JPH0111946Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a soundproof structure that reduces engine front noise.

Generally, various auxiliary devices and parts are placed close to each other around the engine, but if there is a gap between this device or part and the wall of the engine body, the information will be transmitted to the outside through this gap. The sound of
The unique frequency of the sound passing through this gap is amplified to generate a standing wave that makes loud noise, thereby increasing the overall noise of the engine.

For example, when looking at the gap between the crank pulley and the engine body, the meshing noise of the timing gear located at the front of the engine and other sounds transmitted along the crankshaft can be heard between the side of the pulley and the gear case cover adjacent to it. Standing waves that are transmitted to the outside through the gap with the wall surface or induced by this gap increase the overall noise of the engine.

This invention was made in view of the above points,
To provide a soundproof structure for an engine that suppresses noise transmitted to the outside through a gap between a rotating body such as a pulley and a wall surface of a cylinder block of an engine adjacent thereto, and noise induced by this gap. It is an object.

In order to achieve this object, the present invention provides a rib on the outer wall of the cylinder block in the projection plane of the rotating body, which extends over the entire circumferential direction of the rotating body, and connects the tip of this rib to the cylinder block side of the rotating body. It is characterized by being placed extremely close to the side.

Therefore, noise that would otherwise leak through the gap between the cylinder block and the rotating body is contained in this gap by the ribs, so that noise leaking to the outside is reduced.

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

The figure is a sectional view of a main part showing the front part of an engine, showing an example of a soundproof structure for an engine according to the present invention.

This engine 1 has a crankshaft 3 protruding from a cylinder block 2 and a pulley 4 as a rotating body. A member of the cylinder block 2 that is close to the pulley 4 is a timing gear case cover 5, which is attached to the casing body 7 with bolts.

The pulley 4 is fixed to the crankshaft 3 via a sleeve 9 by a tightening nut 8 which is threaded into the threaded portion 3a of the crankshaft 3.
In the figure, 10 is an oil seal.

In particular, in the present invention, the rib 11 protrudes from the outer wall of the case cover 5 toward the side surface 4a of the pulley 4 so that its tip comes very close to the side surface 4a without interfering with the side surface 4a. Here, the rib 11 is provided on the outer wall of the cylinder block 2 (on the surface of the case cover 5) in the projection plane of the pulley 4 and extends all the way around the pulley 4 in the rotational direction (circumferential direction). The diameter is approximately the same as or smaller than the outer diameter of the pulley 4.

With this configuration, the meshing sound of the timing gear (not shown) and the sound generated inside the engine 1, transmitted along the crankshaft 3, and trying to pass through the gap S between the pulley 4 and the case cover 5 to the outside can be avoided. The rib 11 in contact with the case cover 5 closes the gap S, so that it becomes difficult for it to pass through.

Furthermore, if the rib 11 is formed beyond the projection plane of the pulley 4 and the outer diameter of the rib 11 is made larger than the outer diameter of the pulley 11 as described above, there is a gap between the pulley 4 and the rib 11. A large gap is created, which deteriorates the noise containment function, but in this invention, the rib 11 is formed within the projection plane of the pulley 4 (rotating body), so the outer diameter of this rib 11 is equal to that of the pulley 4 (rotating body). It will be approximately the same as or smaller than the outer diameter. Therefore, a large gap is not formed between the rib 11 and the pulley 4, and the containment function of the rib 11 can be enhanced, so that noise does not escape. Since the gap between the side surface 4a of the pulley 4 and the tip of the rib 11 is also extremely small, standing waves induced by this gap can be suppressed.

Note that in this embodiment, the rib 11 close to the pulley and the case cover 5 are integrally constructed; however,
The two may be combined as separate structures, and in this case, if the ribs 11 have a soundproofing effect, the noise reduction effect will be further enhanced.

As is clear from the above explanation, according to the present invention, it is possible to suppress the sound that attempts to pass to the outside through the gap between the rotating body and the tip of the rib adjacent to the rotating body, resulting in a significant noise reduction effect for the engine. It will be done.

[Brief explanation of drawings]

The figure is a sectional view showing an embodiment of the present invention. 1...Engine, 2...Cylinder block, 3
...Crankshaft, 4...Pulley, 4a...
Side, 5...Case cover, 11...Rib.

Claims (1)

[Scope of utility model registration request] In an engine in which a rotating body such as a pulley is attached to a crankshaft protruding from a cylinder block, a rib is provided in the projection plane of the rotating body on the outer wall of the cylinder block, extending all the way around the circumferential direction of the rotating body. 1. A soundproofing device for an engine, characterized in that a tip thereof is brought very close to a side surface of the rotating body on the cylinder block side.