JPH0351211Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an intake duct device for a cab-over type vehicle.

[Prior Art] In a cab-over type vehicle in which the engine is placed under the floor of the cab, as shown in FIG. 2, when servicing the engine, the cab 9 is tilted forward about the tilt axis 2 with respect to the vehicle frame 4. It's becoming like that. In this type of cab-over type vehicle, an intake duct 7 having an intake port 8 is supported on the rear wall of the cab 9, and the lower end of the intake duct 7 can be separated into an inlet pipe 5 of an air cleaner 3 supported on the vehicle frame 4 via a telescoping pipe 6. It is connected to the. As shown in FIG. 3, the outlet pipe 14 of the air cleaner 3 is connected to the collecting pipe 13 of the intake manifold 12 of the engine 10 via a connecting hose 14a.

The structure of the connection between the telescopic pipe 6 and the intake duct 7 is such that, as disclosed in, for example, Japanese Utility Model Application No. 57-95466, the upper end of the telescopic pipe 6 and the lower end of the intake duct 7 are connected by a magnet or the like. The structure is such that the parts are in close contact with each other. That is, as shown in FIG. 4, an end plate 17 is coupled to the lower end of the intake duct 7, and a resonator 15 having a large number of holes 16 arranged inside the intake duct 7 is supported on this end plate 17. .

On the other hand, a lower end 6b of a telescopic tube 6 made of bellows-shaped rubber or the like is fitted onto the inlet tube 5 of the air cleaner 3 and fixed by appropriate means. Also,
A communication pipe 18 having approximately the same inner diameter as the resonator 15 is fixedly supported inside the inlet pipe 5 with an annular connecting plate 19 having a U-shaped cross section. The upper end 6a of the telescopic tube 6 is closely attached to the end plate 17 by means such as a magnet.

[Problems to be solved by the invention] In general, in a vehicle in which the cab 9 is directly supported on the car frame 4, the positional relationship between the car frame 4 and the cab 9, that is, the lower end of the resonator 15 and the upper end of the connecting pipe 18 is The gap s between them can be designed in advance to be narrow, but in the case of a suspension cab in which the cab 9 is suspended vertically and swingably relative to the vehicle frame 4,
The gap s changes due to the vertical vibration of the vehicle body, and when this gap s widens, the intake pulsation noise of the engine is propagated to the outside through the expansion pipe 6, and the function of the resonator 15 to alleviate the intake pulsation noise is impaired. There is a problem in that it impairs quietness.

These problems can be solved to some extent by placing the resonator on the air cleaner outlet pipe or on the engine side, but this makes it difficult to find sufficient installation space, resulting in a lack of resonator capacity, and also reduces the maintainability of the engine. This not only damages the product, but also increases weight and cost.

Therefore, the purpose of this invention is to eliminate sound leakage from the expansion pipe that connects the intake duct and the air cleaner.
An object of the present invention is to provide an intake duct device that can maintain the function of an intake duct resonator.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention is such that the upper end and lower end of the telescopic pipe that separably connects the inlet pipe of the air cleaner and the intake duct supported by the cab. Each of the connecting tubes supports one end of the connecting tube, and one connecting tube is inserted into the inside of the other connecting tube.

[Function] Since the communication pipe 20 is connected to the upper end 6a of the telescopic pipe 6 via the flange 20a, even if the telescoping pipe 6 expands and contracts in response to the vertical vibration of the cab, the distance between the communication pipe 20 and the resonator 15 remains constant. does not change. and,
A connecting pipe 2 is connected between the intake duct 7 and the air cleaner 3.
The intake duct 7
The function of the resonator 15 to suppress intake pulsation noise is effectively exhibited.

[Example of the invention] The invention will be explained based on an example. As shown in FIG. 1, the lower end 6b of the telescopic tube 6 is inserted into the inlet tube 5 of the air cleaner 3 and fastened with a tightening band (not shown). The upper end 6a of the expandable tube 6 is provided with a sufficient wall thickness, and a flange 20a formed at the upper end of the communication tube 20 is connected thereto by baking or the like. This communication pipe 20 is extended to near the inlet of the air cleaner 3. A flange 2 formed at the upper end of the connecting pipe 21 at the lower end 6b of the expandable pipe 6
1a is coupled, and its lower end protrudes into the interior of the air cleaner 3. The lower end portion of the connecting tube 20 is covered by the connecting tube 21 with the radial gap being minimized.

The intake duct 7 is similar to the conventional example, and a resonator 15 having a large number of holes 16 is supported on an end plate 13 provided at its lower end. Then, the upper end 6a of the telescopic tube 6 is brought into close contact with the lower surface of the end plate 17.

As mentioned above, the present invention has the upper end 6a of the telescopic tube 6.
supports the upper end of the communication pipe 20, and this communication pipe 20
Since the lower end extends into the inlet pipe 5 of the air cleaner 3, the distance between the upper end of the connecting pipe 20 and the resonator 15 does not change even if the cab vibrates up and down. Since the lower end is inserted into the connecting pipe 21 with the radial gap as small as possible, the inlet pipe 5 and the intake duct 7 are always connected.
Since the space between the two is doubly covered by the communication pipe 20 and the telescopic pipe 6, it is possible to prevent intake pulsation noise from leaking.

In addition, in the above-mentioned embodiment, the communication pipe 21 is the telescopic pipe 6.
Although it is extended downward from the lower end, almost the same effect can be obtained by extending it upward.

[Effects of the invention] As described above, the present invention supports communication pipes at the upper end and the lower end of the telescopic tube 6, respectively, and causes one communication pipe 20 to protrude into the other communication pipe 21. As a result, the connection between the inlet pipe 5 of the air cleaner 3 and the intake duct 7 is covered twice by the communication pipe 20 and the telescopic pipe 6, thereby preventing leakage of intake pulsation noise propagating inside the intake duct. A resonator 15 provided inside the intake duct 7
This function can be effectively exhibited, and since connecting pipes are simply attached to both ends of the telescopic pipe 6, manufacturing is easy and an increase in cost can be minimized.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of the intake duct device according to the present invention, Fig. 2 is a side view showing how the conventional air intake duct device is installed on a vehicle, Fig. 3 is a configuration diagram showing the intake system of the engine, and Fig. 4 The figure is a side sectional view of a conventional intake duct device. 3: Air cleaner, 5: Inlet pipe, 6: Telescopic pipe,
7: Intake duct, 15: Resonator, 20,2
1: Connecting pipe.

Claims (1)

[Scope of utility model registration request] One end of the connecting pipe is supported at the upper and lower ends of the telescopic pipe that separably connects the air cleaner inlet pipe and the intake duct supported by the cab, and one connecting pipe is connected to the inside of the other connecting pipe. An intake duct device characterized by being inserted.