JPS644045B2 - - Google Patents

Info

Publication number
JPS644045B2
JPS644045B2 JP17997180A JP17997180A JPS644045B2 JP S644045 B2 JPS644045 B2 JP S644045B2 JP 17997180 A JP17997180 A JP 17997180A JP 17997180 A JP17997180 A JP 17997180A JP S644045 B2 JPS644045 B2 JP S644045B2
Authority
JP
Japan
Prior art keywords
camshaft
cams
exhaust valves
close
bearing
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
Application number
JP17997180A
Other languages
Japanese (ja)
Other versions
JPS57102506A (en
Inventor
Ryuichi Ichikawa
Masashi Mizutani
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yamaha Motor Co Ltd
Original Assignee
Yamaha Motor Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Yamaha Motor Co Ltd filed Critical Yamaha Motor Co Ltd
Priority to JP17997180A priority Critical patent/JPS57102506A/en
Publication of JPS57102506A publication Critical patent/JPS57102506A/en
Publication of JPS644045B2 publication Critical patent/JPS644045B2/ja
Granted legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
    • 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
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/242—Arrangement of spark plugs or injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/20—SOHC [Single overhead camshaft]
    • 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
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
    • F02F1/4214—Shape or arrangement of intake or exhaust channels in cylinder heads specially adapted for four or more valves per cylinder
    • 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
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis
    • 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
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis
    • F02F2001/246—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis and orientated radially from the combustion chamber surface

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、燃焼室の中央の上方付近を横断す
る１個の頭上カム軸で複数の吸気弁および２個の
排気弁を開閉駆動する１頭上カム軸式エンジンに
関するものである。Detailed Description of the Invention (Industrial Application Field) The present invention provides a single overhead camshaft that opens and closes a plurality of intake valves and two exhaust valves using one overhead camshaft that traverses near the upper center of a combustion chamber. It concerns an overhead camshaft engine.

（発明の背景） ４サイクルエンジンでは、吸・排気抵抗を減ら
すと共に良好な燃焼室形状を得るために、１つの
気筒につき吸気弁と排気弁をそれぞれ２個づつ備
えたものがある。この場合、２個の頭上カム軸で
各２個づつの吸気弁および排気弁を開閉するよう
にすると、エンジンが大型化する。このためエン
ジン搭載空間に制限がある自動二輪車などでは、
頭上カム軸を１個にすることが好ましい。このよ
うな４バルブ１頭上カム軸式のものとして燃焼室
中央の上方まで延びる短いカム軸に２個のカムを
形成し、各カムに摺接する２個のロツカアームで
４個の吸・排気弁を開閉駆動すると共に、カム軸
と反対側に点火栓を斜めに配置するものがある
（例えば実公昭50−4882、実開昭54−74816）。す
なわちロツカアームは、それぞれ２個の吸気弁ま
たは排気弁を開閉する２本の腕と、カムに摺接す
る１本の腕とを備えていた。(Background of the Invention) Some four-stroke engines are equipped with two intake valves and two exhaust valves per cylinder in order to reduce intake and exhaust resistance and obtain a good combustion chamber shape. In this case, if two overhead camshafts are used to open and close two intake valves and two exhaust valves, the engine will become larger. For this reason, in motorcycles and other vehicles where the space for mounting the engine is limited,
It is preferable to use one overhead camshaft. In this 4-valve, 1-overhead camshaft type, two cams are formed on a short camshaft that extends above the center of the combustion chamber, and four intake and exhaust valves are controlled by two rocker arms that slide into each cam. There are some that are driven to open and close and have the spark plug diagonally arranged on the opposite side of the camshaft (for example, Japanese Utility Model Publication No. 50-4882, Japanese Utility Model Publication No. 54-74816). That is, the rocker arm had two arms that opened and closed two intake valves or two exhaust valves, and one arm that slidably contacted the cam.

ところで吸・排気弁は特に高速運転時における
バルブの踊りを防ぐために弁ばねを十分に強くし
ておく必要があるが、前記のように１個のロツカ
アームで２個の吸・排気弁を開閉する場合には、
カム軸とカム面とロツカアームとの摺動面に加わ
る面圧が非常に大きくなり、潤滑および摩耗の点
で不利になり易い。そこでこのカムの摺動面に加
わる面圧を低くするために弁ばねを弱くすると、
高速運転時にバルブ踊りが発生するという問題が
生じる。 By the way, the valve springs for the intake and exhaust valves need to be strong enough to prevent the valves from moving, especially during high-speed operation, but as mentioned above, one rocker arm opens and closes two intake and exhaust valves. in case of,
The surface pressure applied to the sliding surfaces of the camshaft, cam surface, and rocker arm becomes extremely large, which tends to be disadvantageous in terms of lubrication and wear. Therefore, in order to reduce the surface pressure applied to the sliding surface of this cam, the valve spring is weakened.
A problem arises in that valve movement occurs during high-speed operation.

また点火栓を１気筒に１個設ける場合には点火
栓の着火部を燃焼室の中央付近にできるだけ垂直
に近くなるように位置させるのが望ましい。しか
しこの種の４バルブエンジンでは、燃焼室の上方
に１本のカム軸が位置することになるため、点火
栓の位置を燃焼室中央から離したり、点火栓を大
きく傾けて取付けたりしなければならなかつた。 Further, when one spark plug is provided for each cylinder, it is desirable to position the ignition part of the spark plug as close to the center of the combustion chamber as possible vertically. However, in this type of 4-valve engine, one camshaft is located above the combustion chamber, so the spark plug must be placed away from the center of the combustion chamber or installed at a large angle. It didn't happen.

さらにカム軸には多数のカムが形成されるため
カム軸の軸受間隙が増大し、カム軸を大径にする
必要が生じ、このためエンジンが重く大型化する
という問題があつた。 Furthermore, since a large number of cams are formed on the camshaft, the bearing gap of the camshaft increases, making it necessary to increase the diameter of the camshaft, which causes the problem that the engine becomes heavier and larger.

（第１の発明の目的） 本発明はこのような事情に鑑みなされたもので
あり、吸・排気弁の踊りが発生しにくく高速運転
に適すると共に、点火栓を燃焼室中央付近にでき
るだけ垂直に近くなるように配設でき、燃焼室形
状を悪化させることなくこの点火栓の着脱性を良
好にでき、さらにエンジン全高も低くおさえ、エ
ンジンの軽量小型化が可能な１頭上カム軸式エン
ジンを提供することを第１の目的とする。(First Object of the Invention) The present invention was made in view of the above circumstances, and is suitable for high-speed operation where the movement of the intake and exhaust valves is less likely to occur, and the ignition plug is placed as vertically as possible near the center of the combustion chamber. We provide a single overhead camshaft engine that can be placed close to each other, making it easy to attach and remove the ignition plug without deteriorating the shape of the combustion chamber, and also keeping the overall height of the engine low, making the engine lighter and smaller. The primary purpose is to

（第１の発明の構成） この発明によればこの第１の目的は、１つの気
筒に対し、燃焼室中心の上方付近を横断する１本
の頭上カム軸で複数の吸気弁を複数のロツカアー
ムにより開閉駆動し、また２個の排気弁を２個の
ロツカアームにより開閉駆動するものにおいて、
前記カム軸に形成された複数のカムと、前記燃焼
室中心の上方付近に位置し前記カム間で前記カム
の最大径より小径の軸受面で前記カム軸を支持す
る軸受と、前記カム軸を前記複数のカムの外側で
支持する一対の軸受とを備え、前記カム軸を前記
各吸気弁の弁軸と両排気弁の弁軸との間であつて
各ロツカアーム軸より低い位置に配設する一方、
前記両排気弁の上部を互いに離れるように拡開さ
せ、これら両排気弁間に前記カム間でカム軸を支
持する軸受で近接するように点火栓を配設したこ
とを特徴とする４バルブ１頭上カム軸式エンジン
により達成される。(Structure of the First Invention) According to the present invention, the first object is to connect a plurality of intake valves to a plurality of rocker arms for one cylinder by one overhead camshaft that traverses near the upper part of the center of the combustion chamber. In a device in which the two exhaust valves are driven to open and close by two rocker arms,
a plurality of cams formed on the camshaft; a bearing located near above the center of the combustion chamber and supporting the camshaft with a bearing surface having a smaller diameter than the maximum diameter of the cams between the cams; a pair of bearings supported on the outside of the plurality of cams, and the camshaft is disposed between the valve shaft of each intake valve and the valve shaft of both exhaust valves and at a position lower than each rocker arm shaft. on the other hand,
4-valve 1, characterized in that the upper parts of the two exhaust valves are expanded apart from each other, and a spark plug is arranged between the two exhaust valves so as to be close to each other by a bearing that supports a camshaft between the cams. Achieved by an overhead camshaft engine.

（第２の発明の目的） またこのように２個の排気弁とカム軸とで囲ま
れる位置に点火栓を配設する場合には、点火栓の
冷却を行うことが困難になる。この発明はこのよ
うな場合にも点火栓を十分に冷却でき、点火栓の
発火部を燃焼室中央付近の最適位置に配置するこ
とを可能にすることを第２の目的とする。(Second Object of the Invention) Furthermore, when the ignition plug is disposed at a position surrounded by the two exhaust valves and the camshaft as described above, it becomes difficult to cool the ignition plug. A second object of the present invention is to make it possible to sufficiently cool the ignition plug even in such a case, and to arrange the ignition part of the ignition plug at an optimal position near the center of the combustion chamber.

（第２の発明の構成） 本発明によればこの第２の目的は、前記第１の
発明における２つの排気弁の弁軸間にエンジン前
方へ開口する冷却風通路を形成し、走行風を点火
栓付近へ導くことにより達成される。以下図面に
示す実施例に基づいて、この発明を詳細に説明す
る。(Structure of the second invention) According to the present invention, the second object is to form a cooling air passage that opens toward the front of the engine between the valve stems of the two exhaust valves in the first invention, and to vent the running air. This is achieved by guiding it near the spark plug. The present invention will be described in detail below based on embodiments shown in the drawings.

（実施例） 第１図は自動二輪車に適用したこの発明の一実
施例を一部断面した側面図、第２図はそのエンジ
ンの要部を示す中央縦断面図、第３図は第２図に
おけるシリンダヘツドカバーを取外して動弁機構
を示す平面図、また第４図は各ロツカアームの取
付状態を示すためにシリンダヘツドカバーを一部
断面した平面図である。(Embodiment) Fig. 1 is a partially sectional side view of an embodiment of the present invention applied to a motorcycle, Fig. 2 is a central longitudinal sectional view showing the main parts of the engine, and Fig. 3 is the same as Fig. 2. FIG. 4 is a plan view showing the valve operating mechanism with the cylinder head cover removed, and FIG. 4 is a partially sectional plan view of the cylinder head cover to show how each rocker arm is attached.

第１図において符号１０はメインフレーム、１
２は前輪１４を支持するフロントフオーク、１６
は後輪である。１８は４バルブ１頭上カム軸式１
気筒エンジンであつて、その吸気通路２０が車体
後方をまた排気通路２２が車体前方をそれぞれ指
向するようにメインフレーム１０に取付けられて
いる。２４は吸気通路２０へ混合気を供給する気
化器、また２６は排気管であつて、この排気管２
６は排気通路２２から排出される排気をエンジン
１０の前方からエンジン１０の下方を通つて後方
へ導くように折曲されている。 In FIG. 1, numeral 10 is the main frame, 1
2 is a front fork supporting the front wheel 14; 16;
is the rear wheel. 18 is 4 valves 1 overhead camshaft type 1
The engine is a cylinder engine and is mounted on a main frame 10 so that its intake passage 20 and exhaust passage 22 point toward the rear of the vehicle body and toward the front of the vehicle body, respectively. 24 is a carburetor that supplies air-fuel mixture to the intake passage 20; 26 is an exhaust pipe;
6 is bent so as to guide the exhaust gas discharged from the exhaust passage 22 from the front of the engine 10 to the rear through the lower part of the engine 10.

２８はクランクケース、３０はシリンダ、３２
はシリンダヘツド、３４はシリンダヘツドカバー
（以下ヘツドカバーという）である。シリンダヘ
ツド３２とヘツドカバー３４の接合面間にはカム
軸３６が横向きに軸支され、このカム軸３６の一
端に固定されたスプロケツト３８はクランク軸４
０との間に掛け回されたタイミングチエーン４２
によつて、クランク軸４０の半分の速度で回転さ
れる。このカム軸３６は燃焼室４４の中心の上方
付近を横断する。 28 is a crankcase, 30 is a cylinder, 32
34 is a cylinder head, and 34 is a cylinder head cover (hereinafter referred to as a head cover). A camshaft 36 is laterally supported between the joint surfaces of the cylinder head 32 and the head cover 34, and a sprocket 38 fixed to one end of the camshaft 36 is connected to the crankshaft 4.
The timing chain 42 that runs between
The crankshaft 40 is rotated at half the speed of the crankshaft 40. This camshaft 36 crosses the vicinity above the center of the combustion chamber 44 .

シリンダヘツド３２には燃焼室４４に開口する
２個の吸気口４６，４６（第２，３図）と、２個
の排気口４８，４８が形成され、各吸気口４６，
４６には２個の前記吸気通路２０，２０が連通
し、また各排気口４８，４８には２個の前記排気
通路２２，２２が連通している。なおこの実施例
では前記排気管２６（第１図では一方のみが表わ
れている）を２本備え、各排気通路２２，２２か
ら排気はこれら２本の排気管２６を経て別々に排
出される。 Two intake ports 46, 46 (FIGS. 2 and 3) that open into the combustion chamber 44 and two exhaust ports 48, 48 are formed in the cylinder head 32, and each intake port 46,
46 communicates with the two intake passages 20, 20, and each exhaust port 48, 48 communicates with the two exhaust passages 22, 22. In this embodiment, two exhaust pipes 26 (only one of which is shown in FIG. 1) are provided, and exhaust gas from each exhaust passage 22, 22 is separately discharged through these two exhaust pipes 26. .

５０，５０は吸気弁であつて、第２図から明ら
かなようにその弁軸５２，５２が後方へ傾斜する
ように支持され、弁ばね５４，５４によつてその
傘部５６，５６が吸気口４６，４６を閉じるよう
に付勢されている。第３図において５８，５８は
この吸気弁５０，５０の軸線を示し、この図から
明らかなようにこの軸線５８，５８は前記カム軸
３６と直交する。 Reference numerals 50 and 50 indicate intake valves, and as is clear from FIG. The ports 46, 46 are biased closed. In FIG. 3, reference numerals 58, 58 indicate the axes of the intake valves 50, 50, and as is clear from this figure, the axes 58, 58 are perpendicular to the camshaft 36.

６０，６０は排気弁であつて、第３図から明ら
かなようにその弁軸６２，６２が前方へ傾斜する
ように支持され、弁ばね６４，６４によつてその
傘部６６，６６が前記排気口４８，４８を閉じる
ように付勢されている。第３図において６８，６
８はこの排気弁６０，６０の軸線を示し、この図
から明らかなようにこの排気弁６０，６０はその
上部が相互に次第に離れるように支持されてい
る。 Reference numerals 60 and 60 are exhaust valves, and as is clear from FIG. The exhaust ports 48, 48 are biased to close. 68,6 in Figure 3
Reference numeral 8 indicates the axes of the exhaust valves 60, 60, and as is clear from this figure, the exhaust valves 60, 60 are supported such that their upper portions are gradually separated from each other.

シリンダヘツド３２は各弁５０，５０，６０，
６０および各弁ばね５４，５４，６４，６４を組
付けた後、第３図に示す４本のボトル７０によつ
て前記シリンダ３０（第１図）へ固定される。 The cylinder head 32 has each valve 50, 50, 60,
After assembling 60 and each valve spring 54, 54, 64, 64, it is fixed to the cylinder 30 (FIG. 1) by four bottles 70 shown in FIG.

カム軸３６には、第３図に示すように内側に位
置する２個の吸気側カム７２，７２および外側に
位置する２個の排気側カム７４，７４が形成さ
れ、各１個のカム７２と７４が互いに近接する一
方、内側のカム７２，７２間は離隔している。こ
のカム軸３６は両端部と中央部が、前記シリンダ
ヘツド３２とヘツドカバー３４の接合面間に形成
される３個のすべり軸受７６，７８，８０により
軸支される。すなわち前記内側のカム７２，７２
の間が燃焼室４４中心の上方付近に位置する中央
の軸受８０で、軸支される。この軸受８０の軸受
面は各カム７２，７４の最大径より小径であり、
本実施例では各カム７２，７４の最小径部分より
もさらに小径となつている。このカム軸３６の一
端（第３図で上方）には前記スプロケツト３８が
固定され、また他端（第３図で下方）には回転速
度検出用歯車機構（図示せず）が接続される。 As shown in FIG. 3, the camshaft 36 is formed with two intake-side cams 72, 72 located on the inside and two exhaust-side cams 74, 74 located on the outside. and 74 are close to each other, while the inner cams 72 and 72 are spaced apart. The camshaft 36 is pivotally supported at both ends and the center by three slide bearings 76, 78, and 80 formed between the joint surfaces of the cylinder head 32 and the head cover 34. That is, the inner cams 72, 72
The space between the combustion chambers 44 is supported by a central bearing 80 located above the center of the combustion chamber 44 . The bearing surface of this bearing 80 has a diameter smaller than the maximum diameter of each cam 72, 74,
In this embodiment, the diameter is smaller than the minimum diameter portion of each cam 72, 74. The sprocket 38 is fixed to one end (upper side in FIG. 3) of this camshaft 36, and a gear mechanism (not shown) for detecting rotational speed is connected to the other end (lower side in FIG. 3).

シリンダヘツド３２およびヘツドカバー３４に
は第２，３図に示すように冷却風通路８２が形成
されている。すなわち前記排気弁６０，６０の間
にはエンジン１８の前方および上方へ開口する縦
長の間隙が形成され、この実施例ではさらにこの
間隙は前記中央の軸受８０の下方から前記吸気弁
５０，５０間を通つて後方に開口している。この
冷却風通路８２は、両排気弁６０，６０間におい
て前記軸受８０に近接する部分が略円筒状の空間
となつていて、ここが点火栓着脱孔８４となつて
いる。すなわちこの着脱孔８４を形成する壁は軸
受８０と一体となつている。第２，３図において
８６はこの軸受８０に近接するように配設された
点火栓であり、この点火栓８６の着火部は燃焼室
４４の中央付近に位置する。 A cooling air passage 82 is formed in the cylinder head 32 and the head cover 34, as shown in FIGS. That is, a vertically elongated gap is formed between the exhaust valves 60, 60 that opens forward and upward of the engine 18, and in this embodiment, this gap extends from below the central bearing 80 to between the intake valves 50, 50. It opens to the rear through. The cooling air passage 82 has a substantially cylindrical space between the two exhaust valves 60 and 60 near the bearing 80, and this space serves as a spark plug attachment/removal hole 84. That is, the wall forming the attachment/detachment hole 84 is integrated with the bearing 80. In FIGS. 2 and 3, reference numeral 86 denotes an ignition plug disposed close to the bearing 80, and the ignition portion of the ignition plug 86 is located near the center of the combustion chamber 44.

軸受８０の軸受面はカム７２，７４の最大径よ
りも小径であるから点火栓８６は一層カム軸３６
に接近させて配設できる。すなわちカム軸３６の
中央すなわち燃焼室４４中心の上方付近にカムが
あると、このカムの最大径部分との干渉を避ける
ように動弁機構を収容する動弁室の壁（この壁は
点火栓着脱孔８４ともなる）を設けねばならず、
この壁がカム軸３６の中心から遠くなるのに対
し、本願によればこの位置にはカムは無く軸受８
０があり、その軸受面はカム７２，７４の最大径
より小径なので動弁室の壁をカム軸３６の中心に
接近させることができる。このため点火栓８６は
エンジン全高を低く保ちつつ大きく傾けることも
なく最も垂直に近い角度に配設でき、良好な燃焼
を得るのに好ましい位置となる。 Since the bearing surface of the bearing 80 has a smaller diameter than the maximum diameter of the cams 72 and 74, the spark plug 86 is even closer to the cam shaft 36.
It can be placed close to the In other words, if there is a cam near the center of the camshaft 36, that is, above the center of the combustion chamber 44, the wall of the valve chamber that houses the valve mechanism (this wall is the ignition plug It is necessary to provide a hole (which also serves as the attachment/detachment hole 84),
While this wall is far from the center of the camshaft 36, according to the present application there is no cam at this position and the bearing 8
0, and its bearing surface has a diameter smaller than the maximum diameter of the cams 72 and 74, so that the wall of the valve chamber can be brought closer to the center of the camshaft 36. Therefore, the ignition plug 86 can be disposed at the most vertical angle without greatly tilting the engine while keeping the overall height of the engine low, which is a preferable position for obtaining good combustion.

なおシリンダヘツド３２、ヘツドカバー３４に
は、冷却風流入側に補助用のリブ８８，９０が形
成されている。特にシリンダヘツド３２のリブ８
８内には油路９２（第２図）が形成され、この油
路９２は、第３図で下方に位置する排気弁６０を
潤滑した後の潤滑油を、同図上方に位置する排気
弁６０の弁ばね６４の装填室内を通つて前記スプ
ロケツト３８収容室９４（第３図）へ導く。 The cylinder head 32 and head cover 34 are provided with auxiliary ribs 88 and 90 on the cooling air inflow side. In particular, the rib 8 of the cylinder head 32
An oil passage 92 (FIG. 2) is formed in 8, and this oil passage 92 supplies lubricating oil after lubricating the exhaust valve 60 located below in FIG. 3 to the exhaust valve located above in FIG. The sprocket 38 is guided through the loading chamber of the valve spring 64 into the sprocket receiving chamber 94 (FIG. 3).

一方、両排気弁６０，６０は上部が互いに離れ
るように拡開しているので、冷却風通路８０の流
入側および点火栓着脱孔８４を大きく確保でき、
点火栓８６の冷却性と着脱性が一層向上する。 On the other hand, since both exhaust valves 60, 60 are expanded so that their upper parts are separated from each other, a large area can be secured on the inflow side of the cooling air passage 80 and the ignition plug attachment/removal hole 84.
The cooling performance and detachability of the spark plug 86 are further improved.

なおシリンダヘツド３２およびヘツドカバー３
４に形成された点火栓着脱孔８４の壁は一種の柱
としての機能を持ち、この壁と一体に軸受８０が
形成されているので、シリンダヘツド３２および
ヘツドカバー３４の剛性も向上する。 Note that the cylinder head 32 and head cover 3
The wall of the spark plug attachment/removal hole 84 formed in the cylinder head 4 functions as a kind of pillar, and since the bearing 80 is formed integrally with this wall, the rigidity of the cylinder head 32 and the head cover 34 is also improved.

ヘツドカバー３４は第３図に示すように、多数
のボルト９６〜１０２によつてシリンダヘツド３
２に固定される。すなわち軸受７６，７８がボル
ト９６，９６，９８，９８で、また中央の軸受８
０が３本のボルト１００でさらに接合面の外周が
多数のボルト１０２で、それぞれ締付けられてい
る。 As shown in FIG.
It is fixed at 2. That is, bearings 76, 78 are connected to bolts 96, 96, 98, 98, and central bearing 8 is connected to bolts 96, 96, 98, 98.
0 is tightened with three bolts 100, and the outer periphery of the joint surface is further tightened with a large number of bolts 102, respectively.

１０４，１０４は前記内側のカム７２，７２に
上方から摺接して揺動する内側ロツカアームであ
る。この内側ロツカアーム１０４，１０４は、カ
ム軸３６と平行になるようにヘツドカバー３４の
内面に挿入されたロツカアーム軸１０６に軸支さ
れている（第４図）。このロツカアーム１０４，
１０４は各一方の腕１０８，１０８が内側カム７
２，７２に上方から摺接し、他方の腕１１０，１
１０が前記各吸気弁５０，５０の軸端を押圧す
る。なお第４図において１１２は、ロツカアーム
軸１０６を貫通するようにヘツドカバー３４の内
面側から螺入された位置決め用ボルトである。す
なわちこのロツカアーム軸１０６には、前記多数
のボルト９６〜１０２のうちの２本９８，１００
（第４図）が干渉する位置に凹部１１４，１１４
が形成されているので、この凹部１１４，１１４
の位置を固定してヘツドカバー３４をシリンダヘ
ツド３２に取付ける際にボルト９８，１００を挿
通し易くするために、位置決め用ボルト１１２が
必要になるのである。 Reference numerals 104 and 104 designate inner rocker arms that slide and swing from above on the inner cams 72 and 72, respectively. The inner rocker arms 104, 104 are pivotally supported by a rocker arm shaft 106 inserted into the inner surface of the head cover 34 so as to be parallel to the cam shaft 36 (FIG. 4). This Rotsuka arm 104,
104, each one arm 108, 108 is the inner cam 7
2,72 from above, and the other arm 110,1
10 presses the shaft end of each intake valve 50, 50. In FIG. 4, reference numeral 112 denotes a positioning bolt screwed into the head cover 34 from the inner side so as to pass through the rocker arm shaft 106. That is, two bolts 98, 100 of the large number of bolts 96 to 102 are attached to this rocker arm shaft 106.
(Fig. 4) Recesses 114, 114
are formed, so these recesses 114, 114
The positioning bolt 112 is required to fix the position of the cylinder head 34 and to facilitate the insertion of the bolts 98, 100 when attaching the head cover 34 to the cylinder head 32.

１１６，１１６は外側のカム７４，７４に上方
から摺接する外側ロツカアームである。これらの
ロツカアーム１１６，１１６は、カム軸と平行と
なるようにヘツドカバー３４に保持された２本の
ロツカアーム軸１１８，１１８に軸支されてい
る。このロツカアーム１１６，１１６は一方の腕
１２０，１２０が外側のカム７４，７４に上方か
ら摺接し、他方の腕１２２，１２２が前記各排気
弁６０，６０の軸端を押圧する。なお１２４，１
２４は各ロツカアーム軸１１８，１１８を貫通す
る位置決め用ボルト、１２６，１２６はボルト１
００との干渉を避けるための凹部である。なお前
記カム軸３６は各ロツカアーム軸１０６，１１８
より低い位置に配設されている。この実施例で
は、このように排気側のロツカアーム１１６，１
１６を燃焼室４４に対して外側に配置するばかり
でなく、外側ロツカアーム１１６，１１６を第
３，４図に示すようにその腕１２０，１２０側が
腕１２２，１２２に比べて広がるように形成して
いるので、２本のロツカアーム軸１１８，１１８
の間隔を広げることができ、その結果点火栓着脱
孔８４を十分に拡大することが可能になる。ここ
に排気弁６０，６０を前記したようにその上部の
間隔が次第に広がるように傾斜して設けた点も、
点火栓着脱孔８４の拡大に寄与していることは勿
論である。 Reference numerals 116 and 116 designate outer rocker arms that slide into contact with the outer cams 74 and 74 from above. These rocker arms 116, 116 are supported by two rocker arm shafts 118, 118 held by the head cover 34 so as to be parallel to the cam shaft. One arm 120, 120 of the rocker arms 116, 116 slides into contact with the outer cams 74, 74 from above, and the other arm 122, 122 presses the shaft end of each of the exhaust valves 60, 60. Furthermore, 124,1
24 is a positioning bolt that passes through each rocker arm shaft 118, 118, and 126, 126 is a bolt 1.
This is a recessed portion to avoid interference with 00. Note that the cam shaft 36 is connected to each rocker arm shaft 106, 118.
placed at a lower position. In this embodiment, the rocker arms 116, 1 on the exhaust side are
16 is disposed outside of the combustion chamber 44, and the outer rocker arms 116, 116 are formed so that the arms 120, 120 side thereof are wider than the arms 122, 122, as shown in FIGS. Since there are two rocker arm shafts 118, 118
As a result, the ignition plug attachment/detachment hole 84 can be sufficiently enlarged. The point here is that the exhaust valves 60, 60 are provided in an inclined manner so that the gap between their upper parts gradually widens as described above.
Of course, this contributes to the enlargement of the spark plug attachment/removal hole 84.

ヘツドカバー３４にはロツカアーム１０４，１
０４，１１６，１１６、ロツカアーム軸１０６，
１１８，１１８を予め組付け、さらに位置決め用
ボルト１１２，１２４，１２４によつて各凹部１
１４，１２６，１２６を第４図の位置に位置決め
した後、シリンダヘツド３２に被冠し、各ボルト
９６〜１０２で締付ける。 The rocker arm 104,1 is attached to the head cover 34.
04, 116, 116, Rocker arm shaft 106,
118, 118 are assembled in advance, and each recess 1 is further assembled with positioning bolts 112, 124, 124
14, 126, and 126 are positioned as shown in FIG. 4, they are mounted on the cylinder head 32 and tightened with the respective bolts 96 to 102.

このエンジン１８の運転中にはカム軸２６が回
転しカム７２，７２，７４，７４がロツカアーム
１０４，１０４，１１６，１１６を揺動して吸気
弁５０，５０、排気弁６０，６０を所定の吸・排
気タイミングに従つて開閉する。車両走行中にお
いては排気弁６０，６０間に形成された冷却風通
路８２へ走行風が流入し、点火栓８６の螺着部付
近を特に十分に冷却する。そして冷却風はその一
部が吸気弁５０，５０間を通つてエンジン１８の
後方へ、他の一部は点火栓着脱孔８４からエンジ
ン１８の上方へ流出する。 During operation of the engine 18, the camshaft 26 rotates, and the cams 72, 72, 74, 74 swing the rocker arms 104, 104, 116, 116 to move the intake valves 50, 50 and exhaust valves 60, 60 to predetermined positions. Opens and closes according to intake and exhaust timing. While the vehicle is running, running air flows into the cooling air passage 82 formed between the exhaust valves 60, 60, and particularly sufficiently cools the area around the threaded portion of the ignition plug 86. A portion of the cooling air passes between the intake valves 50 and 50 to the rear of the engine 18, and the other portion flows out from the ignition plug attachment/removal hole 84 to the upper side of the engine 18.

（第１の発明の効果） 第１の発明は以上のように、カム軸をロツカア
ーム軸の下に配置し、カム軸を燃焼室中心の上方
付近と複数のカムの両側との３つの軸受で支持
し、中央軸受の軸受面をカムの最大径より小径と
し、両排気弁上部を互いに拡開させ、両排気弁間
に点火栓を配設したものである。このためカム軸
は燃焼室中心の上方付近と両側との３つの軸受に
て支持されるので中央の軸受荷重は小さくなり、
カム軸の小径化が可能となり特に中央の軸受に支
持される部分の大幅な小径化が可能となる。この
ためエンジンの軽量化と小型化とが図れる。一方
両排気弁は上部が拡開しているのでその間に点火
栓着脱孔をカム軸に十分近く無理なく配設できる
ようになり、燃焼室形状を悪化させることなく点
火栓をできるだけ垂直に近づけて着火部を燃焼室
中央付近の最適位置に配置でき、好ましい燃焼室
を得ることができる。さらに各吸・排気弁はそれ
ぞれ独立にロツカアームで開閉されるので、吸・
排気弁の踊りが発生せず高速運転に適する。(Effect of the first invention) As described above, the first invention arranges the camshaft under the rocker arm shaft, and the camshaft is mounted on three bearings near the upper part of the center of the combustion chamber and on both sides of the plurality of cams. The bearing surface of the central bearing is made smaller in diameter than the maximum diameter of the cam, the upper portions of both exhaust valves are expanded from each other, and a spark plug is disposed between both exhaust valves. For this reason, the camshaft is supported by three bearings, one above the center of the combustion chamber and one on both sides, so the load on the central bearing is reduced.
It becomes possible to reduce the diameter of the camshaft, and in particular, it becomes possible to significantly reduce the diameter of the portion supported by the central bearing. Therefore, the engine can be made lighter and smaller. On the other hand, since the tops of both exhaust valves are widened, the ignition plug attachment/removal hole can be easily placed close enough to the camshaft between them, and the ignition plug can be placed as close to vertical as possible without deteriorating the shape of the combustion chamber. The ignition part can be arranged at an optimal position near the center of the combustion chamber, and a preferable combustion chamber can be obtained. Furthermore, each intake and exhaust valve is opened and closed independently by a rocker arm, so the intake and exhaust valves are
Suitable for high-speed operation without causing exhaust valve movement.

（第２の発明の効果） 第２の発明によれば、両排気弁間に走行風を点
火栓付近に導く冷却風通路を設けたから、点火栓
の冷却性が向上する。(Effects of the Second Invention) According to the second invention, since a cooling air passage is provided between both exhaust valves to guide running air to the vicinity of the ignition plug, the cooling performance of the ignition plug is improved.

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

第１図はこの発明の一実施例を適用した自動二
輪車の一部断面図、第２図はその要部の中央縦断
側面図、第３図は第２図におけるヘツドカバー取
外し状態を示す平面図、また第４図はヘツドカバ
ーの一部断面平面図である。 １８……エンジン、３６……カム軸、５０……
吸気弁、６０……排気弁、７２，７４……カム、
７６，７８……軸受、８０……中央の軸受、８２
……冷却風通路、８４……点火栓着脱孔、８６…
…点火栓、１０４……内側ロツカアーム、１１６
……外側ロツカアーム。 FIG. 1 is a partial sectional view of a motorcycle to which an embodiment of the present invention is applied, FIG. 2 is a central longitudinal sectional side view of the main parts thereof, and FIG. 3 is a plan view showing the state in which the head cover is removed in FIG. 2. FIG. 4 is a partially sectional plan view of the head cover. 18...Engine, 36...Camshaft, 50...
Intake valve, 60... Exhaust valve, 72, 74... Cam,
76, 78...Bearing, 80...Central bearing, 82
...Cooling air passage, 84...Ignition plug attachment/removal hole, 86...
...Spark plug, 104...Inner lock arm, 116
...Outer rotuka arm.

Claims (1)

【特許請求の範囲】 １ １つの気筒に対し、燃焼室中心の上方付近を
横断する１本の頭上カム軸で複数の吸気弁を複数
のロツカアームにより開閉駆動し、また２個の排
気弁を２個のロツカアームにより開閉駆動するも
のにおいて、 前記カム軸に形成された複数のカムと、前記燃
焼室中心の上方付近に位置し前記カム間で前記カ
ムの最大径より小径の軸受面で前記カム軸を支持
する軸受と、前記カム軸を前記複数のカムの外側
で支持する一対の軸受とを備え、前記カム軸を前
記各吸気弁の弁軸と両排気弁の弁軸との間であつ
て各ロツカアーム軸より低い位置に配設する一
方、前記両排気弁の上部を互いに離れるように拡
開させ、これら両排気弁間に前記カム間でカム軸
を支持する軸受に近接するように点火栓を配設し
たことを特徴とする１頭上カム軸式エンジン。 ２ 前記点火栓の着脱孔を形成する壁はカム軸の
内側のカム間を支持する軸受と一体となつている
ことを特徴とする特許請求の範囲第１項記載の１
頭上カム軸式エンジン。 ３ １つの気筒に対し、燃焼室中心の上方付近を
横断する１本の頭上カム軸で複数の吸気弁を複数
のロツカアームにより開閉駆動し、また２個の排
気弁を２個のロツカアームにより開閉駆動するも
のにおいて、 前記カム軸に形成された複数のカムと、前記燃
焼室中心の上方付近に位置し内側のカムの間で前
記カムの最大径より小径の軸受面で前記カム軸を
支持する軸受と、前記カム軸を前記複数のカムの
外側で支持する一対の軸受とを備え、前記カム軸
を前記各吸気弁の弁軸と両排気弁の弁軸との間に
あつて各ロツカアーム軸より低い位置に配設する
一方、前記両排気弁の上部を互いに離れるように
互いに拡開させ、これら両排気弁間に前記内側の
カムの間でカム軸を支持する軸受に近接するよう
に点火栓を配設し、両排気弁の弁軸間にエンジン
前方へ開口する冷却通路を形成して走行風を前記
点火栓付近に導くことを特徴とする１頭上カム軸
式エンジン。[Claims] 1. For one cylinder, a plurality of intake valves are driven to open and close by a plurality of rocker arms by one overhead camshaft that crosses near the upper part of the center of the combustion chamber, and two exhaust valves are driven to open and close by a plurality of rocker arms. The camshaft is driven by a plurality of cams formed on the camshaft and a bearing surface having a smaller diameter than the maximum diameter of the cams between the cams located above the center of the combustion chamber. and a pair of bearings that support the camshaft outside of the plurality of cams, the camshaft being positioned between the valve shaft of each intake valve and the valve shaft of both exhaust valves. While disposed at a lower position than each rocker arm shaft, the upper parts of the two exhaust valves are expanded apart from each other, and a spark plug is placed between the two exhaust valves so as to be close to the bearing that supports the camshaft between the cams. Single overhead camshaft engine. 2. The wall forming the attachment/detachment hole for the ignition plug is integrated with a bearing that supports between the cams inside the camshaft.
Overhead camshaft engine. 3 For one cylinder, multiple intake valves are driven to open and close by multiple rocker arms using one overhead camshaft that crosses above the center of the combustion chamber, and two exhaust valves are driven to open and close by two rocker arms. A bearing supporting the camshaft with a bearing surface having a diameter smaller than the maximum diameter of the cam between a plurality of cams formed on the camshaft and an inner cam located near the upper part of the center of the combustion chamber. and a pair of bearings that support the camshaft on the outside of the plurality of cams, the camshaft is located between the valve shaft of each intake valve and the valve shaft of both exhaust valves, and While disposed at a low position, the upper portions of the two exhaust valves are spread apart from each other, and a spark plug is placed between the two exhaust valves so as to be close to a bearing that supports the camshaft between the inner cams. A single overhead camshaft engine, characterized in that a cooling passage opening toward the front of the engine is formed between the valve stems of both exhaust valves to guide running air to the vicinity of the spark plug.
JP17997180A 1980-12-18 1980-12-18 Engine with four valves and one overhead cam shaft Granted JPS57102506A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17997180A JPS57102506A (en) 1980-12-18 1980-12-18 Engine with four valves and one overhead cam shaft

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17997180A JPS57102506A (en) 1980-12-18 1980-12-18 Engine with four valves and one overhead cam shaft

Related Child Applications (6)

Application Number Title Priority Date Filing Date
JP5642688A Division JPS63227911A (en) 1988-03-11 1988-03-11 Single overhead camshaft type engine
JP5642788A Division JPS63235610A (en) 1988-03-11 1988-03-11 One-overhead camshaft type engine
JP5643188A Division JPS63235667A (en) 1988-03-11 1988-03-11 Single overhead cam engine
JP5642988A Division JPS63235606A (en) 1988-03-11 1988-03-11 One-overhead camshaft type engine
JP5643088A Division JPS63235645A (en) 1988-03-11 1988-03-11 Single over head cam engine
JP5642888A Division JPS63235666A (en) 1988-03-11 1988-03-11 Single overhead cam engine

Publications (2)

Publication Number Publication Date
JPS57102506A JPS57102506A (en) 1982-06-25
JPS644045B2 true JPS644045B2 (en) 1989-01-24

Family

ID=16075176

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17997180A Granted JPS57102506A (en) 1980-12-18 1980-12-18 Engine with four valves and one overhead cam shaft

Country Status (1)

Country Link
JP (1) JPS57102506A (en)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5929709A (en) * 1982-08-12 1984-02-17 Honda Motor Co Ltd Tappet valve mechanism of internal combustion engine
JPS5949706U (en) * 1982-09-27 1984-04-02 本田技研工業株式会社 Internal combustion engine camshaft bearing device
JPS5996405A (en) * 1982-11-24 1984-06-02 Yamaha Motor Co Ltd Overhead cam shaft type four-valve engine
JPS60175807U (en) * 1984-05-01 1985-11-21 本田技研工業株式会社 Lubricating device for SOHC type valve train in internal combustion engine
JPS60190937U (en) * 1984-05-30 1985-12-18 スズキ株式会社 Combustion chamber of a 4-stroke engine
JPH0450404Y2 (en) * 1984-09-04 1992-11-27
JPH0320483Y2 (en) * 1984-09-17 1991-05-02
JPS61138822A (en) * 1984-12-10 1986-06-26 Mazda Motor Corp Four-valve type engine
US4714058A (en) * 1984-12-10 1987-12-22 Mazda Motor Corporation Spark-ignited internal combustion engine
JPS61142321A (en) * 1984-12-14 1986-06-30 Mazda Motor Corp Construction of combustion chamber in engine
US4741302A (en) * 1984-12-10 1988-05-03 Mazda Motor Corporation Internal combustion engine
JPS61160517A (en) * 1985-01-08 1986-07-21 Mazda Motor Corp Four valve type engine
JPH0452408Y2 (en) * 1985-04-30 1992-12-09
JP2554245B2 (en) * 1985-04-30 1996-11-13 マツダ株式会社 Single-over headed cam type engine
AT394249B (en) * 1985-05-22 1992-02-25 Avl Verbrennungskraft Messtech INTERNAL COMBUSTION ENGINE
US5070824A (en) * 1988-05-30 1991-12-10 Yamaha Hatsudoki Kabushiki Kaisha Combustion chamber and valve operating mechanism for multi-valve engine
JP2694898B2 (en) * 1988-05-30 1997-12-24 ヤマハ発動機株式会社 Valve system for 4-cycle engine
US5016592A (en) * 1989-02-14 1991-05-21 Yamaha Hatsudoki Kabushika Kaisha Cylinder head and valve train arrangement for multiple valve engine

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53643Y2 (en) * 1973-03-07 1978-01-11
JPS5543228A (en) * 1978-09-21 1980-03-27 Yamaha Motor Co Ltd Overhead cam-shaft engine

Also Published As

Publication number Publication date
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