JPH0410105Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an engine-powered industrial vehicle such as a forklift or a shovel loader, and specifically relates to a noise reduction device for an engine intake system.

(Prior Art) Generally, in this type of industrial vehicle, a system is used in which the head guard pillar 1 is used as an air intake pipe, as shown in Fig. 2, in order to make the air taken into the engine as clean as possible. Proposed. This uses one of the hollow head guard pillars 1 (usually the rear side) that supports the head guard as an air intake pipe, and the upper side of the head guard pillar 1 has an air intake surface as an air intake surface. By providing the opening 2 and connecting the lower part of the head guard pillar 1 to the air cleaner 4 through the air introduction pipe 3, air with less dust can be taken into the air cleaner 4 from the head guard pillar 1 through the air introduction pipe 3. Afterwards, it is supplied to the engine 5.

(Problem that the invention aims to solve) However, in the above-mentioned intake system, since the intake port of the head guard pillar opens near the driver's seat, the noise generated in the intake system is transmitted through the intake port. It is emitted and becomes a very annoying ear noise for drivers. One of the intake system noises is resonance noise generated due to intake air flowing into the engine side through the head guard pillar and the air introduction pipe.

In view of the above-mentioned problems, the technical problem of the present invention is to add a function of reducing resonance noise generated by intake air to the head guard pillar.

(Means for solving the problem) The technical means for solving the above problem is to connect a hollow head guard pillar that is installed upright on the vehicle body frame and has an intake port at the top and an air cleaner for the engine with air. An intake system noise reduction device for an engine-powered industrial vehicle of a type in which a head guard pillar is connected by an inlet pipe and used as an air intake pipe, and the head guard pillar is located on the bottom side of the connection part with the air inlet pipe. A perforated plate is provided to form an air chamber surrounded by the vehicle body frame, head guard pillar, and perforated plate, and the air chamber is divided into a number of small chambers that communicate with each other. .

(Operation) Therefore, the air sucked in from the intake port by the engine drive enters the head guard pillar in a downward direction, hits the perforated plate at the bottom, changes direction, and then enters the head guard pillar. It is introduced into the engine through a pipe. At this time, even if a resonance sound is generated due to the air flowing inside the head guard pillar, the resonance sound is attenuated by entering the air chamber through the many holes provided in the perforated plate. be done.

In addition, the air chamber is divided into a large number of small chambers that communicate with each other, and these small chambers function similarly to porous sound absorbing materials, and the sound that enters the small chambers cancels each other out, further enhancing the attenuation effect. That is, the resonance sound is effectively attenuated by the synergistic effect of the attenuation effect by the perforated plate and the attenuation effect between the small chambers.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. As shown in the figure, the head guard pillar 1, which is erected on the vehicle body frame 6 and is used as an air intake pipe, is formed into a hollow shape with a rectangular cross section and has an air intake port 2 on the upper side surface. At the same time, the lower side is connected to the engine 5 through an air introduction pipe 3 consisting of a pipe 3a and a hose 3b.
It is connected to an air cleaner 4 for use.

A perforated sound absorbing unit 7 for reducing resonance noise is provided at the bottom of the head guard pillar 1 for the air intake pipe. This perforated sound absorbing unit 7 includes a perforated plate 8 having a large number of small holes 8a.
and a lattice 9 fixed to the lower surface of the perforated plate 8. By being placed at the bottom of the head guard pillar 1, that is, on the upper surface of the vehicle body frame 6, top surface,
An air chamber 10 is formed surrounded by the inner surface of the head guard pillar 1 and the lower surface of the perforated plate 8. The air chamber 10 is a small chamber divided by a lattice 9, and these small chambers are communicated with each other by a notch (or small hole) 9a provided in the lattice 9. Note that the perforated sound absorbing unit 7 is fixed onto the vehicle body frame 6 by, for example, welding.

This embodiment is configured as described above,
Therefore, to drive the engine 5, the air sucked in from the intake port 2 flows downward inside the head guard pillar 1, hits the perforated plate 8 and has its flow direction changed, and then flows through the air introduction pipe 3. The air then flows into the air cleaner 4, where it is filtered by an emerent before being supplied to the engine 5. Such a flow of intake air generates a resonance sound inside the head guard pillar 1, but this resonance sound enters the air chamber 10 through the small hole 8a of the perforated plate 8 together with the flow of the intake air. is attenuated. In this case, in this embodiment, since the air chamber 10 is divided into small chambers by the lattice 9, these small chambers exhibit the same effect as a porous sound absorbing material, that is, a sound absorption function, and reduce the resonance sound. This acts to further enhance the damping effect.

Next, another embodiment of the present invention will be described based on FIG. In this embodiment, a perforated sound absorbing unit 7 (with or without a lattice) is detachable from the vehicle body frame 6. That is, the perforated plate 8 is formed on a rectangular box, fixed to the upper surface of a wider rectangular mounting plate 11, and the perforated plate 8 is attached to the vehicle body through the rectangular mounting hole 6a formed on the vehicle body frame 6 side. After fitting into the bottom of the head guard pillar 1 from the back side of the frame, the four corners of the mounting plate 11 can be fixed to the vehicle body frame 6 with bolts 12. When such a configuration is adopted, the perforated sound absorption unit 7
Since it can be removed as necessary, maintenance such as maintenance and inspection can be easily carried out.

(Effects of the invention) As detailed above, according to the invention, in an industrial vehicle that uses a head guard pillar as an air intake pipe, a perforated plate is provided at the bottom of the head guard pillar to create an air chamber. At the same time, by dividing the air chamber into a large number of small chambers, it is possible to effectively attenuate the resonance sound caused by the inflow of intake air, thereby reducing the resonance caused by the intake air, which is the cause of ear noise emitted from the intake port. It is possible to prevent noise and reduce ear noise that is extremely unpleasant for drivers.

Moreover, since the present invention is a resonance noise reduction method that uses head guard pillars, the structure can be simplified, and in particular, plate materials are combined at the bottom of the head guard pillars and fixed to each other by welding or the like. By configuring the noise reduction structure, the strength of the head guard pillar, particularly the support strength, can be improved.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing an embodiment of the present invention, Fig. 2 is a perspective view showing an engine intake system using a head guard pillar as an air intake pipe, and Fig. 3 is a perspective view of another embodiment of the present invention. FIG. 2 is a perspective view of the perforated sound absorbing unit in a separated state showing an embodiment. 1...Head guard pillar, 2...Intake port, 3
...Air introduction pipe, 4...Air cleaner, 5...
Engine, 7... Perforated sound absorption unit, 8... Perforated plate, 9... Grid, 10... Air chamber.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A head guard pillar constructed by connecting an air cleaner for an engine to a hollow head guard pillar which is installed upright on a vehicle body frame and has an air intake in the upper part through an air introduction pipe. This is an intake system noise reduction device for an engine-powered industrial vehicle of the type that uses the air intake pipe as an air intake pipe, and the head guard pillar is provided with a perforated plate on the bottom side of the connection part with the air intake pipe, and the vehicle body frame is An intake system noise reduction device for an engine-driven industrial vehicle, which forms an air chamber surrounded by a head guard pillar and a perforated plate, and divides the air chamber into a number of small chambers that communicate with each other. (2) The intake system noise reduction device for an engine-powered industrial vehicle according to claim 1, wherein the air chamber is divided into a number of small chambers that communicate with each other through a grid having notches or small holes. . (3) The engine-powered industrial vehicle according to claim 2, wherein the perforated plate and the grid in the air chamber are integrally connected to each other and are removably attached to the vehicle body frame. Intake system noise reduction device.