JPH08158867A - Suction air intake structure of engine in hand working machinery - Google Patents

Abstract

PURPOSE: To constantly take in clean air by forming an air introducing passage on the outside of a crank chamber of a crankcase, opening an outside air inlet port of this air introducing passage on the inside of a cooling fan and communicating the air introducing passage to a carbureter chamber. CONSTITUTION: A chain saw 10 is equipped with a miniature air cooling two cycle gasoline engine in its main body 12 and arranged with a magnet rotor 20 furnished with a cooling fin 18 on one end part of a crankshaft 16 of the engine and a saw chain 24 through a clutch mechanism 22 on the other end part. In this case, a crankcase is formed of aluminium moulded materials 38a, 38b split in two in the longitudinal direction, and an air introducing passage 52 is provided by forming recessed grooves 50a and 50b on the outside of a crank chamber 48 formed by them. Thereafter, an outside air intake port 54 of this air introducing passage 52 is opened at a position corresponding to the inside of the cooling fin 18 of the aluminium moulded material 38a, and an outside air outlet 56 is opened at a position corresponding to a bottom part of carbureler chamber 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hand-held work machine driven by a small gasoline engine, and more particularly to an intake structure for an engine of such a hand-held work machine. is there.

[0002]

2. Description of the Related Art Generally, in hand-held work machines such as chainsaws, brush cutters, and blowers that use a small gasoline engine as a drive source, the engine that is the drive source is forcibly cooled. The cooling fan is used, and a structure is adopted in which air from which dust such as chips, chips, and sand dust generated by work is removed by using the centrifugal effect of the cooling fan is taken in as intake air of the engine.

Specifically, an intake structure in which an outside air intake port is newly provided in the fan housing to form an air guide path (see Japanese Patent Laid-Open No. 61-190111) has been proposed. With such a structure, since an air guide member is provided and an outside air intake port is inserted and arranged in the fan housing, not only new parts are required but also assembly is troublesome, and these parts hinder the flow of cooling air. It has been pointed out that various problems such as cooling efficiency of the engine and noise are to be solved.

[0004]

Therefore, according to the present invention,
Install a cooling fan at one end of the crankshaft of the engine in hand-held work machines such as chainsaws, brush cutters, and blowers, and at the other end, install a working means according to the work purpose via a clutch mechanism. An air duct is integrally formed outside the crank chamber of the case, an outside air introduction port of the air duct is opened inside the cooling fan, and the air duct is communicated with the carburetor chamber. By
This is because it is possible to rationally form an air guide path without using new parts, and to take in clean air as engine intake air without impeding the engine cooling effect.

In this case, as a concrete means for integrally forming the air guide passage outside the crank chamber of the crankcase,
It is preferable that the crankcase is formed of an aluminum molding material that is divided in two in the vertical direction, and a groove for forming an air guide path is provided on the outside of the crank chamber formed of these molding materials.

[0006]

[Operation] According to the present invention, clean air obtained by removing dust such as chips, chips, and sand dust generated by various works by the centrifugal effect of the cooling fan is introduced from the outside air inlet provided inside the cooling fan to the air guide passage. Is introduced into the vaporizer chamber via
It is used as engine intake air.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a detailed description will be given below by exemplifying an intake structure for an engine in a chain saw as a preferred embodiment of an intake structure for an engine in a hand-held work machine according to the present invention. The present invention is not limited to this embodiment, and it goes without saying that various design changes can be made without departing from the spirit of the present invention.

1 and 2, the chain saw 10 according to the present embodiment is equipped with a small air-cooled two-cycle gasoline engine 14 as a drive source in a main body 12,
A magnet rotor 20 having a cooling fin 18 is attached to one end of a crankshaft 16 of the engine 14, and a saw-tooth chain blade (saw chain) 24 is provided to the other end via a clutch mechanism 22. There is.

An air cleaner 32 is connected to an intake port 28 provided in the cylinder 26 of the engine 14 via a carburetor 30, while a muffler 36 is connected to the exhaust port 34. The carburetor 30 and the air cleaner 32 are arranged in a carburetor chamber 42 that is hermetically defined by a crankcase 38 and a removable cleaner cover 40. Rear handle 4 provided integrally at the rear
4 is operated by a throttle lever 46 attached to the vehicle.

On the other hand, in this embodiment, the crankcase 38 is made of aluminum molding material 38a, 38b which is vertically divided into two parts.
Are formed by the above-mentioned molding materials 38a, 38
The groove 5 is formed outside the crank chamber 48 formed by b.
By forming 0a and 50b respectively, the air guide path 52
Configure as. And the outside air intake 5 of this air guide 52
4 is opened at a position corresponding to the inside of the cooling fin 18 of the aluminum molding 38a, and the outside air outlet 56 is opened at a position corresponding to the bottom of the carburetor chamber 42 (see FIG. 3).

In FIG. 1, reference numeral 58 is a fan cover for covering the magnet rotor 20 having the cooling fins 18.

In the chainsaw constructed in this way,
The operator grips the rear handle 44 and a holding handle (not shown) with both hands, drives the engine 14 and cuts a tree or the like with the saw-tooth chain blade (saw chain) 24. The cylinder 26 is cooled by the outside air fed by the cooling fins 18 which rotate together with the magnet rotor 20. It should be noted that the outside air is cleaned by removing dust such as chips by the centrifugal effect of the rotating cooling fins 18 in the centrifugal direction.

A part of the outside air cleaned in this way is passed through the outside air intake 54, the air guide passage 52, and the outside air outlet 56 provided inside the cooling fin 18 by the suction force of the engine 14. It is sucked into the cylinder 26 from the intake port 28 through the air cleaner 32 in the carburetor chamber 42 and the carburetor 30, and is mixed with gasoline.

[0014]

As described above, according to the intake structure of the engine in the hand-held work machine according to the present invention, the air guide passage is integrally formed on the outer side of the crankcase of the crankcase, and The outside air inlet of the passage is opened inside the cooling fan, the air passage is connected to the carburetor chamber, and the dust generated by various works is removed by the centrifugal effect of the cooling fan, and clean air is taken into the engine. Therefore, maintenance work such as cleaning of the air cleaner and the filter of the carburetor can be simplified, and the durability can be improved.

Further, since no new parts are required, it is possible not only to avoid the inconvenience that the cooling air flow is obstructed and the cooling efficiency of the engine is lowered, but also the assembling is performed in the same process as the conventional one. Therefore, it has various advantages such as cost reduction.

[Brief description of drawings]

FIG. 1 is a preferred embodiment of an intake structure for an engine in a hand-held work machine according to the present invention, and is a partially omitted vertical cross-sectional view showing the relationship between the intake structure for an engine in a chainsaw and the whole structure. It is a figure.

FIG. 2 is an explanatory view of a part of the crankcase portion of the engine of the chainsaw shown in FIG. 1 taken along the line AA.

3 is a partially cutaway perspective view of the crankcase shown in FIG. 1. FIG.

[Explanation of symbols]

10 Chain saw, 12 Main body, 14
Engine, 16 crankshaft, 18 cooling fins, 20 magnet rotor, 22 clutch mechanism,
24 sawtooth chain blade (saw chain), 26 cylinder part, 28 intake port, 30 vaporizer, 3
2 Air cleaner, 34 Exhaust port, 36
Muffler, 38 crankcase, 40 cleaner cover, 42 carburetor chamber, 44 rear handle, 46
Throttle lever, 48 crankcase, 50
Groove, 52 air duct, 54 outside air intake,
56 outside air outlet, 58 fan cover,

Claims (1)

[Claims] 1. A hand-held working machine in which a cooling fan is attached to one end of a crankshaft of an engine and a working means is arranged at the other end via a clutch mechanism. An air intake of an engine in a hand-held work machine, characterized in that an air passage is formed, an outside air introduction port of this air passage is opened inside the cooling fan, and the air passage is communicated with a carburetor chamber. Inner structure.