JP2007309166A - Portable working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable working machine capable of largely simplifying troublesome maintenance around a carburetor, by sending clean air to the carburetor. <P>SOLUTION: A chain saw 1 being the portable working machine has a main body 11 storing an engine 15, a cooling fan 19 driven by the engine 15, the carburetor 36 generating an air-fuel mixture to the engine 15, a communicating passage 37 for intake air for directly communicating the vicinity of the cooling fan 19 with an intake passage of the carburetor 36, and an air cleaner 25 arranged outside a cab chamber 43 storing the carburetor 36 in the middle of this communicating passage 37 for the intake air. Among the communicating passage 37 for the intake air, a passage part on the downstream side of at least the air cleaner 25 is formed as a sealed space. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a portable work machine such as a chain saw, a hand saw, or a brush cutter, and more particularly to an improvement of an intake system for an engine mounted on the portable work machine.

  2. Description of the Related Art Conventionally, in a portable working machine driven by a small engine such as a chain saw, various intake systems for preventing dust such as chips and chips generated during work from being sucked into a cab chamber in which a carburetor is housed are employed. . As an example, the cab chamber communicates with the vicinity of a cooling fan driven by the engine through an intake passage, and clean intake air from which dust has been separated by a centrifugal separation function by the cooling fan is sent to the cab chamber via the intake passage. An intake system has been proposed (for example, Patent Document 1).

  According to this intake system, since the intake air with less dust is sent to the cab room, the amount of dust collected by the air cleaner (air filter) attached to the carburetor can be suppressed in the cab room, and the maintenance frequency of the air cleaner is reduced. it can. Also, in this intake system, the case where the negative pressure generated on the cooling fan side is larger than the suction force in the engine is used, dust collected by the air cleaner is removed by negative pressure, and the fan side is removed by the intake passage. Thus, the maintenance frequency of the air cleaner can be further reduced.

JP-A-6-1773797

  By the way, the air cleaner is attached to the carburetor and accommodated in the cab chamber, but the inside of the cab chamber is not strictly sealed depending on the structure, for example, around the opening / closing lid for air cleaner maintenance. In some cases, a slight gap may be formed in the mating portion of the members forming the cab chamber. For this reason, dust enters from this slight gap, and the air cleaner becomes dirty, so it can not be reduced as expected, or dust also adheres around the carburetor, which requires cleaning. There's a problem.

  An object of the present invention is to provide a portable work machine capable of sending clean air to a carburetor and greatly simplifying troublesome maintenance around the carburetor.

  According to a first aspect of the present invention, there is provided a portable work machine including a main body that houses an engine, a cooling fan that is driven by the engine, a carburetor that generates an air-fuel mixture to the engine, and the vicinity of the cooling fan. A communication passage for intake that directly communicates with the intake passage of the carburetor, and an air cleaner disposed in the middle of the communication passage for intake and outside the cab chamber in which the carburetor is accommodated. Features.

  A portable work machine according to a second aspect of the present invention is the portable work machine according to the first aspect, wherein the air cleaner is disposed near the suction port on the cooling fan side of the intake communication path. It is characterized by.

  A portable work machine according to a third aspect of the present invention is the portable work machine according to the second aspect, wherein the upstream side of the air cleaner in the intake communication path is at a position corresponding to the vicinity of the air cleaner. A gap communicating with the outside is formed.

  In the above, according to the first aspect of the present invention, since the intake communication passage that connects the vicinity of the cooling fan and the intake passage of the carburetor is provided, clean intake air from which dust has been removed by the centrifugal separation function on the cooling fan side is provided. Can be sent to the carburetor. In addition, the air cleaner is disposed outside the cab chamber, the intake communication passage is directly connected to the intake passage of the carburetor, and the passage portion downstream of the air cleaner in the intake communication passage is closed. It is possible to prevent the suction force of the engine from acting on the cab chamber, and there is no fear that dust will enter through the gap of the cab chamber and contaminate the outer periphery of the carburetor, so that the maintenance labor can be greatly reduced.

  According to the second aspect of the present invention, since the air cleaner is disposed near the intake port on the cooling fan side in the intake communication passage, the negative pressure generated on the cooling fan side can be effectively applied to the vicinity of the air cleaner, and the air cleaner It is possible to remove the dust collected in step 1 and reliably return it to the cooling fan side.

  According to the third aspect of the present invention, the negative pressure acting in the vicinity of the air cleaner allows the outside air to be sucked into the air cleaner side through the gap, and the dust can be effectively removed by the sucked outside air, thereby greatly improving the removal function. Thus, the maintenance frequency of the air cleaner can be further reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an overall outline of a chainsaw (portable work machine) 1 according to the present embodiment. FIG. 2 is a perspective view showing a main part in the chainsaw 1. FIG. 3 is a perspective view of the chainsaw 1 as viewed from below. FIG. 4 is a side view showing a part of the main part, and FIG. 5 is a view of a part of the part viewed from the rear side.

  The chain saw 1 is a type having a top handle 12 above a main body 11, and one end is on the front side of the top handle 12 on the side of the top handle 12, and the other end is on the lower rear side of the main body 11. Further, separate handles 14 connected to a part of the fuel tank 13 are provided. Here, the fuel tank 13 of this embodiment is provided integrally with the top handle 12.

  As shown in FIG. 2, a small two-cycle engine 15 is accommodated in the main body 11. However, the illustration of the crankcase of the engine 15 is omitted in FIG. Although not shown, a sprocket is pivotally supported at one end of the crankshaft 16 protruding from the engine 15 via a centrifugal clutch, and a saw chain 18 wound around the sprocket and a guide bar 17 beside the main body 11. Is driven by the engine 15.

  A cooling fan 19 having a plurality of fins on the circumference is attached to the other end of the crankshaft 16. A fan case 21 having an air inlet 20 is disposed outside the cooling fan 19. On the back surface of the fan case 21, a volute corresponding to the outer periphery of the cooling fan 19 is formed. This volute functions as a ventilation path for sending out the sucked cooling air to the engine 15 side.

  On the surface of the fan case 21, a communication path forming part 24 having two partition parts 22 and 23 is integrally provided. A mounting portion 26 to which a cartridge type air cleaner 25 is attached is provided on the vertical planar portion on the rear side of the communication path forming portion 24. The mounting portion 26 is composed of a U-shaped protruding portion, and an engaging groove is formed between the protruding portion and the planar portion. The air cleaner 25 drops from above the engaging groove of the mounting portion 26. It is included.

  Thus, in the present embodiment, the air cleaner 25 is disposed on the side of the main body 11. Conventionally, this side portion was a space for the intake communication passage that communicates the vicinity of the cooling fan and the cab chamber, but by utilizing this space for forming the communication passage as a space for arranging the air cleaner 25, The air cleaner 25 can be disposed without increasing the size of the main body 11 in which the air cleaner 25 is accommodated, and the necessity of disposing the air cleaner 25 in the top handle 12 in which the carburetor 36 is accommodated is eliminated, and the top handle 12 is made slim. I am trying.

  In FIG. 4, an opening 26 </ b> A is provided in a planar portion surrounded by the attachment portion 26, and one end of a hollow first communication member 27 is fitted into the opening 26 </ b> A in a grommet manner. This state is shown in FIG. 4 with the air cleaner 25 partially broken.

  On the other hand, the outside of the fan case 21 is covered with a cover 29 having a large number of ventilation holes 28. On the back side of the cover 29, a recoil starter (not shown) that is intermittently connected to the cooling fan 19 via a ratchet mechanism is attached, and a partition wall 30 that protrudes toward the fan case 21 is provided. ing.

  A part of the partition wall 30 is in contact with the partition portions 22 and 23 on the fan case 21 side. Further, the other part of the partition wall 30 protrudes into the air suction port 20 of the fan case 21, and the opening formed by the protruding part and the inner edge of the air suction port 20 faces the disk-shaped part of the cooling fan 19. The suction port 31 (FIG. 4) is located. In the vertical surface portion of the fan case 21, the lower edge and the rear vertical edge along the U-shaped attachment portion 26 are covered with the cover 29.

  Further, a portion of the cover 29 facing the air cleaner 25 is opened, and an opening / closing lid 32 is attached to the opening portion. A hinge 33 is provided on the lower side of the opening / closing lid 32, and the hinge 33 is pivotally supported by the cover 29, so that the opening / closing lid 32 is pivotally opened and closed. Further, an engaging claw 34 is provided on the upper side of the opening / closing lid 32, and the engaging claw 34 is configured to be engageable with and disengageable from an engaging hole 29 </ b> A provided on the upper surface of the cover 29.

  The attachment / detachment operation of the air cleaner 25 is performed by opening and closing the opening / closing lid 32. More specifically, the engaging claw 34 is removed from the engaging hole 29A, the opening / closing lid 32 is opened, and the air cleaner 25 is pulled upward from the mounting portion 26 using the upper opening formed at this time. Or it is inserted from the top down.

  In addition, as shown in FIG. 5, a partition piece 35 protruding toward the fan case 21 is provided on the back surface side of the opening / closing lid 32, and when the opening / closing lid 32 is closed, the tip of the partition piece 35 is provided. The side is brought into contact with the upper edge of the air cleaner 25. As a result, the periphery of the communication path forming portion 24 of the fan case 21 is covered in a semi-sealed state by the cover 29 and the opening / closing lid 32. The semi-sealed space forms an upstream side (upstream side from the air cleaner 25) of the intake communication passage 37 that allows the vicinity of the cooling fan 19 and the carburetor 36 in the top handle 12 to communicate with each other.

  As shown in FIG. 3, on the side of the hinge 33 of the opening / closing lid 32, a gap 38 communicating with the outside is intentionally formed between the opening / closing lid 32 and the cover 29. The operation of the gap 38 will be described later. In addition, since such a gap 38 is provided below the opening / closing lid 32, rainwater or the like is difficult to enter.

  Now, the first communication member 27 fitted into the opening 26A of the fan case 21 extends into the cab chamber 43 in the top handle 12 provided above. As shown in FIGS. 4 and 5, the upper end of the first communication member 27 is fitted into a second communication member 39 formed in a hollow flat box shape. Specifically, the second communication member 39 is provided with an intake inlet 40 and an intake / outlet port 41, and the upper end of the first communication member 27 is connected to the intake inlet 40.

  The second communication member 39 is configured to be screwed to the carburetor 36. When the second communication member 39 is attached to the carburetor 36, the intake air outlet 41 of the second communication member 39 is in direct contact with the intake passage 42 of the carburetor 36. ing. The internal space of the first and second communication members 27 and 39 communicating with each other is a closed space, and intake air does not enter from other than the opening 26A.

  The first and second communication members 27 and 39 form the downstream side of the intake communication passage 37 (downstream side from the air cleaner 25). Further, according to the present embodiment, the air cleaner 25 is disposed outside the cab chamber 43 in which the carburetor 36 is accommodated and close to the intake port 31 in the middle of the intake communication passage 37.

  In the above embodiment, the intake air including dust sucked from the large number of ventilation holes 28 by the cooling fan 19 is sucked in the axial direction with respect to the cooling fan 19 through the air suction port 20 of the fan case 21, and thereafter the diameter is reduced. The direction is changed to the outside of the direction and sent from the outer air passage to the outer periphery of the engine 15 to cool the cylinder and the like.

  A part of the cooling air is sucked into the engine 15 by the suction force of the engine 15 through the suction port 31, the intake communication passage 37, and the carburetor 36 as an air-fuel mixture. The dust in the cooling air sucked in by the cooling fan 19 is blown past the suction port 31 by the centrifugal force after the flow of the cooling air is converted from the axial direction to the radial direction, and reaches the air blowing path. It is discharged to the outside of the main body 11 in the cooling air that cools the air.

  Therefore, the dust sucked from the suction port 31 can be reduced, the amount of dust collected by the air cleaner 25 can be reduced, and the maintenance frequency can be reduced. Further, in the intake communication passage 37, the space downstream of the air cleaner 25 is a closed space and directly communicates with the intake passage 42 of the carburetor 36. The suction force by the engine 15 does not act, the amount of dust in the atmosphere entering from a slight gap in the cab chamber 43 is small, and the carburetor 36 can be effectively prevented from being contaminated with dust.

  By the way, when the throttle 44 is returned and the rotational speed of the engine 15 is lowered to the idling rotational speed, the throttle valve of the carburetor 36 is closed at that moment, and the inertia communication force in the intake communication passage 37 is higher than the suction force by the engine 15. Since the negative pressure on the cooling fan 19 side that maintains the rotational force is larger, a large amount of outside air is sucked from the gap 38 located below the air cleaner 25, and dust collected by the air cleaner 25 is removed. Then, it can be returned to the cooling fan 19 side, put on cooling air, and finally discharged to the outside.

The best configuration, method, and the like for carrying out the present invention have been disclosed above, but the present invention is not limited to this. That is, although the present invention has been illustrated and described with particular reference to particular embodiments, it will be appreciated that the shapes, quantities, and quantities of the above-described embodiments are not deviated from the scope of the technical idea and purpose of the present invention. In other detailed configurations, those skilled in the art can make various modifications.
Therefore, the description limited to the shape, quantity and the like disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

  For example, in the above-described embodiment, the gap 38 is intentionally formed on the lower side of the opening / closing lid 32. However, such a gap is not formed, and around the communication path forming portion 24, that is, the intake communication path. 37 may be sealed on the upstream side of the air cleaner 25 except for the suction port 31 and the opening 26A. Even in such a case, since the air cleaner 25 is arranged near the suction port 31, negative pressure on the cooling fan 19 side can be applied to the vicinity of the air cleaner 25, and dust collected by the air cleaner 25 can be removed. Can be performed satisfactorily.

  The present invention is not limited to a chain saw, and can be used for general working machines such as a cut-off saw, a brush cutter, and a blower.

1 is a perspective view showing an overall outline of a portable work machine according to an embodiment of the present invention. The perspective view which shows the principal part in a portable working machine. The perspective view which looked at the portable work machine from the lower side The side view which shows the part which concerns on the said principal part. The figure which looked at the said part from the back side.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Chain saw which is a portable work machine, 11 ... Main body, 15 ... Engine, 19 ... Cooling fan, 25 ... Air cleaner, 31 ... Inlet, 36 ... Carburetor, 37 ... Inlet communication passage, 38 ... Gap, 42 ... Intake passage, 43 ... Cab room.

Claims (3)

In portable work machines,
A body body that houses the engine;
A cooling fan driven by the engine;
A carburetor for generating an air-fuel mixture to the engine;
An intake communication passage that directly connects the vicinity of the cooling fan and the intake passage of the carburetor;
A portable working machine comprising: an air cleaner disposed in the middle of the intake communication path and outside the cab chamber in which the carburetor is accommodated. The portable work machine according to claim 1, wherein
The air cleaner is disposed near the suction port on the cooling fan side of the intake communication path. The portable work machine according to claim 2, wherein
A portable working machine characterized in that a gap communicating with the outside is formed at a position corresponding to the vicinity of the air cleaner on the upstream side of the air cleaner in the communication passage for intake.

Images