JPH0663484B2 - Cylinder block structure in OHC type water-cooled multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a cylinder block structure in an OHC type water-cooled multi-cylinder, particularly an engine having four or more cylinders.

(2) Conventional Technology In a conventional OHC type water-cooled multi-cylinder engine, a chain chamber, that is, a timing transmission chamber is provided in an intermediate portion of the engine body, and the chain transmission, that is, the timing transmission device is housed in the timing transmission chamber. A device in which a crankshaft and a valve camshaft are interlocked by this device is known (see Japanese Utility Model Laid-Open No. 60-134848).

(3) Problems to be Solved by the Invention In the conventional engine, the chain conduction chamber becomes an obstacle in forming a water jacket for circulating cooling water in the engine block including the cylinder block and the cylinder head. Since the communication path of the water jacket is formed by penetrating the wall surface that constitutes the chain conduction chamber, the structure of the entire water jacket becomes complicated and not only the cost of casting the engine block increases but also the cooling water is cooled. There is a problem that running water resistance increases and causes a decrease in cooling efficiency.

Therefore, in the present invention, a continuous water jacket surrounding a plurality of cylinders is formed in the cylinder block without being affected by the timing working chamber formed in the cylinder block, and the water flow formed in the cylinder block is formed by the water jacket. An object of the present invention is to provide a cylinder block structure in an OHC type water-cooled multi-cylinder engine having a simple structure, which is capable of solving the above-mentioned problems by allowing communication between an inlet and a water outlet opening on the lower surface of the cylinder head. is there.

B. Configuration of the Invention (1) Means for Solving the Problems According to the present invention, a timing transmission device is provided in the cylinder block to achieve the above object, and a timing transmission device housed in the timing transmission chamber is provided. In an OHC type water-cooled multi-cylinder engine in which a crank shaft and a valve operating cam shaft are interlocked with each other, the timing transmission chamber is biased to one side from the center of the cylinder block along the arrangement direction of a plurality of cylinders, and adjacent to each other. Formed laterally between the cylinders, and forming a continuous water jacket around the outer circumference of the cylinders in the cylinder block.The water jacket is formed on the water inlet opening in the cylinder block and the bottom surface of the cylinder head. It communicates with the open water outlet.

(2) Operation According to the above configuration, the cooling water that has flowed into the cylinder block through the water inlet flows with low resistance in the continuous water jackets that surround the outer peripheries of multiple series cylinders, and efficiently cools those cylinders. After that, it flows to the cylinder head side through the water outlet.

(3) Embodiment One embodiment of the present invention will be described below with reference to the drawings.

In the following description, "front, rear" and "left, right" refer to the forward direction of the motorcycle.

In FIG. 1, the body frame F of the motorcycle has a DO
The HC-type water-cooled in-line four-cylinder engine E is mounted horizontally, that is, the cylinders are arranged in a direction orthogonal to the traveling direction of the vehicle, and the output shaft 2 connected to the crankshaft 1 of the engine E transmits power. It is transmitted to the rear wheel 4 via the mechanism 3.

The engine block Eb including the cylinder block 5 and the cylinder head 6 of the engine E is in a forward tilted posture, and its cylinder axis l-l is tilted forward about 35 ° with respect to the vertical line vv. There is.

As shown in FIGS. 1, 3, and 6, a quadruple carburetor Ca connected to the intake system is located behind the engine block Eb.
The four intake passages 7 of the carburetor Ca, which are arranged in parallel with the Eb, are connected to the four intake ports 8 opening on the rear surface of the engine block Eb, and the air cleaner Ac is connected to the inlet of the carburetor Ca. Further, four exhaust ports 9 are opened on the front surface of the engine block Eb, and exhaust pipes 10 are connected to these exhaust ports 9, respectively, which extend from the front surface of the engine block Eb to the rear through the lower surface and the exhaust muffler 11 Connected to.

As shown in FIGS. 1 to 3 and 6, a radiator R connected to the water cooling system of the engine E is disposed in front of the engine E, and the radiator R is provided with a forced cooling fan 12 on its rear surface. Is suspended from the vehicle body frame F, and the lower portion thereof is held by the engine block Eb via the stay 13. Thus forced cooling fan 12, in particular but the motor unit 12 ₁ protrudes toward the engine E, by adding an improved structural to the engine E as described later in detail the motor unit 12 ₁ is the engine E It allows them to be placed close to each other without interfering with their heads.

As clearly shown in FIG. 3, a water pump P driven by the crankshaft 1 is provided on the lower left side of the lower part of the engine E, and a suction side 14 of the water pump P is connected to a radiator R via a water conduit 18. Outlet 17 of the water pump P and the discharge side 15 of the water pump P.
Is connected to a water inlet 20 opened in the cylinder block 15 via a water supply pipe 19. Further, the drain port 21 opened in the cylinder head 6 is communicated with the inlet 16 of the radiator R through a water conduit 22.

The cylinder block 5 as shown in second and third FIG serially in the direction the first to fourth cylinder 24 _{1-24 4} perpendicular to the longitudinal direction of the lateral direction, that the vehicle body frame F, these cylinders 24 _1-24 the _4, piston 26 continuing through a connecting rod 25 in a conventional manner to the crank shaft 1 is fitted slidably, respectively.

As clearly shown in FIGS. 4 and 5, the engine block Eb
, The tone in the center first to biased arrangement direction right of the fourth cylinder 24 _{1-24 4} than, and protrudes backward from the intake side wall 5 ₁ between the third and fourth cylinder 24 _3, 24 ₄ The hour transmission chamber 27 is integrally formed to bulge.

A timing transmission device 28 is housed in the timing transmission chamber 27.
The timing transmission 28 comprises a gear train, and a pair of driven gears 30, 31 fixed to a drive gear 29 on the crankshaft 1 and a pair of valve camshafts 37, 38 on the cylinder head 6, respectively.
And a gear group G for interlocking the drive gear 29 with the driven gears 30 and 31, the gear group G having a large diameter first gear 32 meshed with the drive gear 29 and a second gear meshed with the first gear 32. 33, a small-diameter third gear 34 integrated with the second gear 33, the third gear 34
A fourth gear 35 meshed with the fourth gear 35, and a fifth gear 36 meshed with the fourth gear 35 and the pair of driven gears 30 and 31. Then, the rotation of the crankshaft 1 is transmitted to the pair of valve operating camshafts 37, 38 at a speed reduction ratio of 1/2 via the timing transmission 28 composed of a gear train.

By the way, as mentioned above, the timing transmission chamber 27 is set in the engine block.
By biasing the _first to fourth cylinders 24 _{1 to} 24 _{4 to} the right from the center of Eb, a continuous water jacket 40 having a low flow resistance is formed in the cylinder block 5 over the entire area thereof. The jacket 40 communicates with one water inlet port 20 opened in the cylinder block 5 and a water outlet port 42 (FIG. 5) opened in the lower surface of the cylinder head 6. Since the cylinder block 5 is an open deck type, the upper surface of the water jacket 40 is open to the deck surface thereof, but is closed by the lower surface of the cylinder head 6 superposed on the upper surface thereof.

The water jacket 40 has first to third cylinders 24 _{1 to} 24 ₃ and a fourth cylinder connected in a Siamese type via boundary walls 43 and 44.
It is formed so as to surround the outer periphery of the cylinder 24 _4. Then, as described above, the third and fourth cylinders 24 ₃ and 24 ₄ are spaced apart from each other in order to form the timing transmission chamber 27.
To form a communication passage 40 _1, the third cylinder 24 ₃ around the water jacket and the fourth cylinder 24 ₄ around the water jacket through the communication passage 40 ₁ is communicated enters a portion of the water jacket 40 between It is like this. Cylinder block 5
The site of the second faces the cylinder 24 ₂ of the exhaust-side side wall 5 _2, water inlet communicating with the discharge side 15 of the water pump P (Figure 3)
20 are provided. Also the partition wall 45 which partitions the water jacket 40 and the exhaust-side side wall 5 ₂ between the fourth cylinder 24 ₄ is formed in the vicinity of the partition wall 45, between the exhaust-side side wall 5 ₂ and the partition wall 45, The water jacket 40 is a dead end, and the final water outlet is opened on the cylinder head 6 side.
The water outlet 42 communicates with a water jacket 47 on the cylinder head 6 side. Thus, the cooling water from the water pump P flows into the water jacket 40 through the water supply pipe 19,
As shown by the arrow in FIG.
After continuously flowing along the outer circumference of the third cylinders 24 _{1 to} 24 ₃ , it passes through the communication passage 40 ₁ between the _third and fourth cylinders 24 ₃ and 24 ₄ and bypasses the outer circumference of the fourth cylinder 24 _4. From the water outlet 42 to the water jacket 47 on the cylinder head 6 side. Thus, as described above, while the cooling water flows through the water jacket 40, the cylinder block 5, especially the first to fourth cylinders 24 _{1 to} 24 ₄ can be effectively cooled with water.

It should be noted that on the lower surface of the cylinder head 6, the cylinder block 5
Water jacket 40 and water jacket on the cylinder head 6 side
A plurality of small holes 46 communicating with 47 are opened and the water jacket 40
A part of the cooling water flowing through flows through these small holes 46 to the water jacket 47 on the cylinder head 6 side.

Further, as a modified example of the cylinder block 5, as shown in FIG.
If it is provided on the end wall on the cylinder 24 ₁ side, a water conduit that communicates with this water inlet 20 and the suction side 14 of the water pump P.
19 can be shortened.

As shown in FIGS. 2 and 3, on the cylinder head 6 of the engine block Eb, a pair of valve cam shafts 38 and 37 for directly opening and closing a plurality of intake valves 39 and exhaust valves 41 are rotatably provided. Supported. Next, the structure for supporting the valve operating cam shafts 37, 38 will be described.

Said pair of valve camshafts 37 and 38 the first to fourth cylinders 24 ₁
~ 24 ₄ on both sides of the first to the fourth cylinder
24 ₁ extends in parallel with each other along the 24 ₄ in the arrangement direction, the first to fourth cylinders 24 ₁ to 24 ₄ central respective four before being opposed on both sides of, the rear row of the bearing holder 48 ... , 49
Each is rotatably supported by. Each of the front and rear row bearing holders 48, 49 ... is composed of a bearing half portion 50 integrally formed on the cylinder head 6 and a bearing cap 51 fixed on the bearing half portion 50 with a halt 52. The valve cam shafts 37, 38 are rotatably supported in bearing holes formed by the bearing half 50 and the bearing cap 51 via bearings.

On the cylinder head 6, the pair of valve operating camshafts 3
A head cover 54 covering the valve mechanism including 7,38 is fixed by a plurality of bolts 55. The head cover 54 is
As shown in FIGS. 3 and 6, the front and rear ridges 56 and 57 protruding upward along the valve camshafts 37 and 38 are formed so as to cover the pair of valve camshafts 37 and 38. Formed, those ridges 56,57
A central groove portion 58 is formed between the central groove portion 58 and the first to
Four spark plugs 60 corresponding to the fourth cylinder 24 _{1 to} 24 ₄
The mounting holes 59 ... Are lined up. Further, the head cover 54 is formed with a raised ridge portion 61 which is biased to the right side from the center thereof and covers the open upper surface of the timing transmission chamber 27 in the front-back direction of the head cover 54, that is, in the width direction. Then, as shown in FIG. 4, a pair of driven gears 30, 31 of the timing transmission 28 are formed by the raised ridges 61.
The upper half of is covered.

By the way, as shown in FIGS.
3rd and 4th cylinders 24 ₃ and 24 ₄ excluding between 1st and 2nd cylinders 24 ₁ and 2
Between 4 _2, and between the second, third cylinder 24 _2, 24 _3, between the bearing holder 48, 48 that is adjacent phases, concave section wind guide path 62, 63 having an open front and rear ends are formed. When the motorcycle travels, a part of the traveling wind flows toward the rear of the engine E through the air guide passages 62 and 63 as shown by the arrows in FIGS. The front of the Ca is hit and the head of the engine E and the carburetor Ca are air-cooled.

As is clear from FIGS. 2, 3 and 6, the radiator R is arranged in alignment with the left and right direction of the engine block Eb, and the forced cooling fan 12 on the rear surface of the radiator R has a center portion on the left and right of the radiator R, and accordingly, of the engine block Eb. It is located in front of the left and right center. Forced cooling fan 12 protrudes rearwardly towards the engine block Eb, particularly motor unit 12 ₁ that, although reaching near the head cover 54, the raised ridge 61 projecting toward the foremost of the head cover 54 since it biased from the center in one lateral direction, and the motor unit 12 ₁ and the raised ridge 61 never they shifted in the lateral direction from interfering with each other even overlap around. Therefore, it is possible to dispose the radiator R close to the engine E.

It should be noted that although the case where the present invention is applied to the DOHC engine has been described in the above embodiment, it goes without saying that the present invention can also be applied to the SOHC engine.

C. Effect of the Invention As is clear from the above examples, according to the present invention, the OHC
Type water-cooled multi-cylinder engine, the timing transmission chamber is biased to one side from the center of the cylinder block along the arrangement direction of the plurality of cylinders, and is formed to bulge laterally between adjacent cylinders. A continuous water jacket is formed by surrounding the outer circumference of the cylinder, and this water jacket is connected to the water inlet opening on the cylinder block and the water outlet opening on the lower surface of the cylinder head. A continuous water jacket can be formed, cooling water can be circulated as a continuous flow from the water inlet to the water outlet as a continuous flow, and the cooling efficiency of the engine can be significantly increased. The water jacket structure of the block can be simplified and its casting cost can be reduced.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a side view of a motorcycle equipped with an engine equipped with the device of the present invention, and FIG.
Fig. 1 is an enlarged sectional view taken along the line II-II in Fig. 1, and Fig. 3 is shown in Fig. 2 II.
Sectional view taken along line I-III, FIG. 4 is sectional view taken along line IV-IV in FIG. 2, FIG. 5 is plan view of the cylinder block taken along line VV in FIG. 3, and FIG. VI line arrow plane view, FIG. 7 is the third
FIG. VII is a partially cutaway plan view taken along the arrow VII, and FIG. 8 is the same plan view as FIG. 5 showing a modified example of the cylinder block. 5 ... Cylinder block, 6 ... Cylinder head, 20 ...
… Water inlet, 24 _{1 to} 24 ₄ …… First to fourth cylinders as a plurality of cylinders, 27 …… Timing transmission chamber, 28 …… Timing transmission device, 37, 38 …… Valve camshaft, 40 ...... Water jacket, 42
...... Water outlet

Claims (1)

[Claims] 1. An OHC type water-cooled multi-cylinder engine in which a timing transmission chamber is provided in a cylinder block, and a crankshaft and a valve camshaft are interlocked with each other via a timing transmission device accommodated in the timing transmission chamber. , The timing transmission chamber is biased to one side from the center of the cylinder block along the arrangement direction of the plurality of cylinders, and is formed to bulge laterally between adjacent cylinders, and the cylinder block has outer peripheries of the plurality of cylinders. Surrounding to form a continuous water jacket, this water jacket,
It is characterized by communicating with a water inlet opening in the cylinder block and a water outlet opening in the lower surface of the cylinder head.
Cylinder block structure for OHC type water-cooled multi-cylinder engine.