JPH0720349Y2 - 2-cycle 2-cylinder engine for brush cutter - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention is a two-cycle one-cylinder engine for a brush cutter, which is divided into two in-line two-cylinder engines to reduce the vertical and horizontal dimensions and reduce the weight. 2 cycles with excellent usability 2
For cylinder engines.

[0002]

2. Description of the Related Art Conventionally, as seen in Japanese Utility Model Publication No. 60-41071, a two-cycle two-cylinder horizontally opposed type engine is known as a brush cutter engine.

[0003]

However, in such a horizontally-opposed type, the width of the entire engine becomes large, and when the work is carried in a portable manner, the engine side easily interferes with a tree branch or the like. In addition, it is difficult to operate, because the aircraft easily rotates to the left and right, and it is difficult to operate, and since both cylinders are separated left and right around the crankshaft, the structure related to intake and scavenging of both cylinders It had a problem that it became complicated and the engine as a whole became large and heavy.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised so as to solve such a problem and to reduce the size of the engine by using a 2-cycle 2-cylinder engine so that the engine can be suitably implemented. The displacement of a cylinder engine is equally divided into two cylinders into two cylinders. Both cylinders of the two cylinders are brought close to each other and fixedly arranged in series in a crankcase, and a fuel tank is arranged on the side opposite to the cylinder with respect to the crankcase. A crankshaft is connected to one end of the crankshaft, a cooling fan is connected to the other end of the crankshaft, and a transmission shaft that drives the cutting blade via a centrifugal clutch is interlockingly connected.The intake ports of both cylinders are equipped with a carburetor. Are arranged in close proximity to each other for communication, and the exhaust port on the opposite side of the carburetor is provided with a flat muffler shared by both cylinders that approaches the side regions of both cylinders.

[0005]

Therefore, by constructing a two-cycle one-cylinder engine for a brush cutter into two cylinders in which the displacement is divided into two equal parts, the height of the cylinder can be made low, the diameter can be made small, and the stroke of the piston can be made small. Furthermore, due to the alternate explosion between the two cylinders, the rotation balance is improved and the crank web and the like can be made smaller. As a result, the crankcase can be made smaller, and the carburetor can be made smaller in accordance with the displacement. Since the muffler is configured to be flat for both cylinders, the vertical and horizontal dimensions of the engine can be reduced, and the weight can be reduced.There is little interference of the engine with vegetation during mowing work, and workability is improved. You will be able to operate it well and lightly.

[0006]

FIG. 2 is a side sectional view of an engine portion of a brush cutter, which has a horizontal fin 1 in the horizontal direction and a vertical fin 1a standing upright on the outer peripheral surface, and pistons 7a, 7b connected to a crankshaft 6 are provided. Both of the two cycle type cylinders 2 and 3 which are internally mounted are vertically arranged and are erected in series. The two cylinders 2 and 3 are configured to have the same displacement of, for example, about 20 cc, so that the conventional one cylinder For example 40c
The vertical dimension and the cylinder diameter can be made smaller than the cylinder c, and the scavenging passage 4 of both cylinders 2 and 3
As shown in FIG. 1, a and 5a are arranged so as to face each other between the shaft centers 0 and 0 of the cylinders 2 and 3 so as to face each other in a plan view. A scavenging passage 4 is provided on one lateral side of both cylinders 2 and 3.
exhaust port 4 communicating with a and 4b, and scavenging passages 5a and 5
An exhaust port 5 communicating with b is provided in parallel so as to project to the side regions of both cylinders so that a flat muffler 10 common to both cylinders is communicated and connected. , 9 are small vaporizers 11a and 1 respectively.
1b is connected in series.

A fuel tank 12 is provided below a crankcase 21 fixed to the lower portions of both cylinders 2 and 3, and a recoil starter type is provided at a rear end of a crankshaft 6 mounted in the crankcase 21. Of the crankshaft 6 and the fan 14
And a flywheel 16 having a clutch shoe 15, and a clutch drum 19 that is inscribed in the clutch shoe 15 and that drives a cutting blade drive shaft 18 is mounted inside the front clutch case 17 to form the clutch. The engine cover 20 is attached from the upper rear part of the case 17 to the upper side of both cylinders 2 and 3, and the clutch case 17
A cutting blade driven by the cutting blade drive shaft 18 is provided on the front end side of an operating rod (not shown) extending further forward so that the machine body can be carried and the mowing work can be performed as in the conventional case. To do.

Therefore, both the cylinders 2 and 3 can be made small in vertical dimension and diameter, and the crankcase 21 can be made small because the piston stroke and the like are small. Further, since the carburetor has a small venturi, both length and height can be increased. The muffler 10 can be made compact and can be made small because the amount of exhaust is small because it is divided into two parts, so that the muffler 10 can be made relatively large because the wide side areas of both cylinders 2 and 3 can be effectively used, and the muffler can be silenced. While the effect is enhanced, the projecting dimension is small and can be configured in a flat shape. That is, by reducing the size of both cylinders, crankcases, pistons, crankshafts, mufflers, etc., the overall weight of the engine can be reduced, and as shown in FIG. 6 and FIG. The height H2 and the width W2 of the engine portion of the present invention shown by the solid line can be made smaller than the height H1 and the width W1 of the engine portion in the conventional one-cylinder type brush cutter. It will be possible to operate it easily and with good workability so that the side does not interfere with the plants. In the embodiment, the carburetor is provided for each cylinder, but it may be attached to the exhaust port via a distributor type insulator as a carburetor shared by two cylinders.

[0009]

As described above, according to the present invention, the crankcase 2
The two cylinders 2 and 3 projecting integrally from the unit 1 are arranged close to each other in series, and the fuel tank 12 is arranged on the opposite side of the crankcase 21 from the cylinders 2 and 3, and one end of the crankshaft 6 is provided. A starter 13 is provided on the side, a cooling fan 14 is provided on the other end, and a transmission shaft 18 that drives the cutting blade via a centrifugal clutch
Are connected to each other so that intake ports 8 and 9 of both cylinders 2 and 3 are provided with carburetors 11a and 11b, respectively, and exhaust ports 4 and 5 on the opposite side of the carburetors are provided with both cylinders 2 and 3, respectively. Since the flat muffler 10 for both cylinders is arranged over the side region of the engine, the height and width of the engine are smaller than the conventional type, and the parts such as the cylinder, piston, and crankcase are also smaller. By doing so, it is possible to reduce the weight, increase the muffler muffling effect, and because it is configured with two in-line cylinders, the compression force at the time of starting the engine can be reduced and it can be started lightly. When carrying and mowing work,
The engine side is much less likely to come into contact with vegetation, etc., and it is possible to operate it easily with good workability, and it has a feature that it can be suitably implemented for mowing work.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a side sectional view showing an engine part.

FIG. 3 is a plan view showing a part of an engine unit.

FIG. 4 is a side view showing an outer side surface of an engine portion.

FIG. 5 is a front view showing a front side of an engine unit.

FIG. 6 is an explanatory diagram showing a comparison with a conventional type.

FIG. 7 is an explanatory diagram showing a comparison with a conventional type.

[Explanation of symbols]

 2 cylinder 3 cylinder 4 exhaust port 5 exhaust port 6 crankshaft 8 intake port 9 intake port 10 muffler 11a carburetor 11b carburetor 12 fuel tank 13 starter 14 cooling fan 18 transmission shaft 21 crankcase

Claims (1)

[Scope of utility model registration request] 1. A two-cycle, one-cylinder engine for a brush cutter is divided into two cylinders by dividing the displacement into two cylinders, and the two cylinders 2 and 3 of the two cylinders are closely arranged and fixedly arranged in series to a crankcase 21. Cylinders 2 and 3 for the crankcase 21
A fuel tank 12 is provided on the opposite side of the crankshaft 6, a starter 13 is provided at one end of the crankshaft 6, and a cooling fan 14 is provided at the other end.
The transmission shafts 18 for driving the cutting blades are linked to each other via a centrifugal clutch so that they can be interlocked with each other, and the intake ports 8 and 9 of both cylinders 2 and 3 are provided with carburetors 11a and 11b in close proximity to each other for communication and vaporization A bush muffler 10 common to both cylinders 2 and 3 is arranged in the exhaust ports 4 and 5 on the opposite side of the containers 11a and 11b, and the flat muffler 10 is used for the bush cutter. 2-cycle 2-cylinder engine.