slope of the sliding slope so that the auxiliary cam is released from contact with the cam force transmission part; A pressure reducing device for an internal combustion engine, comprising: a spring that biases a weight portion of the weight portion in a direction toward a rotation center of a camshaft;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6254784U JPS60173607U (en) | 1984-04-26 | 1984-04-26 | Internal combustion engine pressure reducing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6254784U JPS60173607U (en) | 1984-04-26 | 1984-04-26 | Internal combustion engine pressure reducing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60173607U JPS60173607U (en) | 1985-11-18 |
| JPH0244006Y2 true JPH0244006Y2 (en) | 1990-11-22 |
Family
ID=30591866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6254784U Granted JPS60173607U (en) | 1984-04-26 | 1984-04-26 | Internal combustion engine pressure reducing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60173607U (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2647506B2 (en) * | 1989-08-09 | 1997-08-27 | 三菱重工業株式会社 | Variable valve timing device for 4-cycle engine |
| JP5446919B2 (en) * | 2010-01-22 | 2014-03-19 | スズキ株式会社 | 4 cycle engine decompression device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4915484U (en) * | 1972-05-14 | 1974-02-08 |
-
1984
- 1984-04-26 JP JP6254784U patent/JPS60173607U/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4915484U (en) * | 1972-05-14 | 1974-02-08 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60173607U (en) | 1985-11-18 |
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