JPH0721861Y2 - Auxiliary cooling structure for chainsaws - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] This effect relates to an auxiliary cooling structure such as a chain saw having a built-in small engine, and in particular, a part of cooling air generated by an engine cooling fan is used. The present invention relates to an auxiliary cooling structure such as a chain saw that also cools a fuel tank.

[Conventional technology]

In the felling of wood with a chain saw, the inside of the engine reached a high temperature of several hundred degrees due to the high-speed rotation of the engine, and the cylinder, crankcase, fuel tank, muffler, etc. all became hot.

Especially in the summer work, the temperature rise of the fuel system carburetor, fuel pipe, fuel tank and other parts and the fuel itself, and the occurrence of abnormalities due to gasification are not uncommon, and the output of the engine is reduced, seizure, deterioration of startability, etc. As a result, the work efficiency may be drastically reduced or the work may be disabled.

For this reason, a cooling fan is usually attached at a position near the crankcase of the engine, and when the engine is started, the cooling fan also rotates to generate cooling air, which is circulated to forcibly cool the engine.

In addition, the cylinder part, which has the highest temperature in the engine, is usually provided with cooling fins on the outer side to enhance the heat radiation effect.

[Problems to be solved by the present invention]

As mentioned above, in the volute chamber adjacent to the crankcase, a forced cooling fan is attached to one end of the crankshaft, and cooling fins are attached to the cylinder to improve the cooling effect. In order for the temperature in the engine to reach several hundred degrees,
Since the influence of the heat quantity due to this high temperature on the fuel system cannot be ignored, it is strongly desired to further cool the engine components other than the cylinder and the crankcase.

[Means for Solving the Problems]

This device uses a part of the cooling air generated by a cooling fan inside the volute chamber through a conduction hole that is formed at the same time when the crankcase is cast, on the side wall of the crankcase next to the volute chamber, and at the back of the crankcase and the fuel tank. To the upper and side parts of the, to circulate the cooling air to those parts where the cooling air was not circulated in the past,
It is intended to promote forced cooling of the engine. As for the shape and size of the through hole, various shapes can be selected in consideration of the flow of cooling air and various factors for maintaining the strength of the engine, but generally the shape is circular.

[Action]

A part of the cooling air flowing out of the volute chamber passes through the conduction hole in the side wall of the crankcase, traverses the back of the crankcase along the side wall, and is discharged out of the machine through the gap at the other end. In addition to the crank case back, the cooling air passes directly through the upper part and one side of the fuel tank, and the cooling air is exhausted from the gap formed in the back of the fuel tank.
As a result, the fuel tank absorbs heat and is cooled.

〔Example〕

Hereinafter, as an example of implementation of an auxiliary cooling structure for a chain saw or the like according to the present invention, an example applied to a chain saw will be described in detail with reference to the drawings.

FIG. 1 is a side view showing a state in which a starter case and a fan cover of a chain saw are removed in an example of an auxiliary cooling structure for a chain saw according to the present invention.

In the figure, reference numeral 1 is a rear body of a chain saw having a built-in engine. Fuel tanks 2 and 2 ′ which form a part of the engine are arranged at the bottom and the rear of the rear body 1.

Reference numeral 3 is a cylinder of the engine provided with cooling fins on the outside, and reference numerals 4 and 4 ′ are crankcases arranged below the cylinder 3. Further, 5 is a volute chamber adjacent to the crankcases 4, 4 ', and 6 is a handle provided along the longitudinal direction of the chain saw so that an operator can firmly grip the chain saw during work. is there. Reference numeral 7 is a through hole formed in the crankcase for sending a part of the cooling air to the crankcase 4 from the volute chamber 5 formed simultaneously during the casting of the crankcases 4 and 4 ', and 8 is rotated in the volute chamber 5. It is a forced cooling fan built in freely.

Therefore, the cooling air generated by the cooling fan 8 in the volute chamber 5 arranged so as to close the crankcase 4 directly cools the cylinder 3 above.

Then, a part of the cooling air is guided from the conduction hole 7 to the back of the crankcase 4 through the air passage, rapidly circulates from here to the other end, and is discharged from the handle mounting hole at the other end to the outside of the machine. To be done.

At this time, the cooling air passes through not only the back of the crankcase 4 but also the front and side surfaces of the fuel tank 2 and takes heat from its seat surface.

In general, it is possible to form the through hole 7 by machining, but this not only raises the processing cost but also causes a problem such as a decrease in strength. However, the through hole may be integrally formed in consideration of strength during casting. If there is no problem.

Further, the number of the through holes can be increased and the shape thereof can be selected if there is no problem in terms of the machined surface and the strength of the engine.

[Effect of device]

As described above, in the auxiliary cooling structure for a chain saw or the like according to the present invention, the cooling effect of the engine is further enhanced by disposing the through hole on the side wall of the crankcase, and the temperature rise of each part of the fuel system is controlled. The ups and downs of the machine were greatly reduced, and the work efficiency of the worker was improved and improved.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a starter case and a fan cover of a chain saw are removed in an example of an auxiliary cooling structure for a chain saw according to the present invention. 1 ... Rear base 2 ... Fuel tank 3 ... Cylinder 4 ... Crankcase 5 ... Volute chamber 6 ... Handle 7 ... Through hole 8 ... Forced cooling fan

Claims (1)

[Scope of utility model registration request] 1. An engine cooling device such as a chain saw for cooling an engine with a cooling fan in a volute chamber arranged on the side of a crankcase, wherein cooling air is blown on a side wall of the crankcase in a ventilation path from the volute chamber to a cylinder cooling fin. A ventilation hole for supplying a part of the air is provided, and the cooling air before reaching the cooling fins of the cylinder is blown from the ventilation hole to the air passage formed between the fuel tank, volute chamber and crankcase at the rear. An auxiliary cooling structure for a chain saw or the like, characterized in that the fuel tank is cooled by ventilating the top and side surfaces of the fuel tank.