JPH042958Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention reduces the noise generated during the intake stroke of the engine in industrial vehicles such as forklift trucks, especially engine-driven industrial vehicles. This invention relates to improvements to an intake noise reduction mechanism to prevent it from acting as noise near the operator's ears.

[Conventional technology]

In general, in engine-driven forklift trucks, an air cleaner is connected to the intake stroke to supply clean air to the engine, and in addition, air cleaners are installed in connection with the intake stroke to provide clean air to the engine. Because it is necessary to prevent dust and grit from being sucked in, the intake port is usually provided at the upper end of the pillar that supports the head guard.

6 and 7 are drawings showing the specific structure thereof, in which a head guard b is erected on a machine stand a, and a hollow portion d is formed in a pillar c of the head guard b. An inlet e (intake) is opened in the vicinity of the upper end of the pillar c, communicating with the hollow part d, while an outlet f is opened in the vicinity of the lower end of the pillar c, communicating with the hollow part d. It is opened. Also, an air cleaner g is mounted on the machine base a, and the air cleaner g and outlet f are connected by an outlet pipe h, while the air cleaner g is connected to a hose j, an air cleaner connector k, and an intake. It is connected to engine i via manifold 1.

[Problem that the invention attempts to solve]

However, in addition to connecting the air cleaner to the intake stroke of the engine as described above, by opening the inlet near the top of the pillar, it is possible to prevent dust and grit from being sucked in. Although this provides a purifying effect on the intake air, various noises generated in the engine and the intake pipe (e.g. combustion noise, air column resonance, etc.) travel backwards through the intake stroke and are emitted from the inlet. This causes a problem in that the noise is radiated to the outside and acts as noise to the operator's ears.

This invention is an attempt to improve the above-mentioned problems in order to prevent the intake noise generated during the intake stroke of the engine from affecting the operator as a noise source. There are problems that need to be solved. That is, the present invention installs a honeycomb structure facing the inlet that opens near the top end of the pillar, cancels the intake noise through the honeycomb structure, and installs the air intake port downward. This device is characterized by solving the above-mentioned problems, and its specific means and effects are as follows.

[Means for solving problems]

The inlet is opened by communicating with the hollow part formed in the pillar or ceiling frame, and the main body part has an air supply opening facing downward, and the suction cylinder part has an air intake opening facing downward. A duct case is formed, and the main body of the duct case is inserted into the inlet so that the supply port communicates with the hollow part, and the honeycomb having a large number of through holes is formed in the main body, and the through holes are connected to the pillars. Alternatively, the honeycomb is fitted inside the top frame so as to extend in the longitudinal direction, and an inclined surface is formed at the upper end of the honeycomb so as to face the suction cylinder. That is, by forming the inclined surface, the length of the air column in each through hole can be changed, and the noise that has passed through each through hole can be refracted toward the inlet.

[Function] By allowing the noise to pass in a dispersed state through the holes opened in the honeycomb with different air column lengths, the effect of changing the frequency can be obtained.
The noise passing through each through hole is refracted toward the inlet, and the noises having different frequencies interfere with each other, thereby producing a mutually canceling effect, that is, an attenuating effect.

The noise attenuated as described above is radiated downward into the atmosphere from the intake port of the suction cylinder. That is, the noise can be dispersed away from the operator's ears.

〔Example〕

1 to 4 are drawings showing a first embodiment, in which A shows a truck main body and B shows a lift mechanism attached to the front part of the truck main body A. FIG. In the same truck body A, 1 is the front wheel, 2 is the rear wheel, and 3 is the front wheel.
is the machine base, 4 is the front protector, 5 is the driver's seat,
Reference numeral 6 indicates a head guard covering the driver's seat 5.
An air cleaner 11 is mounted on the machine base 3, and the air cleaner 11 is connected to the engine 15 via a hose 12, an air cleaner connector 13, and an intake manifold 14 (see FIG. 6). The head guard 6 also includes a pair of front and rear pillars 6F, 6R rising from the machine base 3, and a top frame 6T mounted between the upper ends of each pillar 6F, 6R.
A roof 9 is formed in the shape of a lattice frame on the top frame 6T. Among the pillars 6F and 6R, a pair of left and right pillars 6R arranged at the rear are formed into a rectangular tube shape with a hollow portion 6A, and one (left) pillar 6R has an outlet 8 near its lower end. is opened, and an outlet pipe 10 extending from an air cleaner 11 is connected to the outlet 8. Further, an inlet 7 is opened near the upper end of the pillar 6R, and a suction duct 16 is attached to the inlet 7.

In the suction duct 16, 17 is a hollow duct case, and the duct case 17 consists of a main body part 17A and a suction cylinder part 17B.
The main body portion 17A has approximately the same height and width as the inlet 7 so that it can be inserted into the inlet 7 as described later, and has approximately the same depth as the hollow portion 6A of the pillar 6R. It is formed into a rectangular shape, and an air supply port 18 is opened downward at the lower end thereof. Further, the suction cylinder portion 17B is connected to the main body portion 17A.
It is also shaped like a rectangle, with a slightly larger height and width. The suction cylinder portion 17B is provided at its upper end portion in communication with the main body portion 17A, and at its lower end portion an air intake port 19 is opened downward.

Further, a honeycomb 21 is fitted into the main body portion 17A through a plurality of through holes 20 having a hexagonal cross section and extending in the vertical direction. An inclined surface 22 is formed at the upper end of the honeycomb 21 with an appropriate inclination angle. More specifically, the inclined surface 22 is formed to face the suction cylinder section 17B, and by forming the slope surface 22, each through hole 20 is formed to face the suction cylinder section 17B.
The holes 20 are opened at an appropriate angle of inclination toward the side, and the air column length L of each through hole 20 is arranged so that it gradually becomes longer from the side of the suction cylinder 17B toward the back, as shown in FIG. It will be done. The duct case 17 formed in this manner is fixed to the pillar 6R via the bolt 23 with the main body 17A inserted into the inlet 7 opening in the pillar 6R, thereby opening the main body 17A. A state is obtained in which the supply port 18 communicates with the hollow portion 6A of the pillar 6R.

FIG. 5 is a drawing showing the second embodiment,
A sound absorbing material 24 is attached to the upper end of the suction cylinder portion 17B, and an inclined surface 25 is provided on the sound absorbing material 24 to face the inclined surface 22 formed at the upper end of the honeycomb 21.

Next, its effect will be explained.

In the first embodiment shown in FIGS. 1 to 4, the air sucked in from the inlet 7 that opens near the upper end of the pillar 6R passes through the hollow portion 6A and various parts of the outlet pipe 10, and then enters the air cleaner 11.
The air is fed into the air cleaner 11 and has the effect of purifying the air while passing through the air cleaner 11. The air that has been purified in this way is then transferred to the hose 1.
2. The air cleaner is fed into the engine 15 through the air cleaner connector 13 and intake manifold 14. On the other hand, various noises (intake sounds) occur during the intake stroke, such as engine combustion sounds and air column resonance sounds generated when air passes through the pipes. On the contrary, intake manifold 14, air cleaner connector 1
3. The air is propagated through the hose 12, air cleaner 11, and outlet pipe 10 into the hollow portion 6A. The noise propagated into the hollow part 6A in this way hits the honeycomb 21 fitted in the hollow part 6A, and is propagated in a dispersed state through the multiple through holes 20 formed in the honeycomb 21. However, since the through holes 20 are formed with different air column lengths L as shown in FIG.
This provides the effect of converting the frequency of noise propagated within. Since an inclined surface 22 is formed at the upper end of the honeycomb 21, the noise propagated inside each through hole 20 as described above is removed from the inlet 7.
However, as the noise passes through each through hole 20 and is refracted in the direction of the inlet 7, a state is obtained in which the noises interfere with each other. , This provides an effect of canceling out noises having different frequencies, that is, an attenuating effect. The noise that has been attenuated in this way is propagated along the suction cylinder portion 17B and is dissipated downward from the intake port 20 toward the atmosphere.

In addition, in the second embodiment shown in FIG. 5, a sound absorbing material 24 is attached to the upper end of the suction cylinder part 17B so as to face the inclined surface 22 formed at the upper end of the honeycomb 21. A state is obtained in which the noise that passes through the through hole 20 and is refracted toward the inlet 7 hits the sound absorbing material 24 and is reflected downward. By colliding with the sound absorbing material 24 and reflecting downward in this way, the effect of further attenuating the noise can be obtained.

In both of the above embodiments, the inlet 7 is opened at the upper end of the pillar 6R, but the opening position of the inlet 7 is not limited to this. It is also possible to provide a hollow portion and provide the inlet 7 in the dowel frame 6T. In addition, the upper end portion of the pillar 6R is curved to provide a horizontal portion, and the inlet 7 is provided in the horizontal portion.
It is also possible to open the

[Effects of the invention] The present invention is constructed as described above.
As mentioned above, a honeycomb in which the air column length of each hole is changed by the slope formed at the upper end is fitted into the hollow part of the pillar, and the frequency of noise passing through the hole of the honeycomb is reduced. The overall sound of the noise can be effectively attenuated by converting it according to the length of each air column and refracting and interfering with each noise as a whole after passing through each hole so that they cancel each other out. I was able to do it. In addition to achieving this kind of noise attenuation effect, the inlet has an air intake opening facing downward, so that the noise attenuated as described above is dissipated downward into the atmosphere. As a result, it has become possible to effectively eliminate the conventional problem of causing noise to the operator's ears. In particular, in the case of the present invention, by fitting a honeycomb forming a large number of through holes into the main body of the duct case that is inserted into the inlet, it is possible to easily provide a large number of through holes in the hollow part. It is possible to easily install it into the hollow part, and by opening the air intake port downward in the suction cylinder part, it is possible to prevent rainwater from entering, and it is also possible to install it into the hollow part. By fitting the honeycomb inside, the intake air can be rectified, which reduces airflow noise (wind noise).
At the same time, it has become possible to obtain various effects such as being able to reduce the sound.

In addition, as shown in the second embodiment, a sound absorbing material is installed opposite the slope formed at the upper end of the honeycomb, and the noise that is refracted and interfered after passing through the honeycomb is reflected by the sound absorbing material. , it has become possible to further enhance the noise attenuation effect.

[Brief explanation of the drawing]

1 to 4 are drawings showing a first embodiment, in which FIG. 1 is a side view showing the entire forklift truck equipped with an intake noise reduction mechanism according to the present invention, and FIG. 2 is an intake noise reduction mechanism. FIG. 3 is an exploded perspective view of the sound reduction mechanism, FIG. 3 is an enlarged sectional view thereof, and FIG. 4 is a sectional view taken along the line A--A in FIG. 3. FIG. 5 is a drawing showing the second embodiment, and is an enlarged sectional view of a portion of the intake noise reduction mechanism. Further, FIGS. 6 and 7 are drawings showing a conventional structure, in which FIG. 6 is a perspective view of a piping section forming the intake stroke of the engine, and FIG. 7 is a sectional view of the pillar section. A... Truck body, B... Lift mechanism, 1...
...Front wheel, 2...Rear wheel, 3...Machine base, 4...Front protector, 5...Driver's seat, 6...Head guard, 6A...Hollow part, 6F, 6R...Pillar, 6
T...Top frame, 7...Inlet, 8...Outlet, 9...Roof, 10...Outlet pipe, 11...Air cleaner, 12...Hose,
13... Air cleaner connector, 14... Intake manifold, 15... Engine, 16...
...Suction duct, 17...Duct case, 17A...
...Body part, 17B...Suction cylinder part, 18...Supply port, 19...Intake port, 20...Through hole, 21...
...honeycomb, 22...slanted surface, 23...bolt,
24...Sound absorbing material, 25...Slanted surface.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A hollow part is provided in the pillar of the head guard installed upright on the machine base, or in the pillar and the top frame, and the upper end of the pillar or the top frame communicates with the hollow part to intake air. While the inlet of the stroke is opened, a hollow-shaped duct case is formed by having a main body part with an air supply port opening downward and an intake cylinder part with an air intake opening downward, and the main body of the duct case A honeycomb is inserted into the inlet so that its supply port communicates with the hollow part, and a honeycomb having a plurality of through holes is formed in the main body part so that the through holes extend along the longitudinal direction of the pillar or ceiling frame. An intake noise reduction mechanism for an industrial vehicle such as a forklift truck, wherein the honeycomb is fitted inside the honeycomb and an inclined surface is formed at the upper end of the honeycomb so as to face the suction cylinder. (2) An industrial vehicle such as a forklift truck as set forth in claim 1 of the above-mentioned utility model registration claim, wherein a sound absorbing material is attached to the suction cylinder portion of the duct case so as to face the slope formed at the upper end portion of the honeycomb. Intake noise reduction mechanism.