JPH088301Y2 - Air cleaner for inline 2-cylinder engine - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cleaner suitable for an in-line two-cylinder engine having two cylinders arranged in series with and close to a crankshaft.

[0002]

2. Description of the Related Art When reducing the size and weight of an engine, which is the power source of a portable work machine such as a brush cutter, a chain saw, a tea cutter, and a sprayer, work such as carrying and brush cutting becomes easy. . Further, in this type of working machine, engine vibration is transmitted to the operator's hand, causing various problems.

As a means for solving the vibration problem, for example, Japanese Utility Model Publication No. 63-11300 discloses an engine in which a two-cycle two-cylinder is horizontally opposed to a crank rotation shaft. However, in the horizontal facing method, the lateral width of the entire engine becomes large, so that the engine side hits a tree branch or the like and workability and transportability are deteriorated. In addition, the balance of the machine body is poor, and the machine body easily swings in the left-right direction, resulting in poor operability. Furthermore, since both engines are arranged on the left and right sides centering on the crank rotation shaft, the structure related to intake and exhaust becomes complicated, and restrictions are imposed on the miniaturization and weight reduction of the entire engine.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention have designed a two-cycle one-cylinder engine having a two-cylinder cylinder having a two-cylinder displacement which is divided into two cylinders so that the engine can be made compact and lightweight. , Proposed to fix the crankcase in series, and filed a utility model registration application. By arranging a plurality of cylinders in series with the crankshaft, the entire device becomes compact and the operability, workability, transportability, etc. are improved as compared with the horizontally opposed type.

In an engine of a type in which a large capacity cylinder is divided into a plurality of cylinders, an ignition plug that causes each cylinder to explode is required. In the conventional engine design, a distributor is required because a voltage for generating a spark is sequentially applied to the spark plugs provided in each cylinder. Therefore, the wiring system becomes complicated and the weight of the entire device also increases.

As a design in which the distributor is omitted, it is conceivable that sparks are generated in each of the plurality of cylinders to cause explosion and misfire depending on the state of the air-fuel mixture in the cylinders. However, the frequency of electromotive force generation is doubled by the number of cylinders, and the temperature rise of the magneto and rotor becomes significant. As a result, in particular, the inner type magnet deteriorates in a short time and stable electromotive force cannot be obtained.

Therefore, the present inventors have developed an in-line multi-cylinder engine which employs a method of air-cooling an outer type magnet by cooling air taken in for cooling the cylinder, and a part of the engine is disclosed in Japanese Patent Application No. 3-194802. Filed as. In this in-line multi-cylinder engine, it is possible to suppress the temperature rise of the magneto and the rotor and to drive the engine under stable conditions for a long period of time, although the electromotive force is generated frequently.

The in-line two-cylinder engine can have a common intake system, exhaust system, and the like. Further, when the suction and the explosion in the individual cylinders are alternately repeated by shifting the cycle, it becomes possible to use a muffler, an air cleaner, etc. having a capacity of approximately one cylinder. Therefore, a compact design around the engine becomes possible, which is suitable for brush cutting work and the like.

The present invention provides a miniaturized portable working machine by paying attention to the advantages of such an in-line two-cylinder engine and adopting an assembly structure suitable for a flat and simple air cleaner. With the goal.

[0010]

In order to achieve the object, an air cleaner for an in-line two-cylinder engine according to the present invention is provided in an in-line two-cylinder engine having two cylinders arranged in series close to a crankshaft. An air cleaner is composed of a flat main body and a lid that are divided into two parts so as to be orthogonal to the direction of intake of air into the cylinder, and a choke valve that can be opened and closed from the outside is provided in the main body, and the lid is attached to the main body. A tightening boss having an embedded nut for fixing is provided substantially in the center of the main body, and an outer peripheral portion of the tightening boss serves as a stopper in the opening direction or the closing direction of the choke valve.

[0011]

Embodiments Embodiments in which the present invention is applied to a brush cutter will be described below. However, the present invention is not restricted to this, and is similarly applied to other portable working machines such as chainsaws, tea mowers and sprayers.

As shown in FIG. 1, the brush cutter engine of the present embodiment has two carburetors 3a, 2b corresponding to two cylinders 2a, 2b arranged in series with respect to the operating main rod 1. 3b
It has. The vaporizers 3a and 3b share one air cleaner 4. Engine output is clutch case 5
It is output via an internal clutch and is transmitted to a cutting blade attached to the tip of the operating main rod 1 via a transmission shaft inserted in the operating main rod 1. Exhaust gas from the cylinders 2a and 2b is discharged through the muffler 6. In addition, number 7
Shows a recoil starter for starting the engine.

In this in-line two-cylinder engine, the crankshaft to which the piston rods that slide in the cylinders 2a and 2b are connected is one for each piston rod.
80 degrees out of phase. Therefore, the suction stroke and the explosion stroke are alternately performed between the two cylinders 2a and 2b. Therefore, the air cleaner 4 only needs to have a capacity to cover the intake amount of one cylinder, and can be downsized.

The air cleaner 4 includes the cylinders 2a and 2b.
The cleaner body 10 and the cleaner lid 20 are divided into two in the intake direction. The cleaner body 10 and the cleaner lid 20 are integrated by being fitted to each other, and are fixed to the engine together with the carburetors 3a and 3b. Further, the cleaner main body 10 and the cleaner lid 20 have an area across the two cylinders 2a and 2b,
Since air is alternately sent to the individual cylinders 2a and 2b, sufficient capacity can be obtained even if the thickness is reduced.

As shown in FIG. 2 showing the internal structure of the cleaner body 10, the outer rim 11 and the inner rim 12 form a groove-shaped air passage 13. Air flow path 13
Communicates with the outside air through the air intake hole 15 of the air intake port 14 protruding outward. This cleaner body 10
Vaporizers 3a, 3b with four mounting bolts 17a-17d
Is fixed to the side engine body.

The inner portion of the inner rim 12 is provided with a pair of suction holes 16a, 16b which communicate with the respective carburetors 3a, 3b. A pair of choke valves 30a and 30b are installed near the suction holes 16a and 16b by mounting bolts 17
It is rotatably provided with b and 17d as fulcrums. The choke valves 30a, 30b have suction holes 16a,
It is equipped with disc parts 31a and 31b for closing 16b,
The other ends are connected to each other by a link bar 32.

When the link bar 32 moves in the left-right direction in FIG. 2, the choke valves 30a, 30b rotate at the same angle with the mounting bolts 17b, 17d as fulcrums, and the suction holes 16a, 16b by the disc portions 31a, 31b. Open and close in conjunction. An appropriate frictional force is applied to the choke valves 30a and 30b by the pressing force of the spring washers used when tightening the mounting bolts 17b and 17d.

A lever 33 projecting to the outside of the air cleaner 4 is integrally provided on one choke valve 30b. The lever 33 moves along the notch 18 formed in the cleaner body 10, and the state of the alternate long and short dash line in FIG. 2 is the fully closed position. Small holes 34a, 34b are provided in the disk portions 31a, 31b of the choke valves 30a, 30b. The small holes 34a and 34b are used for the choke valve 30.
The suction holes 16a, 1 are formed by the disk portions 31a, 31b of a, 30b.
Even when 6b is fully closed, a small amount of air is supplied to the cylinder 2a,
It has the effect of feeding into 2b.

A tightening boss 40 is provided so as to protrude substantially in the center of the cleaner body 10. An embedding nut 41 is embedded in the tightening boss 40 as shown in FIG. The cleaner lid 20 corresponding to the tightening boss 40
A bolt insertion portion 42 is formed at this position. The cleaner lid 20 is firmly integrated with the cleaner body 10 by screwing the tightening bolt 43 pierced through the bolt insertion portion 42 into the embedding nut 41.

The tightening boss 40 has a choke valve 30.
It has a function as a stopper when moving a and 30b to the fully open position. That is, the tightening boss 40
The position and the outer diameter are set so that the side surfaces of the disk portions 31a and 31b of the choke valves 30a and 30b in the fully opened position come into contact with each other. As a result, the disc portion 31a,
The lever 33 moves in the opening direction until the side surface of 31b contacts the tightening boss 40. Then, the fully open position shown by the solid line in FIG. 2 can be reliably obtained.

In the illustrated example, the tightening boss 40 is
Although the stoppers restrict the fully open positions of the choke valves 30a and 30b, the stoppers may restrict the fully closed positions. In this case, the side walls of the notch 18 serve as stoppers for restricting the fully open positions of the choke valves 30a, 30b so that the choke valves 30a, 30b
30b, the link bar 32, the lever 33, etc. are replaced.

Inside the cleaner lid 20, as shown in FIGS. 3 and 4, a cleaner element 21 is provided. The cleaner element 21 is made of an open-cell urethane rubber or the like, and is stretched over a plurality of pins 22a to 22i provided upright inside the cleaner lid 20. The substantially central portion of the cleaner element 21 conforms to the shape of the inner rim 12 when the cleaner element 21 is hung over the pins 22a to 22i. Therefore, when the cleaner lid 20 is integrated with the cleaner body 10, the cleaner element 21 is brought into pressure contact with the inner rim 12 of the cleaner body 10 and air in the air flow path 13 between the inner rim 12 and the outer rim 11 is compressed. Acts as a filter for cleaning and feeding into the inner rim 12.

Inside the cleaner lid 20, arcuate bosses 23a and 23b are provided upright. Arcuate boss 23a,
23b are suction holes 16a, 16b on the cleaner body 10 side.
It is curved with a curvature along with, and faces the peripheral edges of the suction holes 16a and 16b when the cleaner lid 20 is aligned with the cleaner body 10. The arcuate bosses 23a and 23b are provided in the suction hole 16
It acts as a receiving portion for temporarily receiving the blowback of fuel from a and 16b.

Next, the operation of the air cleaner described above will be described. The air introduced from the air suction hole 15 into the air flow path 13 between the outer rim 11 and the inner rim 12 of the cleaner body 10 is cleaned by the cleaner element 21 provided inside the cleaner lid body 20, Inner rim 12
Of the choke valves 30a and 30b, and enters the carburetor 4 through the suction holes 16a and 16b, and is sucked into the engine.

At this time, the choke valves 30a, 30b
The two choke valves 30a and 30b are operated in synchronization with each other by the lever 33 protruding outside the air cleaner 4. The choke valves 30a and 30b are closed at the time of start-up under cold conditions, but are normally kept at the open position. The holding of the choke valves 30a and 30b in the open position can be correctly and easily set by bringing the side surfaces of the disk portions of the choke valves 30a and 30b into contact with the tightening boss 40.
Moreover, since the choke valves 30a and 30b are formed of flat plates, the thickness of the air cleaner 4 is not increased.

As described above, the tightening boss 40 required for attaching the cleaner lid 20 to the cleaner body 10 is
It also serves as a stopper that regulates the open positions of the choke valves 30a and 30b. Therefore, it is not necessary to provide a dedicated stopper that causes an increase in thickness inside the cleaner body 10 or the cleaner lid body 20, and the cleaner body 10
Also, the thickness of the lid can be reduced. The area of the cleaner body 10 and the cleaner lid body 20 in FIGS. 2 and 3 can be set to a size that spans the two cylinders 2a and 2b. As a result, the air cleaner 4 becomes a thin lunch box type, and does not largely project in the radial direction of the operating rod 1.

[0027]

As described above, according to the present invention, the structural characteristics of the in-line two-cylinder engine in which two cylinders are arranged in series with respect to the crankshaft are utilized, and individual explosions that repeat alternating explosions are utilized. A small air cleaner with an internal volume commensurate with the amount of intake air sent to the cylinder is adopted, and the internal volume is secured in an area that spans two cylinders, thereby significantly reducing the thickness. As a result, the flat volume of the air cleaner is sufficiently utilized and the intake noise can be reduced, so that a compact design around the engine is facilitated. Moreover, the tightening boss into which the tightening bolt for fixing the cleaner lid to the cleaner body is inserted also serves as the choke valve stopper.
The air cleaner assembled in this manner has a small amount of protruding laterally, which improves the operability of the portable working machine and facilitates handling and transportation.

[Brief description of drawings]

FIG. 1 is a schematic view of an engine part of a brush cutter to which the present invention is applied.

FIG. 2A in FIG. 1 showing the internal structure of the air cleaner body
-A arrow view

3 is a sectional view taken along line BB of FIG.

FIG. 4 C of FIG. 3 showing the internal structure of the air cleaner lid.
-C arrow view

[Explanation of symbols]

1 Operating main rod 2a, 2b Cylinder 3
a, 3b Vaporizer 4 Air cleaner 10 Air cleaner body 20
Air cleaner lid 30a, 30b Choke valve 40
Tightening boss 41 Embedded nut

Claims (1)

[Scope of utility model registration request] 1. An in-line two-cylinder engine comprising two cylinders arranged in series close to a crankshaft,
2 so that it is orthogonal to the suction direction of the intake air into the cylinder.
An air cleaner is composed of a flat body and a lid that are divided, a choke valve that can be opened and closed from the outside is provided in the body, and a tightening boss that has an embedded nut that fixes the lid to the body is provided on the body. An air cleaner for an in-line two-cylinder engine, which is provided at a center, and an outer peripheral portion of the tightening boss serves as a stopper in an opening direction or a closing direction of the choke valve.