JPS6315583Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention particularly relates to an air intake device for an air-cooled engine such as a lawn mower or brush cutter.

Lawn mowers and brush cutters are used exclusively in environments where a large amount of dust is generated. However, in the past, the air supplied to the carburetor was taken directly into an external air cleaner installed outside the air guide cover that covered the cooling fan and cylinder, and dust was easily sucked into the air cleaner. Moreover, it had the disadvantage of increasing air intake noise. One example of this is the one described in Japanese Patent Application Laid-Open No. 55-32980.

This invention addresses the drawbacks of the conventional example described above.In an air-cooled engine that has a cooling fan that generates cooling air and an air guide cover that covers at least the cooling fan of the cylinder, the carburetor is located upstream of the air cleaner. A pre-chamber is provided in the air guiding cover to take in air to be supplied to the pre-chamber, and an air intake port for introducing air into the pre-chamber is provided on a partition wall along the flow of the cooling air in the pre-chamber, thereby making it difficult for dust to enter. The object of the present invention is to provide an air intake system for an air-cooled engine that can suppress intake noise to a low level.

An embodiment of this invention will be described below based on the drawings.

In Figure 1, 1 is a flywheel, 2 is a cooling fan, 3 is a fan case that covers the cooling fan,
4 is a cylinder cover that covers a cylinder (not shown);
Reference numeral 5 designates an air guide cover formed by the fan case 3 and the cylinder cover 4, which guides the cooling air from the cooling fan 2 in the flow direction F to cool the cylinder and cylinder head within the cylinder cover 4. Reference numeral 6 denotes a prechamber, which is disposed at the upper corner of the fan case 3 so as not to disturb the normal flow F of the cooling air, and is opened into the fan case 3 in the partition wall 6A along the flow F of the cooling air. An air intake port 7 is provided. Here, the partition wall 6A along the direction F of the cooling air flow refers to the wall at a position excluding the wall 6D at a position facing the outer periphery of the centrifugal blade 2a of the cooling fan 2 in the radial direction; Does not include 6D. C
is the flow of air taken into the prechamber 6 through the air intake port 7.

In FIG. 2, reference numeral 8 denotes an external air cleaner, which is communicated with the pre-chamber 6 through a communication pipe 9, and an element 10 is held at the vertical center position by a gripping piece 11. Air cleaner 8
is a polymer consisting of a front cover 8A and a rear cover 8B that can be freely divided, and the front cover 8A can be removed to facilitate cleaning and replacement of the element 10. D is the flow of air sent from the prechamber 6 to the upper chamber 8C of the air cleaner 8 through the communication pipe 9, and E is the flow of air supplied from the lower chamber 8D of the air cleaner 8 to the carburetor (not shown) through the intake pipe 12. supply air flow. Note that 18 is a muffler, and 14 is a starting rope knob. In this embodiment, an air-cooled engine for a working machine such as a lawn mower or a brush cutter is shown.

In the above configuration, when the engine is operated,
The cooling fan 2 shown in FIG. 1 allows cooling air to flow toward the cylinder in the direction F with a relatively high velocity. Therefore, the dust mixed in the cooling air is blown in the F direction along with the cooling air. On the other hand, an air intake 7 is provided in the partition wall 6A along the F direction.
Therefore, a portion of the cooling air is taken into the pre-chamber 6 from the air intake port 7 due to the static pressure difference. Therefore, with the dust separated just before the air intake 7, relatively clean air flows from the air intake 7 into the prechamber 6.
be taken in the direction.

Since the air taken into the pre-chamber 6 is decelerated within the pre-chamber 6, dust that is heavier than air falls into the lower chamber 6B of the pre-chamber 6 and is separated. Only clean air from which dust has been removed is sent from the upper chamber 6C to the external air cleaner 8 in the direction D through the communication pipe 9.

The air sent into the air cleaner 8 is further filtered by the element 10 from the upper chamber 8C in FIG. 2, purified and sent to the lower chamber 8D,
Air is supplied from this lower chamber 8D to the carburetor in the direction F through the intake pipe 12.

Impurities such as dust are caused by the fan case 3 and pre-chamber 6 in addition to the element 10.
The dust is difficult to enter the air cleaner 8, and the air cleaner 8
clogging is prevented. In addition, the intake air is effectively throttled twice by the air intake port 7 and the communication pipe 9, and the intake noise is muffled. 3 also effectively muffles the sound.

Note that even if an air intake port is provided in the wall 6D facing the direction of flow F, dust enters the pre-chamber 6 along with the air due to dynamic pressure, so the effect of purifying the air at the air intake port 7 cannot be obtained.

FIG. 3 shows a second embodiment of this invention. In the same figure, reference numeral 15 is a discharge hole for discharging dust provided in the pre-chamber 6, which is opened at the lower end of the partition wall 6A, and is used to collect dust that falls into the lower chamber 6B. The dust that
The cooling air is sucked back into the fan case 3 by the flow F to keep the inside of the pre-chamber 6 clean. The discharge hole 15 is a long hole (FIG. 4) to facilitate the discharge of dust.

FIG. 5 shows a third embodiment, in which the pre-chamber 6 has a sixth embodiment that guides the cooling air F to the cylinder 16.
It is integrally molded in the upper corner of the cylinder cover 4 on the air cleaner side shown in the figure, and dust is separated in the pre-chamber 6 as well, and intake noise can be muffled by the cylinder cover 4.

FIG. 7 shows the fourth embodiment, and in the same figure, 6E is a partition wall, which is provided by screws or spot welding (not shown) to cover the opening 7a of the partition wall 6A, and as shown in FIG. A portion along the wind flow direction F is opened to form an air intake port 7. This partition wall 6E opens the opening 7a into the cylinder cover 4 through the air intake port 7, and effectively blocks dust and grass clippings, making it difficult for them to be sucked into the pre-chamber 6 and improving the dust separation effect. It's increasing.

FIG. 9 shows a fifth embodiment, in which an air cleaner 8 is provided inside the fan case 3 and is partitioned by a prechamber 6 and a partition plate 18.
External air cleaner can be omitted. The air cleaner 8 and pre-chamber 6 communicate with each other through a communication hole 19 provided in the partition plate 18, and the element 1
The purified air is supplied to the carburetor 20 through the intake pipe 12 in the E direction.

As described above, according to this invention, the pre-chamber is provided inside the air guide cover, and in particular, the air intake is provided in the partition wall along the flow of cooling air in the pre-chamber, so that it is difficult for dust to enter and the air intake noise is reduced. An intake system for an air-cooled engine that can suppress the noise to a small level can be obtained.

[Brief explanation of the drawing]

Figures 1 to 9 show one embodiment of this invention. Figures 1, 3, 5, and 7 are front views with main parts cut away, and Figure 2 is a front view of the main parts. Fig. 4 is a side view of Fig. 3, Fig. 6 is a plan view of Fig. 5, Fig. 8 is a plan view of Fig. 7, Fig. 9 is a plan view with main parts crossed. It is. 2...Cooling fan, 2a...Centrifugal spring, 3...
Fan case, 5... Air guide cover, 6... Pre-chamber, 6A, 6E... Bulkhead, 7... Air intake, 8... Air cleaner, F... Cooling air flow.

Claims (1)

[Scope of utility model registration request] In an air-cooled engine that has a cooling fan that generates cooling air and an air guide cover that covers at least the cooling fan of the cylinder, a prechamber that is located upstream of the air cleaner and takes in air to be supplied to the carburetor is located within the air guide cover. an air intake for introducing air into the prechamber at a partition wall disposed at a position other than a position radially facing the outer periphery of the centrifugal blade of the cooling fan and along the flow of the cooling air in the prechamber; An air-cooled engine intake device characterized by being provided with a mouth.