JP3815931B2 - engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine, and more particularly to an engine having cooling fins protruding from a cylinder block in a direction perpendicular to the axis of a cylinder.
[0002]
[Prior art]
Conventionally, in order to reduce the overall height of the engine and reduce the size, an inclined engine in which a cylinder is inclined is employed. FIG. 3 is a schematic diagram showing a conventional example. Reference numeral 1 denotes a general-purpose engine used for a portable small generator or the like, and includes an engine body 2, a fuel tank 3, an air cleaner 4, and the like.
[0003]
The engine body 2 includes a cylinder block 7 in which a crankcase 5 and a cylinder 6 are integrally formed, and a cylinder head 8 provided at an upper portion in the axial direction of the cylinder 6.
[0004]
The crankcase 5 of the cylinder block 7 is provided with a base 5a for fixing to a frame (not shown), and a cylinder 6 is formed to be inclined obliquely upward to the right at the upper right portion of the crankcase 5 in the drawing. ing.
[0005]
The cylinder 6 has a substantially cylindrical shape, and cooling fins 11 project from the side wall portion 6a. The cooling fins 11 are for maintaining the temperature of the engine body 2 in an appropriate state by heat radiation cooling, and project so as to extend from the side wall portion 6a of the cylinder 6 in a direction orthogonal to the axis 6b of the cylinder 6. A plurality of them are provided at predetermined intervals in the axial direction and continuously in the circumferential direction and spaced apart from each other by a predetermined distance.
[0006]
On the other hand, the fuel tank 3 is disposed above the cylinder block 7, and the air cleaner 4 is disposed above the cylinder head 8. The fuel tank 3 is fixed to a frame (not shown), and a fuel filler port 3a is provided on the upper portion thereof.
[0007]
Further, the lower surface 3b faces the upper portion of the cylinder block 7 with a predetermined distance therebetween, and a portion of the lower surface 3b of the fuel tank 3 facing the cylinder 6 extends substantially parallel to the cylinder 6. Thus, the tank inclined bottom surface 3c is formed.
[0008]
In this way, the cylinder 6 is inclined and the fuel tank 3 and the air cleaner 4 are placed close to the engine body 2 and arranged at a low position, thereby reducing the overall height of the engine 1 and reducing the size.
[0009]
[Problems to be solved by the invention]
However, in order to maintain the temperature of the engine main body 2 in an appropriate state by heat radiation from the cooling fins 11, it is necessary to make the cooling fins 11 protrude by a predetermined length or more to ensure a predetermined heat radiation area.
[0010]
Therefore, when the surrounding space of the engine body 2 is limited, for example, when the fuel tank 3 or the like is brought close to the engine body 2 in order to reduce the size of the engine 1, the portion facing the tank inclined bottom surface 3c It may be difficult to ensure a sufficient length of the cooling fins 11 and the cooling efficiency of the engine body 2 may be reduced.
[0011]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an engine capable of ensuring an appropriate heat radiation area of cooling fins in a limited space.
[0012]
[Means for Solving the Problems]
In order to solve the above problem, an engine according to the first aspect of the present invention is an engine having cooling fins that project from a cylinder block side wall of the engine in a direction perpendicular to the axis of the cylinder. A part of the cooling fin is bent to the cylinder head side so that the side away from the cylinder block side wall portion is located on the cylinder head side rather than the cylinder block side wall portion side .
[0013]
Thereby, the protrusion length of a cooling fin can be extended without changing the protrusion width from a cylinder, and the heat radiation area can be expanded. Therefore, when the space around the cylinder is limited, the cooling fins at that part are bent and extended to ensure an appropriate heat radiation area and cool the engine body to an appropriate temperature state. can do.
[0014]
According to a second aspect of the invention, the engine according to claim 1, characterized in that is bent a part of the cooling fins on the cylinder head side in a tangential portion in contact with the cylinder block side wall. According to this, the length of the cooling fin of the part which protrudes from the outer wall surface of a cylinder can be ensured longer. Therefore, the heat dissipation area can be further expanded.
[0015]
According to a third aspect of the present invention , in the engine according to the first or second aspect, a part of the cooling fin is bent so as to gradually move toward the cylinder head side as the distance from the side wall of the cylinder block increases. Features. And, according to claim 4 invention is the engine according to any one of claims 1 to 3, the axial direction of the cylinder is arranged a cylinder so as to be inclined in the installed state, the cylinder block side wall portion characterized in that a part of the cooling fins located above the upper surface was bent.
[0016]
According to the fourth aspect of the present invention , when the cylinder block is manufactured using the mold, the mold forming the cylinder upper portion can be pulled upward. Therefore, conventionally, when casting an engine with a tilted cylinder, there are two molds, ie, a mold that forms the upper part of the cylinder and a mold that forms the upper part of the crankcase, and cooling fins protrude from the mold that forms the upper part of the cylinder. The mold that forms the upper part of the crankcase and the mold that forms the upper part of the cylinder and the mold that forms the upper part of the crankcase must be removed upward. These can be combined into a single template. Therefore, it is possible to shorten the casting time due to the ease of removing the mold and reduce the cost by reducing the number of molds.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an engine in the embodiment. Note that the same components as those in the above-described conventional example are denoted by the same reference numerals, and detailed description thereof is omitted.
[0018]
The cooling fin 11 is bent at a tangential portion 12 extending in the horizontal direction in contact with the upper portion 6c of the side wall portion 6a, and a portion below the tangential portion 12 extends in a direction perpendicular to the axis 6b as in the conventional case. It is continuous along the outer periphery of the cylinder 6 and is provided at a predetermined distance apart from each other by a predetermined distance in the axial direction.
[0019]
The upper protruding portion 13 positioned above the tangential portion 12 is bent toward the cylinder head 8 at the tangential portion 12 and is formed so as to extend in a substantially vertical direction.
[0020]
FIG. 2 is an enlarged view of a portion X in FIG. The solid line in the figure shows the upwardly protruding portion 13 of the cooling fin in the present embodiment, and the dotted line in the figure shows the shape of the conventional cooling fin 11.
[0021]
The upward projecting portion 13 in the present embodiment has a projecting width substantially equal to that of the conventional art and has a length h longer than the conventional projecting length h ′ (h ′ <h). Therefore, even in the space where the periphery of the cylinder 6 is limited by the fuel tank 3 or the like, the protruding length of the cooling fin can be made longer, and the heat radiation area of the cooling fin can be sufficiently secured.
[0022]
Further, since the upper projecting portions 13 are formed so as to extend in the vertical direction, the mold that forms the upper portion of the cylinder 6 can be pulled upward when the cylinder block 7 is cast.
[0023]
Therefore, conventionally, when casting the engine body 2 in which the cylinder 6 is inclined, two molds, that is, a mold that forms the upper part of the cylinder 6 and a mold that forms the upper part of the crankcase 5, are required, and the upper part of the cylinder is further formed. The mold for forming the upper portion of the crankcase 5 and the mold for forming the upper portion of the cylinder 6 and the upper portion of the crankcase 5 are formed. Both the mold release directions can be extracted upward.
[0024]
In addition, these two molds can be combined into one mold to facilitate die cutting. For this reason, it is possible to shorten the casting time due to the ease of removing the mold and to reduce the cost by reducing the number of molds.
[0025]
In addition, this invention is not limited to the above-mentioned embodiment, A various change is possible within the summary of this invention. For example, in the above-described embodiment, the example in which the portion located above the inclined cylinder of the cooling fin is bent is shown. However, when the space below the cylinder 6 is limited, it corresponds to that portion. The cooling fin 11 may be bent.
[0026]
【The invention's effect】
As described above, according to the engine according to the present invention, in the engine having the cooling fins protruding from the cylinder block side wall portion of the engine in the direction orthogonal to the axis of the cylinder, a part of the cooling fins is provided. since side away from the cylinder block side wall portion of the cylinder block side wall portion side was bent on the cylinder head side so as to be positioned on the cylinder head side, and extending the length of the cooling fins, to expand the heat radiation area Can do. Therefore, an appropriate heat radiation area of the cooling fin can be ensured even in a space where the periphery of the cylinder is limited.
[Brief description of the drawings]
FIG. 1 is a schematic view of an engine in an embodiment.
2 is an enlarged view of a portion X in FIG.
FIG. 3 is a schematic view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 2 Engine main body 3 Fuel tank 3c Tank inclined bottom face 6 Cylinder 6a Side wall part 7 Cylinder block 8 Cylinder head 11 Cooling fin 13 Upper protrusion part

Claims (4)

In an engine having cooling fins protruding from a cylinder block side wall of the engine in a direction perpendicular to the axis of the cylinder,
An engine, wherein a part of the cooling fin is bent toward the cylinder head such that a side farther from the cylinder block side wall than the cylinder block side wall is positioned on the cylinder head side . Engine according to claim 1, characterized in that said part of the cooling fins is bent to the cylinder head side in a tangential portion in contact with the cylinder block side wall. 3. The engine according to claim 1, wherein a part of the cooling fin is bent so as to gradually move toward the cylinder head as it is separated from the cylinder block side wall. The cylinder is arranged so that the axial direction of the cylinder is inclined in the installed state,
Engine according to any one of claims 1 to 3, characterized in that a portion of the cooling fins located above the upper surface of the cylinder block side wall portion was bent.

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