JPS5960054A - Cooling fin for engine - Google Patents

Abstract

PURPOSE:To cool the outer surface of a cylinder uniformly, by forming through- holes extended longitudinally between the cylinder of an engine and a cam chain chamber formed by the side of the cylinder, and forming fins in the through- holes. CONSTITUTION:A cam chain chamber 25 incorporating therein a cam chain is disposed by the side of a cylinder bore 15 of an air-cooled engine 1 which is mounted on a down-tube 4 of a motor cycle, and through-holes 28 are formed between the cylinder bore 15 and the cam chain chamber 25 to extend longitudinally of the engine 1. Further, a proper number of longitudinally extended, horizontal cooling fins 27 are formed on the inside of the through-holes 28.

Description

[Detailed description of the invention] The present invention relates to cooling fins for air-cooled engines.

Conventionally, in air-cooled engines mounted on two-axle motor vehicles, etc., there is a cam chain chamber on one side of the engine, which serves as a passage for the cam chain that links the rotation of the crankshaft to the valve mechanism installed in the cylinder head of the engine. is provided. Therefore, since the cam chain chamber side has a large heat capacity and the fins on the cam chain chamber side are separated from the cylinder, there is a problem in that the cam chain side of the cylinder tends to be insufficiently cooled.

The present invention has been made in view of the above problems, and provides an air-cooled engine having a cam chain chamber on the side surface of the engine, in which a through hole is formed between the cylinder of the engine and the cam chain chamber, penetrating in the longitudinal direction of the engine. The present invention provides an engine cooling fin in which a cooling fin is provided in the through hole to cool the engine sufficiently and uniformly.

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows a schematic side view of a motorcycle equipped with an engine to which the present invention is applied, and FIG. is connected to the steering head 2 of the vehicle via a gazette plate 3,
It is attached to two down tubes 4 that extend downward and to the rear of the vehicle body, and is located at the bottom of the fuel tank 5. As shown in FIGS. 3 and 4, the details of the engine 1 are as shown in FIG. and arranged in a V-shape. Exhaust pipes 7a and 7b of the front engine 1a and the rear engine 1b extend toward the rear of the vehicle body from the front and rear parts of the engines la and lb, respectively.

Engine 1 has crankcase 8. Cylinder block9.
The cylinder head 10 is joined through gaskets 11 and 12, and cooling fins 13 and 14 are formed on the outer circumferences of the cylinder block 9 and the cylinder head. 2 in the diagram
9 is an oil filter, which is attached to the upper part of the crankcase 8 and has a recess in the cooling fin 13 of the front engine 1a]-
3a is provided on the side of the front cylinder block 9.

A piston 16 is fitted into a cylinder bore 15 formed in the cylinder block 9, and the piston 16 is connected to the crankshaft 6 by a connecting rod 17.

A spark plug 18 is attached to the cylinder head 10, and its tip faces a combustion chamber 19 at the top of the cylinder pore 15.

A valve mechanism 20 that operates an intake valve and an exhaust valve (not shown) is disposed in the upper part of the cylinder head 10, and a cam chain 24 is connected to a camshaft 21 of the valve mechanism 20 and sprockets 22 and 23 provided on the crankshaft 6. The cam chain 24 is wound around the crankcase 8, cylinder block 9,
It is housed in a cam chain chamber 25 formed through the cylinder head IO. Breather chambers 26 are vertically formed between the cam chain chamber 25 and the cylinder side wall to communicate the inside of the crankcase 8 with outside air.

13b is a recess provided in the cooling fin 13 of the rear cylinder block 9 to prevent interference with the exhaust pipe 7a.

The cooling fins 27 according to the present invention are provided in the breather chamber 26, and have a through hole 28 penetrating the breather chamber 26 of the cylinder block 9 in the longitudinal direction of the engine 1. A suitable number of extending horizontal cooling fins 27 are provided.

In the embodiment shown in FIG. 4, the through holes 28 provided with the cooling fins 27 are formed in the side wall on the cylinder side.

Even if it is formed on the cam chain chamber 24 side as shown in FIG. 5, the same effect can be obtained.

3- In addition, in engines where a breather chamber is not provided between the cylinder and the cam chain chamber, the gap between the cylinder and the cam chain chamber should be widened, and a through hole with cooling fins similar to the above should be formed between them. Bye.

In the above-described configuration, the wind from the front of the vehicle flows around the front engine 1a and the rear engine 1b, contacts the cooling fins 13 and 14 formed on the outer periphery of the cylinder block 9 and the cylinder head 10, and cools the front engine. 1a and rear engine 1b are cooled. And some of the driving wind is caused by each engine 1. It enters the through holes 28 of a and lb, flows rearward between the cooling fins 27, and cools the cam chain chamber 25 side with the same effect as the other cooling fins 13, 14 on the outer circumference of the cylinder.

As described above, in the present invention, in an air-cooled engine having a cam chain chamber on the side surface of the engine, a through hole is formed between the cylinder of the engine and the cam chain chamber, penetrating in the longitudinal direction of the engine.

By providing cooling fins in the through holes, the cooling area near the cylinder has been expanded, and the cam chain chamber side, which previously had insufficient cooling performance, now has the same cooling performance as the other three directions. effect can be obtained.

Therefore, the outer periphery of the cylinder is evenly cooled, preventing the occurrence of thermal stress, increasing the output of the engine, and extending the service life.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 is a schematic side view of a two-axle automatic vehicle equipped with an engine to which the present invention is applied, FIG. 2 is a detailed view taken in the direction of arrow A in FIG. 1, FIG. Figure 4 shows details of the engine section, and Figure 3 shows B-B in Figure 1.
FIG. 4 is a sectional view taken along the line C--C in FIG. 1, and FIG. 5 is a partial view of main parts showing another embodiment. DESCRIPTION OF SYMBOLS 1...Engine, 6...Crankshaft, 8...Crank case, 9...Cylinder block, ]0...Cylinder head, 13,14.27...Cooling fin, 1
5... Cylinder bore, 19... Valve mechanism, 20...
Camshaft, 24...cam chain, 25...cam chain chamber, 26...breather chamber, 28...through hole. Figure 2 Figure 3 Kazuo Wakasugi, Commissioner of the Patent Office 1. Display of the case 1982 Patent Application No. 170003 2, Name of the invention Engine cooling fin 3, Person making the amendment Relationship to the case Patent applicant address 6-27-8 Jingumae, Shibuya-ku, Tokyo Name (5
32) Honda Motor Co., Ltd. Representative Kawa
Yoshiyoshi Shima 4, Agent Address: Sunshine Koken Plaza 30゛1, 3-2-4 Higashiikebukuro, Toshima-ku, Tokyo 170 Telephone: 03 (98)
3) 0926 (Representative) Name Patent Attorney (818g) Toshihiko Watanabe 5. Drawings to be amended (all drawings) 6. Details of the amendment as shown in the attached sheet. (engraved drawing)

Claims (1)

[Claims] 1. In an air-cooled engine having a cam chain chamber on the side of the engine, a through hole is formed between the cylinder of the engine and the cam chain chamber, penetrating in the longitudinal direction of the engine, and cooling fins are provided in the through hole. An engine cooling fin characterized by: