JPH09189259A - Internal combustion engine for motorcycle - Google Patents

Internal combustion engine for motorcycle

Info

Publication number
JPH09189259A
JPH09189259A JP3851997A JP3851997A JPH09189259A JP H09189259 A JPH09189259 A JP H09189259A JP 3851997 A JP3851997 A JP 3851997A JP 3851997 A JP3851997 A JP 3851997A JP H09189259 A JPH09189259 A JP H09189259A
Authority
JP
Japan
Prior art keywords
cam
cylinder
intake
combustion engine
internal combustion
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.)
Granted
Application number
JP3851997A
Other languages
Japanese (ja)
Other versions
JP2981436B2 (en
Inventor
Hiroki Onodera
洋樹 小野寺
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 JP9038519A priority Critical patent/JP2981436B2/en
Publication of JPH09189259A publication Critical patent/JPH09189259A/en
Application granted granted Critical
Publication of JP2981436B2 publication Critical patent/JP2981436B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • 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
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B75/20—Multi-cylinder engines with cylinders all in one line
    • 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
    • F02B61/00—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing
    • F02B61/02—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving cycles
    • 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
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
    • 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
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B2075/1804—Number of cylinders
    • F02B2075/1816—Number of cylinders four
    • 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
    • F02B2275/18—DOHC [Double 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
    • 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

Abstract

PROBLEM TO BE SOLVED: To diminish the bending angle of an intake air passage so as to improve intake efficiency without changing the exhaust side forward tilting of the cylinder of an internal combustion engine. SOLUTION: An internal combustion engine 14 for a motorcycle is loaded on the motorcycle by being forwardly tilted so that the intake side 15b of the head of a cylinder 15 is upwardly directed and the exhaust side 15a thereof is directed to a traveling direction. A joint surface 25a between a cylinder block 25 and a cylinder head 26 is arranged vertically relative to a cylinder axis, and a part upper than the intake/exhaust passages 32, 34 of the cylinder head 26 is divided so as to be made to serve as a cam case 27 having a cam bearing surface 27a for supporting cam shafts 40, 41. The cam bearing surface 27a of the cam case 27 is tilted in the forwardly lowering direction relative to the joint surface of the cylinder head 26.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】この発明は、自動二輪車用内
燃機関に関する。TECHNICAL FIELD The present invention relates to an internal combustion engine for a motorcycle.

【０００２】[0002]

【従来の技術】シリンダの頭部の吸気側を上方に向けか
つ排気側を走行方向へ向けた内燃機関を搭載した自動二
輪車が知られている。この自動二輪車用内燃機関では、
シリンダブロックとシリンダヘッドとの接合面がシリン
ダ軸線に対して垂直であり、カムケースのカム軸受面も
ヘッドカバーの表面もシリンダ軸線に対して垂直であ
る。そのため、吸気バルブと排気バルブとは長さが同じ
で、吸気通路と排気通路とが略同様の形状となってい
る。2. Description of the Related Art There is known a motorcycle equipped with an internal combustion engine in which an intake side of a cylinder head is directed upward and an exhaust side is directed in a traveling direction. In this internal combustion engine for motorcycles,
The joint surface between the cylinder block and the cylinder head is perpendicular to the cylinder axis, and the cam bearing surface of the cam case and the surface of the head cover are perpendicular to the cylinder axis. Therefore, the intake valve and the exhaust valve have the same length, and the intake passage and the exhaust passage have substantially the same shape.

【０００３】自動二輪車に搭載された内燃機関につい
て、シリンダの吸気側を上方に向け、シリンダの排気側
を前側へ傾斜させて走行方向へ向けるのは、例えば自動
車の重心を下げたい等の理由による。このように排気側
を前側へ傾斜させると、吸気系や排気系の配置位置によ
って、例えば吸気通路の曲げ角度が大きくなって吸気効
率の低下を招くことがある。このため、内燃機関の吸気
系や排気系の配置位置を変更して、吸気通路の曲げ角度
が大きくならないようにすることが考えられるが、吸気
系や排気系の配置位置を変更したくない場合がある。In an internal combustion engine mounted on a motorcycle, the reason why the intake side of the cylinder is directed upward and the exhaust side of the cylinder is inclined toward the front side in the traveling direction is, for example, to lower the center of gravity of the vehicle. . When the exhaust side is inclined forward as described above, the bending angle of the intake passage may be increased depending on the positions where the intake system and the exhaust system are arranged, and the intake efficiency may be reduced. Therefore, it is conceivable to change the arrangement position of the intake system and exhaust system of the internal combustion engine so that the bending angle of the intake passage does not become large, but if you do not want to change the arrangement position of the intake system and exhaust system There is.

【０００４】[0004]

【発明が解決しようとする課題】この発明はこのような
実情に鑑みてなされたもので、自動二輪車用内燃機関に
おいて、内燃機関のシリンダの排気側の前傾姿勢を変化
させることなく、吸気通路の曲げ角度を少なくして吸気
効率を向上させることを課題とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in an internal combustion engine for a motorcycle, the intake passage is maintained without changing the forward leaning posture of the exhaust side of the cylinder of the internal combustion engine. The subject is to improve the intake efficiency by reducing the bending angle of.

【課題を解決するための手段】[Means for Solving the Problems]

【０００５】この発明は、内燃機関がシリンダの頭部の
吸気側を上方に向けかつ排気側を走行方向へ向くように
前傾して搭載された自動二輪車用内燃機関において、シ
リンダブロックとシリンダヘッドとの接合面をシリンダ
軸線に対して垂直となし、シリンダヘッドの吸排気通路
より上方を分割して、カム軸を支持するカム軸受面を有
するカムケースとし、前記シリンダの接合面に対してカ
ムケースのカム軸受面を前下がり方向に傾斜させたこと
を構成とする。According to the present invention, a cylinder block and a cylinder head are provided in an internal combustion engine for a motorcycle, in which the internal combustion engine is tilted forward so that the intake side of the cylinder head faces upward and the exhaust side faces the running direction. A joining surface perpendicular to the cylinder axis, divided above the intake / exhaust passage of the cylinder head to form a cam case having a cam bearing surface for supporting the cam shaft. The cam bearing surface is inclined in the front downward direction.

【０００６】[0006]

【実施の形態】次に、この発明の実施の形態第１を図１
〜図４に基づいて説明する。図１において、符号１は自
動二輪車で、車体フレーム２のヘッドパイプ３にはフロ
ントフォーク４が旋回可能に支持され、この下部には前
輪５が設けられ、上部にはハンドル６が設けられてい
る。ヘッドパイプ３から後方に延びるメインフレーム７
の後端にはリヤアーム８を介して後輪９が支持され、ま
たメインフレーム７の上方はタンクカバー10で覆われて
いる。さらに、メインフレーム７の後方にシートレール
11が接続され、このシートレール11にシート12が設けら
れている。メインフレーム７の前端から下方に延びるダ
ウンチューブ13とメインフレーム７との間には、内燃機
関14がそのシリンダ15を前傾させて搭載され、この内燃
機関14は４サイクルの並列４気筒で、ツインカム（ＤＯ
ＨＣ）バルブ機構が採用されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the first embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 1, reference numeral 1 is a motorcycle, and a front fork 4 is rotatably supported by a head pipe 3 of a vehicle body frame 2, a front wheel 5 is provided at a lower portion thereof, and a handle 6 is provided at an upper portion thereof. . Main frame 7 extending rearward from the head pipe 3
A rear wheel 9 is supported at the rear end of the main frame 7 via a rear arm 8, and a tank cover 10 covers the upper portion of the main frame 7. Furthermore, a seat rail is provided behind the main frame 7.
11 are connected, and a seat 12 is provided on the seat rail 11. Between the down tube 13 extending downward from the front end of the main frame 7 and the main frame 7, an internal combustion engine 14 is mounted with its cylinder 15 tilted forward, and this internal combustion engine 14 is a four-cycle parallel four cylinder, Twincam (DO
HC) valve mechanism is adopted.

【０００７】この内燃機関14はシリンダ15の頭部の排気
側が走行方向を向き、吸気側は上方を向くようにして搭
載されており、吸気管16はシリンダ15の上部から上方へ
伸び、この吸気管16に接続された気化器17及びエアクリ
ーナ18はタンクカバー10で覆われている。また、排気管
19はシリンダ15の前側から車体下方を通って、後方へ伸
びている。また、この内燃機関14には水冷式の冷却装置
が備えられ、そのラジエータ20はシリンダ15の頭部前方
に位置するダウンチューブ13に取付けられている。The internal combustion engine 14 is mounted so that the exhaust side of the head of the cylinder 15 faces the traveling direction and the intake side faces upward, and the intake pipe 16 extends upward from the upper part of the cylinder 15 A carburetor 17 and an air cleaner 18 connected to the pipe 16 are covered with a tank cover 10. Also the exhaust pipe
Numeral 19 extends from the front side of the cylinder 15 to the rear side through the lower side of the vehicle body. Further, the internal combustion engine 14 is provided with a water-cooling type cooling device, and its radiator 20 is attached to the down tube 13 located in front of the head of the cylinder 15.

【０００８】自動二輪車１の前面と側部はカウリング21
で覆われており、前部開口部22から走行風が導入され、
ラジエータ20を通過するとき内燃機関14を冷却する冷却
水と熱交換を行い、冷却水の温度を下げる。この導入さ
れた走行風はシリンダ15の頭部と、ラジエータ20との間
に後述の方法により形成された導風通路23で、カウリン
グ21の左右側部に形成された側部開口部24に導かれ、車
体外部へ送り出されるようになっている。そして、図２
・図３に示すように、内燃機関14の側部前面がカウリン
グ21で覆われており、カウリング21の側部開口部24は内
燃機関14の両側部に形成されている。A cowling 21 is provided on the front and sides of the motorcycle 1.
It is covered with, running wind is introduced from the front opening 22,
When passing through the radiator 20, heat is exchanged with the cooling water for cooling the internal combustion engine 14 to lower the temperature of the cooling water. The introduced running wind is guided to side opening portions 24 formed on the left and right side portions of the cowling 21 by an air guide passage 23 formed by a method described later between the head of the cylinder 15 and the radiator 20. Then, it is sent out to the outside of the car body. And FIG.
As shown in FIG. 3, the front side surface of the internal combustion engine 14 is covered with the cowling 21, and the side opening portions 24 of the cowling 21 are formed on both sides of the internal combustion engine 14.

【０００９】図４に示すように、シリンダブロック25と
シリンダヘッド26との接合面25ａをシリンダ15の軸線に
対して垂直となし、シリンダヘッド26の吸排気通路32、
34より上方を分割して、カム軸40、41を支持するカム軸
受面27ａを有するカムケース27とし、前記シリンダヘッ
ド26の接合面に対してカムケース27のカム軸受面27ａを
前下がり方向に傾斜させている。ここにシリンダヘッド
の接合面25ａは、シリンダブロック25とシリンダヘッド
26とを接合する面であり、カム軸40、41を支持するカム
軸受面27ａはカムケース27とカムキャップ28（カバー2
9）とを接合する面である。As shown in FIG. 4, the joint surface 25a between the cylinder block 25 and the cylinder head 26 is perpendicular to the axis of the cylinder 15, and the intake / exhaust passage 32 of the cylinder head 26,
A portion above 34 is divided into a cam case 27 having a cam bearing surface 27a for supporting the cam shafts 40, 41, and the cam bearing surface 27a of the cam case 27 is inclined in the front downward direction with respect to the joint surface of the cylinder head 26. ing. Here, the joining surface 25a of the cylinder head is the cylinder block 25 and the cylinder head.
The cam bearing surface 27a, which is a surface that joins the cam shafts 40 and 41, is a surface that joins the cam case 27 and the cam cap 28 (cover 2
9) This is the surface that joins with.

【００１０】従来は、シリンダヘッドの接合面25ａに対
してシリンダヘッド26とカムケース27との接合面26ａ及
びカム軸受面27ａは略平行とされていた。これに対し
て、この発明の実施の形態第１では、シリンダヘッドの
接合面25ａに対してカム軸受面27ａを従来よりも所定角
度αだけ傾斜させ、カム軸受面27ａを前側へ傾斜させて
いる。そのため、下方の排気側15ａの長さ（高さ）をそ
の儘にして、比較的スペースの余裕のある上方の吸気側
15ｂの長さ（高さ）を増加させることができる。従っ
て、吸気通路32の曲がりの程度を少なくでき、吸気効率
を高めることによって内燃機関の出力の増加を図ること
ができる。また、吸気側の長さの増加により、吸気バル
ブを長くすることができ、長くなった吸気バルブの組付
性を向上させることができる。なお、このようにカム軸
受面27ａに接合して取付けられるカバー29が前側へ傾斜
するため、シリンダ15の頭部のラジエータ20に近接する
排気側15ａが下方かつ後方に偏倚され、シリンダ15の頭
部とラジエータ20との間に所定の大きさの空間が確保さ
れ、この空間で導風通路23が形成される。Conventionally, the joint surface 26a between the cylinder head 26 and the cam case 27 and the cam bearing surface 27a are substantially parallel to the joint surface 25a of the cylinder head. On the other hand, in the first embodiment of the present invention, the cam bearing surface 27a is inclined to the joining surface 25a of the cylinder head by a predetermined angle α, and the cam bearing surface 27a is inclined to the front side. . For this reason, the length (height) of the lower exhaust side 15a is set to the same value, and the upper intake side with a relatively large space is available.
The length (height) of 15b can be increased. Therefore, the degree of bending of the intake passage 32 can be reduced, and the output of the internal combustion engine can be increased by increasing the intake efficiency. Further, the intake valve can be lengthened by increasing the length on the intake side, and the assembling property of the lengthened intake valve can be improved. Since the cover 29 attached to the cam bearing surface 27a is inclined forward, the exhaust side 15a of the head of the cylinder 15 close to the radiator 20 is biased downward and rearward, and the head of the cylinder 15 is displaced. A space of a predetermined size is secured between the portion and the radiator 20, and the air guide passage 23 is formed in this space.

【００１１】内燃機関14のシリンダ15はシリンダブロッ
ク25、シリンダヘッド26、カムケース27、カムキャップ
28及びカバー29等から構成されている。このシリンダブ
ロック25にはピストン30が嵌合され、シリンダヘッド26
に燃焼室31から上方に伸びるように形成された吸気通路
32には吸気管16が接続され、この吸気通路32は吸気バル
ブ33で開閉されるようになっている。シリンダヘッド26
にはまた排気通路34が燃焼室31から下方へ屈曲して伸び
るように形成されており、この排気通路34に排気管19が
接続され、この排気通路34は排気バルブ35で開閉され
る。このシリンダヘッド26に形成された吸気通路32は混
合気の温度を上げて燃焼効率を向上させるように長く形
成され、一方排気通路34は燃焼ガスの温度を低下させる
ように短く形成されている。The cylinder 15 of the internal combustion engine 14 includes a cylinder block 25, a cylinder head 26, a cam case 27, and a cam cap.
It is composed of 28 and a cover 29. A piston 30 is fitted in the cylinder block 25, and a cylinder head 26
The intake passage formed to extend upward from the combustion chamber 31
An intake pipe 16 is connected to 32, and the intake passage 32 is opened and closed by an intake valve 33. Cylinder head 26
Further, an exhaust passage 34 is formed so as to bend and extend downward from the combustion chamber 31, the exhaust pipe 19 is connected to the exhaust passage 34, and the exhaust passage 34 is opened and closed by an exhaust valve 35. The intake passage 32 formed in the cylinder head 26 is long so as to raise the temperature of the air-fuel mixture and improve the combustion efficiency, while the exhaust passage 34 is made short so as to lower the temperature of the combustion gas.

【００１２】これらの吸気バルブ33及び排気バルブ35は
スプリング36，37で吸気通路32及び排気通路34を常に閉
鎖する方向に付勢され、吸気バルブ33及び排気バルブ35
のリフタ38，39はカムケース27に摺動可能に支持されて
いる。リフタ38，39はカム軸40，41のカム40ａ，41ａに
当接しており、このカム軸40，41はカムケース27に設け
られたカムキャップ28を介して回転可能に支持されてい
る。カムケース27には前記カバー29が設けられ、カムキ
ャップ28と、カム軸40，41を駆動するカムギア（図示せ
ず）とを覆っている。前記排気バルブ35（長さＬ１）は
吸気バルブ33（長さＬ２）に比べて短く形成されてい
る。このため、排気側のリフタ39は吸気側のリフタ38よ
りも大径に形成され、吸気側のスプリング36の係止部が
リフタ38の下方に位置するのに対して、排気側のスプリ
ング37の係止部がリフタ39の内側に位置するように形成
されている。The intake valve 33 and the exhaust valve 35 are urged by springs 36 and 37 in a direction to always close the intake passage 32 and the exhaust passage 34, and the intake valve 33 and the exhaust valve 35.
The lifters 38 and 39 are slidably supported by the cam case 27. The lifters 38, 39 are in contact with the cams 40a, 41a of the cam shafts 40, 41, and the cam shafts 40, 41 are rotatably supported via a cam cap 28 provided on the cam case 27. The cover 29 is provided on the cam case 27, and covers the cam cap 28 and a cam gear (not shown) that drives the cam shafts 40 and 41. The exhaust valve 35 (length L1) is formed shorter than the intake valve 33 (length L2). Therefore, the lifter 39 on the exhaust side is formed to have a larger diameter than the lifter 38 on the intake side, and the engaging portion of the spring 36 on the intake side is located below the lifter 38, whereas the lifter 39 on the exhaust side is The locking portion is formed inside the lifter 39.

【００１３】従って、走行風がカウリング21の前側に形
成された前部開口部22から導入され、ラジエータ20を通
過し、このとき熱交換により内燃機関14の冷却水を冷却
する。この走行風は内燃機関14のシリンダ15の頭部とラ
ジエータ20との間に形成された導風通路23によって、内
燃機関14の両側へ案内されて、カウリング21の左右の側
部開口部24に導かれ、外部へ出される。このとき、内燃
機関14のシリンダ15とラジエータ20との間には、所定の
大きさの導風通路23が形成されているため、左右に流れ
易くなって、ラジエータ23を通過する走行風の流量が増
加し、ラジエータ20の冷却効率が向上する。Therefore, the traveling wind is introduced from the front opening 22 formed on the front side of the cowling 21, passes through the radiator 20, and at this time, the cooling water of the internal combustion engine 14 is cooled by heat exchange. This traveling wind is guided to both sides of the internal combustion engine 14 by an air guide passage 23 formed between the head of the cylinder 15 of the internal combustion engine 14 and the radiator 20, and is guided to the left and right side openings 24 of the cowling 21. Guided and sent out. At this time, since the air guide passage 23 of a predetermined size is formed between the cylinder 15 of the internal combustion engine 14 and the radiator 20, it becomes easy to flow to the left and right, and the flow rate of the traveling wind passing through the radiator 23. Is increased, and the cooling efficiency of the radiator 20 is improved.

【００１４】図５はこの発明の実施の形態第２の内燃機
関を示す断面図であり、実施の形態のその他の事項は図
１〜図３に示されたことと同様であるので説明は省略す
る。シリンダブロック55とシリンダヘッド56との接合面
55ａをシリンダ50の軸線に対して垂直となし、シリンダ
ヘッド56の吸排気通路32、34より上方を分割して、カム
軸40、41を支持するカム軸受面53ａを有するカムケース
53とし、前記シリンダヘッド56の接合面に対してカムケ
ース53のカム軸受面53ａを前下がり方向に傾斜させてい
る。ここにシリンダヘッドの接合面55ａは、シリンダブ
ロック55とシリンダヘッド56とを接合する面であり、カ
ム軸40、41を支持するカム軸受面53ａはカムケース53と
カムキャップ54（カバー29）とを接合する面である。こ
の発明の実施の形態第２では、シリンダヘッドの接合面
55ａに対してカム軸受面53ａを従来よりも所定角度αだ
け傾斜させ、カム軸受面53ａを前側へ傾斜させている。
そのため、下方の排気側50ａの長さ（高さ）をその儘に
して、比較的スペースの余裕のある上方の吸気側50ｂの
長さ（高さ）を増加させることができる。従って、吸気
通路32の曲がりの程度を少なくでき、吸気効率を高める
ことによって内燃機関の出力の増加を図ることができ
る。また、吸気側の長さの増加により、吸気バルブを長
くすることができ、長くなった吸気バルブの組付性を向
上させることができる。なお、このようにカム軸受面53
ａに接合して取付けられるカバー29が前側へ傾斜するた
め、シリンダ50の頭部のラジエータ20に近接する排気側
50ａが下方かつ後方に偏倚され、シリンダ50の頭部とラ
ジエータ20との間に所定の大きさの空間が確保され、こ
の空間で導風通路23が形成される。FIG. 5 is a cross-sectional view showing a second internal combustion engine according to the second embodiment of the present invention. Since other matters of the embodiment are the same as those shown in FIGS. 1 to 3, the description thereof will be omitted. To do. Joining surface of cylinder block 55 and cylinder head 56
A cam case having a cam bearing surface 53a that supports the cam shafts 40 and 41 by dividing 55a perpendicular to the axis of the cylinder 50 and dividing the cylinder head 56 from above the intake and exhaust passages 32 and 34.
53, the cam bearing surface 53a of the cam case 53 is inclined in the front downward direction with respect to the joint surface of the cylinder head 56. Here, the joint surface 55a of the cylinder head is a surface that joins the cylinder block 55 and the cylinder head 56, and the cam bearing surface 53a that supports the cam shafts 40 and 41 connects the cam case 53 and the cam cap 54 (cover 29). It is the surface to be joined. In the second embodiment of the present invention, the joint surface of the cylinder head
The cam bearing surface 53a is inclined with respect to 55a by a predetermined angle α, and the cam bearing surface 53a is inclined to the front side.
Therefore, the length (height) of the lower exhaust side 50a can be set to the same value, and the length (height) of the upper intake side 50b with a relatively large space can be increased. Therefore, the degree of bending of the intake passage 32 can be reduced, and the output of the internal combustion engine can be increased by increasing the intake efficiency. Further, the intake valve can be lengthened by increasing the length on the intake side, and the assembling property of the lengthened intake valve can be improved. Note that the cam bearing surface 53
Since the cover 29 attached to the a is inclined to the front side, the exhaust side of the head of the cylinder 50 close to the radiator 20
50a is biased downward and rearward, a space of a predetermined size is secured between the head of the cylinder 50 and the radiator 20, and the air guide passage 23 is formed in this space.

【００１５】この内燃機関のシリンダ50は実施の形態第
１のシリンダ15と同様に、排気バルブ51（長さＬ1'）は
吸気バルブ52（長さＬ2'）に比べて短く形成されてお
り、これに伴いカム軸受面53ａをシリンダヘッドの接合
面55ａに対して所定角度α’だけ前側へ傾斜させてい
る。そして、シリンダヘッド56とカムケース52との接合
面56ａはカム軸受面53ａと略平行であり、シリンダヘッ
ドの接合面55ａに対して同様に所定角度α’だけ偏倚さ
せて形成している。前記の角度α’がある程度大きくな
ってもカムケース53は同じ幅Ｄを維持することができ、
特に排気側50ａのリフタ57のガイド穴53ｂが、カムケー
ス53とシリンダヘッド56との間にまたがって形成される
ことがなく、吸気側50ｂのリフタ58のガイド穴53ｃと同
様にカムケース53の幅Ｄの中に収めることができる。In the cylinder 50 of this internal combustion engine, the exhaust valve 51 (length L1 ') is formed shorter than the intake valve 52 (length L2'), like the cylinder 15 of the first embodiment. Along with this, the cam bearing surface 53a is inclined forward by a predetermined angle α'with respect to the joint surface 55a of the cylinder head. The joint surface 56a between the cylinder head 56 and the cam case 52 is substantially parallel to the cam bearing surface 53a, and is formed so as to be offset from the joint surface 55a of the cylinder head by a predetermined angle α '. Even if the angle α ′ is increased to some extent, the cam case 53 can maintain the same width D,
In particular, the guide hole 53b of the lifter 57 on the exhaust side 50a is not formed across the cam case 53 and the cylinder head 56, and the width D of the cam case 53 is the same as the guide hole 53c of the lifter 58 on the intake side 50b. Can be placed inside.

【００１６】従って、特に排気側50ａのガイド穴53ｂを
カムケース53とシリンダヘッド56の双方にまたがって形
成する場合のように、高度な加工技術が要求されず、ガ
イド穴53ｂ，53ｃの加工は従来通りカムケース53の側だ
け行えばよい。また、シリンダヘッド56とカムケース53
との位置決めも容易である。なお、この実施の形態第２
では排気側50ａと吸気側50ｂのリフタ57、58は同径に形
成され、リフタ57、58の内側にスプリング59、60の係止
部が設けられており、他の部分は前記実施の形態第１と
同様であるので、同符号を付して説明を省略する。Therefore, particularly when the guide hole 53b on the exhaust side 50a is formed over both the cam case 53 and the cylinder head 56, a high processing technique is not required, and the guide holes 53b and 53c are conventionally processed. Only the side of the street cam case 53 is required. In addition, the cylinder head 56 and the cam case 53
Positioning with is also easy. In addition, the second embodiment
In the exhaust side 50a and the intake side 50b, the lifters 57 and 58 are formed to have the same diameter, the locking portions of the springs 59 and 60 are provided inside the lifters 57 and 58, and the other portions are the same as those in the first embodiment. Since it is the same as No. 1, the same reference numerals are given and the description is omitted.

【００１７】[0017]

【発明の効果】この発明は、シリンダブロックとシリン
ダヘッドとの接合面をシリンダ軸線に対して垂直とな
し、シリンダヘッドの吸排気通路より上方を分割して、
カム軸を支持するカム軸受面を有するカムケースとし、
前記シリンダヘッドの接合面に対してカムケースのカム
軸受面を前下がり方向に傾斜させた。そのため、下方の
排気側の長さ（高さ）をその儘にして、比較的スペース
の余裕のある上方の吸気側の長さ（高さ）を増加させる
ことができる。従って、吸気通路の曲がりの程度を少な
くでき、吸気効率を高めることによって内燃機関の出力
の増加を図ることができる。また、吸気側の長さの増加
により、吸気バルブを長くすることができ、長くなった
吸気バルブの組付性を向上させることができる。また、
この発明は、シリンダヘッドの吸排気通路より上方を分
割して、カム軸を支持するカム軸受面を有するカムケー
スとしたので、シリンダヘッドとカムケースとの間に接
合面が形成され、吸気バルブ・排気バルブのリフタのガ
イド孔等の加工が容易となる。According to the present invention, the joint surface between the cylinder block and the cylinder head is perpendicular to the cylinder axis, and the portion above the intake / exhaust passage of the cylinder head is divided,
A cam case having a cam bearing surface that supports the cam shaft,
The cam bearing surface of the cam case was inclined in the front downward direction with respect to the joint surface of the cylinder head. Therefore, it is possible to increase the length (height) on the upper intake side with a relatively large space by setting the length (height) on the lower exhaust side to the same value. Therefore, the degree of bending of the intake passage can be reduced, and the output of the internal combustion engine can be increased by increasing the intake efficiency. Further, the intake valve can be lengthened by increasing the length on the intake side, and the assembling property of the lengthened intake valve can be improved. Also,
According to the present invention, the upper portion of the intake / exhaust passage of the cylinder head is divided into a cam case having a cam bearing surface for supporting the cam shaft. Therefore, a joint surface is formed between the cylinder head and the cam case, and the intake valve / exhaust valve This makes it easy to machine the guide holes in the valve lifter.

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

【図１】この発明を適用した自動二輪車の側面図であ
る。FIG. 1 is a side view of a motorcycle to which the present invention is applied.

【図２】図１の自動二輪車の正面図である。FIG. 2 is a front view of the motorcycle shown in FIG.

【図３】図１の要部の断面図である。3 is a cross-sectional view of a main part of FIG.

【図４】この発明の実施の形態第１の内燃機関の断面図
である。FIG. 4 is a sectional view of a first internal combustion engine according to an embodiment of the present invention.

【図５】この発明の実施の形態第２の内燃機関の断面図
である。FIG. 5 is a sectional view of a second internal combustion engine according to an embodiment of the present invention.

【符号の説明】[Explanation of symbols]

14 内燃機関 15 シリンダ 15ａ 排気側 15ｂ 吸気側 25 シリンダブロック 25ａ シリンダヘッドの接合面 26 シリンダヘッド 27 カムケース 27ａ カム軸受面 40 カム軸 41 カム軸 50 シリンダ 50ａ 排気側 50ｂ 吸気側 53 カムケース 53ａ カム軸受面 55 シリンダブロック 55ａ シリンダヘッドの接合面 56 シリンダヘッド 14 Internal Combustion Engine 15 Cylinder 15a Exhaust Side 15b Intake Side 25 Cylinder Block 25a Cylinder Head Joint Surface 26 Cylinder Head 27 Cam Case 27a Cam Bearing Surface 40 Cam Shaft 41 Cam Shaft 50 Cylinder 50a Exhaust Side 50b Intake Side 53 Cam Case 53a Cam Bearing Surface 55 Cylinder block 55a Cylinder head joint surface 56 Cylinder head

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 内燃機関がシリンダの頭部の吸気側を上
方に向けかつ排気側を走行方向へ向くように前傾して搭
載された自動二輪車用内燃機関において、シリンダブロ
ックとシリンダヘッドとの接合面をシリンダ軸線に対し
て垂直となし、シリンダヘッドの吸排気通路より上方を
分割して、カム軸を支持するカム軸受面を有するカムケ
ースとし、前記シリンダヘッドの接合面に対してカムケ
ースのカム軸受面を前下がり方向に傾斜させたことを特
徴とする自動二輪車用内燃機関。1. An internal combustion engine for a motorcycle, wherein the internal combustion engine is mounted so as to be tilted forward so that an intake side of a cylinder head faces upward and an exhaust side faces a traveling direction. A cam case having a cam bearing surface for supporting the cam shaft is formed by dividing the joint surface perpendicular to the cylinder axis and above the intake / exhaust passage of the cylinder head, and the cam of the cam case with respect to the joint surface of the cylinder head. An internal combustion engine for a motorcycle, characterized in that a bearing surface is inclined forward and downward.
JP9038519A 1997-02-07 1997-02-07 Internal combustion engine for motorcycles Expired - Fee Related JP2981436B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9038519A JP2981436B2 (en) 1997-02-07 1997-02-07 Internal combustion engine for motorcycles

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9038519A JP2981436B2 (en) 1997-02-07 1997-02-07 Internal combustion engine for motorcycles

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
JP62315692A Division JP2688903B2 (en) 1987-08-20 1987-12-14 Motorcycle wind guide device

Publications (2)

Publication Number Publication Date
JPH09189259A true JPH09189259A (en) 1997-07-22
JP2981436B2 JP2981436B2 (en) 1999-11-22

Family

ID=12527530

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9038519A Expired - Fee Related JP2981436B2 (en) 1997-02-07 1997-02-07 Internal combustion engine for motorcycles

Country Status (1)

Country Link
JP (1) JP2981436B2 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19757286C2 (en) * 1996-12-27 2000-04-27 Honda Motor Co Ltd Cylinder head structure in an internal combustion engine
JP2009243401A (en) * 2008-03-31 2009-10-22 Honda Motor Co Ltd Cylinder head structure in four-cycle engine
US7703423B2 (en) 2004-11-18 2010-04-27 S & S Cycle, Inc. Vehicle and propulsion system including an internal combustion engine
JP2015190341A (en) * 2014-03-27 2015-11-02 川崎重工業株式会社 Motor cycle

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19757286C2 (en) * 1996-12-27 2000-04-27 Honda Motor Co Ltd Cylinder head structure in an internal combustion engine
US7703423B2 (en) 2004-11-18 2010-04-27 S & S Cycle, Inc. Vehicle and propulsion system including an internal combustion engine
US8011333B2 (en) 2004-11-18 2011-09-06 S & S Cycle, Inc. Vehicle and propulsion system including an internal combustion engine
US8919321B2 (en) 2004-11-18 2014-12-30 S & S Cycle, Inc. Internal combustion engine with lubrication system
JP2009243401A (en) * 2008-03-31 2009-10-22 Honda Motor Co Ltd Cylinder head structure in four-cycle engine
JP2015190341A (en) * 2014-03-27 2015-11-02 川崎重工業株式会社 Motor cycle

Also Published As

Publication number Publication date
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