JPH0346177Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is based on a fan case that is provided on one side of the crankcase, and cooling air is drawn in through the cooling air intake hole formed in the fan case. This invention relates to an engine cooling air intake device.

(Prior art) For example, in a two-stroke engine used in a brush cutter, an integrated fan case is provided on one side of the crankcase, and cooling air intake holes are provided on the outer periphery of the fan case near the crankcase. The structure is such that cooling air from outside the engine is sucked through the cooling air intake hole.

Conventionally, the structure for sucking in cooling air was simply a through-hole, but with the above-mentioned through-hole type, the intake air becomes turbulent, resulting in low fan efficiency. , there is a risk that foreign substances such as dust may easily enter from the outside. For this reason, instead of simply opening the cooling air intake hole, some solutions have been developed by installing a separate dustproof plate or guard device to cover the cooling air intake hole (for example, (Refer to Utility Model Application Publication No. 163631/1983).

However, even if a dustproof plate or a guard device is installed in this way, while the intake air itself is not rectified, the intake resistance increases, which may further reduce fan efficiency.

In addition, in the cooling system for a small air-cooled internal combustion engine shown in Utility Model Application Publication No. 56-101498, there is a rotor blade in which a large number of blades are installed facing forward on the outer circumference of the flywheel of the internal combustion engine, and this rotor blade. A structure is disclosed in which a stator vane is fixed to a casing, in which a large number of vanes are implanted on the outer periphery of the stator vane, facing the cooperating vane.

Although the above configuration improves fan efficiency,
Issues remained in terms of dustproof function and strong member function to prevent foreign matter such as dirt from entering the fan.

(Purpose of the invention) This invention was made in view of the above problems, and its main purpose is to improve fan efficiency.

(Structure of the device) In order to achieve the above object, this device integrates stator blades that are located in the cooling air intake hole and guides the cooling air into the fan case, thereby allowing the cooling air to flow through the fan case. The flow is rectified and guided to the cooling fan.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

FIG. 1 relates to a two-stroke engine used in a brush cutter, and in this case, the illustrated numeral 1 is a cylinder, which has a piston 2 and a spark plug 3. As shown in FIG.

4 is the crank case, this crank case 4
is formed by a pair of first and second casings 4A and 4B having mating surfaces 5.

Here, 6A and 6B are side walls, and each of these side walls 6A and 6B has bearing portions 7A and 7 at the center thereof.
B is formed.

Reference numeral 8 denotes a bearing, which is provided in bearing parts 7A and 7B that protrude outward from each side wall 6A and 6B, and allows a crankshaft 10 connected to each other by a crank pin 9 to be freely rotated by these bearing parts 8 and 8. support.

On the other hand, one end of the crankshaft 10 is
A cooling fan 12 is attached to one end of the crankshaft 10, and a drive-side clutch 13 is attached to the outside of the cooling fan 12. is installed.

The cooling fan 12 has a magnetic pole portion 15 facing the coil 14 supported by the cylinder 1, and a driven gear 16 for starting the engine.

Such a cooling fan 12 is surrounded by the fan case 11 and a fan cover 17 attached to the outer end of the fan case 11, and here, the crank case 4 (first casing 4A) of the fan case 11 At the base of the side, there is a second
As shown in the figure, cooling air intake holes 18 are formed at three locations around the crankshaft 10.
The cooling air intake holes 18 have elongated holes shaped like arcs, and here, in particular, each cooling air intake hole 18 has a plurality of stationary blades 19 that guide cooling air into the fan case 11. are arranged together,
A cooling air passage is formed by the gap between each stationary blade 19.

In addition, 20 is a recoil starter, and this recoil starter 20 is driven by the driven gear 1 in FIG.
It has a drive gear therein that meshes with the drive gear 6, and here it is of the Bendex type in which the drive gear and the driven gear 16 mesh orthogonally. In this case, the recoil starter 20 shown in FIG. 2 is attached using the fan cover 17 shown in FIG. If it is an outer circumferential position, the cooling air intake hole 18 is arranged so as not to correspond to that specific outer circumferential position. Of course, if the recoil starter 20 shown in FIG. 2 is placed outside the bearing part 7B shown in FIG. be able to.

In the above configuration, the stator blade 1 is provided in the cooling air intake hole 18.
9 are arranged, the cooling air taken in by the stator vanes 19 is rectified, thereby improving the fan efficiency of the cooling fan 12 shown in FIG. 1, and the intake noise is also reduced due to the rectification.

Furthermore, since the stator vanes 19 are integrally formed within the cooling air intake hole 18, the stator vanes 19 become a strength member, thereby suppressing the vibration of the fan case 11, and the stator vanes 19 become a strength member. As a result, each of the cooling air intake holes 18 provided at the joint between the first casing 4A of the crankcase 4 and the fan case 11 can be made sufficiently large, thereby further improving the fan efficiency. I can do it.

Further, the stator vanes 19 also serve as dustproof means for preventing inhalation of large dust that would clog the cylinder fins. That is, the distance between the stationary vanes 19 may be narrow enough to prevent the inhalation of large dust that would clog the cylinder fins, and does not need to be narrow enough to prevent the inhalation of fine dust. This is because, in general, foreign objects such as large particles that clog the cylinder fins of the cooling passages are sucked into the cooling passages and cause problems such as reduced cooling efficiency. This is because since it is discharged outside, it does not adversely affect the cooling effect. In this case, if the pitch between the stationary blades 19 is made sufficiently small, even small foreign objects can be prevented from entering.

In addition, since the stator blades 19 integrated with the fan case 11 are cooled by the intake air, the fan case 11
The crankcase 4 connected to the crankcase 1 is also effectively cooled, thereby effectively suppressing the temperature rise of the crankcase 4.

Furthermore, since the stator blades 19 are integrated, costs can be reduced compared to the case where the stator blades 19 are provided separately.

(Effects of the invention) As explained above, according to this invention, the stationary blades that are located in the cooling air intake holes and guide the cooling air into the fan case are integrally formed in the fan case. Air is rectified and fan efficiency can be increased.

Not only that, the air flow can be rectified to reduce intake air noise, and since the stator blades are integrally formed with the fan case, the stator blades become a strength member and suppress vibrations of the fan case. At the same time, each of the cooling air suction holes can be made sufficiently large, and the fan efficiency can be further improved.

Furthermore, since the stator vanes also serve as dustproof means, intrusion of foreign matter such as dust is prevented. In addition, since the stator vanes that are integrated with the fan case are cooled by the intake air, the crankcase that is connected to the fan case is also effectively cooled, thereby effectively suppressing the temperature rise in the crankcase. I can do it.

Furthermore, since the stationary blades are integrated with the fan case, costs can be reduced.

[Brief explanation of the drawing]

Figure 1 shows an embodiment of this invention.
Cross-sectional view of the cycle engine, Figure 2 is Figure 1-
FIG. 1...Cylinder, 4...Crankcase, 10
...Crankshaft, 11...Fan case,
12...Cooling fan, 18...Cooling air intake hole,
19... Shizuka.

Claims (1)

[Scope of utility model registration request] A crankshaft is made to protrude from one side of the crankcase, a cooling fan is attached to the protruding outer periphery of the crankshaft, and a fan case surrounding the cooling fan is provided to one side of the crankcase. In a cooling air intake device for an engine that has a cooling air intake hole on the outer periphery of the crankcase side, a stator vane that is located inside the cooling air intake hole and guides cooling air into the fan case is integrated into the fan case. A cooling air intake device for an engine, characterized in that: