JPS643780Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a forced air-cooled engine for motorcycles, etc., which is equipped with noise prevention measures.

Prior Art Noise generated from an engine includes vibration noise caused by resonance of the cylinder and cooling fins of the cylinder head due to vibrations caused by inertia of reciprocating parts, torque fluctuations of the crankshaft, etc., piston hitting noise, and There is a combustion sound, etc.

In a forced air-cooled engine, the air sucked in by the fan flows from inside the fan cover into the shroud that surrounds the cylinder and cylinder head, cooling the cylinder and cylinder head. Relatively thin anti-vibration materials were attached to the fan cover and shroud. (Utility Model Application Publication No. 18733, Utility Model Application No. 18733, Utility Model Application Publication No. 1873-
(Refer to Publication No. 168442) Problems to be Solved by the Invention However, in the above-mentioned conventional technology, since the vibration isolating member is attached to the shroud or cylinder cover, the shape of the shroud is not suitable for attaching the vibration isolating member. Since the structure is limited to a simple structure, it may not necessarily be possible to satisfy the desired cooling performance, and the thickness, shape, etc. of the vibration isolating member are limited due to the attachment, which limits the vibration and sound insulation capabilities.

Means and Effects for Solving the Problems The present invention attempts to overcome the drawbacks of the prior art described above, and aims to provide a fan that is driven and rotated by an engine, a shroud that surrounds the cylinder and cylinder head of the engine, and a draft generated by the fan. In a forced air-cooled engine having a fan cover that guides the fan into the shroud, a vibration-proof elastic body formed in advance so as to be in close contact with the outer surface of the shroud is engaged with a plurality of claw pieces integrally attached to the shroud. This is a forced air-cooled engine characterized by the following: A pre-formed vibration-isolating elastic body is fitted onto the outer surface of the shroud, and the vibration-isolating elastic body is secured by engaging a plurality of claws attached to the outer surface of the shroud. can be easily attached to the outer surface of the shroud without any gaps and without any processing. The air introduced into the fan cover by the fan cools the cylinder and cylinder head while being guided by the fan cover and shroud, and is then released to the outside.

Embodiment Hereinafter, an embodiment of the present invention shown in FIGS. 1 to 4 will be described.

1 is a scooter-type motorcycle, in which the front part of a power unit 5, which is integrally constituted by a forced air-cooled two-stroke engine 6 and a transmission case 8 located between a front wheel 3 and a rear wheel 4, is connected via a link. and is supported by the vehicle body frame 2, and its rear portion is also supported by the vehicle body frame 2 via a shock absorber 2a.

Therefore, the power unit 5 itself constitutes a substitute for the rear fork, and the rear wheel 4 is supported by a rear wheel axle disposed at the rear of the power unit 5 (see FIG. 1).

A resin fan cover 13 is attached to the right side of the engine 6 to cover the crankcase 7, the fan 12 attached to the end of the crankshaft 11, the cylinder 9, and the cylinder head 10 (a third (see figure).

Also, cylinder 9 and cylinder head 1
A metal shroud 14 is attached to the crankcase 7 to cover the top, front, rear and left side surfaces of the fan cover 1.
It is connected to the open side 13a of No. 3. An exhaust opening 14b and an opening 14c for avoiding the spark plug P are formed in the upper wall of the shroud 14, and the front wall, rear wall, upper wall, and side wall have
Locking claws 15a, 15 for locking the vibration-proofing rubber 16
b, 15c, and 15d are attached respectively (see FIGS. 2 to 4).

Further, on the outer surface of the shroud 14, a vibration-proofing rubber 16, which is previously formed in a shape corresponding to the shroud 14, is attached in close contact.
An opening 16 formed in the upper wall of the vibration-proofing rubber 16
a and 16b are the exhaust opening 14b of the shroud 14 and the opening 14c for the spark plug P, respectively.
It corresponds to

Therefore, on the surface of the shroud 14, small pieces 14A, 15B (only 15b is shown), 15C, 15D, which are bent to form locking claws 15a, 15b, 15c, 15d, are attached, and the anti-vibration rubber 1
6 into the shroud 14, each of the above-mentioned locking claws 1
It can be attached very easily by holding and fixing each open side to 5a to 15d.

Since the embodiment of the present invention has the above-described configuration, when the engine is operating, the air (airflow) introduced into the fan cover 13 through the louver 13b by the fan 12 that rotates together with the crankshaft 11 is as follows: The cylinder 9 and cylinder head 10 are cooled while being guided by the fan cover 13 and shroud 14, and the exhaust openings 14b and 14 are cooled.
It is released to the outside through c.

Various noises such as vibrations generated by the engine 6 are suppressed from being directly released to the outside by the fan cover 13 and the shroud 14, and are effectively suppressed by the anti-vibration rubber 16 that covers the outer surface of the shroud 14. It is absorbed and a good sound insulation effect can be obtained. Moreover, since the anti-vibration rubber 16 is in close contact with the outer surface of the shroud 14,
It has the effect of damping its own vibration and has a great vibration sound absorption effect.

Effects of the invention The present invention has a structure in which a vibration-proof elastic body formed in advance so as to be in close contact with the shroud's outer surface is locked to a plurality of claw pieces integrally attached to the shroud's outer surface. It can attenuate the vibrations of the shroud transmitted from the engine, etc., as well as absorb the noise generated from the engine and the vibration sound of the shroud itself, achieving a good sound deadening effect. Since it is pre-formed, it is easy to attach it to the shroud because it does not require any effort such as simply fitting it and locking it to the locking claw, or bending or pasting it. Since it is not fixed and can be fitted into the shroud without any gaps, it has excellent soundproofing and vibration-proofing properties, and since there are no restrictions on the shape of the shroud, the desired cooling capacity can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a side view of a motorcycle equipped with a forced air cooling engine according to an embodiment of the present invention, Fig. 2 is a vertical left side view of the same engine, and Fig. 3 is a cross-section taken along the - line in Fig. 2. , FIG. 4 is an exploded perspective view of the same engine. 1...Motorcycle, 2...Vehicle frame, 2a
...Buffer, 3...Front wheel, 4...Rear wheel, 5...Power unit, 6...Engine, 7...Crank case, 8...Mission case, 9...Cylinder, 10...Cylinder head , 11... Crankshaft, 12... Fan, 13... Fan cover, 14... Shroud, 14a... Open side,
14b...Exhaust opening, 14c...Opening, 15
a, 15b, 15c, 15d...Latching claw, 16...
...Anti-vibration rubber.

Claims (1)

[Scope of utility model registration request] A forced air-cooled engine having a fan driven and rotated by the engine, a shroud surrounding a cylinder and a cylinder head of the engine, and a fan cover that guides airflow generated by the fan into the shroud, which is integrally attached to the shroud. A forced air-cooled engine characterized in that a vibration-proof elastic body formed in advance so as to be in close contact with the outer surface of the shroud is engaged with a plurality of claw pieces.