JPH11190226A - Sound insulating device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a compression wave in a space between the opposed end faces even when a deflection is produced in a rotating position of a rotary body due to the precessional motion, etc., of a crankshaft. SOLUTION: With the sound insulating device of an engine, a rotary body 2 is fixed to a crankshaft 1, and an end face opposite space 5 is provided between the end face 3 of the rotary body 2 and a wall 4 opposed to the rotary body. Through holes 6 which face the space 5 are provided in the rotary body 2. Further, at positions equally spaced apart from the center 8 of rotation of the rotary body 2, the through holes 6 are provided at equal intervals in the direction 9 of rotation of the rotary body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof device for an engine.

[0002]

2. Description of the Related Art Conventionally, an engine has a structure in which a rotating body such as a pulley or a flywheel is fixed to a crankshaft, and an end face facing space is provided between an end face of the rotating body and a facing wall thereof. . For this reason, if the rotational attitude of the rotating body is deviated due to the slack motion of the crankshaft or the like, the air density in the space facing the end face becomes uneven, and compression waves are generated. The conventional engine has no means for suppressing the generation of the compression wave.

[0003]

In the conventional engine,
Since there is no means for suppressing the generation of the compression wave in the opposed space, the compression wave is propagated around the space opposed to the end face, and this causes the engine noise to increase.

An object of the present invention is to solve the above problems.

[0005]

The main invention of claim 1 is configured as follows. As shown in FIG. 1 or FIG. 2, a rotating body (2) is fixed to a crankshaft (1), and an end face facing space is provided between an end face (3) of the rotating body (2) and its facing wall (4). (5) is provided, and the rotating body (2) is provided with a space (5) facing the end face.
Is provided.

[0006]

Operation and Effect of the Invention (Invention of claim 1) The invention of claim 1 has the following operation and effects (see FIG. 1 or FIG. 2). According to the present invention, the rotating body (2) is provided with the space facing the end face.
Since the through-hole (6) facing the (5) is provided, even if the rotation posture of the rotating body (2) is deviated due to the slewing motion of the crankshaft (1) or the like, the end face facing space (5) can be used. Generation of compression waves is suppressed.

That is, when a part of the rotating body (2) approaches the opposing wall (4) due to the deviation of the rotating posture of the rotating body (2), a part of the air in the space (5) opposed to the end face is compressed. The pressure here temporarily increases, and a part of the compressed air is pushed out of the through hole (6) into the space in front of the rotating body (2). Also, the rotating body
When the rotation posture of (2) shifts, a part of the rotating body (2) separates from the opposing wall (4) and a part of the air in the end face opposing space (5) is stretched. Lowered, rotating body (2)
Is drawn from the through hole (6) into the space (5) facing the end face. For this reason, the nonuniformity of the air density in the space 5 facing the end face is suppressed, the generation of compression waves is suppressed, and the engine noise is suppressed.

(Invention of claim 2) The invention of claim 2 has the following effect in addition to the effect of the invention of claim 1 (see FIG. 1 or FIG. 2). According to the present invention, since the generation of the compression wave in the space (5) opposed to the end face of the pulley (7) in the exposed state is suppressed, the propagation of the compression wave to the periphery thereof is suppressed,
Engine noise is more efficiently suppressed.

(Invention of claim 3) The invention of claim 3 provides the function and effect of the invention of claim 1 or 2 and
The following operational effects are obtained (see FIG. 1 or FIG. 2). According to the present invention, the through holes are equally spaced from the rotation center (8) of the rotating body (2) in the rotating direction (9) of the rotating body (2).
Since the through holes (6) are provided, the displacement of the center of gravity of the rotating body (2) due to the provision of the through holes (6) is reduced. For this reason,
The shake of the rotating body (2) is suppressed, and the generation of compression waves in the space (5) facing the end face is suppressed.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an embodiment of the present invention. In this embodiment, a vertical diesel engine is used.

The structure of this engine is as follows. A timing gear case (1) is provided at the front of the crankcase (11).
0) is assembled, and an oil pump (12) is provided at the front of the timing gear case (10). Crankshaft for timing gear case (10) and oil pump (12)
(1) is penetrated, and a rotating body is attached to the protruding end of the crankshaft (1).
(2) is fixed, and an end face opposing space (5) is provided between the end face (3) of the rotating body (2) and the opposing wall (4). The rotating body (2) is provided with a through hole (6) facing the space (5) facing the end face.

The rotating body (2) includes an exposed pulley (7).
It is. A fan belt (19) is wound around the pulley (7). The pulley (7) is provided with a mounting screw boss (18) for the PTO shaft. A collar (16) and a pulley (7) are externally fitted to the tip of the crankshaft (1). The collar (16) is press-fitted and fixed to the crankshaft (1). The pulley (7) is spline-fitted to the crankshaft (1), and is fixed by sandwiching the mounting bolt (17) and the collar (16). The rotating body (2) may be a flywheel or a gear.

At the same position from the rotation center (8) of the rotating body (2), through holes (6) are provided at equal intervals in the rotating direction (9) of the rotating body (2). Each through hole (6) is constituted by a round hole having an equal opening area. Also, at the same position from the rotation center (8) of the rotating body (2), the rotating direction (9) of the rotating body (2)
At regular intervals, mounting screw bosses (18) are provided. Each mounting screw boss (18) is formed of a cylinder of equal size. Therefore, the displacement of the center of gravity of the rotating body (2) due to the provision of the through holes (6) and the mounting screw bosses (18) is suppressed.

As shown in FIG. 1 (A) or FIG. 2, a crank arm (13) connected to a piston of a combustion chamber during combustion, as viewed in a direction parallel to the direction in which the crank shaft (1) is installed.
The end on the side of the crankpin (14) is oriented in the direction in which the through hole (6) is located. For this reason, large deflection of the rotating body (2) caused by twisting of the crankshaft (1) due to the explosion pressure occurs at a position where the through hole (6) is present, so that the amount of compressional waves can be reduced and noise is reduced. Can be suppressed. The end of the crank arm (13) on the side of the crank pin (14) is
The same function can be obtained by turning the center of rotation (8) to the side opposite to the through hole (6).

In a modified example of the rotating body shown in FIG.
(6) is composed of long holes having the same opening area. Other configurations are the same as those of the rotating body of FIG. 2, the same elements as those in FIG. 1 are denoted by the same reference numerals.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a soundproofing device for an engine according to an embodiment of the present invention. FIG. 1A is a front view of a rotating body, and FIG.
(B) is a longitudinal sectional view of a main part.

FIG. 2 is a front view of a modified example of a rotating body.

[Explanation of symbols]

(1) ... crankshaft, (2) ... rotating body, (3) ... end face, (4) ...
Opposing wall, (5): End face opposing space, (6): Through hole, (7): Pulley, (8): Rotation center, (9): Rotation direction.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Mikumo 64 Ishizukitamachi, Sakai-shi, Osaka, Japan, inside Kubota Sakai Factory (72) Inventor Nori Takii 64, Ishizukitamachi, Sakai-shi, Osaka Prefecture, inside Kubota Sakai Factory (72) Inventor Jun Koyama 64 Ishizu-Kitacho, Sakai-shi, Osaka, Japan Inside Kubota Sakai Factory (72) Inventor Sada Tsuji 64 Ishizu-Kitamachi, Sakai-shi, Osaka Prefecture Inside Kubota Sakai Factory, Inc. (72) Inventor Yosuke Morimoto Ishizu, Sakai-shi, Osaka Kitamachi 64 Kubota Sakai Co., Ltd. (72) Inventor Kiyoshi Hataura 64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd. (72) Inventor Miyagasaki Saku ▼ 64 Ishizukitamachi, Sakai City, Osaka 64 Kubota Sakai Co., Ltd. In the factory

Claims (3)

[Claims] A rotating body (2) is fixed to a crankshaft (1), and an end face facing space (5) is provided between an end face (3) of the rotating body (2) and a facing wall (4). And a through hole (6) facing the end face facing space (5) in the rotating body (2). 2. The soundproofing device for an engine according to claim 1, wherein the rotating body (2) is an exposed pulley (7). 3. The soundproofing device for an engine according to claim 1, wherein the rotation direction (9) of the rotating body (2) is equal to the rotation center (8) of the rotating body (2). A through hole (6) is provided at intervals.