JPH0424101Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a forced engine cooling device suitable for air-cooled engines in small-sized motorcycles and the like.

(Prior art) The power unit including the engine of a small motorcycle adopts a type that can swing freely relative to the vehicle body, and the engine, exhaust pipe, etc. are covered with a vehicle body cover.
Therefore, as a cooling means for the engine, a cooling fan is installed at one end of the engine output shaft, the fan is surrounded by a cover, cooling air is taken into the shroud by the cooling fan, the cooling air is guided to the engine by the shroud, and the engine is cooled. Forced air cooling.

Conventionally, this type of cooling device was developed in 1988-122677.
As can be seen in Figure 2, the shroud is curved and extends above the cylinder head of the engine, and a cooling fan is provided below the shroud in front of the cooling air intake.

(Problem to be solved by the invention) In the above conventional technology, since the cooling air guide inner wall surface of the shroud is only curved toward the cylinder head, the cooling air raked upward by the fan is directed upward. The air tends to flow toward the cylinder head, and the air volume in this part is large, while the air volume to the cylinder block is small, and the air volume to the cylinder part becomes unbalanced depending on the part.

This invention was made to solve the above problems, and its purpose is to
To provide a forced engine cooling device capable of distributing and feeding a necessary amount of cooling air to each cylinder head.

(Means for solving the problem) A means for solving the above problem is a forced cooling system for a vehicle engine in which at least the engine and the exhaust pipe connected to the engine are covered with a vehicle body cover. In a forced cooling system for an engine that covers a cylinder part with a shroud and sends cooling air into the shroud by a cooling fan driven by the engine, a recessed part bent toward the cylinder part is formed in a part of the shroud, The exhaust pipe is disposed in the gap between the shroud and the vehicle body cover in the recess.

(Effects of the above means) According to the above means, the cooling air taken into the shroud by the cooling fan is distributed and sent to the cylinder block and cylinder head by the recessed portion bent within the shroud.

(Embodiment) Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The embodiment shows a forced cooling system for the engine of a small scooter-type motorcycle 1, and as shown in FIG.
It is equipped with a front wheel 4 and a handlebar 5 that can be steered freely through the vehicle body cover 6.
The front portion 6a of the vehicle also serves as a seat post cover, and a seat 7 is provided above the seat 7, and a fuel tank 8 is provided below the seat 7. A power unit 10 is swingably provided at the rear of the vehicle body 2, a rear wheel 9 serving as a driving wheel is provided at the rear of the power unit 10, and the upper half of the power unit 10 is covered with a cover 6.

The power unit 10 consists of an engine 11 and a transmission case 19, as shown in FIG. The transmission case 19 is integrally extended rearward, the cylinder part 14 stands up in the front part, the piston 16 is fitted in the cylinder block 12, and the crank case 15
A crankshaft 17 is horizontally suspended inside, and each is connected by a connecting rod 18.

A driving pulley 20 is provided in the front part of the transmission case 19, and the pulley 20 is connected to the extended output part 17a on this side of the crankshaft 17, and a driven pulley 21 is provided in the rear part of the transmission case 19.
A belt 22 is wound between pulleys 20 and 21, and a centrifugal continuously variable speed belt and pulley mechanism is used.

Extending output section 1 on the opposite side of the crankshaft 17
A flywheel 24 constituting the AC generator 23 is attached to 7b, and a cooling fan 25 is attached to the outer end wall 24a of the flywheel 24. On the other hand, a shroud 26 is provided to surround this side of the cooling fan 25 and the engine 11.
6 has a lower end portion 26a connected to a stay portion 15a extending to this side end of the crankcase 15 via a bolt 27, and an upper end portion 26b secured to an end portion of the cylinder head cover 28 on this side. .

A lower part 26c of the shroud 26 bulges outward, a bottom 26d is spaced apart from the outer periphery of the fan 25, and a gear-shaped cooling air intake 29 with a downward lattice is provided in a portion corresponding to the outer side of the fan 25. There is a guide piece 30 with a larger diameter around it.
is provided so as to protrude outward in a ring shape. The shroud 26 is inclined upward so that the upper side approaches the cylinder part 14 from the guide piece 30 described above, and the intermediate part 26e is gently inclined upward, and the upper end 2
From 6f to cylinder block 12 of cylinder section 14
The cylinder block 12 is provided with an intermediate upper part 26g whose slope increases toward the middle part or the upper part of the cylinder block 12, and an upper part 26h that suddenly rises from the inner end of the intermediate upper part 26g is continuously formed. 13, the upper end portion 26b
is bent inward and attached to the head cover 28. The intermediate upper portion 26g forms a recess 31 that is bent toward the cylinder portion 14 between the intermediate portion 26e and the upper portion 26h of the shroud 26. A recess 31 is formed on the outer surface of the shroud 26, and the exhaust pipe 32 faces this part, and the side piece 6b of the vehicle body cover 6, which has been described above, hangs down and is spaced apart from the exhaust pipe 32. The lower end faces near the middle of the guide piece 30 in the height direction.

In the above, the fan 25 is driven by the rotation of the crankshaft 17, takes in outside air from the intake port 29, and sends it into the space S in the shroud 26 by the rotation of the fan 25. The cooling air fed into the shroud 26 rises along the inner wall of the shroud, but its direction is bent when it hits the aforementioned recess 31, that is, the middle upper part 26g, and a portion flows toward the cylinder block 12. A portion also rises along the inner wall of the upper portion 26h and flows in the direction of the cylinder head 13. This is indicated by an arrow. In this way, the cooling air is directionally distributed to the cylinder block 12 and the cylinder head 13, cooling each of them, eliminating the biased direction toward the cylinder head 13, and allowing the cylinder portion 14 to be cooled in a balanced manner.

By the way, since the recess 31 is provided in a part of the shroud 26, the exhaust pipe 32 passing through this part of the shroud 26 in the front-rear direction can be disposed in the recess 31. As a result, the exhaust pipe 32 can be disposed inside, and the side piece 6b of the vehicle body cover 6 can be brought closer to the inside. As a result, the width of the vehicle body cover, that is, the vehicle width can be reduced, and compactness can be achieved. Although the above embodiments have shown an engine for a motorcycle, the engine is not limited to this, and can be used in various forced air-cooled engines equipped with a fan and a shroud.

(Effects of the invention) As is clear from the above, according to the invention, in a cooling system that forcibly cools an engine by providing a shroud and taking in outside air using a cooling fan, the cooling air is distributed to the cylinder block and the cylinder head, respectively. The fuel can be oriented and fed, improving the cooling performance of the engine, and the above can be achieved with a simple configuration of providing a recess in a part of the shroud.

When used in a motorcycle engine that is covered with a body cover, the exhaust pipe can be exposed to the concave part of the shroud, and the side wall of the body cover can be brought closer to the inside, reducing the width of the body cover and making it more compact. can be achieved.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a partially cutaway view of the engine, and FIG. 2 is a side view of the motorcycle. In the drawing, 11 is the engine, 14 is the cylinder part,
25 is a cooling fan, 26 is a shroud, and 31 is a recess.

Claims (1)

[Scope of utility model registration request] A forced cooling system for a vehicle engine in which at least the engine and the exhaust pipe connected to the engine are covered with a vehicle body cover, the cylinder portion of the engine being covered with a shroud, and a cooling fan driven by the engine blowing cooling air into the shroud. In the forced cooling system for an engine that supplies air, a recessed portion bent toward the cylinder portion is formed in a part of the shroud, and the exhaust pipe is disposed in a gap between the shroud and the vehicle body cover in the recessed portion. A forced engine cooling system featuring: