JP2003139223A - Noise insulation cover for transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise insulation cover for transmission improving the cooling performance of a transmission. SOLUTION: This noise insulation cover is structured so that running wind may run through the inside of a cover body 15a smoothly by disposing it so as to cover the periphery of the transmission 6 and forming a venturi section S (a throttle section) for throttling a clearance 31 to a transmission wall surface at the inner surface of the cover body 15a shielding the noise from the transmission to increase the wind velocity of the running wind running through the clearance 31. Thus, the heat of the transmission 6 is led out to the open air by the running wind immediately without remaining inside the cover body 15a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof cover for a transmission, which shields noise generated from a transmission mounted on a truck or the like together with an engine.

[0002]

2. Description of the Related Art A cab-over type truck (vehicle) is
An engine and a transmission directly connected to the engine are mounted between side frames extending in the front-rear direction of the vehicle body, and a cab is provided directly above these engines, which is a structure in which most of the transmission is exposed to the outside air.

Therefore, the cab-over type truck is
The noise generated from the transmission is apt to be emitted to the outside air. Therefore, in a cab-over type truck, for example, as shown in Japanese Utility Model Publication No. 64-2868, the engine cover that covers the engine is linked to the side of the transmission. A soundproof cover for the transmission, which covers the lower surface and both side surfaces of the transmission exposed from the frame, is provided to block the noise generated from the transmission (usually the upper surface of the transmission is covered with a luggage carrier etc. Often not attached).

By the way, the transmission is required to be cooled so that the temperature of the lubricating oil (for lubrication of gears and shafts that mesh with each other) does not rise excessively.

Therefore, conventionally, a gap is provided between the soundproof cover for the transmission and the outer surface of the transmission so that air can pass through and the traveling wind flowing out from the engine cover can be directly transmitted between the outer surface of the transmission and the inner surface of the soundproof cover. A means is provided to allow the heat from the transmission to be dissipated to the outside air by the traveling wind by circulating the heat in the gap (ventilation path) formed therebetween.

[0006]

However, since the soundproof cover for the transmission is introduced with a weak driving wind after passing through the narrow gap (ventilation passage) between the engine and the engine cover, The wind tends to accumulate inside the soundproof cover.

For this reason, the heat of the transmission may stagnate inside the soundproof cover, resulting in poor heat dissipation.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a soundproof cover for a transmission, which can improve the cooling performance of the transmission.

[0009]

In order to achieve the above object, a soundproof cover according to a first aspect of the present invention is provided with a clearance between an inner surface of a cover body that surrounds the transmission and an outer surface of the transmission protruding from the inner surface. By forming a throttle part that narrows the airflow, the wind speed of the traveling wind flowing through the gap is positively increased by the throttle part so that the traveling wind can flow in the soundproof cover without interruption.

Thus, the heat of the transmission is
Due to the running wind that increases the wind speed, it does not stay in the soundproof cover,
It is quickly discharged to the outside air and has high heat dissipation.

Therefore, the cooling performance of the transmission is improved. Moreover, since the transmission noise is blocked by the cover body, both cooling performance and soundproofing can be achieved.

In addition to the above object, the soundproof cover of the invention according to claim 2 is, in order to increase the wind speed of traveling wind with a simple structure, as a cover body, a sound insulating substrate covering the periphery of the transmission, and an inner surface of the sound insulating substrate. In addition to using a structure having a sound absorbing layer provided in the, the throttle portion has an inner surface facing the transmission of the sound absorbing layer, the top closest to the middle of the transmission, and from the top to the front and rear in the direction of traveling wind. The venturi structure is formed in the gap by forming a mountain shape having a slope facing away from the transmission.

In addition to the above object, in the soundproof cover of the invention according to claim 3, in order to improve the soundproof performance with a simple structure, the angle-shaped sound absorbing layer has a plurality of different lengths and openings facing the gap. By adopting a structure with holes, the inner surface of the hole is also used as a sound absorbing part, and the space of the hole with different length acts as an air column that resonates the noise with different frequencies, effectively reducing the transmission noise. The sound is absorbed and the sound pressure energy is effectively reduced.

According to the invention of claim 4, in addition to the above object, in order to increase the flow velocity of traveling wind with a simple structure, as in the invention according to claim 2, as a cover main body, a sound insulating substrate covering the periphery of the transmission, In addition to using a structure having a sound absorbing layer provided on the inner surface of the sound insulation board, the sound insulation board has a top approaching in the middle of the transmission in the throttle part, and from the top the front and back of the running wind flow direction. The venturi structure is formed in the gap by curving in a chevron shape having a slope away from the transmission as it goes toward.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the first embodiment shown in FIGS.

FIG. 1 shows a side surface of a vehicle, for example, a cab-over type truck body. Reference numeral 1 in the figure denotes a pair of side frames extending in the front-rear direction. The side frames 1 are arranged at predetermined intervals in the vehicle width direction as shown in FIG. The front wheels 2 (steering wheels) are attached to the front side, and the rear wheels 3 (driving wheels) are attached to the rear side.

Between the side frames 1 on the front side, as shown in FIG. 2, a radiator 4, an engine 5,
A transmission 6 directly connected to the engine 5 is installed. And the output part of the transmission 6
Propeller shaft 7, differential (not shown)
The driving force output from the engine 5 is transmitted to the rear wheel 3 via the. A cab 8a having a driver's seat (not shown) and the like is arranged directly above the engine 5. Reference numeral 8b denotes a cargo bed which is arranged adjacent to the cab 8 and above the transmission 6 and the side frame 1.

Around the engine 5, a soundproof cover 10 (corresponding to an engine cover) for the engine, which has a U-shape and covers the surroundings, is attached together with the radiator 4. The engine soundproof cover 10 is attached to each front portion of the side frame 1 as shown in FIG. 2, and has a pair of side walls 10a covering both sides of the engine 5 in the vehicle width direction, and the side walls 10a.
And a bottom wall 10b that covers the lower surface of the engine 5. That is, the side wall 10a and the bottom wall 10b cover three sides of the engine 5 to block noise of the engine 5. Further, as shown in FIG. 4, a gap 11 serving as an air passage is formed between each of the side walls 10a and 10b and the outer surface of the engine 1, and the traveling wind is introduced into the gap 11 from the front of the engine soundproof cover 10. I am doing it.
That is, the engine 1 can be cooled by the traveling wind passing through the gap 11.

On the front side of the side frame 1, the transmission 6 is connected to the engine soundproof cover 10.
A soundproof cover 15 for transmission that covers the vehicle is installed. Soundproof cover for this transmission 1
As shown in FIG. 3 (a), a U-shaped cover main body 15 a that matches the engine soundproof cover 10 is used for 5, for example. This cover body 15a is shown in FIG.
A structure in which a U-shaped sound insulating substrate 16 as shown in (b) and sound absorbing layers 20 to 22 attached to all the inner surfaces (three surfaces) of the sound insulating substrate 16 are combined is used. The cover structure covers the periphery of the transmission portion that protrudes downward from between the side frames 1 and is exposed to the outside air.

Specifically, the sound insulation board 16 is detachably attached to each front portion of the side frame 1 by a bracket 17 and bolts (not shown) as shown in FIGS. 2 and 3B. A pair of left and right flat side walls 18a that cover both sides of the transmission 6 in the vehicle width direction and a flat bottom wall 18b that extends between the side walls 18a and covers the lower surface of the transmission 6 are configured. Each part of the sound insulating board 16 is made of a synthetic resin member or a metal member, and has a structure for blocking noise emitted from the transmission 6.

Each of the sound absorbing layers 20 to 22 is a layer that absorbs noise emitted from the transmission 6. Of the sound absorbing layers 20 to 22, the sound absorbing layer 21 of the bottom wall 18b is, for example, as shown in FIG. 3 (b), a plate-like glass window whose front surface side is covered with an aluminum sheet 24 (sheet material).
25 (sound absorbing material) is used. The glass wool 25 is attached to the inner surface of the bottom wall 18b so that the upper surface thereof is separated from the lower surface of the transmission 6. Also, the sound absorbing layers 2 attached to the left and right side walls 1a.
For example, as shown in FIG. 3A, 0 and 22 have a mountain-shaped inner surface facing the transmission 6. Also in these chevron-shaped sound absorbing layers 20 and 22, FIG.
As shown in (b), glass wool 28 (sound absorbing material) whose surface side is covered with an aluminum sheet 27 (sheet material) is used. The chevron shape of each glass wool 28 forms a top portion 29a that is closest to the front-rear direction center (middle) of the transmission 6 at the center of the front-rear direction (flow direction of traveling wind), and the top portions 29a are formed on both sides of the top portion 29a. From the front to the front-rear direction of the transmission 6 (corresponding to the flow direction of traveling wind), a pair of slopes 29b is formed away from the wall surface of the transmission 6.

That is, the glass wool 25 covers the lower surface of the transmission 6 with a gap 30 therebetween, and each glass wool 28 covers the left and right sides of the transmission 6 with a gap 31 therebetween.

The mission soundproof cover 15 thus constructed is connected in series to the rear end of the engine soundproof cover 10 so that the gaps between the corresponding parts communicate with each other. The traveling wind taken in from 10 flows around the transmission 6 through the ventilation passage formed by the gaps 30 and 31.

Due to the chevron shape of the transmission soundproof cover 15, a narrowed portion S, specifically, a venturi structure is formed in each of the gaps 31 (ventilation passages) on the left and right sides of the transmission 6. By each Venturi structure, the running wind from the engine soundproof cover 10
It is designed to flow in the mission soundproof cover 15 without staying.

That is, the traveling wind introduced into the mission soundproof cover 15 is for the mission because the wind is weak after passing through the narrow gap 11 (ventilation path) between the engine 5 and the engine soundproof cover 10. It easily stays in the soundproof cover 15.

At this time, since the narrowed portions S are formed in the left and right gaps 31 of the mission soundproof cover 15, traveling wind quickly flows through the gaps 31.

That is, as shown in FIG. 5 (a), in the narrowed portion S, the open regions formed on both sides of the top portion 29a serve to reduce the static pressure of the traveling wind, thereby improving the wind velocity of the traveling wind. The narrow area formed by the top portion 29a increases the wind speed of the traveling wind. That is, the gap 31
The running wind introduced in FIG. 2 shows a behavior in which the static pressure is reduced by the open region and the wind speed rapidly increases at the top portion 29a as shown by the solid line in FIG. 5B.

Due to this increase in wind speed, the traveling wind in the gap 31 does not become stagnant as shown by the arrow in FIG.
Gap 31, that is, soundproof cover 1 for transmission
It comes to flow in 5.

As a result, the heat of the transmission 6 does not stay in the transmission soundproof cover 15 and is immediately discharged to the outside air by the traveling wind.

Therefore, the heat transfer coefficient on the wall surface of the transmission 6 is improved by the increase in the wind speed of the traveling wind performed in the throttle portion 29a, and a high heat radiation amount, that is, the heat radiation amount of the transmission 6 can be improved, and the transmission by the traveling wind can be improved. The cooling performance of No. 6 can be improved. Moreover, the noise from the transmission 6 is generated by the cover body 1
5a has a soundproofing effect, that is, each sound absorbing layer 20-21
Since it is blocked by the sound absorption effect by the sound absorption by the sound insulation and the sound insulation by the sound insulation substrate 16, the cooling performance and the sound insulation can be compatible.

In addition, if the sound absorbing layers 20 and 22 provided on the inner surface of the sound insulating substrate 16 have a Venturi structure in the shape of a mountain,
With a simple structure, it is possible to increase the wind speed of the traveling wind flowing through the gap 31. In particular, with the mountain-shaped venturi structure in which the top portion 29a is arranged at the center of the transmission 6 in the front-rear direction, one venturi structure can most effectively increase the wind speed of the traveling wind.

6 to 8 show a second embodiment of the present invention.

The present embodiment shows an example in which the sound absorbing layers 20 and 22 are provided with a plurality of holes 40 having different lengths with openings arranged in the gap 31 (however, only one side is shown in the drawing).

The sound absorbing layers 20 and 22 have, for example, the structure shown in FIG.
Also, as shown in FIG. 7, a structure is used in which a plurality of horizontal members 42 made of glass wool (sound absorbing material) and a plurality of vertical members 43 also made of glass wool (sound absorbing material) are assembled in a lattice shape ( (Only one side shown). Specifically, the lateral member 42 is a laterally extending member having an arcuate front surface having a concave-convex portion 42a for incorporation formed on the front surface thereof, and the vertical member 43 is for incorporation on the back surface thereof. A member extending in the vertical direction on which the uneven portion 43a is formed is used. Sound absorbing layer 2
Nos. 0 and 22 are formed by incorporating the horizontal member 42 and the vertical member 43 in a lattice shape to form a mountain-shaped main body, and then covering the mountain-shaped surface with an aluminum sheet 44 (sheet material). . Then, the chevron-shaped sound absorbing layers 20 and 22 are formed on each side wall 1
As shown in FIG. 8, by attaching to the inner surface of 0a, a plurality of rectangular members having a different overall length and having openings facing the gap 31 are formed between the horizontal member 42 and the vertical member 43 which are assembled in a lattice shape. The hole 40 is formed. Needless to say, like the first embodiment, the Venturi structure is formed between the wall surface of the transmission 6 and the chevron surface facing the transmission 6.

Sound absorbing layer 2 having a plurality of such holes 40
When it is 0 or 22, the portion that absorbs the noise of the transmission 6 can be used not only on the arc surface facing the gap 31 but also on the inner surface of each hole 40. Therefore, the noise of the transmission 6 can be effectively increased by increasing the sound absorbing area. Can absorb sound. Moreover, the air columns of different lengths formed in the space of the holes 40 act as a resonance silencer (energy absorption by air column resonance of the tube) that attenuates the energy of the sound of different frequencies by resonance, and each of the noise. Since the sound pressure energy of the frequency is effectively reduced, it is possible to obtain a high soundproofing effect by combining the increase of the sound absorbing area. Moreover, since only the holes 40 are formed, the structure is simple. Especially, when the horizontal member 42 (sound absorbing material) and the vertical member 43 (sound absorbing material) are assembled in a lattice shape and the arc surface is covered with the aluminum sheet 43 (sheet material), the venturi structure and the resonance type sound deadening are achieved with a simple structure. Both can be formed.

FIG. 9 shows a third embodiment of the present invention.

In this embodiment, the sound absorbing layers 20 and 22 are not formed in a mountain shape as in the first embodiment, but the left and right side walls 10a of the sound insulating substrate 16 are curved to form the narrowed portion S.
The Venturi structure is formed.

That is, the left and right sidewalls 10 of the sound insulation board 16
In a, a top portion 49a is formed at the center in the front-rear direction, which approaches the intermediate wall surface of the transmission 6 in the front-rear direction,
On the both sides of the top portion 49a, by forming a slope 49b away from the wall surface of the transmission 6 in the forward and backward direction of the traveling wind of the transmission 6 from the top portion 49a, using a structure which is curved in a chevron shape,
Plate-like glass wool forming the sound absorbing layers 20 and 22 is attached to the inner surface of each of the side walls 10a to form a venturi structure forming the narrowed portion S.

Even with this structure, the same effect as that of the first embodiment can be obtained.

FIG. 10 shows a fourth embodiment of the present invention.

In this embodiment, the sound absorbing layers 20 and 22 are formed into a bell mouth shape instead of the venturi structure as in the first and second embodiments. The narrowed portion S is formed on the.

The bellhouse structure also has the same effect as that of the first embodiment. Of course, similarly to the third embodiment, the left and right sidewalls 10a of the sound insulating board 16 may be formed in a bell mouth shape to form the narrowed portion S between the transmission 6 and the transmission 6. In addition, the bell mouth shape approaches the wall surface of the transmission 6 after the flow direction,
Transmission 6 according to the direction of flow
A curved shape that gradually moves away from the wall surface.

However, in FIGS. 6 to 10, the same parts as those of the first embodiment are designated by the same reference numerals and the description thereof is omitted.

The present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in the embodiment, the throttle portion (Venturi structure or Bellmouth structure) is formed on the inner surface of the cover body that covers the left and right sides of the transmission, but the present invention is not limited to this, and the throttle portion is also formed on the inner surface that covers the lower surface of the transmission. Alternatively, the wind speed of the traveling wind flowing along the wall surface of the transmission may be increased. Of course, a cover body that covers the upper surface of the transmission may be used, and the throttle portion may be formed on the inner surface of the cover body that covers the upper surface of the transmission.

[0045]

As described above, according to the first aspect of the invention, the wind speed of the traveling wind flowing through the soundproof cover is increased by the throttle portion so that the running wind can pass through the soundproof cover without being blocked. Become.

Therefore, the heat of the transmission is quickly radiated to the outside air by the traveling wind without being disturbed by the soundproof cover, and the cooling performance of the transmission can be improved. Moreover, since the transmission noise is blocked by the cover body, both cooling performance and soundproofing of the transmission can be achieved.

According to the inventions of claims 2 and 4,
In addition to the above effects, the wind velocity of traveling wind can be increased with a simple Venturi structure.

According to the invention of claim 3, in addition to the above effects, a simple structure in which a plurality of holes are provided in the sound absorbing layer,
The soundproofing performance can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing a soundproof cover of a transmission according to a first embodiment of the present invention together with a vehicle equipped with the cover.

FIG. 2 is a perspective view showing a state in which a soundproof cover of the transmission is attached.

FIG. 3A is a perspective view showing an appearance of the soundproof cover.
(B) The perspective view which carried out the partial cross section of the soundproof cover.

FIG. 4 is a plan sectional view taken along the line AA in FIG.

FIG. 5A is a diagram for explaining the behavior of traveling wind flowing in the soundproof cover. (B) is a diagram showing a wind speed distribution of traveling wind near the top of the throttle at that time.

FIG. 6 is a perspective view showing a structure of a main part of a soundproof cover for a transmission according to a second embodiment of the present invention.

FIG. 7 is an exploded perspective view for explaining the structure of a sound absorbing layer with holes of the soundproof cover.

FIG. 8 is a diagram for explaining sound absorbing performance and sound pressure energy damping performance of the soundproof cover.

FIG. 9 is a perspective view showing a structure of a main part of a soundproof cover for a transmission according to a third embodiment of the present invention.

FIG. 10 is a perspective view showing a structure of a main part of a soundproof cover for a transmission according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 ... Side frame 5 ... Engine 6 ... Transmission 15. Soundproof cover for engine 15a ... Cover body 16 ... Sound insulation board 20, 22 ... Sound absorbing layer 29a ... top 29b ... Slope 31 ... Gap 40 ... hole S ... diaphragm part.

Claims (4)

[Claims] 1. A cover main body, which is arranged so as to cover the periphery of the transmission with a gap between the outer surface of the transmission and a flow of traveling air, and which covers the noise from the transmission, and protrudes from an inner surface of the cover main body. Narrow the gap,
A soundproof cover for a transmission, comprising: a throttle portion for increasing a wind speed of traveling wind flowing through the gap. 2. The cover main body is configured to have a sound insulation substrate arranged so as to cover the periphery of the transmission, and a sound absorption layer provided on an inner surface of the sound insulation substrate, and the throttle unit is The inner surface of the sound absorbing layer facing the transmission has a top that is closest to the middle of the transmission, and has a sloped shape that is further away from the transmission as the front and the rear move in the flow direction of traveling wind. The soundproof cover for a transmission according to claim 1, wherein the soundproof cover is provided. 3. The soundproof cover for a transmission according to claim 2, wherein the chevron-shaped sound-absorbing layer is formed with a plurality of holes having different lengths inside and an opening facing the gap. . 4. The cover main body is configured to have a sound insulating substrate arranged so as to cover the periphery of the transmission, and a sound absorbing layer provided on an inner surface of the sound insulating substrate. The sound insulating substrate has a top portion approaching in the middle of the transmission, and is curved in a mountain shape having a slope away from the transmission along the front and rear direction of the traveling wind from the top portion. The soundproof cover for a transmission according to claim 1.