JPH06344779A - Soundproof and cooling system of engine room - Google Patents

Abstract

PURPOSE:To provide an under cover structure that prevents all of operator ear noises and ambient noises from enlarging by introducing the outside air produced by car running into an engine room positively, while preventing any noise emitted out of an engine wall surface from being directly propagated from an air inlet part. CONSTITUTION:An under cover 7 is bent aslant downward in its forward direction, using it as a guide piece 13, and simultaneously a part of this guide piece 13 bent aslant downward is lapped in the longitudinal direction, and the upper side is by upward, using it as a guide piece 14, and further an air inlet part 11 provided with a slit 12 is formed in the vertical direction, then the under cover 7, having a sound insulating material attached to both surfaces of this slip 12, is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproofing / cooling device for an engine room of an engine type industrial vehicle such as a forklift or shovel loader.

[0002]

2. Description of the Related Art In a conventional industrial vehicle having a structure in which the lower side of an engine room is opened, noise (mainly engine sound) emitted from the engine room is large, and problems such as pollution of various facilities in the engine room occur. As a solution to this problem, a low noise specification in which the lower surface of the engine room is covered with an under cover C shown in FIGS. 5 and 6 is provided. FIG. 7 is a side view showing the entire standard specification forklift. Conventionally, as a structure of an undercover of an industrial vehicle that covers a lower surface of an engine room, for example, those disclosed in Japanese Utility Model Publication No. 62-125648 and Japanese Utility Model Publication No. 2-88826 are provided. That is, in Japanese Utility Model Laid-Open No. 62-125648, the air inlet is formed by bending the front edge of the under cover attached to the lower end of the side frame obliquely downward. The plurality of air introducing portions shown in FIG. 4 are provided side by side on the under cover to enhance the cooling effect. In Japanese Utility Model Laid-Open No. 2-88826, air is introduced into the engine room through an intake port formed in the undercover, and a guide member is provided for causing the air flowing from the intake port to flow toward the wall surface of the hydraulic oil tank. Therefore, the contact of the cooling air with the wall surface of the hydraulic oil tank is positively performed, and the heat radiation of the hydraulic oil is positively performed. Further, a plurality of air introduction parts shown in FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 7, e is an engine, d is a sound absorbing material, c is an under cover,
s is a side frame, r is a radiator, w is a counterweight, f is a fan, and p is an exhaust hole.

[0003]

However, in the case of the above-mentioned closed structure with the undercover, the structure shown in FIG. 6 is obtained, and the air intake is insufficient, which causes engine overheat due to insufficient engine cooling. In order to enhance the cooling effect, the air introduction part and the guide member shown in Fig. 3 and Fig. 4 are provided. However, the noise radiated to the outside is reflected on the road surface and the operation ear noise and ambient noise are increased. There was a problem of doing it. That is, in Japanese Utility Model Laid-Open No. 62-125648, sound emitted from a plurality of air introduction sections from the engine wall surface, which is a noise source, directly propagates to the outside and is reflected on the road surface to increase operation ear noise and ambient noise. In fact, the same is true for Kaikaihei 2-88826.
Although the hydraulic oil tank is cooled, the noise radiated from the engine wall, which is a noise source, directly propagates to the outside from the air intake port formed in the under cover, and is reflected on the road surface to increase operation ear noise and ambient noise. I had done it.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in an industrial vehicle of low noise specification with an undercover, outside air is actively introduced into the engine room while the vehicle is running, and And the structure that prevents the sound radiated from the wall of the engine from directly propagating to the outside from the air introduction part, that is, the under cover is bent diagonally downward in the front direction of the under cover and is also bent diagonally downward. The undercover is used by wrapping it in the front-back direction and bending the upper side upward so as to form an air introduction part with a certain interval in the vertical direction.

[0005]

Since the present invention has the under cover having the above-mentioned structure, the outside air can be positively introduced into the engine room by the air introducing portions at several places, and the air is adhered to both sides of the passage of the air introducing portion. The sound absorbing material reduces the direct sound and absorbs the reflected sound, prevents the direct sound and the reflected sound from propagating to the outside, and reduces the noise leakage as much as possible, which is effective in reducing the ambient noise. large.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a structural diagram showing an embodiment of an under cover 7 according to the present invention, and FIG. 2 is a view showing that in the embodiment of FIG. 1, sound waves emitted from the wall surface of the engine 4 propagate to the outside from the air introduction portion 11 of the under cover 7. As shown in FIG. 1 which is a schematic view showing the process of forming the slits, the under cover 7 is provided with two air introducing portions 11, and the slits 12 that are long at the appropriate intervals in the vehicle width direction are the slits 12. A guide piece 13 that projects obliquely forward to the lower side, and a guide piece 14 that wraps around the guide piece 13 in the front-rear direction and has a certain interval on the upper side of the slit 12 and is inclined obliquely rearward.
To form an air introduction portion 11. Therefore, when the vehicle is traveling, as shown by the arrow, the outside air is guided through the gap formed by the upper and lower guide pieces 13 and 14 of the slit 12 of the air introducing portion 11 of the under cover 7 to be guided to the upper surface of the under cover 7. . That is, air is positively taken into the engine room during traveling, the air is guided from the lower part of the engine 4 to the wall surface of the engine 4, passes through the radiator 6, and is discharged from the exhaust hole 3a to the rear of the vehicle body.

Further, of the acoustic power Wo radiated from the sound source (engine sound, transmission sound, etc.), a part thereof becomes the power Wt of the transmitted sound, and a part thereof is the sound absorbing material 16 adhered to the upper surface of the under cover 7. Power absorbed
Therefore, a part of the power Wd of the direct sound that does not enter the sound absorbing material 16 at all or the power Wr of the reflected sound that is reflected from the under cover 7 and leaks from the slit 12 of the air introduction portion 11 propagates to the outside. The following equation shows this relationship. Wo = Wt + Wa + Wd + Wr That is, in the structure of the present invention shown in FIG.
The sound absorbing material 16 adhered to both sides of the slit 12 which is the passage of the air introduction part 11 made of 3, 14 reduces the direct sound, absorbs the reflected sound, and propagates both the direct sound and the reflected sound to the outside. Since the noise can be prevented and the leakage of noise can be reduced as much as possible, the effect of reducing ambient noise is remarkable.

[0008]

As described above in detail, the present invention has a slit that is long in the vehicle width direction and is inclined obliquely forward to the lower side of the slit, with an appropriate interval in front, back, left and right of the under cover that covers the lower part of the engine room. Since the air guide part is formed by the guide piece protruding to the front and the guide piece that is wrapped back and forth with a gap above the slit and is provided obliquely rearward, it is possible to introduce air when the vehicle is traveling. The outside air is positively taken into the engine room above the undercover from the section, and the hot air in the engine room is sufficiently scavenged.
Without damaging the cooling effect, the sound absorbing material adhered to both the upper surface of the undercover and both sides of the air introduction passage, absorbs the direct sound of the engine sound and the transmission sound, and prevents the direct sound from propagating to the outside. Noise leakage can be reduced as much as possible.

[Brief description of drawings]

FIG. 1 is a structural view showing an embodiment of an undercover according to the present invention.

FIG. 2 is a schematic diagram showing a process in which a sound wave radiated from an engine wall surface propagates from an air introduction portion of an undercover to the outside in the embodiment of FIG.

FIG. 3 is a schematic diagram showing a process in which a sound wave radiated from an engine wall surface propagates from an air introducing portion of the under cover in the conventional under cover.

FIG. 4 is a schematic diagram showing a process in which a sound wave emitted from an engine wall surface propagates from an air introducing portion of the undercover to the outside in another conventional undercover.

FIG. 5 is an explanatory view of attaching an under cover.

FIG. 6 is a structural explanatory view of a conventional under cover.

FIG. 7 is a side view showing the entire forklift.

[Explanation of symbols]

 4 Engine 7 Undercover 11 Air Inlet 12 Slit 13 Guide Piece 14 Guide Piece 16 Sound Absorbing Material

Claims (3)

[Claims] 1. An undercover 7 that covers the lower surface of an engine room is bent diagonally downward to form a guide 13 piece, and the diagonally bent portion is lapped in the front-back direction. The upper side is a guide piece 14 bent upward, and the slit 1 in the vertical direction is used.
A sound insulation of an engine room in an industrial vehicle, characterized in that an air introduction portion 11 having 2 is formed.
Cooling system. 2. The soundproofing / cooling device for an engine room according to claim 1, wherein the undercover 7 is provided with a plurality of air introducing portions 11 arranged side by side in the front-rear direction. 3. The soundproofing / cooling device for an engine room according to claim 1 or 2, wherein the undercover 7 has a sound absorbing material 16 adhered and attached to an upper surface thereof and both sides of the slit 12 of the air introduction portion 11.