JPS62223444A - Engine for motorcycle, and the like - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to an engine for a small motorcycle, and particularly to a cooling fin thereof.

[Conventional technology]

Traditionally, air-cooled engines have been widely used in small motorcycles used for business purposes or by female riders to reduce weight and simplify the structure. In order to provide extra legroom, the cylinder is often placed roughly horizontally below the center of the motorcycle, with the cylinder facing forward.

The cylinder head of such an engine is provided with cooling fins arranged in a criss-cross pattern with horizontal and vertical fins; Equipped with horizontal fins (Product Catalog: Yamaha Mate 50
80).

In addition, this type of motorcycle is generally provided with a windshield called a leg shield from the upper part of the front to the lower part of the center. A uniform air passage is formed at the rear of the fender, extending from the upper part of the front to the lower part of the center, and the engine mounting ring faces this passage. Note that even when the leg shield is not provided, the air guide path is formed by the front fender.

[Problem that the invention seeks to solve]

When the motorcycle is running, cooling air is generated in the air guide path from the upper front of the motorcycle to the lower rear, and hits the engine diagonally from above.

However, as mentioned above, the cooling fins installed in this engine do not follow the diagonal cooling air, so
Is the cooling air circular? There was a problem in that the cooling effect of the cooling fins was small.

Furthermore, the wind that flows horizontally under the front fender while the vehicle is running hits the cylinder head and a portion of the lower part of the cylinder, and only cools this portion, and is not effectively used to cool the engine.

This invention was made to solve the above-mentioned conventional problems, and provides cooling with a large cooling effect by effectively utilizing the oblique cooling air behind the front fender and the cooling air flowing horizontally below the front fender. The purpose of the present invention is to provide a carrot for a motorcycle, etc. equipped with fins.

[Means for solving problems]

In order to achieve the above object, the present invention has an engine cylinder facing forward and arranged in a substantially horizontal direction immediately behind the front fender, and in the center of the cylinder head of the engine in the left-right direction. Vertical fins extending in the vertical direction are provided, vertical fins are provided below the center in the left-right direction of the cylinder, and diagonal fins extending from the top of the front toward the bottom of the rear are provided in a portion of the cylinder other than the bottom of the center. It is being

[Effect]

According to this invention, the diagonal fins in the cylinder flow smoothly between the mesh fins. Further, since vertical fins are provided from the left-right center of the cylinder head to the lower center of the cylinder in the left-right direction, the cooling air passes through the nine cylinder heads and is sufficiently directed to the lower center of the cylinder. In addition, by using the horizontal wind flowing below the front fender, the diagonal cooling air and the cooling air that has been shunted to the lower center of the yy wing are sucked and flow smoothly.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view of a small motorcycle according to the present invention. As shown in the figure, a front fork 12 is supported at the front of a single frame 11 of a motorcycle 10 so as to be rotatable left and right, and a front fender 13 is fixed to this front fork 12.

Further, the vehicle body frame IIK has a carrot 14 attached to the central portion thereof in the longitudinal direction, and a front side cleaner 17 and a capretor 18 attached thereto. The engine 14 is arranged so that the cylinder 15 faces forward and is substantially horizontal. 19 is engine 14
This is the exhaust pipe.

Furthermore, the base frame IIK includes a front fender 13
A windshield leg shield 20 is installed at the rear of the vehicle body and extends from the upper front part to the lower center part of the vehicle body.As shown in the exploded perspective view of FIG.
3 and the recess 20a of the leg shield 20, an air guide path 21 is formed that extends from the upper part of the front part to the lower part of the rear part.

This air guide path 21 is connected to the cylinder 1 of the engine 14 shown in FIG.
5, an air cleaner 17, a capretor 18, etc. are facing.

Here, the cylinder 15 and cylinder head 16 are shown in FIGS. 3 to 7. First, the third factor is a side view of the cylinder 15 and cylinder head 16. As shown in the figure, diagonal cooling fins 30a and 30b are provided on the side surfaces of the V-cylinder 15 and the cylinder head 16, extending from the upper part of the front part to the lower part of the rear part.

Next, a plan view of this FIG. 3 is shown in FIG. 4.

As shown in the figure, an intake hole 32 is provided at the center of the cylinder head 5 in the left-right direction (vertical direction in FIG. This vertical fin 31b is provided with the cylinder head 1, as shown in FIG. 5 which is a front view.
6 from the top to the bottom.

Further, as shown in FIG. 6 which is a bottom view, an exhaust hole 33 is provided in the lower part of the cylinder 15, and a vertical fin 31a connected to the vertical fin 31b of the cylinder head 16 is connected to the exhaust hole 33. It has been extended to.

The intake hole 32, the exhaust hole 33 and the vertical fin 31a
, 31b is shown in FIG. Note that 34 is a spark plug.

In the above configuration, as shown in FIG.
When 0 is running, wind A from the front hits the front fender 13.
It got caught in the rear and hit the leg y-A/de 20, the front fender 13 and the leg y-/I/de 2.
Arrow B inside the air guide path 21 (Fig. 2) formed between
As shown in Fig. 2, the flow diagonally from the upper part of the front to the lower part of the rear part.
corresponds to

On the other hand, as shown by arrow C, part of the wind C flowing horizontally below the front fender 13 is
5 and the lower part of the cylinder head 16, it passes under the cylinder 15 and cylinder head 16, merges with the oblique wind flowing in the direction B (Fig. 2), and flows backward in the direction of the arrow. .

Here, as shown in FIG. 4, the oblique wind B is divided into two parts, and the cooling wind directed toward the center of the cylinder 15 and the cylinder head 16 is designated as B1, and the cooling wind directed toward the side portions is designated as B2.

First, the cooling air B2 directed toward the side flows through the oblique cooling fins 30a in the same direction as the flow of the cooling air B2.

30b smoothly flows below the cylinder 15, so that the sides of the cylinder 15 and cylinder head 16 are effectively cooled.

On the other hand, the cooling air Bl heading toward the center is as shown in Figure 7.
The air flows downward through the front part of the cylinder head 16, merges with the wind C that has been flowing horizontally below the front fender 13 (FIG. 1), and flows as shown by the arrow D1. In this way, the top (front center) of the cylinder head 16 and the area around the exhaust hole 33, which are at the highest temperature, are effectively cooled.

Note that, as shown in FIG. 6, the rear side of the exhaust hole 33 is cooled by cooling air B2 from the side.

cooled down.

In this way, the cooling air B1 flows through the vertical fins 31a.

31b, and the cooling air B2 flows smoothly along the diagonal fins 30a and 30b, as shown in FIG. Moreover, the diagonal KB and the downward horizontal wind C
Since it forms an acute angle, the oblique wind B is pulled by the horizontal wind C. Therefore, the amount of oblique wind B increases, and the cylinder cylinder 5 and y-cylinder head 16 are effectively cooled.

Incidentally, according to an experiment by Akira Kabuto et al., the oblique wind B mainly occurs in the 70-ton fender 13. Therefore, the present invention is effective even if the leg shield 20 is omitted. Furthermore, with the above structure, the present invention is not limited to motorcycles, but can also be applied to tricycles and four-wheel vehicles.

〔Effect of the invention〕

As explained above, according to the present invention, the diagonal fins and the vertical fins allow the diagonal cooling air to flow smoothly around the circumference of the cylinder and cylinder head. cooling air is pulled. Therefore, the amount of oblique air increases, and the cylinder and cylinder head are effectively cooled.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a motorcycle according to the present invention, FIG. 2 is an exploded perspective view of the sandwich part of FIG. 1, FIG. 3 is a side view showing an embodiment of the present invention, and FIG. Figure 5 is the same front view as seen from direction V in Figure 3;
Figure 6 is a bottom view of the same as seen from direction ■ in Figure 3, Figure 7 is M
FIG. 4 is a sectional view taken along the line ■-■ in FIG. 4; 10...Motorcycle army, 13...Front fender,
14...Engine, 15...Cylinder, 16...
Cylinder head, 21-...Air guide path, 30a, 3
0 b--Diagonal fin, 31 a, 3 l b
= Vertical fin, Bl, B2, Di...Cooling air. Figure 2

Claims (2)

[Claims] (1) Immediately behind the front fender, the cylinder of the engine faces forward and is arranged in a nearly horizontal direction, and the cylinder head of this engine is provided with a vertical fin extending vertically in the center in the left-right direction. , a vertical fin is provided below the center of the cylinder in the left-right direction,
Furthermore, in the part other than the center lower side of the above cylinder,
An engine for a motorcycle, etc., characterized by having diagonal fins extending from the upper part of the front part to the lower part of the rear part. (2) An engine for a motorcycle or the like according to claim 1, wherein diagonal fins are provided on both left and right sides of the cylinder head, extending from the upper part of the front part to the lower part of the rear part.