JP3205708B2 - Air-cooled engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine body provided with a cooling fan at one end of a crankshaft supported by the engine body to guide cooling air generated by the cooling fan to a cylinder block of the engine body. The present invention relates to an air-cooled engine provided with a shroud covering one side.

[0002]

2. Description of the Related Art Such an air-cooled engine is, for example,
It is already known, as disclosed in JP-A-7-30407.

[0003]

Generally, in an air-cooled engine, a surplus portion exists on the open surface of the shroud toward the engine body due to the difference in the shape of the facing surface between the engine body and the shroud. The part causes unnecessary leakage of cooling air, which is not preferable for cooling the engine.

In mounting a control lever for operating a throttle valve of a carburetor mounted on the engine main body, a bracket plate used exclusively for supporting the lever of the carburetor is fixed to the engine main body, and this is used to support the control lever. The largest share of the cost of the structure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents a cooling air from leaking from a surplus opening portion of an opening surface of a shroud toward an engine body, and a means for preventing the cooling air from supporting a control lever. An object of the present invention is to provide the air-cooled engine which has good cooling performance and can reduce the cost of the control lever support structure by utilizing the means as a means.

[0006]

In order to achieve the above object, the present invention provides a crankshaft supported on an engine body.
The carburetor and exhaust muffler attached to the engine body.
To extend at right angles to the arrangement direction of the
And attaching a cooling fan at one end of the shaft, a shroud the occurrence cooling air cover one side surface of the engine body so as to induce the cylinder block of the engine body by the cooling fan,
In the air-cooled engine fixed to the engine body, the open surface of the shroud that opens toward the engine body is vaporized.
It has a surplus opening that opens on the gasifier side,
Open to excess opening portion to close the air guide plate secured to the engine body, the axis of the bracket extends outwardly of the shroud to the air guide plate is formed integrally, a control lever for operating the throttle valve of the vaporizer to the bracket It is characterized by being supported. Thus, the air guide plate prevents the cooling air from leaking from the surplus opening of the shroud and functions as a bracket plate for supporting the control lever.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.

FIG. 1 is a partially cutaway side view of an air-cooled engine according to the present invention, FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1, FIG. It is a perspective view.

As shown in FIGS. 1 to 3, a carburetor 2 and a fuel tank 3 are mounted on the front of the engine body 1 of the air-cooled engine E, and an exhaust muffler 4 is mounted on the rear.

The engine body 1 comprises a head-integrated cylinder block 6 having a number of cooling fins 5 on its outer periphery, and a crankcase 7 connected to the lower end of the cylinder block 6. The crankshaft 8 supported by the crankcase 7 is disposed so as to extend at right angles to the direction in which the carburetor 2 and the exhaust muffler 4 are arranged, and a cooling fan 9 also serving as a flywheel is fixed to one outer end of the crankshaft 8. Is an output end. A shroud 10 that accommodates the cooling fan 9 and covers one side surface of the cylinder block 6 and the crankcase 7 is fixed to the engine body 1.

The shroud 10 has an intake port 11 at a front wall facing the cooling fan 9, and a rear surface thereof is open toward the engine body 1. A fan cover 13 having many intake holes 12 is attached to the intake port 11.
A recoil starter is provided therein.

The open rear surface of the shroud 10 is formed to be larger than the side surface of the engine body 1 covered by the shroud 10 and has a surplus opening portion 14 that opens on the carburetor 2 side. A baffle plate 15 for closing the surplus opening portion 14 is fixed to the engine body 1 by a plurality of bolts 16.

As shown in FIGS. 1, 2 and 4, a bracket 15a is formed integrally with the air guide plate 15 so as to protrude outside the shroud 10 on the carburetor 2 side and stand upright in the axial direction of the crankshaft 8. A support shaft 17 extending parallel to the intake path axis of the carburetor 2 is fixed to the bracket 15a, and a control lever 18 is rotatably attached to the support shaft 17.

On the other hand, a governor lever 21 having a pair of long and short arms 21 a and 21 b is attached to the side wall of the crankcase 7 via a pivot 19 so as to be swingable. The long arm 21a of the governor lever 21 is connected to the throttle lever 20 of the carburetor 2 via a link 21 outside the crankcase 7, and swings clockwise in FIG. ) In the opening direction. A governor spring 22 that urges the governor lever 21 in the opening direction of the throttle valve is stretched between the long arm 21a and the control lever 18, and rotates the control lever 18 from the low speed position S to the high speed position H. As a result, the load of the spring 22 is increased.

The short arm 21b of the governor lever 21 is
In the crankcase 7, a known centrifugal governor 23 driven by the crankshaft 8 is connected. The centrifugal governor 23 generates a thrust that increases as the engine speed increases, and the thrust urges the governor lever 21 to swing in the direction of closing the throttle valve. Therefore, when an arbitrary load is applied to the governor spring 22 by operating the control lever 18 during the rotation of the engine, the governor lever 21 is swung so that the load and the generated thrust of the centrifugal governor 23 are balanced, thereby causing the engine to rotate. The throttle valve of the carburetor 2 is opened and closed so that the number is stabilized at a value corresponding to the load of the governor spring 22.

In the figure, reference numeral 25 denotes an air cleaner connected to the inlet of the intake passage of the carburetor 2.

Next, the operation of this embodiment will be described.

During operation of the engine E, a cooling fan 9 driven to rotate by a crankshaft 8 sends outside air, ie, cooling air, taken in through a number of intake holes 12 to the cylinder block 6 along the inner wall of the shroud 10 under pressure. ， Cool it. At this time, the surplus opening portion 14 of the shroud 10 is closed by the baffle plate 15 fixed to the engine body 1, so that the cooling air is prevented from leaking from the surplus opening portion 14 to cool the cylinder block 6. It is possible to secure sufficient wind and enhance its cooling effect.

Further, since the air guide plate 15 is integrally provided with the bracket 15a for supporting the control lever 18, a bracket plate dedicated to the control lever is not required, and the cost of the control lever support structure can be greatly reduced. Can be.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the gist of the present invention. For example, cooling fins can be formed on the outer peripheral surface of the crankcase 7 to enhance its cooling performance.

[0021]

As described above, according to the present invention, the crank
The axis extends at right angles to the direction of the vaporizer and exhaust muffler
And a cooling fan attached to one end of the crankshaft.
The cooling air generated by the
Shroud covering one side of the engine body
In the air-cooled engine fixed to the gin body, the open surface of the shroud that opens toward the engine body is located on the carburetor side.
It has a surplus opening part to be opened, and it is opened on the vaporizer side.
The air guide plate that closes the surplus opening is fixed to the engine body,
Forming a bracket extending outwardly of the shroud to the air guide plate integrally, since the control lever for operating the throttle valve of the vaporizer was axially supported by this bracket, by the baffle plates, the vaporizer side of the shroud open face It is possible to prevent the cooling air from leaking from the surplus opening part which is opened by the control and to support the control lever, thereby improving the cooling effect of the engine and reducing the cost of the control lever support structure.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of an air-cooled engine according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a view taken in the direction of arrow 3 in FIG. 1;

FIG. 4 is a perspective view of a baffle plate.

[Explanation of symbols]

 1 ... Engine body 2 ... Vaporizer 8 ... Crankshaft 9 ... Cooling fan 10 ... Shroud 14 ... Surplus opening part 15 ... -Wind guide plate 15a-Bracket 18-Control lever E-Engine

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01P 5/06 502 F02B 63/00

Claims (1)

(57) [Claims] A crankshaft (8) supported by an engine body (1) is connected to a vaporizer attached to the engine body (1).
Extending at right angles to the arrangement direction of the vessel (2) and the exhaust muffler (4)
A cooling fan (9) is attached to one end of the crankshaft (8) , and cooling air generated by the cooling fan (9) is guided to a cylinder block (6) of the engine body (1). a shroud (10) covering one side surface of the Subeku engine body (1), fixed to the engine body (1)
In the air-cooled engine, the open surface of the shroud (10) opening toward the engine body (1) has a surplus opening opening on the carburetor (2) side.
(14), a baffle plate (15) that closes a surplus opening portion (14) that opens on the carburetor (2) side is fixed to the engine body (1), and a bracket (15a) extending outwardly and integrally formed of the shroud (10) to Kazeban (15), journalled vaporizer control lever for operating the throttle valve (2) (18) to the bracket (15a) An air-cooled engine characterized by: