JP2002070555A - Air cooling device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a proper oil film in a sliding, part and hold the lubricating performance of lubricating oil 11 by sufficiently cooling the bottom wall 5 of a crankcase 1 and lowering the temperature of the lubricating oil 11 accumulated in the bottom of the crankcase 1. SOLUTION: In this air cooling device for the engine, an air guide passage 6 is opened from the circumferential wall 2 to the bottom wall 5 of the crankcase 1, an inlet 6a of the air guide passage 6 is made to face to a fan cover 4 inside, and its outlet 6b is made to face to a lower space 7 of the bottom wall 5 of the crankcase 1 so that the cooling air generated in the fan cover 4 into is guided to the lower space 7 of the bottom wall 5 of the crankcase 1 via the air guide passage 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an engine, and more particularly, to a device capable of strongly cooling lubricating oil accumulated at the bottom of a crankcase.

[0002]

2. Description of the Related Art Conventionally, as a cooling device for an engine, there is a cooling device in which a cooling fan is provided at a position facing a peripheral wall of a crankcase and the cooling fan is covered with a fan cover. In this type of cooling device, since cooling air is not supplied to the bottom wall and the peripheral wall of the crankcase, the cooling of the crankcase is not sufficient, and the temperature of the lubricating oil accumulated at the bottom of the crankcase increases.

[0003]

The above prior art has the following problems. << 1 >> The lubricating oil has low lubrication performance. Since the temperature of the lubricating oil accumulated at the bottom of the crankcase increases, an appropriate oil film is not formed on the sliding portion, and the lubricating oil has poor lubricating performance.

<2> Lubricating oil tends to deteriorate. Since the temperature of the lubricating oil accumulated at the bottom of the crankcase is high, the lubricating oil is easily deteriorated.

An object of the present invention is to provide an air cooling device for an engine which can solve the above problems.

[0006]

Means for Solving the Problems (Invention of Claim 1) FIG.
As shown in FIG. 1A, a cooling fan (3) is provided at a position facing a peripheral wall (2) of a crankcase (1), and the cooling fan (3) is covered with a fan cover (4). An air guide passage (6) is formed from the peripheral wall (2) to the bottom wall (5) of the crankcase (1), and an inlet of the air guide passage (6) is provided.
(6a) facing the fan cover (4) and the exit (6b)
To the space (7) below the bottom wall (5) of the crankcase (1), and the cooling air generated in the fan cover (4)
After (6), the space below the bottom wall (5) of the crankcase (1)
(7) An air cooling device for an engine, which is guided to (7).

[0007] (Invention of claim 2) In the air cooling device for an engine according to claim 1, as shown in Fig. 1 (A), an air intake (8) is opened in the cooling fan (3), The inlet (8a) of (8) faces the fan cover (4), the outlet (8b) faces the peripheral wall (2) of the crankcase (1), and the cooling air in the fan cover (4) Is blown to the peripheral wall (2) of the crankcase (1) through an air intake (8).

(Invention of Claim 3) In the air cooling system for an engine according to Claim 2, as shown in FIGS.
The rotation direction of the cooling fan (3) is provided on the inner peripheral surface of the air intake (8).
(3a) An inclined surface (9) inclined to the cooling fan
By the rotation of (3), the cooling air in the fan cover (4) is
A cooling device for an engine, characterized in that a slope (9) sucks air from an air inlet (8).

[0009]

Operation and Effect of the Invention (Invention of claim 1) The invention of claim 1 has the following operation and effects. << 1 >> Lubricating oil can maintain high lubricating performance. As shown in FIG. 1A, the cooling air generated in the fan cover (4)
Since the air is guided to the space (7) below the bottom wall (5) of the crankcase (1) through the air guide passage (6), the bottom wall (5) of the crankcase (1) is sufficiently cooled. As a result, the temperature of the lubricating oil (11) accumulated at the bottom of the crankcase (1) decreases, so that an appropriate oil film is formed on the sliding portion, and the lubricating oil (11) can maintain a high lubricating performance.

<2> Thermal deterioration of the lubricating oil is suppressed. Since the temperature of the lubricating oil (11) accumulated at the bottom of the crankcase (1) decreases, thermal deterioration of the lubricating oil (11) is suppressed.

(Invention of claim 2) The invention of claim 2 has the following effect in addition to the effect of the invention of claim 1. << 3 >> The above effects <1> and <2> can be further enhanced. As shown in FIG. 1 (A), cooling air in the fan cover (4) passes through the air inlet (8), and flows through the peripheral wall of the crankcase (1).
The peripheral wall of the crankcase (1) to be sprayed on (2)
(2) is sufficiently cooled. Thereby, the above-mentioned effects <1> and <2> can be further enhanced.

(Invention of claim 3) The invention of claim 3 has the following effect in addition to the effect of the invention of claim 2. << 4 >> The cooling air can be blown to the peripheral wall of the crankcase with a simple structure. Fig. 1 (B) (C)
As shown in the figure, the cooling fan
By providing the slope (9) inclined with respect to the rotation direction (3a) of (3), it is possible to blow cooling air to the peripheral wall (2) of the crankcase (1). It can be implemented with a simple structure.

[0013]

Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are views for explaining an embodiment of the present invention. In this embodiment, a single cylinder inclined gasoline engine is used.

The structure of this engine is as follows.
As shown in FIG. 2, this engine has a cylinder block
(10) is provided. The cylinder block (10) is formed by extending a cylinder (10a) obliquely upward from the crankcase (1). As shown in FIG. 1A, an igniter (26) is attached to the front of the cylinder (10a). At the leading end of the cylinder (10a), a cylinder head
(12) is assembled. In the cylinder head (12),
An intake valve (13) and an exhaust valve (14) are assembled, and these are driven by a valve operating device (15). The valve gear (15) is covered with a head cover (16) shown in FIG.

As shown in FIG. 2, the cylinder head (12)
Is equipped with a carburetor (17). An air cleaner (18) is attached to the front of the carburetor (17). Above the cylinder block (10), a fuel tank (19) and an exhaust muffler (20) are arranged. A fan cover (4) is attached to the front of the cylinder block (10). The fan cover (4) is attached to the cylinder head (1).
It is derived up to the front of 2). A recoil case (21) is attached to the front of the fan cover (4). FIG.
As shown in (A), a recoil reel (22) is mounted in a recoil case (21), and a recoil rope (2) is attached thereto.
3) is wound.

The structure of the air cooling device for this engine is as follows. As shown in FIG. 1A, the crankcase (1)
In the peripheral wall (2), a cooling fan (3) also serving as a fly weight is provided at a position facing the front wall, and the cooling fan (3) is covered with a fan cover (4). The cooling fan (3) is fixed to the crankshaft (29). An outer air intake (24) is provided on the peripheral wall of the recoil case (21). The recoil case (21) communicates with the fan cover (4). The cooling fan (3) is a centrifugal fan, and the outside air introduced from the outside air intake (24) becomes cooling air and is supplied to the cylinder (10a) and the cylinder head (12).

The bottom wall (5) of the crankcase (1) has a recess.
(25), which forms a space (7) below the bottom wall (5). An air guide passage (6) is opened from the front wall to the bottom wall (5) of the peripheral wall (2) of the crankcase (1). The inlet (6a) of the air guide passage (6) faces the inside of the fan cover (4), and the outlet (6b) faces the space (7) below the bottom wall (5) of the crankcase (1). I have. Because of this, the fan cover
The cooling air generated in (4) is guided to the space below the bottom wall (5) of the crankcase (1) through the air guide passage (6). The cooling air flows along the bottom wall (5) of the crankcase (1) and cools the bottom wall (5).

The structure of the cooling fan (3) is as follows. As shown in FIG. 1A, the cooling fan (3) includes a flywheel portion (27) and a fan portion (28). The flywheel part (27) is a disk-shaped casting. The fan portion (28) is made of synthetic resin, has a plurality of blades on the surface of the disk, and is fixed to the surface of the flywheel portion (27). The cooling fan (3) has an air inlet (8). As shown in FIG. 1 (B), the air inlet (8) is arranged at a predetermined interval in the rotation direction (3a) of the cooling fan (3).
Are provided.

As shown in FIGS. 1 (B) and 1 (C), a slope (9) which is inclined with respect to the rotation direction (3a) of the cooling fan (3) is provided on the inner peripheral surface of the air intake (8). ing. The slope (9) is the air intake
The rotation direction of the cooling fan (3) on the inner peripheral surface of the opening (8)
(3a) formed on the upper surface. For this reason, by the rotation of the cooling fan (3), the cooling air in the fan cover (4) is sucked into the air inlet (8) through the slope (9). Then, the entrance (8a) of the air intake (8) faces the fan cover (4),
The outlet (8b) faces the front wall of the peripheral wall (2) of the crankcase (1). For this reason, the cooling air in the fan cover (4) passes through the air inlet (8), and flows through the crankcase (1)
Is sprayed on the front wall of the peripheral wall (2).

In the engine of this embodiment, the cooling air generated in the fan cover (4) passes through the air guide passage (6) and enters the space (7) below the bottom wall (5) of the crankcase (1). Be guided. The cooling air in the fan cover (4) is
Through (8), it is blown to the front wall of the peripheral wall (2) of the crankcase (1). Therefore, the bottom wall and the front wall of the crankcase (1) are sufficiently cooled. As a result, the temperature of the lubricating oil (11) accumulated at the bottom of the crankcase (1) decreases, so that an appropriate oil film is formed on the sliding portion, and the lubricating oil (11)
High lubrication performance can be maintained. Further, thermal deterioration of the lubricating oil (11) is suppressed. Further, malfunction due to heat of the igniter (26) is also suppressed.

[Brief description of the drawings]

FIG. 1 is a view for explaining an engine according to an embodiment of the present invention. FIG. 1 (A) is a sectional view taken along line AA of FIG. 2, and FIG. 1 (B) is a front view of a flywheel portion of a cooling fan and an igniter. Figure, Figure 1
FIG. 1C is a cross-sectional view taken along line CC of FIG.

FIG. 2 is an overall front view of the engine according to the embodiment of the present invention.

[Description of Signs] (1) Crank case, (2) Peripheral wall, (3) Cooling fan, (3a) Rotation direction, (4) Fan cover, (5) Bottom wall, (6) Guide Wind passage, (6a) ... entrance, (6b) ... exit,
(7) ... lower space, (8) ... air inlet, (8a) ... inlet, (8b)
... Exit, (9) ... Slope.

Claims (3)

[Claims] An air cooling device for an engine, wherein a cooling fan (3) is provided at a position facing a peripheral wall (2) of a crankcase (1), and the cooling fan (3) is covered with a fan cover (4). An air guide passage (6) is opened from the peripheral wall (2) to the bottom wall (5) of (1), and an inlet (6) of the air guide passage (6) is opened.
a) faces the inside of the fan cover (4), and the outlet (6b) faces the space (7) below the bottom wall (5) of the crankcase (1), and the cooling generated in the fan cover (4). The wind is the wind guide passage
After (6), the space below the bottom wall (5) of the crankcase (1)
(7) An air cooling device for an engine, which is guided to (7). 2. An air cooling device for an engine according to claim 1, wherein an air inlet (8) is provided in said cooling fan (3).
With the entrance (8a) of (8) facing the inside of the fan cover (4),
The outlet (8b) faces the peripheral wall (2) of the crankcase (1), and the cooling air in the fan cover (4) is supplied to the air inlet (8).
The air cooling device for an engine, characterized in that the air is blown onto the peripheral wall (2) of the crankcase (1) through the following. 3. The cooling device for an engine according to claim 2, wherein a rotation direction of a cooling fan (3) is provided on an inner peripheral surface of the air intake port (8).
(3a) An inclined surface (9) inclined to the cooling fan
By the rotation of (3), the cooling air in the fan cover (4) is
A cooling device for an engine, characterized in that a slope (9) sucks air from an air inlet (8).