JP2019052594A - Air cleaner for engine - Google Patents

Abstract

To provide an air cleaner for an engine which is suitable for building a passage structure for introducing blow-by gas into a carburetor.SOLUTION: An air cleaner 50 for an engine includes: a body part 52 having a filter part 51 and a storage chamber S of a blow-back fuel-air mixture collision member 57; an outer air inlet part 53; a blow-by gas inlet part 54; an air outlet part 55; and an internal passage 56 for guiding the blow-by gas flowed thereinto to the air outlet part 55. The blow-by gas inlet part 54 and the air outlet part 55 are formed at a carburetor side end wall 522 of the body part 52. The storage chamber S is divided into a first area S1 located at the outer air inlet part 53 side and a second area S2 located at the air outlet part 55 and the collision member 57 side. The collision member 57 is positioned between a second area side opening end 55a of the air outlet part 55 and the filter part 51 and integrally has a collision part 57a and a passage formation part 57b which cooperates with the carburetor side end wall 522 to form the internal passage 56.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an air cleaner for an engine provided in a portable work machine including an engine (internal combustion engine) and a carburetor.

  In a portable work machine equipped with an engine and a carburetor, a part of the air-fuel mixture sucked into the engine is pushed back in the downward stroke of the piston and flows backward, and the air-fuel mixture blows back from the carburetor inlet to the air cleaner side. May occur. This blown-back air-fuel mixture contains mist-like fuel, and this fuel adheres to the air purifying filter section of the air cleaner. When the amount of fuel adhering to the filter portion increases, the ventilation resistance of the filter portion increases, and as a result, the engine output may decrease.

  For this reason, for example, in the air cleaner described in Patent Document 1, a collision surface that faces the intake inlet of the carburetor and collides with the air-fuel mixture from the carburetor is formed integrally with a part of the filter portion. And this air cleaner is suppressing the amount of fuel adhering to the filter part of an air cleaner, and suppressing the fall of an engine output by making a blown back air-fuel mixture collide with the collision surface of a filter part.

JP 2017-2839 A

  By the way, as a portable working machine provided with an engine and a carburetor, there are, for example, a portable chain saw and a brush cutter. Since these portable work machines need to be light and compact as a whole so that they can be handled with one hand, carburetors and air cleaners are installed in a limited space near the engine (for example, the side of the engine). Has been placed. In this type of portable work machine, when blow-by gas leaks from the combustion chamber of the engine, this blow-by gas is introduced into the intake system (that is, carburetor) of the engine, and the blow-by gas is burned in the combustion chamber. Also, it is necessary to prevent the blow-by gas from being discharged to the outside in a large amount without being burned.

  Therefore, in the portable work machine, a carburetor and an air cleaner are arranged in the narrow space near the engine, and a structure for suppressing the adhesion of the blown back air-fuel mixture from the carburetor to the filter part and the blow-by gas in the engine are introduced into the carburetor. When it is necessary to provide a passage structure for this purpose, it is required to construct these structures in the narrow space.

  Therefore, the present invention is suitable for construction of a passage structure for introducing blow-by gas into the carburetor in the narrow space in an engine air cleaner having a structure for suppressing the adhesion of the blown back air-fuel mixture from the carburetor to the filter portion. An object is to provide an air cleaner for an engine.

  According to one aspect of the present invention, a filter unit that is provided in a portable work machine including an engine and a carburetor, purifies air to be supplied to the carburetor, and a collision member that collides with a blown mixture from the carburetor. An engine air cleaner having a storage chamber for storing the above is provided. The air cleaner for an engine has the housing chamber inside and is attached to an intake side end wall of the carburetor, an outside air inlet portion into which outside air flows, and a blow-by gas inlet portion into which blow-by gas in the engine flows. And an air outlet that flows out of the air after passing through the filter and is connected to the carburetor, and an internal passage that guides the blowby gas that has flowed into the blowby gas inlet to the air outlet. Including. The blow-by gas inlet portion and the air outlet portion are formed on a carburetor side end wall of the main body portion. The storage chamber is partitioned by the filter portion into a first region to which the outside air inlet portion is connected and a second region to which the air outlet portion is connected and the collision member is stored. The collision member is positioned between the second region-side opening end of the air outlet portion and the filter portion, and collides with the collision portion where the blown mixture collides with the carburetor-side end wall of the main body portion. And a passage forming portion that works to form the internal passage.

  In the engine air cleaner according to one aspect of the present invention, the blown back air-fuel mixture from the carburetor collides with the collision portion of the collision member, and blow-by gas in the engine flows into the blow-by gas inlet. The blow-by gas that has flowed into the blow-by gas inlet portion passes through the internal passage formed by the passage forming portion of the collision member and the carburetor-side end wall of the main body portion in cooperation with the air outlet portion. And then introduced into the carburetor.

  Thus, the internal passage for guiding the blow-by gas that has flowed into the blow-by gas inlet portion to the air outlet portion is the passage forming portion which is one portion of the collision member and the one portion of the main body portion. Since the carburetor side end wall can be used, the internal passage can be constructed without providing the internal passage forming parts separately from the collision member and the main body. Therefore, it is possible to provide an engine air cleaner suitable for constructing a passage structure for supplying blow-by gas to the carburetor in a limited narrow space near the engine.

It is a perspective view of a portable working machine provided with the air cleaner for engines in one embodiment of the present invention. It is the disassembled perspective view of the said air cleaner for engines, and the perspective view which looked at the said portable working machine from another angle. It is a figure for demonstrating the use condition of the said portable working machine. It is a fragmentary sectional view containing the air cleaner for engines of the portable operation machine. It is the principal part expanded sectional view which expanded the principal part in FIG. It is a conceptual diagram for demonstrating the flow of a blow-back mixture. It is a perspective view of the case of the air cleaner for engines. It is the front view of the said case seen from the arrow A direction shown in FIG. FIG. 9 is a cross-sectional view taken along line B-B in FIG. 8. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is a front view of the cover of the air cleaner for engines. It is the perspective view which looked at the said cover from the back side. It is a perspective view of the collision member of the air cleaner for engines. It is a top view of the said collision member. It is a bottom view of the collision member. FIG. 16 is a partial cross-sectional view taken along line EE in FIG. 15. It is the figure which showed the assembly | attachment state of the choke mechanism part provided in the said case.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view of a brush cutter as an example of a portable work machine to which an engine air cleaner according to an embodiment of the present invention is applied. FIG. 2 is an exploded perspective view of the engine air cleaner, and is a perspective view of the brush cutter viewed from a different angle from FIG. 1. FIG. 3 shows a perspective view of the brush cutter in use. In FIG. 1 and FIG. 2, the operation rod 151 described later and the components (the cutting blade 152, the safety cover 153, and the gear head 154) attached to the front end portion thereof are not shown.

  As shown in FIGS. 1 to 3, the brush cutter 150, which is an example of a portable work machine according to the present embodiment, includes an engine 1, a carburetor (vaporizer) 30, and an engine air cleaner (hereinafter referred to as “air cleaner”) 50. The brush cutter main body 100 provided, an operating rod 151 having one end attached to the front portion of the brush cutter main body 100, a disk-shaped cutting blade 152 rotatably attached to the other end of the operating rod 151, And a safety cover 153 attached to the other end of the operation rod 151 so as to cover the cutting blade 152.

  A gear head 154 is attached to the other end of the operation rod 151. A later-described crankshaft 9 of the engine 1 and a gear head 154 are connected via a drive shaft (not shown) provided in the operation rod 151. Therefore, power from the engine 1 can be transmitted to the gear head 154. A cutting blade 152 is attached to the gear head 154. Therefore, the power of the engine 1 is transmitted to the cutting blade 152 via the gear head 154, and the cutting blade 152 rotates.

  A handle 155 is attached to an intermediate portion of the operation rod 151. A control lever (not shown) for adjusting the power of the engine 1 is attached to the handle 155. The worker M performs the brushing work by holding and operating the handle 155.

  Hereinafter, the brush cutter main body 100 will be described in detail. FIG. 4 is a partial cross-sectional view of a portion including the air cleaner 50 of the brush cutter main body 100, and FIG. 5 is an enlarged cross-sectional view of a main part of the main part in FIG. FIG. 6 is a conceptual diagram for explaining the flow of the blown-back mixture.

  The engine 1 is an OHV (Over Head Valve) type four-stroke engine and is mounted as a power source (prime mover) of the brush cutter 150.

  As shown in FIG. 4, the engine 1 includes a cylinder block 4 formed with a cylinder 3 that accommodates a piston 2 so as to reciprocate, and a crank chamber that is attached to the lower portion of the cylinder block 4 and cooperates with the cylinder block 4. 5, a cylinder case 8 that is attached to the upper portion of the cylinder block 4 and forms a combustion chamber 7 in cooperation with the cylinder block 4, and is disposed below the crankcase 6 to store oil. An oil tank (not shown).

  A crankshaft 9 is rotatably supported at a connecting portion between the cylinder block 4 and the crankcase 6. The piston 2 is connected to the crankshaft 9 via a connecting rod 10. Thereby, the reciprocating motion of the piston 2 is converted into the rotational motion of the crankshaft 9. Then, the rotational movement of the crankshaft 9 is transmitted to the cutting blade 152 via the drive shaft and the gear head 154 in the operating rod 151, so that the cutting blade 152 is rotationally driven.

  The cylinder head 8 is formed with an intake port 11 for introducing a mixture of fuel and air to the combustion chamber 7 and an exhaust port 12 for discharging combustion gas from the combustion chamber 7. An intake valve 13 is disposed in the intake port 11, and an exhaust valve 14 is disposed in the exhaust port 12. The intake port 11 communicates with the air cleaner 50 via a communication passage portion 21 formed in the insulator 20 and an air-fuel mixture passage portion 31 described later formed in the carburetor 30. That is, the insulator 20 is a member disposed between the opening end of the intake port 11 and the carburetor 30 in the engine 1. Further, the exhaust port 12 communicates with an exhaust muffler (not shown).

  The intake valve 13 and the exhaust valve 14 are driven to open and close by a valve gear that includes the first rocker arm 15 and the second rocker arm 16. The first rocker arm 15 and the second rocker arm 16 are accommodated in a valve operating chamber 18 formed by a recess formed in a portion of the cylinder head 8 above the combustion chamber 7 and a head cover 17 covering the recess. Yes. One end of the first rocker arm 15 is connected to the intake valve 13, and one end of the second rocker arm 16 is connected to the exhaust valve 14. Although not shown in the figure, the valve gear is attached to the crankshaft 9 and rotates with the crankshaft. The rotation of the drive gear is caused by the swinging motion of the first rocker arm 15 and the second rocker arm 16. And a oscillating motion transmission mechanism that transmits the oscillating motion in a converted manner.

  Here, the engine 1 supplies oil or oil mist around the crankshaft 9 and the valve operating device using pressure fluctuation in the crank chamber 5, and lubricates the crankshaft 9 and the valve operating device. It has a lubrication structure.

  Specifically, when the piston 2 moves from the bottom dead center toward the top dead center and the crank chamber 5 is in a negative pressure state, the oil in the oil tank is sucked up into the crank chamber 5. An oil passage 19 to be supplied (in FIG. 4, an end portion on the crank chamber 5 side is shown) is provided between the oil tank and the crank chamber 5. The oil supplied into the crank chamber 5 is mainly stirred by the crankshaft 9 to be misted (oil mist is generated), thereby lubricating the crankshaft 9 and the surroundings. Further, when the piston 2 moves from the top dead center toward the bottom dead center and the inside of the crank chamber 5 becomes a positive pressure state, the oil mist generated in the crank chamber 5 and the oil mist generated in the crank chamber 5 are retained. A passage (not shown) for sending the oil to the oil tank is provided between the crank chamber 5 and the oil tank. An oil passage (not shown) for supplying the oil mist in the oil tank into the valve operating chamber 18 via the accommodation region (not shown) of the swing motion transmission mechanism is provided between the oil tank and the valve operating chamber. 18 is provided so as to pass through the accommodation region of the swing motion transmission mechanism. When the crank chamber 5 is in a negative pressure state, an oil passage (not shown) that sucks up the oil accumulated in the valve chamber 18 and sends it to the crank chamber 5 is provided between the valve chamber 18 and the crank chamber 5. It is provided in between. The oil sent into the crank chamber 5 is made mist in the crank chamber 5 or stays in the crank chamber 5 and then sent to the oil tank. Thus, the lubricating structure for lubricating the periphery of the crankshaft 9 and the valve gear using the pressure fluctuation in the crank chamber 5 including the oil passages described above is configured.

  Further, blow-by gas leaking from the combustion chamber 7 exists in the valve chamber 18 of the engine 1. The engine 1 is connected to one end of a breather passage (extraction passage) 22 for introducing the blow-by gas into the intake system (that is, the carburetor 30) of the engine 1. Specifically, one end of the breather passage 22 opens into the valve operating chamber 18, and the other end of the breather passage 22 is connected to a blow-by gas inlet 54 described later of the air cleaner 50. The breather passage 22 is constituted by, for example, a flexible tube and a connection joint.

  The carburetor 30 generates an air-fuel mixture of fuel and air purified by the air cleaner 50 and supplies the air-fuel mixture to the engine 1. The carburetor 30 has an air-fuel mixture passage section 31 into which air flows and fuel is injected and supplied. The carburetor 30 is fixed to the end of the insulator 20 by a plurality of bolts 32 together with the air cleaner 50. An intake inlet side end 31 a of the mixture passage portion 31 is connected to an air outlet portion 55 described later of the air cleaner 50, and an mixture outlet side end portion 31 b of the mixture passage portion 31 is connected to the communication passage portion 21 of the insulator 20. Connected to the inlet end 21a.

  The air cleaner 50 is provided in a brush cutter 150, which is a portable working machine including the engine 1 and the carburetor 30, and supplies purified air to the intake system (that is, the carburetor 30) of the engine 1. The air cleaner 50 is disposed above the fuel tank 40 disposed on the side of the engine 1 together with the insulator 20 and the carburetor 30. In the brush cutter 150, the insulator 20, the carburetor 30, and the air cleaner 50 are arranged in a limited narrow space near the engine that is on the side of the engine 1 and above the fuel tank 40.

  As shown in FIGS. 4 and 5, the air cleaner 50 includes a filter portion 51, a main body portion 52, an outside air inlet portion 53, a blow-by gas inlet portion 54, an air outlet portion 55, an internal passage 56, and a collision member. 57.

  The filter unit 51 purifies air to be supplied to the carburetor 30 (specifically, the air-fuel mixture passage unit 31), and includes, for example, a first air cleaner element 51a and a second air cleaner element 51b. The filter part 51 is accommodated in the accommodating chamber S formed in the main body part 52 together with the collision member 57. The 1st air cleaner element 51a and the 2nd air cleaner element 51b consist of appropriate members, such as sponge and felt, and have the plane shape and thickness which matched the shape of storage room S. The first air cleaner element 51a is disposed on the upstream side in the flow direction, and the second air cleaner element is disposed on the downstream side in the flow direction.

  The main body 52 has a housing chamber S for housing the filter portion 51 and the collision member 57 therein, and is a member that forms an outer shell of the air cleaner 50, and is formed so as to cover the carburetor 30. The main body 52 is attached to the intake side end wall 30 a of the carburetor 30 with bolts 32. The structure of the main body 52 will be described in detail later.

  The outside air inlet 53 is a portion into which outside air flows in the air cleaner 50. The outside air inlet 53 is formed in the lower part of the end wall 521 on the opposite side to the carburetor 30 in the main body 52. The outside air inlet 53 has a pipe line extending substantially in the vertical direction when in use, and one end of the pipe line opens to the outside, and the other end of the pipe line opens into the storage chamber S.

  The blow-by gas inlet 54 is a portion into which blow-by gas in the engine 1 flows. The blow-by gas inlet 54 is formed in the carburetor side end wall 522 of the main body 52. Specifically, the blow-by gas inlet 54 is formed as a tubular body that protrudes outward (outside the storage chamber S) from the carburetor-side end wall 522 of the main body 52. The other end of the breather passage 22 made of a flexible tube extending from the valve operating chamber 18 is connected to the blow-by gas inlet 54.

  The air outlet part 55 is a part where the air after passing through the filter part 51 flows out and is connected to the carburetor 30. The air outlet portion 55 is formed in the carburetor side end wall 522 of the main body portion 52, similarly to the blow-by gas inlet portion 54. Specifically, the air outlet portion 55 is formed as a tubular body projecting inward (inside the storage chamber S) from the carburetor side end wall 522 of the main body portion 52. The air outlet portion 55 is connected to the intake inlet side end portion 31 a of the mixture passage portion 31 of the carburetor 30.

  The storage chamber S of the main body 52 is partitioned by the filter unit 51 into a first region S1 to which the outside air inlet 53 is connected and a second region S2 to which the air outlet 55 is connected and the collision member 57 is stored. ing. That is, in a state where the filter unit 51 is accommodated in the accommodation chamber S, the accommodation chamber S is divided into two regions, the first region S1 and the second region S2, by the filter unit 51. One end of the outside air inlet portion 53 opens to the first region S1, one end of the air outlet portion 55 opens to the second region S2, and the collision member 57 is disposed in the second region S2.

  The internal passage 56 is a passage for guiding the blow-by gas that has flowed into the blow-by gas inlet 54 to the air outlet 55. That is, the internal passage 56 is a passage for communicating between the blow-by gas inlet portion 54 and the air outlet portion 55. The shape and the like of the internal passage 56 will be described in detail later.

  The collision member 57 is a member with which the blown back air-fuel mixture from the carburetor 30 collides. That is, when the air-fuel mixture blows back from the engine 1, the collision member 57 causes the air-fuel mixture to collide with the predetermined portion (a collision portion 57 a described later) and blow-back air-fuel mixture to the filter unit 51. It is a member provided mainly for the purpose of suppressing adhesion of the fuel component inside.

  The collision member 57 integrally includes a collision part 57a and a passage forming part 57b. In this embodiment, the collision part 57a and the channel | path formation part 57b are integrally formed by the sheet-metal member of a metal thin plate, as shown in FIGS. 14-17 mentioned later.

  As shown in FIG. 6, the collision part 57a is located between the second region side opening end 55a of the air outlet part 55 and the filter part 51, and is a part where the blown-back air-fuel mixture collides. Therefore, the collision part 57 a is a part that constitutes an adhesion suppression structure that suppresses the fuel component in the blowback mixture from adhering to the filter part 51.

  The passage forming portion 57 b is a member that forms the internal passage 56 in cooperation with the carburetor side end wall 522 of the main body portion 52. That is, the passage forming portion 57 b is a portion that constitutes a passage structure (internal passage 56) for introducing blow-by gas in the engine 1 into the carburetor 30 together with the carburetor side end wall 522 of the main body portion 52.

  Therefore, the collision member 57 has an adhesion suppression function that suppresses the fuel component in the blowback mixture from adhering to the filter unit 51 in the collision unit 57a, and the blow-by gas is supplied to the engine in the passage formation unit 57b. 1 has a function of forming an internal passage 56 for returning to the intake system. The shape of the collision member 57 will be described in detail later.

  Next, the structure of the main body 52 and the shape of the internal passage 56 will be described in detail with reference to FIGS. 7 to 11 are views for explaining the structure of a case 52a (described later) and the internal passage 56 of the main body 52, and FIGS. FIG. 7 is a perspective view of the case 52a, FIG. 8 is a front view as seen from the direction of arrow A in FIG. 7, FIG. 9 is a sectional view taken along the line BB in FIG. 11 and 11 are partial cross-sectional views taken along the line DD in FIG. FIG. 12 is a front view of the cover 52b, and FIG. 13 is a perspective view of the cover 52b of FIG.

  In the present embodiment, the main body 52 includes a case 52 a, a cover 52 b, and a cover fixing screw 58.

  As shown in FIG. 7, the case 52 a is formed in a box shape with one end opening, has a blow-by gas inlet 54 and an air outlet 55, and is attached to the intake side end wall 30 a of the carburetor 30.

  Specifically, one end opening of the case 52a is opened in a substantially rectangular shape, and the case 52a is formed as a generally rectangular box-shaped box. The case 52a is made of a resin member molded by, for example, injection molding. A box bottom wall 52 a 1 of the case 52 a as a box body constitutes a carburetor side end wall 522 of the main body 52. A peripheral wall 52a2 of the case 52a as a box is formed to have a substantially rectangular cylindrical cross section. One end of the peripheral wall 52a2 is closed by the box bottom wall 52a1, and the other end of the peripheral wall 52a2 is open. The peripheral wall 52a2 connects the small rectangular portion 52a3 on one end side, the large rectangular portion 52a4 on the other end side larger than the small rectangular portion 52a3, and the end of the small rectangular portion 52a3 and the end of the large rectangular portion 52a4. And a rectangular ring-shaped flange portion 52a5.

  As shown in FIGS. 7 to 9, an air outlet portion 55 as a tubular body protrudes from the central portion of the box bottom wall 52 a 1 on the inner surface of the box. A central portion of the box bottom wall 52a1 on the outer surface of the box is formed with a large diameter portion 52a6 (see FIG. 9) having a diameter larger than that of the pipe communicating with the pipe of the air outlet 55. The large-diameter portion 52a6 is inserted with the intake inlet side end portion 31a of the mixture passage portion 31 of the carburetor 30. That is, as shown in FIGS. 4 to 6, the intake inlet side end portion 31a of the air-fuel mixture passage portion 31 protrudes from the intake side end wall 30a of the carburetor 30, and the protruding intake inlet side end portion 31a is the bottom of the box. The wall 52a1 is fitted in the large diameter portion 52a6. The box bottom wall 52a1 has a plurality of (two in the figure) bolt through holes 52a7 for insertion of the bolts 32 and mounting holes 52a8 for mounting choke mechanism portions 59 to be described later.

  A blow-by gas inlet 54 as a tubular body protrudes above the large-diameter portion 52a6 on the outer surface of the box bottom wall 52a1. One end of the pipe line of the blow-by gas inlet part 54 opens to the outside, and the other end of the pipe line of the blow-by gas inlet part 54 penetrates the box bottom wall 52a1.

  A first groove 52a9 for forming an internal passage 56 is formed above the air outlet 55 on the inner surface of the box bottom wall 52a1 as shown in FIGS. Specifically, as shown in FIG. 8, the first groove 52 a 9 is located above the blow-by gas inlet portion 54 between the other end of the pipe line of the blow-by gas inlet portion 54 and the vicinity of the pipe wall of the air outlet portion 55. It is formed to bend so as to bypass the bolt through hole 52a7. As shown in FIG. 11, one end of the first groove 52 a 9 is open to the region of the other end of the pipe line of the blow-by gas inlet portion 54. In addition, an annular connection portion 52a10 (see FIGS. 9 and 11) that connects the large diameter portion 52a6 and the air outlet portion 55 in the box bottom wall 52a1 has a tube wall at the proximal end portion of the air outlet portion 55. A second groove 52a11 that penetrates and communicates between the other end of the first groove 52a9 and the duct of the air outlet 55 is formed. The groove opening of the first groove 52a9 constituting the internal passage 56 is covered by the passage forming portion 57b of the collision member 57, and the groove opening of the second groove 52a11 is covered by the intake inlet side end portion 31a of the carburetor 30. . Therefore, in the present embodiment, the internal passage 56 is formed by the groove opening of the first groove 52a9 and the blow-by gas inlet 54 formed in the box bottom wall 52a1 of the case 52a (in other words, the carburetor side end wall 522 of the main body 52). The other end of the pipe is formed by being covered with a passage forming portion 57b. In this manner, the internal passage 56 is formed in cooperation with the carburetor side end wall 522 (box bottom wall 52a1) of the main body 52.

  Moreover, as shown in FIG. 5, the 2nd air cleaner element 51b is arrange | positioned in the site | part of the large rectangular part 52a4 in the surrounding wall 52a2 of case 52a. The peripheral portion of the second air cleaner element 51b is fixed by being sandwiched between a flange portion 52a5 and an end portion of a partition wall 52b2 described later of the cover 52b.

  The cover 52b closes the one end opening of the case 52a and has an outside air inlet 53, and is detachably attached to the case 52a.

  Specifically, as shown in FIGS. 4, 5, 12, and 13, the cover 52 b is generally box-shaped with a large opening at the carburetor 30 side and the fuel tank 40 side (left side and lower side in FIG. 4). Formed. The cover 52b is made of a resin member molded by, for example, injection molding, like the case 52a. The facing wall 52b1 facing the intake side end wall 30a of the carburetor 30 in the cover 52b constitutes the end wall 521 on the opposite side to the carburetor 30 in the main body 52 described above.

  A plurality of outside air inlet portions 53 are formed in the lower portion of the facing wall 52b1. Further, a partition wall 52b2 for accommodating the first air cleaner element 51a protrudes from the inner surface of the box of the opposing wall 52b1. The partition wall 52b2 has a rectangular cylindrical cross section and protrudes from the opposing wall 52b1. The first air cleaner element 51a is accommodated in the partition wall 52b2. The end of the partition wall 52b2 is inserted inside the large rectangular portion 52a4 of the case 52a and presses the peripheral edge of the second air cleaner element 51b.

  As shown in FIG. 5, the cover fixing screw 58 is provided at a portion of the cover 52 b facing the collision portion 57 a, and the one end portion 58 a passes through the filter portion 51. Specifically, the cover fixing screw 58 is provided at the center of the facing wall 52b1 of the cover 52b (that is, the end wall 521 opposite to the carburetor 30 in the main body 52). One end portion 58a of the cover fixing screw 58 passes through the opposing wall 52b1 and the filter portion 51, and the other end portion of the cover fixing screw 58 is exposed to the outside. At the other end of the cover fixing screw 58, a detachable knob 58b that is operated by an operator or the like is formed. The screw portion of one end portion 58 a of the cover fixing screw 58 is configured to be able to be screwed into a screwing portion 57 c described later of the collision member 57. Thereby, the operator can remove the cover 52b from the case 52a by operating the attaching / detaching knob portion 58b of the cover fixing screw 58, and perform maintenance work such as cleaning of the filter portion 51.

  Next, the shape of the collision member 57 will be described in detail with reference to FIGS. 4 to 6 and FIGS. 15 to 17. 15 is a top view of the collision member 57, FIG. 16 is a bottom view of the collision member 57, and FIG. 17 is a partial cross-sectional view taken along line EE in FIG.

  In the present embodiment, the collision member 57 includes a screwing portion 57c in addition to the collision portion 57a and the passage forming portion 57b, and the passage forming portion 57b is the box bottom wall 52a1 of the case 52a (that is, the carburetor side of the main body portion 52). It is fixed to the end wall 522). The screwing part 57c is a part where the one end part 58a of the cover fixing screw 58 is screwed.

  Specifically, the collision portion 57a is disposed so as to face the second region side opening end 55a of the air outlet portion 55, and is formed in a generally rhombus shape in plan view as shown in FIGS. Yes. The blown air-fuel mixture collides with a collision surface 57a1 that faces the second region side opening end 55a of the air outlet 55 in the collision portion 57a.

  Moreover, as shown in FIG. 17, the 1st extending | stretching part 57a2 is extended in the one side part in the collision part 57a. The first extending portion 57a2 extends in the direction perpendicular to the collision surface 57a1 from the one side portion. A first contact portion 57a3 extends in parallel to the collision surface 57a1 at the tip of the first extending portion 57a2. The first abutting portion 57a3 abuts on one (through the lower side in FIG. 5) bolt through hole 52a7 in the box bottom wall 52a1 of the case 52a. The first extending portion 57a2 and the first contact portion 57a3 constitute an L-shaped first leg portion in a side view.

  A second extending portion 57a4 is extended on the opposite side portion of the collision portion 57a that faces the one side portion. The second extending portion 57a4 extends in the direction perpendicular to the collision surface 57a1 from the opposite side portion. A second contact portion 57a5 extends in parallel with the collision surface 57a1 at the tip of the second extending portion 57a4. The second contact portion 57a5 contacts the other bolt through hole 52a7 (upper side in FIG. 5) of the box bottom wall 52a1 of the case 52a. The entirety of the second extending portion 57a4 and the second contact portion 57a5 also constitutes an L-shaped second leg portion in a side view. The second contact portion 57a5 is formed so as to cover all the other ends of the groove opening of the first groove 52a9 and the pipe line of the blow-by gas inlet portion 54 in a state of contacting the box bottom wall 52a1. Therefore, in the present embodiment, the second contact portion 57a5 constitutes the passage forming portion 57b.

  The first contact portion 57a3 and the second contact portion 57a5 have through holes 57a6 through which the bolts 32 are inserted. The first contact portion 57a3 and the second contact portion 57a5 are fixed to the box bottom wall 52a1 of the case 52a by the bolt 32. That is, the collision member 57 is fixed to the box inner surface side (surface on the second region S2 side) of the box bottom wall 52a1 by the bolt 32 so as to straddle the second region side opening end 55a of the air outlet portion 55.

  Then, the screw portion of the one end portion 58a of the cover fixing screw 58 is screwed into the screwing portion 57c of the collision member 57 fixed to the case 52a (box bottom wall 52a1), so that the cover 52b is interposed via the collision member 57. It is fixed to the case 52a.

  Further, the two opposing side portions where the first extending portion 57a2 and the second extending portion 57a4 of the collision portion 57a are not extended are bent toward the air outlet portion 55 side. Therefore, the blown air-fuel mixture that has collided with the collision surface 57a1 is effectively suppressed from flowing toward the filter unit 51.

  In this embodiment, parts other than the screwing part 57c in the collision member 57 are integrally formed of a metal sheet metal member.

  In the present embodiment, the screwing portion 57c is formed in the collision portion 57a as shown in FIG. Specifically, the screwing portion 57c is formed of a nut member that is welded to the collision surface 57a1 with the screw hole center aligned with the hole center of the through hole 57a7 opened in the collision portion 57a.

  In the present embodiment, the cover fixing screw 58 and the screwing portion 57 c are provided on the extension line X of the center line of the air-fuel mixture passage portion 31 of the carburetor 30.

  In the present embodiment, the air cleaner 50 has a choke mechanism 59 for the carburetor 30 as shown in FIGS. 2 and 4 to 6. FIG. 18 is a view showing an assembled state of the choke mechanism.

  The choke mechanism 59 adjusts the opening of the air outlet 55 to adjust the intake amount of the carburetor 30 and is assembled to the case 52 a of the main body 52. The choke mechanism 59 includes a choke plate 59a and an operation choke lever 59b. 2, FIG. 4 to FIG. 6 and FIG. 18 show the state when the opening of the air outlet portion 55 is fully opened. During normal operation of the brush cutter 150, the air outlet portion 55 is fully opened. ing.

  The choke plate 59a is supported so as to be slidable along the second region side opening end 55a of the air outlet portion 55 in a region between the collision portion 57a and the passage forming portion 57b (second contact portion 57a5). . As shown in FIG. 18, one end portion of the choke plate 59 a is formed in a circular shape in accordance with the shape of the second region side opening end 55 a of the air outlet portion 55. The other end portion of the choke plate 59a is connected to one end portion of the choke lever 59b through a connection screw 59c inserted into a mounting hole 52a8 opened in the box bottom wall 52a1 of the case 52a.

  The choke lever 59b is an operating lever member having one end connected to the choke plate 59a and the other end exposed to the outside of the main body 52 (specifically, outside the case 52a). The choke lever 59b is located on the outer side of the box bottom wall 52a1 of the case 52a, and one end thereof is connected to the other end of the choke plate 59a via a connection screw 59c.

  Next, the flow of air, blow-by gas, and blow-back mixture in the air cleaner 50 will be schematically described with reference to FIGS. 5 and 6.

  As indicated by a thick arrow in FIG. 5, the air (outside air) that flows from the outside air inlet portion 53 into the first region S <b> 1 of the storage chamber S passes through the filter portion 51 and is purified. Then, the air purified by the filter unit 51 flows through the second region S2 and the air outlet 55 and is supplied to the air-fuel mixture passage unit 31 of the carburetor 30.

  As indicated by broken line arrows in FIG. 5, the blow-by gas in the valve operating chamber 18 passes through the breather passage 22, the blow-by gas inlet 54, the internal passage 56 (first groove 52 a 9), and the second groove 52 a 11. After flowing into the outlet portion 55, it is then introduced into the mixture passage portion 31 of the carburetor 30. That is, the blowby gas that has flowed into the blowby gas inlet 54 is guided to the air outlet 55 through the internal passage 56 (first groove 52a9).

  As indicated by broken line arrows in FIG. 6, the blown-back mixture flows backward through the air-fuel mixture passage 31 of the carburetor 30, flows into the second region S2 through the air outlet 55, and then collides with the collision part 57a. To do. Therefore, the adhesion of the fuel component in the blow-back mixture to the filter unit 51 is suppressed.

  According to the air cleaner 50 according to the present embodiment, the blow-back mixture from the carburetor 30 collides with the collision portion 57a of the collision member 57, and the blow-by gas in the engine 1 (the valve operating chamber 18) is blow-by gas inlet. 54 flows in. The blow-by gas that has flowed into the blow-by gas inlet portion 54 is formed by the cooperation of the passage forming portion 57b (second contact portion 57a5) of the collision member 57 and the carburetor side end wall 522 (box bottom wall 52a1) of the main body portion 52. Then, the air is guided to the air outlet 55 via the internal passage 56 and then introduced into the carburetor 30.

  As described above, the internal passage 56 for guiding the blow-by gas flowing into the blow-by gas inlet portion 54 to the air outlet portion 55 is replaced by a carburetor that is a portion of the collision member 57 and a portion of the main body 52. Since it can be formed using the side end wall 522, the internal passage 56 can be constructed without providing the components for forming the internal passage 56 separately from the collision member 57 and the main body 52. Therefore, it is possible to provide an air cleaner 50 suitable for constructing a passage structure for supplying blow-by gas to the carburetor 30 in a limited narrow space near the engine.

  In this embodiment, the main body 52 has a case 52a, a cover 52b, and a cover fixing screw 58, and the collision member 57 has a screwing portion 57c into which one end portion 58a of the cover fixing screw 58 is screwed. In addition. The passage forming portion 57 b is fixed to the carburetor side end wall 522 (box bottom wall 52 a 1) of the main body portion 52, and the cover 52 b is fixed to the case 52 a via the collision member 57. The collision member 57 has the adhesion suppressing function in the collision portion 57a, the function of forming the internal passage 56 in the passage formation portion 57b, and the cover fixing function of fixing the cover 52b in the screwing portion 57c. That is, the collision member 57, which is a single member, can be provided with the three functions of the adhesion suppression function, the function of forming the internal passage 56, and the cover fixing function. Therefore, the air cleaner 50 suitable for making the air cleaner 50 compact can be provided.

  In this embodiment, the screwing part 57c is formed in the collision part 57a. Thereby, since the screwing part 57c can be provided in the collision part 57a which will be arrange | positioned in the position close | similar to the filter part 51 rather than the channel | path formation part 57b, the one end part 58a of the cover fixing screw 58 is screwed together. A structure that can be easily screwed into the portion 57c can be configured.

  In the present embodiment, the cover fixing screw 58 and the screwing portion 57 c are provided on the extension line X of the center line of the air-fuel mixture passage portion 31 of the carburetor 30. As a result, the cover fixing screw 58 and the screwing portion 57c can be gathered together with the collision portion 57a on the extension line X of the center line of the air-fuel mixture passage portion 31 of the carburetor 30, so that it is more effective and compact. Can be achieved.

  In this embodiment, parts other than the screwing part 57c in the collision member 57 are integrally formed of a metal sheet metal member. That is, the collision portion 57a, the first extending portion 57a2, the first abutting portion 57a3, the second extending portion 57a4, and the second abutting portion 57a5 (passage forming portion 57b) are integrally formed of a sheet metal member. Thereby, the collision member 57 can be formed easily.

  In the present embodiment, the air cleaner 50 further includes a choke mechanism 59 that adjusts the opening of the air outlet 55 to adjust the intake air amount of the carburetor 30. The choke mechanism 59 includes a choke plate 59a that is slidably supported along the second region-side opening end 55a of the air outlet 55 in the region between the collision portion 57a and the passage forming portion 57b. An operation choke lever 59b having one end connected to the choke plate 59a and the other end exposed to the outside of the main body 52 is configured. As a result, a part (choke plate 59a) of the choke mechanism 59 that adjusts the intake air amount of the carburetor 30 is replaced with the collision part 57a and the passage forming part 57b in the storage chamber S (second region S2) of the air cleaner 50. The space between the two can be used effectively. As a result, the carburetor 30 and the air cleaner 50 as a whole can be made compact, and a more suitable air cleaner 50 can be provided when the carburetor 30 and the air cleaner 50 are arranged together with the carburetor 30 in the narrow space.

  In this embodiment, the case where the blow-by gas inlet portion 54 and the air outlet portion 55 are communicated with each other through the internal passage 56 (first groove 52a9) and the second groove 52a11 has been described as an example. Not only this but you may comprise so that it may be connected only by the internal channel | path 56. FIG. In this case, although not illustrated, for example, the air outlet portion 55 and the case are arranged so that the second region side opening end 55a of the air outlet portion 55 is flush with the groove forming surface of the first groove 52a9 in the case 52a. A box bottom wall 52a1 of 52a is formed. And the 1st groove | channel 52a9 is extended and formed so that a part of 2nd area | region side opening end 55a of the air outlet part 55 may be notched. Thereby, one end of the first groove 52a9 opens to the region of the other end of the pipe line of the blow-by gas inlet 54, and the other end of the first groove 52a9 opens to the second region side opening end 55a of the air outlet 55. Through the tube wall. And the 2nd contact part 57a5 as the channel | path formation part 57b should just be formed according to the shape of this 1st groove | channel 52a9. Thereby, an internal passage 56 that directly communicates between the blow-by gas inlet portion 54 and the air outlet portion 55 can be formed.

  Further, the cover fixing screw 58 and the screwing portion 57c are not limited to the extension line X of the center line of the air-fuel mixture passage portion 31 of the carburetor 30, and may be arranged at appropriate positions. Further, the screwing portion 57c is not limited to the collision portion 57a, and may be provided at an appropriate position of the collision member 57. Although the screwing part 57c shall consist of nut members, it is not restricted to this. For example, a screw hole may be provided at the position of the through hole 57a7 opened in the collision part 57a of the collision member 57, and this screw hole part may be used as the screwing part 57c. Thereby, the whole collision member 57 can be easily formed only by sheet metal processing. The air cleaner 50 has the choke mechanism 59, but the choke mechanism 59 need not be provided.

  Further, the brush cutter 150 has been described as an example of the portable work machine. However, the present invention is not limited thereto, and any portable work machine including the engine 1 and the carburetor 30 may be used. For example, an engine blower or an engine cutter may be used. There may be.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the said embodiment, A various deformation | transformation and change are possible based on the technical idea of this invention.

DESCRIPTION OF SYMBOLS 1 ... Engine, 30 ... Carburetor, 30a ... Inlet side wall of carburetor, 31 ... Mixture passage part of carburetor, 50 ... Air cleaner (air cleaner for engine), 51 ... Filter part, 52 ... Main part, 522 ... Main part Carburetor side end wall, 52a ... Case, 52a1 ... Box bottom wall (carburetor side end wall of the main body), 52b ... Cover, 53 ... Outside air inlet part, 54 ... Blowby gas inlet part, 55 ... Air outlet part, 55a ... Air outlet 2nd region side opening end of the part, 56 ... internal passage, 57 ... collision member, 57a ... collision part, 57a5 ... second contact part (passage formation part), 57b ... passage formation part, 57c ... screwing part, 58 ... cover fixing screw, 58a ... one end of cover fixing screw, 59 ... choke mechanism, 59a ... choke plate, 59b ... choke lever, 150 ... brush cutter (portable work machine) , S ... accommodation chamber, S1 ... first area, S2 ... second region, X ... extension line

Claims (6)

Provided in a portable work machine having an engine and a carburetor, and having a storage chamber for storing a filter section for purifying air to be supplied to the carburetor, and a collision member that collides with a blown mixture from the carburetor. An air cleaner for an engine,
A main body having the accommodating chamber inside and attached to an intake side end wall of the carburetor;
An outside air inlet through which outside air flows,
A blow-by gas inlet into which blow-by gas in the engine flows;
An air outlet that is connected to the carburetor and flows out of the air after passing through the filter;
An internal passage for guiding the blow-by gas flowing into the blow-by gas inlet to the air outlet;
Including
The blow-by gas inlet part and the air outlet part are formed on a carburetor side end wall of the main body part,
The storage chamber is partitioned by the filter portion into a first region to which the outside air inlet portion is connected and a second region to which the air outlet portion is connected and the collision member is stored.
The collision member is
A collision part located between the second region side opening end of the air outlet part and the filter part, and the blown air-fuel mixture collides,
A passage forming portion that forms the internal passage in cooperation with the carburetor side end wall of the main body portion;
An air cleaner for an engine having The main body is
A case which is formed in a box shape with one end opening and has the blow-by gas inlet and the air outlet, and is attached to the intake side end wall of the carburetor;
A cover that closes the one end opening of the case and has the outside air inlet, and is detachably attached to the case;
A cover fixing screw provided at a portion of the cover facing the collision portion and having one end portion penetrating the filter portion;
Have
The collision member further includes a screwing portion into which the one end portion of the cover fixing screw is screwed, and the passage forming portion is fixed to the carburetor side end wall of the main body portion,
The engine air cleaner according to claim 1, wherein the cover is fixed to the case via the collision member.   The engine air cleaner according to claim 2, wherein the screwing portion is formed in the collision portion.   The engine air cleaner according to claim 2 or 3, wherein the cover fixing screw and the screwing portion are provided on an extension line of a center line of an air-fuel mixture passage portion of the carburetor.   The engine air cleaner according to any one of claims 1 to 4, wherein at least the collision portion and the passage formation portion of the collision member are integrally formed by a thin sheet metal member. A choke mechanism for adjusting the opening of the air outlet and adjusting the intake amount of the carburetor;
The choke mechanism portion includes a choke plate that is slidably supported along the second region side opening end of the air outlet portion in a region between the collision portion and the passage forming portion, and one end portion of the choke mechanism portion is The engine air cleaner according to any one of claims 1 to 5, further comprising an operation choke lever connected to the choke plate and having the other end exposed to the outside of the main body.