JP2015132235A - Portable work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable work machine which performs icing measures of a carburetor so that an engine is less likely to stall in cold areas.SOLUTION: A portable work machine 1 having an engine 25 and a carburetor 23 includes: a division member 61 which divides the engine 25 from the carburetor 23; an air hole 62 which is formed in the division member 61; and a hole cover 66 which closes the air hole 62 so as to open the air hole 62. The hole cover 66 is disposed at the air hole 62 or an area near the air hole 62 when opening the air hole 62 and functions as an airflow guide that guides air flowing from the engine side of the division member 61 to the carburetor side through the air hole 62.

Description

  The present invention relates to a portable work machine.

In a portable work machine, an engine is used to drive a tool such as a brush cutter. This engine is housed in a casing together with a carburetor or the like in order to prevent a high temperature part from being exposed to the outside.
In Patent Documents 1 and 2, a partition member such as an air guide plate or a casing wall is provided between the engine and the carburetor. The partition member can partition the space in which the carburetor is provided and the space in which the engine is provided in the casing, so that the heat of the engine is hardly transmitted to the carburetor. It is difficult for the gasoline in the carburetor to vaporize due to the heat of the engine after using the portable work machine. As the gasoline in the carburetor vaporizes, the restartability of the engine deteriorates.

Japanese Utility Model Publication No. 04-077755 JP 2003-139033 A

By the way, the portable work machine is used not only in a tropical region and a temperate region where the restartability of the engine is a concern, but also in a cold region and a very cold region. In portable work machines used in cold regions and extremely cold regions, measures different from the above-described measures against high temperatures are required. For example, when a portable work machine is used in a cold region, fuel is vaporized in the carburetor and cooling of the carburetor proceeds. In the cooled carburetor, water in gasoline may freeze and the engine may stall. . A portable work machine needs icing countermeasures for carburetors.
Therefore, as disclosed in Patent Document 1 or 2, it is conceivable that air holes are formed in a partition member that partitions the engine cylinder and the carburetor, and a cover for the air holes is rotatably attached to the partition member. In this case, it is considered that the air hole can be opened by rotating the cover of the air hole along the side surface of the partition member, and the air warmed by the engine can be sent to the carburetor side through the air hole. It is considered that the progress of cooling of the carburetor can be suppressed by the heat of the air warmed by the engine.
However, as disclosed in Patent Documents 1 and 2, simply rotating the air hole cover rotatably attached to the partition member to open the air hole formed in the partition member is used in cold regions and extremely cold regions. In some portable work machines, sufficient heat cannot be sent to the carburetor side to prevent freezing of water in gasoline in the carburetor. In portable work machines used in cold regions and extremely cold regions, carburetor icing measures are not sufficient.

  As described above, the portable work machine is required to implement sufficient measures for icing the carburetor when used in a cold region or a very cold region.

  The portable work machine according to the present invention is a portable work machine having an engine and a carburetor, and can open a partition member that partitions the engine and the carburetor, an air hole formed in the partition member, and an air hole. The hole cover is disposed at or near the air hole when opening the air hole, and serves as an airflow guide for air flowing from the engine side of the partition member to the carburetor side through the air hole. Function.

  Preferably, the hole cover has a guide surface extending in a direction standing with respect to a side surface of the partition member in which the air hole is opened when the hole cover is disposed at or near the air hole so as to open the air hole, It is preferable to direct the flow of air flowing from the engine side of the partition member to the carburetor side through the air hole in a direction away from the side surface of the partition member where the air hole opens.

  Preferably, the hole cover has a cover part that closes so that the air hole can be opened, and the cover part has a closed position that closes the air hole and an open position near the air hole that opened the air hole. It is preferable that one surface of the cover portion in the open position functions as a guide surface that stands against the side surface of the partition member near the air hole.

  Preferably, the casing includes a casing that accommodates the engine, the carburetor, and the partition member, and a first slit and a second slit formed in the casing, and the hole cover is changed between the first slit and the second slit. When the cover portion is inserted into the first slit, the air hole is closed at the closed position, and when the cover portion is inserted into the second slit, the air hole is preferably opened at the open position.

  Preferably, the first slit and the second slit are formed side by side in the casing, and the hole cover is integrated with the cover portion, and is fixed to the outside of the casing with the cover portion inserted into the first slit. There is a fixing part that is fixed to the outside of the casing in a state of being inserted into the two slits, and the fixing part includes a case where the cover part is inserted into the first slit and a case where the cover part is inserted into the second slit. And it is good to fix to a different direction or position in the outer side of a casing.

  Preferably, the casing includes a casing that accommodates the engine, the carburetor, and the partition plate, and a slide slit formed in the casing. The hole cover is slidably inserted into the slide slit, and the hole cover is slid by sliding. The part may be switched between a closed position and an open position.

  Preferably, the hole cover has an operation part that is integrated with the cover part and is located outside the casing in a state in which the hole cover is inserted into the slide slit, and the operation part is provided when the cover part is in the closed position. It is good to be operated to a different position on the outside of the casing depending on the case where it is in the open position.

  Preferably, the casing has a casing that accommodates the engine, the carburetor, and the partition plate, and a through hole formed in the casing. The hole cover is rotatably inserted into the through hole, and the hole cover rotates to rotate the cover. The part may be switched between a closed position and an open position.

  Preferably, the hole cover has an operation part that is integrated with the cover part and is located outside the casing, and the operation part has a casing in a case where the cover part is in a closed position and a case in which the cover part is in an open position. It is good to be operated in different directions on the outside.

When the portable work machine of the present invention is used in a cold region or an extremely cold region, the air hole formed in the partition member is opened, and the hole cover is disposed at or near the air hole. The hole cover can function as an airflow guide for air flowing from the engine side of the partition member to the carburetor side through the air hole.
Therefore, the flow of air from the engine side of the partition member to the carburetor side through the air hole is improved. The air warmed by the engine can efficiently move to the carburetor side through the air hole due to the rectifying effect by the hole cover arranged at or near the air hole.
As a result, when a portable work machine is used in a cold region or a very cold region, sufficient measures for icing the carburetor can be implemented. It can be expected to take measures against carburetor icing to such an extent that the engine is less likely to stall in cold regions.

FIG. 1 is a perspective view of a brush cutter according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram of the usage posture of the brush cutter of FIG. FIG. 3 is a top view of the engine module of FIG. 4 is a cross-sectional view taken along the line A-A ′ of the engine module of FIG. 3. FIG. 5 is an explanatory diagram of a replaceable opening / closing mechanism according to the first embodiment of the present invention. FIG. 6 is an explanatory diagram when the air hole is closed by the hole cover of FIG. 5. FIG. 7 is an explanatory diagram showing the flow of air in the casing when the air hole of FIG. 5 is closed by the cover portion. FIG. 8 is an explanatory diagram of opening the air holes of FIG. FIG. 9 is an explanatory view showing the flow of air in the casing when the air hole of FIG. 5 is opened. FIG. 10 is an explanatory diagram of a rotary opening / closing mechanism according to the second embodiment of the present invention. FIG. 11 is an explanatory diagram when the air hole is closed by the hole cover of FIG. 10. FIG. 12 is an explanatory diagram for opening the air hole of FIG. FIG. 13 is an explanatory diagram illustrating a modification of the second embodiment. FIG. 14 is an explanatory view of a sliding type opening / closing mechanism according to the third embodiment of the present invention. FIG. 15 is an explanatory diagram of a state in which the air hole of FIG. 14 is opened. FIG. 16 is a partial cross-sectional view showing a state in which the sliding hole cover of FIG. 14 is opened. FIG. 17 is an explanatory diagram illustrating a modification of the third embodiment. FIG. 18 is an explanatory view showing a modification of the replaceable opening / closing mechanism. FIG. 19 is an explanatory view showing a modification of the rotary opening / closing mechanism. FIG. 20 is an explanatory view showing a first modification of the sliding type opening / closing mechanism. FIG. 21 is an explanatory view showing a second modification of the sliding type opening / closing mechanism.

[First Embodiment]
FIG. 1 is a perspective view of a brush cutter 1 according to a first embodiment of the present invention. The brush cutter 1 is an example of a portable work machine.
The brush cutter 1 in FIG. 1 includes, for example, an operating rod 2, a tool mounting portion 3, an engine module 4, and a handle 5.
The operation rod 2 is formed of, for example, a long pipe member. The operating rod 2 may be a divided structure that connects a plurality of pipes. In the longitudinal direction of the operating rod 2, an engine module 4 is provided at the rear end, a tool mounting portion 3 is provided at the front end, and a handle 5 is attached at the center. Between the fixing member 6 and the engine module 4, a vibration-proof housing 7 that covers the periphery of the operating rod is provided.
The tool mounting unit 3 includes, for example, a tool chuck 11 and a tool cover 12. The tool chuck 11 is rotatably attached to the other end of the operation rod 2. A tool is detachably brought into the tool chuck 11. Tools include circular cutting blades. The tool cover 12 covers the rear side of the tool attached to the tool chuck 11.
The engine module 4 has a casing 28. As described later, the engine 25 and the like are accommodated in the casing 28. The output shaft of the engine 25 and the tool chuck 11 are connected by a drive shaft that is rotatably disposed in the operation rod 2. The tool chuck 11 is rotationally driven by the driving force of the engine 25.
The handle 5 is, for example, a U-shaped pipe. A central portion of the U-shaped handle 5 is fixed to the operation rod 2 by a fixing member 6. At both ends of the U-shaped pipe, a pair of grips that the operator holds with both hands are arranged. An accelerator lever or the like is disposed around the grip.

FIG. 2 is an explanatory diagram of the usage posture of the brush cutter 1 of FIG.
FIG. 2 shows the operator together with the brush cutter 1.
A hanger 8 is attached to the outer periphery of the vibration-proof housing 7 of the brush cutter 1. The hanger 8 is connected to the hanging tool 9. When the worker wears the lifting tool 9, the brush cutter 1 is suspended from the shoulder of the worker.
The operator hangs the brush cutter 1 from the shoulder, holds the handle 5 with both hands, and operates the brush cutter 1. The operator holds the handle 5 in a state where the cutting blade is lifted from the ground, and moves forward while swinging the brush cutter 1 left and right, for example. Thereby, the grass in front of the worker is mowed.
Hereinafter, front, back, left, right, up and down are used with reference to the use posture of FIG.

FIG. 3 is a top view of the engine module 4 of FIG.
FIG. 4 is a cross-sectional view of the engine module 4 of FIG. 3 taken along the line AA ′. FIG. 4 is a view of the longitudinal section of the engine module 4 as viewed from the rear side.
The engine module 4 includes a tank 21, an air cleaner 22, a carburetor 23, an insulator 24, an engine 25, a muffler 26, a cooling fan 27, and a casing 28.

The casing 28 is formed of, for example, a heat resistant resin. The casing 28 is formed, for example, in a substantially cubic box shape without a bottom.
An engine 25 is disposed in the center of the box-shaped casing 28. An air cleaner 22 and a carburetor 23 are disposed on the left side of the engine 25. A tank 21 is attached below the air cleaner 22 and the carburetor 23. A muffler 26 is disposed on the right side of the engine 25. As shown in FIG. 3, a cooling fan 27 is disposed on the rear side of the engine 25.
In this case, the casing 28 covers the periphery of the air cleaner 22, the carburetor 23, the insulator 24, the engine 25, the muffler 26, and the cooling fan 27 together with the tank 21. Heat generating parts such as the engine 25 and the heated parts of the muffler 26 and the carburetor 23 are not exposed to the outside.
A plurality of case slits 31 for ventilation are formed in the casing 28 covering the periphery of the engine 25 and the like. As shown in FIG. 3, the ventilation case slit 31 is formed, for example, on the left surface, the right surface, the rear surface, and the upper surface of the substantially cubic casing 28. The case slit 31 on the left side is a slit for the air cleaner 22 to take in outside air. The rear case slit 31 is a slit for the cooling fan 27 to suck in outside air. The case slit 31 on the right side is a slit for exhausting the air in the casing 28 that has been warmed by cooling the engine 25 and the like. The case slit 31 on the right side of the rear surface is a slit for exhausting exhaust gas from the muffler 26.

The engine 25 generates driving force. The engine 25 of this embodiment is a four-cycle engine. The engine 25 may be a two-cycle engine. The engine 25 includes a crankcase 41, a cylinder block 42, and a cylinder head 43. The crankcase 41, the cylinder block 42, and the cylinder head 43 constitute an engine body.
The cylinder block 42 has a substantially columnar outer shape. A cylindrical cylinder chamber 44 is formed in the columnar cylinder block 42. A plurality of fins 46 are formed on the outer peripheral surface of the columnar cylinder block 42 so as to be arranged vertically.
And in order to comprise an engine main body, the cylinder head 43 is attached on the cylinder block 42. As shown in FIG. A crankcase 41 is attached under the cylinder block 42. A crank chamber 47 is formed in the crankcase 41. The crank chamber 47 and the cylinder chamber 44 form an inner space 48 of the engine 25. An internal space 48 of the engine 25 is a closed space covered with the crankcase 41, the cylinder block 42, and the cylinder head 43.
A piston 45 is disposed in the cylinder chamber 44. The piston 45 moves up and down in the cylinder chamber 44.
A crankshaft 49 is rotatably disposed in the crank chamber 47. A balance weight 50 is fixed to the crankshaft 49. The balance weight 50 is connected to the piston 45 by a connecting rod 51. When the piston 45 moves up and down in the cylinder chamber 44, the crankshaft 49 is rotated by the link mechanism including the connecting rod 51 and the balance weight 50. The rotation of the crankshaft 49 is transmitted to the drive shaft through the output shaft. The tool is driven.
A space between the piston 45 and the cylinder head 43 becomes a combustion chamber. An ignition plug (not shown) is provided in the combustion chamber. An intake port 52 and an exhaust port 53 communicate with the combustion chamber. The intake port 52 is provided with an intake valve 54. The exhaust port 53 is provided with an exhaust valve 55. The intake valve 54 and the exhaust valve 55 are opened and closed in accordance with the rotation of the crankshaft 49 by an OHV (Over Head Valve) type valve mechanism composed of a camshaft, a rocker arm, and the like.

In the four-cycle engine 25, the air-fuel mixture burns in the combustion chamber when the exhaust valve 55 and the intake valve 54 are closed. The piston 45 moves downward in FIG. 4 due to the expansion pressure of the burned air-fuel mixture. Thereby, the crankshaft 49 rotates. Further, the drive shaft connected to the crankshaft 49 rotates.
As the crankshaft 49 rotates, the piston 45 that has passed the bottom dead center moves upward in FIG. The exhaust valve 55 is opened, and the exhaust gas in the combustion chamber is output to the exhaust port 53.
When the crankshaft 49 further rotates and the piston 45 passes the top dead center, the exhaust valve 55 is closed and the intake valve 54 is opened. New fuel and air are drawn from the intake port 52 into the combustion chamber.
When the crankshaft 49 further rotates and the piston 45 passes the bottom dead center, the intake valve 54 is closed. The fuel and air in the combustion chamber are compressed as the piston 45 rises.
The spark plug is ignited at a timing immediately after the piston 45 passes through the top dead center. The fuel compressed in the combustion chamber burns.
By repeating the above intake, compression, combustion, and exhaust combustion cycles, the crankshaft 49 rotates continuously. The drive shaft rotates together with the crankshaft 49. The tool attached to the mounting part 3 is rotationally driven.

The tank 21 stores fuel such as gasoline and alcohol.
The air cleaner 22 sucks outside air.
The tank 21 and the air cleaner 22 are connected to the carburetor 23.
The carburetor 23 is connected to the intake port 52 of the engine 25 via the insulator 24.
The carburetor 23 includes, for example, a venturi tube and a diaphragm. The venturi tube is supplied with air sucked by the air cleaner 22 and fuel supplied from the tank 21. The fuel is supplied to the venturi pipe by a diaphragm that operates based on the negative pressure from the engine 25, for example. The fuel supplied to the venturi is vaporized in the venturi. The fuel absorbs the heat of vaporization when it is vaporized. A mixture of fuel and air is formed. The air-fuel mixture is supplied to the intake port 52 of the engine 25 through the insulator 24. The air-fuel mixture is sucked into the combustion chamber of the engine 25 and burned in the combustion chamber.
The muffler 26 is connected to an exhaust port 53 of the engine 25. The muffler 26 cools and dilutes the exhaust gas discharged from the engine 25 and discharges it to the outside.

The cooling fan 27 mainly cools the engine 25 and the muffler 26. As shown in FIG. 4, a plurality of fins 46 are formed on the outer peripheral surface of the cylinder block 42. The fins 46 are formed along the circumferential direction of the cylinder block 42. The plurality of fins 46 are formed vertically overlapping the cylinder block 42. The cooling fan 27 is arranged upright on the rear side of the engine 25 as shown in FIG. The cooling fan 27 is rotationally driven by the rotation of the crankshaft 49, for example.
As the cooling fan 27 rotates, outside air is sucked into the casing 28 from the case slit 31 at the center of the rear surface of the casing 28. The sucked outside air advances forward and flows between the plurality of fins 46 of the engine 25. At this time, when passing between the plurality of fins 46, the heat of the engine 25 is transmitted to the outside air, and the engine 25 is cooled.
The air heated by the heat of the engine 25 reaches the front surface of the casing 28 after passing through the engine 25. As will be described later, a partition plate 61 that partitions the engine 25 and the carburetor 23 is provided on the left side of the engine 25, so that air that has reached the front surface of the casing 28 extends along the front surface of the casing 28. It moves to the right side where the muffler 26 is provided, and is exhausted out of the casing 28 through the case slit 31 on the right side of the casing 28 and the case slit 31 on the top surface.
In this way, the engine 25 and the muffler 26 are cooled by the outside air.

By the way, in the brush cutter 1, in order to reduce the size of the engine module 4 and improve workability, the carburetor 23 is directly connected to the engine 25, and the carburetor 23 is disposed as close to the cylinder block 42 of the engine 25 as possible. .
However, if the carburetor 23 is disposed near the engine 25, the heat of the engine 25 is easily transmitted to the carburetor 23. For example, to the carburetor 23 attached directly to the engine 25, the heat of the engine 25 is directly transmitted to the carburetor 23. When the engine 25 is stopped with the intake port 52 opened, the heated exhaust gas in the combustion chamber flows backward toward the carburetor 23. When these heats are transmitted, the carburetor 23 is heated and a part of gasoline in the carburetor 23 is vaporized. If the highly volatile component in gasoline volatilizes, the restartability of the engine 25 deteriorates.

Therefore, in the brush cutter 1, the carburetor 23 is fixed to the cylinder block 42 of the engine 25 with the insulator 24 interposed, as shown in FIG. 4. A partition plate 61 is provided between the engine 25 and the carburetor 23.
The partition plate 61 is formed integrally with the insulator 24 using, for example, a heat resistant resin material. The partition plate 61 of FIG. 4 is integrated with the insulator 24 in a state where the insulator 24 passes through the substantial center thereof. The partition plate 61 extends around the insulator 24. The outer peripheral edge of the partition plate 61 contacts the inner peripheral surface of the casing 28. The space in the casing 28 is separated by the partition plate 61 into a space in which the cylinder block 42 is disposed and a space in which the carburetor 23 is disposed.
Thereby, the air warmed by the engine 25 does not flow toward the carburetor 23. It becomes difficult for the heat on the engine 25 side to be transmitted to the carburetor 23. The restartability of the engine 25 can be improved. Good restartability is obtained.

While such a measure for preventing the carburetor 23 from being heated is required, the brush cutter 1 is also used, for example, in extremely cold regions, and measures for cold regions are required. In the brush cutter 1 used in a cold region or a very cold region, a countermeasure different from the above-described countermeasure against high temperature is required.
For example, when the brush cutter 1 is used in a cold region, the fuel is vaporized in the carburetor 23, the cooling of the carburetor 23 proceeds, the water in the gasoline freezes in the cooled carburetor 23, and the fuel supply is stopped. May stall. The brush cutter 1 needs to take measures against icing of the carburetor 23.

Therefore, in the present embodiment, air holes 62 are formed in the partition plate 61, and the air holes 62 are closed using a removable hole cover 66. Thereby, the cooling air warmed by the engine 25 can be introduced from the space in which the engine 25 is disposed to the space in which the carburetor 23 is disposed as necessary.
When the air hole 62 is opened, the hole cover 66 is disposed near the air hole 62 to form an airflow guide for the air flowing from the engine plate 25 side of the partition plate 61 to the carburetor 23 side through the air hole 62. By this airflow guide, the airflow of the air flowing from the engine 25 side of the partition plate 61 to the carburetor 23 side through the air hole 62 is improved.
With these measures, the brush cutter 1 implements sufficient icing measures for the carburetor 23 when used in a cold region or a very cold region.

  FIG. 5 is an explanatory diagram showing the partition plate 61, the upper part of the casing 28, and the hole cover 66 according to the first embodiment of the present invention. The hole cover 66 in FIG. 5 is detachable.

  FIG. 5 shows the left side surface S1 of the partition plate 61 on the carburetor 23 side. An insulator 24 to which the carburetor 23 is attached is located in the center of the left side surface S1 of the partition plate 61. An air hole 62 is formed on the front side of the insulator 24. The air holes 62 are aligned with the insulator 24 in the front-rear direction.

  The air hole 62 is formed in a rectangular shape that is long in the vertical direction. The air hole 62 allows communication between the space where the engine 25 for the partition plate 61 is disposed and the space where the carburetor 23 is disposed.

  A holder 63 for the hole cover 66 is formed on the left side surface S <b> 1 on the carburetor 23 side of the partition plate 61. The holder 63 is formed along the front edge, the rear edge, and the lower edge of the rectangular air hole 62. The hole cover 66 is inserted between the holder 63 and the left side surface S <b> 1 of the partition plate 61. The hole cover 66 can block the air hole 62.

A first slit 64 and a second slit 65 are formed in the upper surface portion of the casing 28.
The first slit 64 is a slit that is long in the front-rear direction. In the state where the casing 28 and the partition plate 61 are assembled as shown in FIG. 5, the first slit 64 is positioned directly above the holder 63. The first slit 64 extends in the front-rear direction along the left side surface S <b> 1 extending in the front-rear direction of the partition plate 61.
The second slit 65 is a slit that is long in the left-right direction. In a state where the casing 28 is assembled with the partition plate 61, the second slit 65 is located on the front side of the first slit 64. The second slit 65 is located on the left side of the carburetor 23 with reference to the left side surface S <b> 1 extending in the front-rear direction of the partition plate 61.
The first slit 64 and the second slit 65 are formed in the casing 28 side by side at an angle of 90 degrees. The first slit 64 and the second slit 65 are formed side by side on the casing 28 so as to cross each other. The right end of the second slit 65 and the front end of the first slit 64 are close to each other.

The hole cover 66 has a cover part 67 and a fixing part 68.
The hole cover 66 is made of resin, for example.

The cover portion 67 overlaps with the air hole 62 and closes the air hole 62.
The cover part 67 has a long rectangular plate shape. The cover 67 is formed with a width wider than the width of the air hole 62 in the front-rear direction. The cover portion 67 of the present embodiment is formed to be vertically longer than the air holes 62. The cover portion 67 has a length extending from the first slit 64 to the lower end of the air hole 62.
The cover part 67 is inserted into the first slit 64 or the second slit 65.
When inserted into the first slit 64, the cover portion 67 is inserted between the left side surface S <b> 1 of the partition plate 61 and the holder 63. The lower end of the cover part 67 hits the holder 63. The cover portion 67 overlaps with the air hole 62 and closes the air hole 62. In this state, the upper end of the cover portion 67 protrudes outside the casing 28.

The fixing portion 68 has a rectangular plate shape.
The fixing portion 68 is connected to the upper end of the cover portion 67. The cover part 67 and the fixed part 68 are connected in a substantially L shape.
A fixing hole 69 is formed in the fixing portion 68. In a state where the cover portion 67 is inserted into the first slit 64 or the second slit 65, the fixing portion 68 overlaps the outer surface of the casing 28. By inserting the screw 70 into the fixing hole 69 in this state, the fixing portion 68 can be fixed to the casing 28 as shown in FIG.
Further, the hole cover 66 can be replaced between the first slit 64 and the second slit 65 by removing the screw 70.

FIG. 6 is an explanatory diagram when the air hole 62 is closed by the hole cover 66. FIG. 6A is a partial top view of the casing 28. FIG. 6B is a partial cross-sectional view of the engine module 4. FIG. 6B is a top view of the cross section at the position BB ′ in FIG.
When the air hole 62 is closed by the hole cover 66, the cover portion 67 of the hole cover 66 is inserted into the first slit 64. The fixing portion 68 of the hole cover 66 is screwed to the upper surface of the casing 28 in the left-right direction. The cover part 67 is fixed in the front-rear direction so as to close the air hole 62. The air hole 62 is closed and closed by the cover portion 67.

FIG. 7 is an explanatory view showing the flow of air in the casing 28 when the air hole 62 is closed by the cover portion 67.
Due to the wind force of the cooling fan 27 installed on the rear side of the engine 25, an air flow is generated in the casing 28 from the rear to the front around the engine 25. The air passes between the fins 46 of the engine 25 and hits the front surface of the casing 28. Thereafter, the air is regulated by the partition plate 61 and discharged outside through the case slit 31 formed on the right side of the casing 28.
In FIG. 7, the air hole 62 is closed by the cover portion 67. The air warmed by being used for cooling the engine 25 does not flow from the engine 25 side to the carburetor 23 side of the partition plate 61. The carburetor 23 is not heated by the cooling air. Deterioration of restartability due to heating of the carburetor 23 is unlikely to occur.

FIG. 8 is an explanatory diagram when the air hole 62 is opened. FIGS. 8A and 8B correspond to FIGS. 6A and 6B.
When opening the air hole 62, the cover portion 67 of the hole cover 66 is inserted into the second slit 65. The fixing portion 68 of the hole cover 66 is screwed to the upper surface of the casing 28 in the front-rear direction. The cover part 67 is fixed in the left-right direction along the hole direction of the air hole 62. The cover portion 67 is disposed near the front side of the air hole 62. The cover part 67 is arranged side by side with the holder 63. The flat plate surface 67S of the cover portion 67 extends in the left-right direction and is aligned with the front edge of the air hole 62 in a straight line.

FIG. 9 is an explanatory diagram showing the flow of air in the casing 28 when the air hole 62 is opened.
Due to the wind force of the cooling fan 27 installed on the rear side of the engine 25, an air flow is generated in the casing 28 from the rear to the front around the engine 25. The air passes between the fins 46 of the engine 25 and hits the front surface of the casing 28. Thereafter, the air is regulated by the partition plate 61 and discharged outside through the case slit 31 formed on the right side of the casing 28.
In the case of FIG. 9, the air hole 62 is open. A part of the air warmed by being used for cooling the engine 25 flows from the engine 25 side to the carburetor 23 side of the partition plate 61 through the air holes 62.
The flat plate surface 67S of the cover part 67 is arranged upright on the left side surface S1 of the partition plate 61. The air that has flowed into the carburetor 23 side moves toward the hole direction of the air hole 62 so as to be away from the left side surface S <b> 1 of the partition plate 61. The air that has flowed in moves directly from the air hole 62 toward the position where the carburetor 23 is arranged without being collected around the partition plate 61, and is blown directly onto the carburetor 23. Thereafter, the air passes around the carburetor 23 and is discharged outside from a case slit 31 formed on the rear left side of the casing 28.
Thereby, the carburetor 23 is warmed by the air warmed by the engine 25. A gasoline supply tube or the like disposed around the carburetor 23 is also warmed. As a result, even if the fuel is vaporized in the carburetor 23 and the carburetor 23 is cooled, the cooling of the carburetor 23 is difficult to proceed. Moisture in gasoline becomes difficult to freeze in the carburetor 23. Therefore, it becomes difficult to stop the fuel supply due to freezing of water in gasoline in the carburetor 23, and the engine 25 is difficult to stall. Even if the brush cutter 1 is used in a cold region, the engine 25 is less likely to stall.

As described above, in the present embodiment, the hole cover 66 is replaced between the first slit 64 and the second slit 65 formed in the casing 28. Replacing the hole cover 66 at a timing such as the turn of the season makes it difficult for the engine 25 to stall even in the cold season. Further, the hole cover 66 can be fixed to the casing 28. The replaced hole cover 66 is difficult to drop off from the casing 28. It is difficult to remove the hole cover 66.
When the hole cover 66 is inserted into the first slit 64, the air hole 62 formed in the partition plate 61 is closed. When used at a normal operating temperature, the space on the engine 25 side and the space on the carburetor 23 side of the partition plate 61 can be separated. It becomes difficult for the heat of the engine 25 to be transmitted to the carburetor 23. The volatilization of gasoline from the carburetor 23 can be suppressed. The occurrence of problems such as restartability due to the volatilization of gasoline from the carburetor 23 can be suppressed. For example, in a warm region other than a cold region or a very cold region, it can be used all year round in this state. The engine 25 can be used throughout the year without deteriorating the restartability of the engine 25.
On the other hand, the hole cover 66 is inserted into the second slit 65 when used in a cold region or an extremely cold region where freezing of moisture in gasoline is a problem. The air hole 62 is opened. The cooling air warmed by cooling the engine 25 is introduced to the carburetor 23 side through the air holes 62.

In addition, the hole cover 66 is inserted into the second slit 65 and fixed. Near the air hole 62, the cover portion 67 of the hole cover 66 is arranged upright on the left side surface S <b> 1 where the air hole 62 for the partition plate 61 opens. The cover part 67 is arranged upright near the air hole 62.
The cooling air of the engine 25 introduced to the carburetor 23 side moves along the rear surface of the cover portion 67 and moves so as to be directly blown onto the carburetor 23. The cooling air warmed by the engine 25 warms the carburetor 23. Even if the water in the gasoline is frozen, it is difficult to clog the ice in the carburetor 23. Engine stall can be effectively suppressed.
On the other hand, when the hole cover 66 is not raised with respect to the left side surface S1 where the air hole 62 opens, the cooling air of the engine 25 introduced to the carburetor 23 side moves while the air flow on the engine 25 side remains unchanged. To do. The cooling air introduced to the carburetor 23 side moves toward the front surface of the casing 28. The cooling air introduced to the carburetor 23 side is cooled on the front surface of the casing 28. The cooling air introduced to the carburetor 23 side circulates and cools in the space where the carburetor 23 is disposed, and then travels toward the carburetor 23. The cooling air introduced into the carburetor 23 side is cooled when it reaches the carburetor 23. The carburetor 23 cannot be warmed appropriately. Even if the air holes 62 are formed in the partition plate 61, ice is easily clogged in the carburetor 23. Engine stall is likely to occur.

  In the present embodiment, the hole cover 66 is fixed to the casing 28 by replacing the first slit 64 or the second slit 65 formed in the casing 28. The casing 28 is a member that is integrated with the partition plate 61 by assembly. In addition, for example, the first slit 64 and the second slit 65 for detachably attaching the hole cover 66 may be formed in the partition plate 61 itself. In this case, for example, an opening / closing part is provided in the casing 28, and the operator may open the opening / closing part and replace the hole cover 66. The hole cover 66 can be replaced from the outside of the brush cutter 1 without opening the casing 28 situation.

In the present embodiment, the hole cover 66 is fixed by being replaced between the first slit 64 and the second slit 65 formed in the casing 28. As shown in FIGS. 6A and 8A, the hole cover 66 is fixed in different directions on the outer surface of the casing 28 of the brush cutter 1. The operator can easily grasp whether the air hole 62 is open or closed depending on the fixing direction of the hole cover 66. The setting state of the air hole 62 can be easily understood.
On the other hand, for example, if the hole cover 66 is fixed at the same position on the casing 28 by changing the direction, it is not easy to know the open / closed state of the air hole 62 from the fixed state of the hole cover 66. In order to know the open / closed state of the air holes 62, it is necessary to remove and check the hole cover 66 from the casing 28.

  In the present embodiment, the hole cover 66 is fixed in different directions on the outer surface of the casing 28. In addition, for example, the hole cover 66 may be fixed at different positions on the outer surface of the casing 28. For example, in the case of FIG. 8A, the fixing portion 68 may be fixed to the front side of the second slit 65. Even in this case, the operator can easily confirm the open / closed state of the air hole 62 without removing the hole cover 66 from the casing 28.

[Second Embodiment]
Next, the brush cutter 1 according to the second embodiment of the present invention will be described.
The brush cutter 1 according to the present embodiment is the same as the brush cutter 1 according to the first embodiment except that the mechanism for opening and closing the air holes 62 of the partition plate 61 is changed from the replacement type to the rotary type. Illustrations and descriptions are omitted by using symbols and names.

FIG. 10 is an explanatory diagram of a rotary opening / closing mechanism according to the second embodiment of the present invention.
A through hole 71 is formed in the upper surface portion of the casing 28.
The through hole 71 is located substantially above the front edge of the air hole 62 formed in the partition plate 61. The through hole 71 is located on the left side on the carburetor 23 side with respect to the left side surface S1 of the partition plate 61 in a top view.

The hole cover 72 includes a cover part 73, a connecting part 74, and an operation part 75.
The hole cover 72 is made of resin, for example.

The connecting portion 74 has a rod shape.
The connecting portion 74 is rotatably inserted into the through hole 71 of the casing 28. Both ends of the connecting portion 74 inserted into the through hole 71 of the casing 28 protrude in and out of the casing 28.
The connecting part 74 connects the cover part 73 and the operation part 75. An operation portion 75 is attached to the upper end of the connecting portion 74 that protrudes outside the casing 28. A cover portion 73 is attached to the lower end of the connecting portion 74 that protrudes inside the casing 28.

The cover portion 73 has a vertically long rectangular flat plate shape that is slightly larger than the air hole 62.
The lower end of the connecting portion 74 is attached to a front position at the upper edge of the rectangular cover portion 73. The cover portion 73 can rotate around the front edge of the air hole 62 as a rotation axis.
As shown in FIG. 10, the flat cover portion 73 overlaps with the air holes 62. The air hole 62 is closed by the cover portion 73 that overlaps with the air hole 62.

The operation unit 75 has a bar shape, for example.
The operation unit 75 is disposed on the casing 28. The operation unit 75 is exposed on the casing 28. In FIG. 10, the rod-shaped operation portion 75 extends in the front-rear direction on the casing 28.
The upper end of the connecting portion 74 is connected to one end of the rod-shaped operation portion 75. The operation unit 75 disposed outside the casing 28 can be rotated by an operator without opening the casing 28.
The operation unit 75 can rotate in a plane constituted by front and rear, right and left directions. When the operation unit 75 is rotated, the cover unit 73 also rotates.
When the rod-shaped operation portion 75 is in the front-rear direction, the cover portion 73 overlaps with the air hole 62 and closes the air hole 62.
When the rod-shaped operation part 75 is in the left-right direction, the cover part 73 opens the air hole 62. The cover portion 73 extends in a direction standing with respect to the left side surface S <b> 1 of the partition plate 61 at a position on the front side of the air hole 62.

FIG. 11 is an explanatory diagram when the air hole 62 is closed by the hole cover 72. FIG. 11A is a partial top view of the casing 28. FIG. 11B is a partial cross-sectional view of the engine module 4.
When the rod-shaped operation part 75 is positioned in the front-rear direction, the cover part 73 overlaps the air hole 62. The air hole 62 is closed.
As a result, as in FIG. 7, the air heated to cool the engine 25 moves in the space where the engine 25 is disposed, and does not flow into the space where the carburetor 23 is disposed.

FIG. 12 is an explanatory diagram when the air hole 62 is opened. FIGS. 12A and 12B correspond to FIGS. 11A and 11B.
And if the rod-shaped operation part 75 is rotated at 90 degree | times and it is located in the left-right direction, the cover part 73 will rotate so that it may leave | separate from the air hole 62. The air hole 62 is opened. Further, the cover portion 73 is disposed near the front side of the air hole 62 along the hole direction of the air hole 62. The cover portion 73 extends along the direction standing on the left side surface S <b> 1 of the partition plate 61 near the air hole 62. The flat plate surface 73 </ b> S of the cover part 73 is aligned with the front edge of the air hole 62.
As a result, as shown in FIG. 9, the air warmed to cool the engine 25 flows through the air holes 62 into the space where the carburetor 23 is disposed. The air that has flowed into the space in which the carburetor 23 is disposed moves along the flat plate surface 73S of the cover portion 73 and moves from the air hole 62 toward the carburetor 23. Directly sprayed onto the carburetor 23.

  As described above, in the present embodiment, the hole cover 72 is configured such that the operation unit 75 is rotated 90 degrees in the front-rear direction, so that the cover unit 73 overlaps the air hole 62 and the cover unit 73 is the air hole. It switches between the state standing on the left side S1 of the partition plate 61 near 62. The operation unit 75 has different directions on the upper surface of the casing 28 when the air hole 62 is opened and when the air hole 62 is closed. The operator can easily confirm the open / closed state of the air hole 62 from the direction of the operation portion 75 on the upper surface of the casing 28. The setting state of the hole cover 72 is easy to understand.

  On the other hand, for example, when the hole cover 72 can be switched in direction at 180 degrees at the same position on the casing 28, it is not easy to know the open / closed state of the air hole 62 from the switching state of the hole cover 72.

In the present embodiment, the operating portion 75 of the hole cover 72 is provided exposed on the upper surface of the casing 28.
In addition, for example, as shown in FIG. 13, the operation portion 75 of the hole cover 72 may be provided on the side surface of the casing 28.
FIG. 13 is an explanatory diagram showing a modification of the present embodiment. FIG. 13A shows a state in which the air hole 62 is blocked by the cover portion 73. FIG. 13B shows a state in which the air holes 62 are opened with the cover portion 73 upright.
Also in the case of FIG. 13, the air hole 62 can be opened and closed by the cover portion 73 when the operation portion 75 is rotated by 90 degrees in the vertical direction. Further, in the state where the air holes 62 are opened, the flat plate surface 73 </ b> S on the lower side of the cover portion 73 can function as a guide surface that stands on the partition plate 61 near the air holes 62.

[Third Embodiment]
Next, a brush cutter 1 according to a third embodiment of the present invention will be described.
The brush cutter 1 according to the present embodiment is the same as the brush cutter 1 according to the first embodiment except that the mechanism for opening and closing the air holes 62 of the partition plate 61 is changed from the replacement type to the slide type. Illustrations and descriptions are omitted using symbols and names.

14 and 15 are explanatory views of a sliding type opening / closing mechanism according to a third embodiment of the present invention.
FIG. 14 is an explanatory view showing a state in which the air hole 62 is closed by the hole cover 82. FIG. 14A is a partial top view of the casing 28. FIG. 14B is a partial longitudinal sectional view of the engine module 4. FIG. 14B corresponds to FIG.
FIG. 15 is an explanatory view showing a state in which the air hole 62 is opened. FIGS. 15A and 15B correspond to FIGS. 14A and 14B.

A long slide slit 81 is formed in the upper portion of the casing 28.
The slide slit 81 extends in the front-rear direction.
The slide slit 81 is formed at a position substantially above the air hole 62 of the partition plate 61. The slide slit 81 is located on the left side on the carburetor 23 side with respect to the left side surface S1 of the partition plate 61 in a top view.

  The hole cover 82 includes a cover part 83 and an operation part 84.

The cover part 83 has a long rectangular plate shape. The cover 83 is formed with a width wider than the width of the air hole 62 in the front-rear direction. The cover portion 83 of this embodiment is formed to be vertically longer than the air hole 62. The cover part 83 has a length extending from the slide slit 81 to the lower end of the air hole 62.
Then, the cover part 83 is inserted into the slide slit 81. The cover portion 83 inserted into the slide slit 81 overlaps with the air hole 62 and can close the air hole 62. In this state, the upper end of the cover portion 83 protrudes outside the casing 28.

The operation unit 84 has a flat plate shape.
The operation unit 84 is connected to the upper end of the cover unit 83. The operation unit 84 is connected to the operation unit 84 in a substantially L shape.
With the hole cover 82 inserted into the slide slit 81, the operation unit 84 is positioned on the casing 28.
As shown in FIGS. 14 and 15, the hole cover 82 can slide in the front-rear direction along the slide slit 81.
When the operation part 84 is slid back and forth, the cover part 73 also slides back and forth.

As shown in FIG. 14, when the operation portion 84 is positioned on the rear side of the slide slit 81, the cover portion 83 overlaps the air hole 62. The air hole 62 is closed.
As a result, as in FIG. 7, the air warmed by cooling the engine 25 moves in the space where the engine 25 is disposed, and does not flow into the space where the carburetor 23 is disposed.

As shown in FIG. 15, when the operation portion 84 is positioned on the front side of the slide slit 81, the cover portion 83 is detached from the air hole 62 and the air hole 62 is opened.
The cover 83 is disposed near the air hole 62 at a position on the front side of the air hole 62 with the air hole 62 opened. As shown in FIG. 16, the cover portion 83 extends along the direction standing on the left side surface S <b> 1 of the partition plate 61 near the air hole 62. The flat plate surface 83 </ b> S of the cover part 83 is aligned with the front edge of the air hole 62. FIG. 16 is a partial cross-sectional view showing a state in which the slide type hole cover 82 is opened.
As a result, as shown in FIG. 9, the air warmed by the engine 25 flows into the space where the carburetor 23 is disposed through the air hole 62. The air that has flowed into the space where the carburetor 23 is disposed moves along the flat plate surface 83S on the air hole 62 side of the cover portion 83 away from the partition plate 61, and moves from the air hole 62 toward the carburetor 23. To do.

  As described above, in the present embodiment, the hole cover 82 is in a state where the cover part 83 overlaps the air hole 62 and the cover part 83 is close to the air hole 62 when the operation part 84 is slid in the front-rear direction. It switches between the state which stands on the partition plate 61 by. The operation portion 84 is at a different position on the upper surface of the casing 28 when the air hole 62 is opened and when the air hole 62 is closed. The operator can easily confirm the open / closed state of the air hole 62 from the position of the operation portion 84 on the upper surface of the casing 28. Easy to understand setting status.

  On the other hand, for example, if the hole cover 82 is fixed at the same position on the casing 28, it is not easy to know the open / closed state of the air hole 62 from the fixed state of the hole cover 82.

In the present embodiment, the operation portion 84 of the hole cover 82 is provided exposed on the upper surface of the casing 28.
In addition to this, for example, as shown in FIG. 17, the operation portion 84 of the hole cover 82 may be provided exposed on the front surface of the casing 28.
The cover portion 83 and the operation portion 84 of the hole cover 82 are connected by a connecting portion 85. The connecting portion 85 passes through the slide slit 81 of the casing 28 and can move up and down.
FIG. 17 is an explanatory diagram showing a modification of the present embodiment. FIG. 17A shows a state where the air hole 62 is closed by the cover portion 83. FIG. 17B shows a state in which the air hole 62 is opened. In FIG. 17B, the flat plate surface 83 </ b> S on the air hole 62 side of the cover portion 83 stands on the left side surface S <b> 1 of the partition plate 61.
Even in the case of FIG. 17, the air hole 62 can be opened and closed by the cover portion 83 when the operation portion 84 is slid in the vertical direction. Further, in a state where the air hole 62 is opened, the flat plate surface 83 </ b> S on the lower side of the cover portion 83 functions as a guide surface that stands on the partition plate 61 near the air hole 62.

[Effect of the embodiment]
In each of the above-described embodiments, the air hole 62 is formed in the partition plate 61 that partitions the engine 25 and the carburetor 23. Further, the hole covers 66, 72, 82 for closing the air hole 62 are arranged at or near the air hole 62 when the air hole 62 is opened. The hole covers 66, 72, and 82 function as an airflow guide that extends along the air flow from the engine 25 side to the carburetor 23 side of the partition plate 61 through the air hole 62.
Therefore, the air flowing from the engine 25 side to the carburetor 23 side of the partition plate 61 moves along the guide surface on the air hole 62 side with respect to the hole covers 66, 72, 82 arranged near the air hole 62. The flow of air that flows from the engine 25 side to the carburetor 23 side of the partition plate 61 flows toward the carburetor 23 away from the partition plate 61. The carburetor 23 can be suitably warmed by the air warmed by the engine 25.
In particular, in each of the above-described embodiments, the guide surface extends in a direction standing on the left side surface S1 where the air holes 62 of the partition plate 61 are opened. Therefore, the air flowing from the engine 25 side to the carburetor 23 side flows away from the partition plate 61, moves toward the carburetor 23, and is blown directly onto the carburetor 23.
As a result, in each of the embodiments described above, cooling of the carburetor 23 is difficult to proceed even when used in a very cold region in a narrow space between the engine 25 and the carburetor 23. The carburetor 23 can be sufficiently warmed, and even when used in a very cold region, moisture in the fuel becomes difficult to freeze in the carburetor 23 cooled by the heat of vaporization. In the carburetor 23, engine stall due to freezing of water in the fuel is less likely to occur.

  On the other hand, when the hole covers 66, 72, 82 are arranged near the air holes 62 and are not used as the airflow guide, the flow of air flowing from the engine 25 side of the partition plate 61 to the carburetor 23 side is the engine 25 side. The air flow will remain as it is. On the engine 25 side, air flows from the rear side of the engine 25 toward the front side by the wind power of the fan. The air that flows into the carburetor 23 also flows from the rear toward the front. The air flowing into the carburetor 23 side hits the front part of the casing 28 and is cooled. After the cooling, a part of the cooled air moves in the space where the carburetor 23 is arranged. As described above, since the air is cooled before the carburetor 23 is warmed, the carburetor 23 cannot be sufficiently warmed. In extremely cold regions, engine stall due to freezing of the carburetor 23 cannot be effectively suppressed.

Each of the above embodiments is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications or changes can be made without departing from the scope of the invention. .
For example, in the first embodiment, the hole cover 66 is replaceable. In the second embodiment, the hole cover 72 is a rotary type. In the third embodiment, the hole cover 82 is a slide type. The hole cover of the present invention is not limited to these.
18 to 21 are explanatory views showing modifications of the hole cover 82 that opens and closes the air hole 62.

FIG. 18 shows a modification of the replaceable hole cover 66.
FIG. 18A shows the replaceable hole cover 66 of the first embodiment. A dotted line is a state in which the air hole 62 is opened. A solid line indicates a state in which the air hole 62 is closed. The same applies to the following modifications.
In the replaceable hole cover 66 in FIG. 18B, a cover portion 67 is disposed in the air hole 62. When opening the air hole 62, the cover part 67 is arrange | positioned in the range ranging from right side S2 by the side of the engine 25 about the partition plate 61 to left side S1 by the side of the carburetor 23. Projects on both sides.
The replaceable hole cover 82 in FIG. 18C can be replaced with respect to the right side surface S <b> 2 on the engine 25 side of the partition plate 61. The cover part 83 closes the air hole 62 from the engine 25 side. When opening the air hole 62, the cover portion 83 is arranged near the front edge of the air hole 62 with the partition plate 61 standing on the right side S <b> 2 on the engine 25 side.

FIG. 19 shows a modification of the rotary hole cover 72.
FIG. 19A shows the rotary hole cover 72 of the second embodiment.
In the rotary hole cover 72 of FIG. 19B, a cover portion 73 is disposed in the air hole 62. When opening the air hole 62, the cover portion 73 rotates so as to extend from the air hole 62 toward the carburetor 23 side.
The rotary hole cover 72 of FIG. 19C is rotatable about the right side surface S <b> 2 on the engine 25 side of the partition plate 61. The cover portion 73 is disposed on the engine 25 side of the air hole 62. When opening the air hole 62, the cover portion 73 is rotated so as to stand on the side surface of the partition plate 61 on the engine 25 side.

FIG. 20 shows a modification of the slide type hole cover 82.
FIG. 20A shows a slide type hole cover 82 of the third embodiment.
In the sliding hole cover 82 of FIG. 20B, a cover portion 83 is disposed in the air hole 62. When opening the air hole 62, the cover portion 83 slides out from the air hole 62.
The sliding hole cover 82 shown in FIG. 20C is slidable on the right side S2 of the partition plate 61 on the engine 25 side. The cover portion 83 is disposed on the engine 25 side of the air hole 62. When opening the air hole 62, the cover 83 is slid on the right side S <b> 2 on the engine 25 side of the partition plate 61.

FIG. 21 shows a modification of the slide type hole cover 82. 21 has a substantially L-shaped cross section.
FIG. 21A shows a state in which the air hole 62 is closed by the hole cover 82.
FIG. 21B shows a state where the air hole 62 is opened by sliding the hole cover 82 in the left-right direction.
By using such a cover portion 83, the hole cover 82 can be slid in the left-right direction. Further, the cover portion 83 protrudes toward the engine 25 with the hole cover 82 slid and opened. The warmed air flowing around the engine 25 can be taken into the carburetor 23 side while maintaining the flow of airflow on the engine side. The air taken into the carburetor 23 side flows in a direction away from the left side surface S <b> 1 of the partition plate 61 due to the wind pressure of the cooling fan 27, and is blown directly onto the carburetor 23.

  The said embodiment is an example which applied this invention to the brush cutter 1 of the portable side. Other portable work machines include, for example, a pole saw, a pole hedge trimmer, and a coffee harvester. The present invention can be used as a countermeasure against icing of the carburetor 23 in these portable work machines.

DESCRIPTION OF SYMBOLS 1 Brush cutter (portable working machine), 23 Carburetor, 25 Engine, 28 Casing, 61 Partition plate (partition member), S1 Left side surface (side surface), S2 Right side surface (side surface), 62 Air hole, 63 Holder, 64 1 slit, 65 2nd slit, 66 hole cover, 67 cover part, 67S flat plate surface (guide surface), 68 fixing part, 71 through hole, 72 hole cover, 73 cover part, 73S flat plate surface (guide surface), 81 slide Slit, 82 hole cover, 83 cover part, 83S flat plate surface (guide surface), 84 operation part

Claims (9)

In a portable work machine having an engine and a carburetor,
A partition member that partitions between the engine and the carburetor;
Air holes formed in the partition member;
A hole cover for closing the air hole so that the air hole can be opened;
Have
The hole cover is
When opening the air hole, it is arranged at or near the air hole and functions as an airflow guide for air flowing from the engine side of the partition member to the carburetor side through the air hole,
Portable work machine. The hole cover is
A guide surface extending in a direction standing with respect to a side surface of the partition member where the air hole opens when the air hole is arranged at or near the air hole so as to open the air hole, Directing the flow of air flowing from the engine side of the partition member to the carburetor side through the air hole in a direction away from the side surface of the partition member where the air hole opens;
The portable work machine according to claim 1. The hole cover has a cover portion that is closed so as to open the air hole,
The cover part is
Switchable between a closed position that closes the air hole and an open position near the air hole that opened the air hole;
One surface of the cover portion in the open position functions as a guide surface that stands against the side surface of the partition member in the vicinity of the air hole or the air hole.
The portable work machine according to claim 1 or 2. A casing that houses the engine, the carburetor, and the partition member;
A first slit and a second slit formed in the casing;
Have
The hole cover is
Inserted between the first slit and the second slit,
The cover portion closes the air hole in the closed position when inserted into the first slit;
The cover portion opens the air hole at the open position when inserted into the second slit;
The portable work machine according to claim 3. The first slit and the second slit are formed side by side on the casing,
The hole cover is
A fixing part that is integrated with the cover part and fixed to the outside of the casing in a state in which the cover part is inserted into the first slit, or fixed to the outside of the casing in a state of being inserted into the second slit; Have
The fixing part is
The case where the cover portion is inserted into the first slit and the case where the cover portion is inserted into the second slit are fixed in different directions or positions outside the casing.
The portable work machine according to claim 4. A casing for housing the engine, the carburetor and the partition plate;
A slide slit formed in the casing;
Have
The hole cover is
Slidably inserted into the slide slit,
The cover part is switched between the closed position and the open position by sliding the hole cover;
The portable work machine according to claim 3. The hole cover is
An operation part that is integrated with the cover part and is located outside the casing in a state in which the hole cover is inserted into the slide slit;
The operation unit is
The cover portion is operated to a different position on the outside of the casing depending on whether the cover portion is in the closed position or the open position.
The portable work machine according to claim 6. A casing for housing the engine, the carburetor and the partition plate;
A through hole formed in the casing;
Have
The hole cover is
Inserted into the through hole so as to be rotatable,
The cover portion is switched between the closed position and the open position by rotating the hole cover.
The portable work machine according to claim 3. The hole cover is
An operation unit integrated with the cover unit and positioned outside the casing;
The operation unit is
When the cover portion is in the closed position and in the open position, it is operated in different directions on the outside of the casing.
The portable work machine according to claim 8.

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