JPH0592431U - 2-cycle 2-cylinder engine for brush cutter - Google Patents

Abstract

(57) [Summary] [Objective] By making the two-cycle engine for the mowing work machine into the in-line two-cylinder type, the vertical and lateral dimensions of the engine can be made smaller and the weight can be reduced, which is excellent in utility. Provide the engine. [Structure] The displacement of a two-cycle one-cylinder engine for a bush cutter is equally divided into two cylinders, and the two cylinders 2 and 3 of the two cylinders are brought close to each other and fixedly arranged in series in a crankcase 21. A fuel tank 12 is provided on the side opposite to the cylinders 2 and 3 with respect to the case 21, a starter 13 is provided on one end of the crankshaft 6, a cooling fan 14 is provided on the other end, and a cutting blade is provided via a centrifugal clutch. The transmission shafts 18 for driving the cylinders are linked to each other, and the carburetors 11a and 11b are arranged in close proximity to and communicate with the intake ports 8 and 9 of both cylinders 2 and 3, and the opposite sides of the carburetors 11a and 11b In each of the exhaust ports 4 and 5, a flat muffler 10 which is shared by both cylinders and approaches the side regions of both cylinders 2 and 3 is arranged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a two-cycle one-cylinder engine for a brush cutter, which is configured as an in-line two-cylinder engine in which the displacement of the two-cycle one-cylinder engine is equally divided into two parts. 2 cycle 2 cylinder engine.

[0002]

[Prior Art]

 Conventionally, as shown 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]

[Problems to be solved by the device]

 However, in such a horizontally-opposed type, the width of the entire engine becomes large, and when carrying it out and carrying out the work, the engine side easily interferes with the branches of the tree, etc. It is easy to rotate in any direction, difficult to operate, and dangerous.In addition, since both cylinders are separated left and right around the crankshaft, the structure related to intake and scavenging of both cylinders becomes complicated, and the engine as a whole The problem was that it became larger and heavier.

[0004]

[Means for Solving the Problems]

 The present invention solves such a problem, and devises so that the engine can be miniaturized with a two-cycle two-cylinder engine and suitably implemented. Therefore, the displacement of the two-cycle one-cylinder engine for a brush cutter is 2 etc. It is divided into two cylinders, and both cylinders of the two cylinders are brought close to each other and fixedly arranged in series in the crankcase. A fuel tank is arranged on the side opposite to the cylinder with respect to the crankcase, and one end of the crankshaft is arranged. Side, a starter on the other side, a cooling fan on the other side, and a transmission shaft that drives the cutting blade via a centrifugal clutch so that they can be interlocked with each other, and a carburetor is brought close to the intake ports of both cylinders. In addition to providing communication, 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]

[Action]

 Therefore, by constructing a two-cycle one-cylinder engine for a brush cutter into two cylinders with the displacement divided into two, the height of the cylinder can be reduced, the diameter can be made small, and the stroke of the piston can be made small. Due to the alternating explosions, the rotational balance is improved and the crank web, etc. can be made smaller.As a result, the crankcase can be made smaller, and the carburetor can be made smaller in proportion to the displacement. The muffler has a flat shape that can be used for both cylinders, which makes it possible to reduce the vertical and horizontal dimensions of the engine, and also to reduce the weight of the muffler. It will be easy to operate.

[0006]

【Example】

 FIG. 2 shows a side sectional view of the engine part of the brush cutter, which has horizontal fins 1 in the horizontal direction and vertical fins 1a standing upright on the outer peripheral surface, and is equipped with pistons 7a, 7b connected to the crankshaft 6, respectively. Both cylinders 2 and 3 of the two-cycle type are made vertical and are erected in series, but since both cylinders 2 and 3 are configured to have the same displacement of, for example, about 20 cc, the conventional one cylinder, for example, 40 cc The vertical dimension and the cylinder diameter can be made smaller than the cylinder, and the scavenging passages 4a and 5a of both cylinders 2 and 3 are flat between the axis 0 and 0 of the cylinders 2 and 3 as shown in FIG. They are arranged so as to approach each other so as to face each other visually. An exhaust port 4 communicating with the scavenging passages 4a and 4b and an exhaust port 5 communicating with the scavenging passages 5a and 5b are juxtaposed in parallel on one lateral side of the two cylinders 2 and 3 so that both cylinders have the same side. A flat muffler 10 for both cylinders is communicatively connected to a partial area, and small carburetors 11a and 11b are communicatively connected to both intake ports 8 and 9 on both sides of both cylinders 2 and 3, respectively. To do.

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 one rear end of a crankshaft 6 mounted in the crankcase 21. Of the crankshaft 6, a flywheel 16 having a fan 14 and a clutch shoe 15 is mounted on the other front side of the crankshaft 6, and a clutch shoe 17 is provided inside the front clutch case 17. A clutch drum 19 which is inscribed in 15 and drives a cutting blade drive shaft 18 is mounted on the clutch drum 17, and an engine cover 20 is attached from the upper rear portion of the clutch case 17 to the upper portions of both cylinders 2 and 3 so that the clutch 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 forward from the case 17, and the body is constructed in the same manner as before. It is constructed so that it can be carried and mowed off.

Therefore, both the cylinders 2 and 3 can be made small in vertical dimension and diameter, and the crankcase 21 can also be made small because the piston stroke and the like are small. Further, since the carburetor has a small venturi, the length and height are small. Both of them can be made small, and because the displacement is small by dividing into two, there is little blowback of fuel, so it can be made small, and the muffler 10 can be made relatively large because the wide side areas of both cylinders 2 and 3 can be effectively used. The protrusion size can be made small and the flat shape can be formed while enhancing the sound deadening effect. 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 FIGS. 6 and 7, it is shown by a virtual line. In contrast to the height H1 and the width W1 of the engine section in the conventional one-cylinder brush cutter, both the height H2 and the width W2 of the engine section of the present invention shown by the solid line can be configured to be small. It will be easy to operate 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 configured as a carburetor shared by two cylinders and attached to the exhaust port via a distributor-type insulator.

[0009]

[Effect of the device]

 As described above, according to the present invention, the two cylinders 2 and 3 integrally projecting from the crankcase 21 are arranged close to each other in series, and the fuel tank 12 is provided on the opposite side of the crankcase 21 from the cylinders 2 and 3. The crankshaft 6 is provided with a starter 13 at one end, and the other end is connected with a cooling fan 14 and a transmission shaft 18 for driving a cutting blade via a centrifugal clutch so as to be interlocked. The carburetors 11a and 11b are provided in the intake ports 8 and 9 of the cylinder 3, respectively, and the exhaust ports 4 and 5 on the opposite side of the carburetor extend to the side regions of the cylinders 2 and 3 and are flat for both cylinders. Since the engine-shaped muffler 10 is arranged, 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, which leads to weight reduction. The muffler's muffling effect can be increased, and since it is configured with two in-line cylinders, the compression force at engine startup can be reduced and it can be started lightly. In this case, the engine side is much less likely to come into contact with vegetation, etc., which allows easy operation with light workability, and has the 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 section.

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 cylinders 3 cylinders 4 exhaust port 5 exhaust port 6 crankshaft 8 intake port 9 intake port 10 muffler 11a vaporizer 11b vaporizer 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 bush 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 in a crankcase 21. Cylinders 2 and 3 for the crankcase 21
A fuel tank 12 is arranged on the opposite side to the starter 13 on one end side of the crankshaft 6, and a cooling fan 14 on the other end side.
The transmission shafts 18 for driving the cutting blades are linked to each other via a centrifugal clutch in an interlockable manner, 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. For the brush cutter, the exhaust ports 4 and 5 on the opposite side of the chambers 11a and 11b are provided with a flat muffler 10 for both cylinders that approaches the side regions of both cylinders 2 and 3. 2-cycle 2-cylinder engine.