JPH07107362B2 - Valve timing switching device for internal combustion engine - Google Patents
Valve timing switching device for internal combustion engineInfo
- Publication number
- JPH07107362B2 JPH07107362B2 JP3130512A JP13051291A JPH07107362B2 JP H07107362 B2 JPH07107362 B2 JP H07107362B2 JP 3130512 A JP3130512 A JP 3130512A JP 13051291 A JP13051291 A JP 13051291A JP H07107362 B2 JPH07107362 B2 JP H07107362B2
- Authority
- JP
- Japan
- Prior art keywords
- cam
- rocker arm
- rocker
- valve
- high speed
- 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 - Fee Related
Links
Landscapes
- Valve-Gear Or Valve Arrangements (AREA)
- Valve Device For Special Equipments (AREA)
Description
【0001】[0001]
【産業上の利用分野】この発明は、4サイクル内燃機関
のバルブタイミング切換装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing switching device for a 4-cycle internal combustion engine.
【0002】[0002]
【従来の技術】4サイクルの内燃機関は、クランクシャ
フトに連動するカムシャフトのカムの回転によってロッ
カーアームを揺動させ、吸気および排気用の各々の傘形
のバルブをバネに抗して押下げて開くようにしている。
したがって、バルブの開閉タイミングと、バルブの開き
量であるリフト量はカムの形状によって定まる。高速で
高出力を要求されるエンジンでは、バルブタイミングを
大きくし、リフト量を大きくして、高速で吸排気量が多
いとき、吸排気効率を高めて出力を高くしている。2. Description of the Related Art In a four-cycle internal combustion engine, a rocker arm is swung by the rotation of a cam of a camshaft which is interlocked with a crankshaft, and each umbrella valve for intake and exhaust is pushed down against a spring. I am trying to open it.
Therefore, the valve opening / closing timing and the lift amount, which is the valve opening amount, are determined by the shape of the cam. In an engine that requires high output at high speed, the valve timing is increased, the lift amount is increased, and when the intake / exhaust amount is high at high speed, the intake / exhaust efficiency is increased to increase the output.
【0003】[0003]
【発明が解決しようとする課題】ところが、カムをこの
ように設定すると、吸排気量が少い低速では、吸気の流
速が遅くなり、渦流ができず、燃焼効率が低下して、出
力が低下する。また、吸排気バルブのオーバーラップに
よって吸気の吹抜けも多くなり、燃料消費も増加する不
都合がある。However, when the cam is set in this way, the flow velocity of intake air becomes slow at low speeds with a small intake and exhaust amount, swirling is not possible, combustion efficiency is reduced, and output is reduced. To do. In addition, the intake and exhaust valves overlap each other, which increases the amount of blow-through of intake air, resulting in an increase in fuel consumption.
【0004】この発明は、かかる点に鑑み、低速カムと
高速カムとを用意し、摺動アームで低高速カムを使い分
け、高低速共に高出力が得られるようにするとともに、
低速運転時に適合する低速状態と高速運転時に適合する
高速状態にオイルポンプの油圧を利用して切換えるよう
にした内燃機関のバルブタイミング切換装置を提供する
ことを目的としてなされたものである。In view of the above point, the present invention prepares a low speed cam and a high speed cam, and uses a low speed cam and a low speed cam by a sliding arm so that a high output can be obtained in both high speed and low speed.
An object of the present invention is to provide a valve timing switching device for an internal combustion engine, which switches between a low speed state suitable for low speed operation and a high speed state suitable for high speed operation by utilizing the oil pressure of an oil pump.
【0005】[0005]
【課題を解決するための手段】上記問題点を解決する手
段として本発明は、バネ手段により常時閉弁付勢される
とともにクランクシャフトと連動回転するカムシャフト
のカムによりロッカーシャフトに回動自在に軸支された
ロッカーアームを介して開弁駆動される内燃機関の吸気
または排気バルブにおいて、前記カムシャフトに低速用
カムと高速用カムとを併設し、機関の低速運転時には低
速用カムを、高速運転時には高速用カムを選択的に切換
える切換装置であって、前記ロッカーシャフトに軸支さ
れカムシャフトのカム面により該ロッカーシャフト軸支
部を中心として端部のバルブ押圧部を介しバルブを開閉
させる第1のロッカーアームと、この第1のロッカーア
ームに隣接して前記ロッカーシャフトに軸支され高速時
に前記高速用カムに当接する第2のロッカーアームと、
前記第1のロッカーアームのロッカーシャフト軸支部か
らカム摺接部に延びるアーム部に該カム摺接部に隣接し
て設けられた第1,第2のロッカーアームの連結切換部
とを備え、前記連結切換部は機関に連動するオイルポン
プの油圧を受けて作動するプランジャにより前記第2の
ロッカーアームを切換移動させる油圧選択切換手段を有
し、前記プランジャの油圧室とは反対側に常時プランジ
ャを低速状熊を保つよう付勢するバネ手段を持ち、前記
オイルポンプの油圧が所定値以上となった高速運転時に
前記プランジャをバネ手段に抗して作動させ、前記第2
のロッカーアームを高速側へ切換えて第1,第2のロッ
カーアームを前記連結切換部により一体的に連結し、高
速用カムに摺接しかつ前記ロッカーシャフトに軸支され
た第2のロッカーアームで第1のロッカーアームを介し
てバルブを開閉動作させるようにしたことを特徴とす
る。SUMMARY OF THE INVENTION As a means for solving the above problems, the present invention provides a rocker shaft which can be freely rotated by a cam of a cam shaft which is constantly urged to be closed by a spring means and which rotates in conjunction with a crankshaft. In an intake or exhaust valve of an internal combustion engine that is driven to open by a rocker arm that is pivotally supported, a low speed cam and a high speed cam are provided side by side on the cam shaft, and when the engine is operating at a low speed, the low speed cam is operated at a high speed. A switching device for selectively switching a high-speed cam during operation, which opens and closes a valve by means of a cam surface of the rocker shaft which is pivotally supported by the rocker shaft and is centered on the rocker shaft pivotal support portion and an end valve pressing portion. No. 1 rocker arm and the high-speed cam that is pivotally supported by the rocker shaft adjacent to the first rocker arm at high speed A second rocker arm which abuts,
An arm portion extending from the rocker shaft pivotal support portion of the first rocker arm to the cam sliding contact portion, and a connection switching portion of the first and second rocker arms provided adjacent to the cam sliding contact portion, The connection switching unit has a hydraulic pressure selection switching unit that switches and moves the second rocker arm by a plunger that operates by receiving the hydraulic pressure of an oil pump that interlocks with the engine, and the plunger is always provided on the side opposite to the hydraulic chamber of the plunger. A spring means for urging the bear to keep the low speed bear, and when the oil pressure of the oil pump is higher than a predetermined value, the plunger is actuated against the spring means during high speed operation,
The rocker arm of the second rocker arm is switched to the high speed side, the first and second rocker arms are integrally connected by the connection switching portion, and the second rocker arm is slidably contacted to the high speed cam and pivotally supported by the rocker shaft. It is characterized in that the valve is opened / closed via the first rocker arm.
【0006】[0006]
【作用】高速運転時にはオイルポンプの油圧により油圧
室内のプランジャがバネの付勢に抗して押されるので第
2のロッカーアームが高速側へ移動して第1,第2のロ
ッカーアームが連結切換部により一体的に連結され、第
2のロッカーアームにより第1のロッカーアームを介し
てバルブが開閉される。低速運転時にはオイルポンプの
油圧が低いのでプランジャはバネの付勢により第2のロ
ッカーアームは戻され、連結切換部が切離されて第1の
ロッカーアームが低速カムにより作動され、低速状態に
おかれる。オイルポンプの故障等により高速運転時でも
所定圧の油圧が作用しなくなると低速運転時と同様にバ
ネの作用で低速状態に切換えられ、機関の安定が図られ
る。In the high speed operation, the oil pressure of the oil pump pushes the plunger in the hydraulic chamber against the urging of the spring, so that the second rocker arm moves to the high speed side and the first and second rocker arms are switched. And the valve is opened and closed by the second rocker arm via the first rocker arm. During low speed operation, the oil pressure of the oil pump is low, so the second rocker arm of the plunger is returned by the biasing of the spring, the connection switching part is separated, and the first rocker arm is operated by the low speed cam, and the low speed state is reached. Get burned. When the oil pressure of a predetermined pressure is not applied even during high speed operation due to a failure of the oil pump or the like, the spring is switched to the low speed state similarly to the low speed operation, and the engine is stabilized.
【0007】[0007]
【実施例】以下、本発明を図面に示す実施例を参照して
説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.
【0008】クランクシャフトにチエン等で連動するカ
ムシャフト1には、低速カム2と高速カム3とが並設さ
れている。低速カム2は、バルブの開くタイミングを短
く、リフト量が小さい形状に設定してあり、高速カム3
は、バルブの開くタイミングを長く、リフト量も大きく
なる形状に設定されている。A low speed cam 2 and a high speed cam 3 are arranged in parallel on a cam shaft 1 which is interlocked with the crank shaft by a chain or the like. The low speed cam 2 has a shape in which the valve opening timing is short and the lift amount is small.
Is designed to have a long valve opening timing and a large lift amount.
【0009】ロッカーシャフト4に軸着された第1のロ
ッカーアーム5は、その揺動により吸気または排気用の
傘形のバルブ6をバネ7に抗して押下げて開くようにさ
れていて、低速カム2の下方に位置されている。The first rocker arm 5 pivotally attached to the rocker shaft 4 is adapted to push and open an umbrella-shaped valve 6 for intake or exhaust air against a spring 7 by its swinging. It is located below the low speed cam 2.
【0010】第2のロッカーアーム8は、ロッカーシャ
フト4にその軸方向に摺動可能でかつ揺動自在に軸支さ
れていて、高速カム3と、第1のロッカーアーム5の側
方突起9との間に係脱するようになされおり、連結切換
部を構成している。この第2のロッカーアーム8は、レ
バー10を介して油圧室11のプランジャ12に連結さ
れている。この油圧室11には、エンジンに連動するオ
イルポンプの油圧配管14が接続され、高速域で油圧が
高くなると、バネ13に抗してプランジャ12を押し、
第2のロッカーアーム8を高速カム3と第1のロッカー
アーム5の側方突起9との間に係合させて連結状態とす
る。油圧が下がるとバネ13の付勢により第2のロッカ
ーアーム8が高速カム3から外される。これらにより油
圧選択切換手段を構成している。The second rocker arm 8 is axially slidably and swingably supported on the rocker shaft 4, and has a high-speed cam 3 and side projections 9 of the first rocker arm 5. It is adapted to be engaged and disengaged between and, and constitutes a connection switching unit. The second rocker arm 8 is connected to the plunger 12 of the hydraulic chamber 11 via the lever 10. A hydraulic pipe 14 of an oil pump interlocking with the engine is connected to the hydraulic chamber 11, and when the hydraulic pressure becomes high in a high speed region, the plunger 12 is pushed against the spring 13 and
The second rocker arm 8 is engaged between the high-speed cam 3 and the side projection 9 of the first rocker arm 5 to establish a connected state. When the hydraulic pressure is reduced, the second rocker arm 8 is disengaged from the high speed cam 3 by the biasing force of the spring 13. These constitute a hydraulic pressure selection switching means.
【0011】つぎに作用について説明する。Next, the operation will be described.
【0012】低速域では、オイルポンプからの油圧が低
く、バネ13の付勢により第2のロッカーアーム8が高
速カム3から外れており(図2)、カムシャフト1の回
転によって低速カム2で第1のロッカーアーム5を揺動
させ、バルブ6をバネ7に抗して押し開く。低速カム2
は、バルブ6が開くタイミングを短く、リフト量を小さ
く設定してあるので、低速で吸排気量が少なくても、バ
ルブ6の近くで吸気の早い流速が得られ、シリンダー内
に渦流ができて燃焼効率が上昇し、高出力が得られる。
また、吸気の吹抜けもなくて燃料消費も少なくできる。
このときは、第2のロッカーアーム8は外れているので
高速カム3は遊んでいる。In the low speed range, the oil pressure from the oil pump is low, the second rocker arm 8 is disengaged from the high speed cam 3 by the bias of the spring 13 (FIG. 2), and the rotation of the cam shaft 1 causes the low speed cam 2 to move. The first rocker arm 5 is swung, and the valve 6 is pushed open against the spring 7. Low speed cam 2
The valve 6 has a short opening timing and a small lift amount, so even if the intake and exhaust amounts are low at a low speed, a high flow velocity of intake air can be obtained near the valve 6 and swirl can be generated in the cylinder. Combustion efficiency is increased and high output is obtained.
Further, there is no blow-by of intake air, and fuel consumption can be reduced.
At this time, since the second rocker arm 8 is disengaged, the high speed cam 3 is idle.
【0013】高速域になって、オイルポンプからの油圧
が所定値以上に高くなると、プランジャ12がバネ13
に抗して押され、第2のロッカーアーム8が高速カム3
とロッカーアーム5との間に図2に鎖線で示すように係
合される。したがって高速カム3が第2のロッカーアー
ム8を介し第1のロッカーアーム5を揺動させてバルブ
6を開く。高速カム3は、バルブ6の開くタイミングを
大きく、リフト量も大きく設定してあるので、高速で吸
排気量が増しても、吸排気効率を高くできて高出力にで
きる。このとき低速カム2は遊んでいることになる。When the hydraulic pressure from the oil pump becomes higher than a predetermined value in the high speed range, the plunger 12 moves to the spring 13
The second rocker arm 8 is pushed against the high speed cam 3
And the rocker arm 5 are engaged with each other as shown by a chain line in FIG. Therefore, the high-speed cam 3 swings the first rocker arm 5 via the second rocker arm 8 to open the valve 6. Since the high-speed cam 3 has a large opening timing of the valve 6 and a large lift amount, the intake / exhaust efficiency can be increased and the output can be increased even if the intake / exhaust amount increases at high speed. At this time, the low speed cam 2 is playing.
【0014】[0014]
【発明の効果】以上説明したように、この発明によれ
ば、高速域ではその回転によりオイルポンプにおいて発
生する所定圧以上の油圧によりプランジャを高速状態に
移行し、低速域では油圧が下ることによりバネ付勢によ
ってプランジャを低速状熊に移行して機関の回転に応じ
バルブの開度が自動的に切換えられ、低速域と高速域と
で各々バルブのタイミングとリフト量とを回転に適応さ
せることができ、高低速共高い出力が得られ、燃料も節
約できる。高速時にオイルポンプやポンプ回路の電磁弁
等油圧関連部分に故障が生じたり、配管に損傷が生じた
場合に所定圧の油圧が作用しなくなったときはバネ付勢
によりプランジャが自動的に低速側に移動されて低速状
熊を保つので、高速時における機関に不調をきたすこと
がなく、安定側での運転を継続することができる。As described above, according to the present invention, in the high speed range, the rotation of the plunger causes the plunger to shift to the high speed state by the hydraulic pressure above the predetermined pressure generated in the oil pump, and in the low speed range, the hydraulic pressure decreases. By moving the plunger to a low speed bear by the spring bias, the valve opening is automatically switched according to the rotation of the engine, and the valve timing and lift amount are adapted to the rotation in the low speed region and the high speed region respectively. It is possible to obtain high output at high speed and low speed, and save fuel. When the hydraulic pump, solenoid valve of the pump circuit, or other hydraulic-related parts fail at high speed, or when the hydraulic pressure of the specified pressure stops working due to damage to the piping, the plunger automatically moves to the low speed side due to spring bias. Since the low speed bear is moved to, the engine can be kept operating smoothly at high speed without any trouble.
【図1】図1は本発明の一実施例を示す縦断側面図。FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.
【図2】図2は図1A−A矢視図。FIG. 2 is a view on arrow in FIG. 1A-A.
1 カムシャフト 2 低速カム 3 高速カム 5 第1のロッカーアーム 6 バルブ 8 第2のロッカーアーム 1 camshaft 2 low speed cam 3 high speed cam 5 first rocker arm 6 valve 8 second rocker arm
Claims (1)
にクランクシャフトと連動回転するカムシャフトのカム
によりロッカーシャフトに回動自在に軸支されたロッカ
ーアームを介して開弁駆動される内燃機関の吸気または
排気バルブにおいて、前記カムシャフトに低速用カムと
高速用カムとを併設し、機関の低速運転時には低速用カ
ムを、高速運転時には高速用カムを選択的に切換える切
換装置であって、前記ロッカーシャフトに軸支されカム
シャフトのカム面により該ロッカーシャフト軸支部を中
心として端部のバルブ押圧部を介しバルブを開閉させる
第1のロッカーアームと、この第1のロッカーアームに
隣接して前記ロッカーシャフトに軸支され高速時に前記
高速用カムに当接する第2のロッカーアームと、前記第
1のロッカーアームのロッカーシャフト軸支部からカム
摺接部に延びるアーム部に該カム摺接部に隣接して設け
られた第1,第2のロッカーアームの連結切換部とを備
え、前記連結切換部は機関に連動するオイルポンプの油
圧を受けて作動するプランジャにより前記第2のロッカ
ーアームを切換移動させる油圧選択切換手段を有し、前
記プランジャの油圧室とは反対側に常時プランジャを低
速状態を保つよう付勢するバネ手段を持ち、前記オイル
ポンプの油圧が所定値以上となった高速運転時に前記プ
ランジャをバネ手段に抗して作動させ、前紀第2のロッ
カーアームを高速側へ切換えて第1,第2のロッカーア
ームを前記連結切換部により一体的に連結し、高速用カ
ムに摺接しかつ前記ロッカーシャフトに軸支された第2
のロッカーアームで第1のロッカーアームを介してバル
ブを開閉動作させるようにしたことを特徴とする内燃機
関のバルブタイミング切換装置。1. An internal combustion engine in which valve opening is driven via a rocker arm that is rotatably supported by a rocker shaft by a cam of a cam shaft that is urged to always close the valve by spring means and that rotates in conjunction with a crankshaft. In the intake or exhaust valve of the above, a switching device for providing a low speed cam and a high speed cam together on the cam shaft, and selectively switching the low speed cam during low speed operation of the engine and the high speed cam during high speed operation, A first rocker arm that is pivotally supported by the rocker shaft and that opens and closes a valve by a cam surface of the cam shaft centering around the rocker shaft pivotal portion through a valve pressing portion at an end, and adjacent to the first rocker arm. A second rocker arm pivotally supported by the rocker shaft and contacting the high speed cam at a high speed; and a first rocker arm. An arm portion extending from the rocker shaft pivotal support portion to the cam sliding contact portion, and a coupling switching portion for the first and second rocker arms provided adjacent to the cam sliding contact portion, the coupling switching portion being provided to an engine. There is provided a hydraulic pressure selection switching means for switching and moving the second rocker arm by a plunger that operates by receiving the hydraulic pressure of an interlocking oil pump, and is provided on the side opposite to the hydraulic chamber of the plunger so that the plunger is always kept in a low speed state. A spring means for urging is provided, and the plunger is operated against the spring means at the time of high-speed operation when the oil pressure of the oil pump becomes equal to or higher than a predetermined value, and the second rocker arm of the previous period is switched to the high-speed side. A second rocker arm integrally connected by the connection switching portion, slidably contacting a high speed cam, and pivotally supported by the rocker shaft.
A valve timing switching device for an internal combustion engine, characterized in that the valve is opened / closed by the rocker arm via the first rocker arm.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3130512A JPH07107362B2 (en) | 1991-05-02 | 1991-05-02 | Valve timing switching device for internal combustion engine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3130512A JPH07107362B2 (en) | 1991-05-02 | 1991-05-02 | Valve timing switching device for internal combustion engine |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8775484A Division JPH0629524B2 (en) | 1984-05-02 | 1984-05-02 | Valve timing switching device for internal combustion engine |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0598919A JPH0598919A (en) | 1993-04-20 |
JPH07107362B2 true JPH07107362B2 (en) | 1995-11-15 |
Family
ID=15036069
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3130512A Expired - Fee Related JPH07107362B2 (en) | 1991-05-02 | 1991-05-02 | Valve timing switching device for internal combustion engine |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07107362B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19681086D2 (en) * | 1995-12-11 | 1997-12-11 | Fev Motorentech Gmbh & Co Kg | Device for actuating valves on a piston machine with a variable valve lift, in particular a piston internal combustion engine |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55151107A (en) * | 1979-05-11 | 1980-11-25 | Nissan Motor Co Ltd | Valve lifting mechanism for internal combustion engine |
JPS57179314A (en) * | 1981-04-27 | 1982-11-04 | Nippon Soken Inc | Engine equipped with valve acting in variable condition |
-
1991
- 1991-05-02 JP JP3130512A patent/JPH07107362B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH0598919A (en) | 1993-04-20 |
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