JP2008255877A - Blower working machine and casing for blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blower working machine capable of surely improving the cooling efficiency of an air cooled internal combustion engine. <P>SOLUTION: A centrifugal blower 3 for working driven by the air cooled internal combustion engine 2 is provided with a fan case 10 including an intake air port 9 only at one side surface 13, a centrifugal fan case 11 rotatably supported in the fan case 10, and a hot air intake path 30 formed at an outside of the fan case 10 as one body. A hot air side of a high temperature part 16 and the intake air port 9 are mutually connected via the hot air intake path 30. Since cooling air (hot air) getting high temperature with cooling the high temperature part of the internal combustion engine is surely sucked into the fan case 10 via the hot air intake path 30, flow of engine cooling air is accelerated and engine cooling efficiency is improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a blower working machine and a casing of a blower constituting the work machine.

  As a type of blower working machine, a portable or hand-held power blower suitable for use in a fallen leaf blowing work or the like is known. The power blower includes an air-cooled internal combustion engine, a blower that blows air to a high temperature portion of the internal combustion engine, and a work blower that is driven by the internal combustion engine (see Patent Document 1).

  In the power blower, it is needless to say that the internal combustion engine is required to have good cooling performance. In particular, since the power blower is portable or handheld, the internal combustion engine does not increase the weight of the entire work machine. Must be able to be efficiently cooled.

By the way, as a prior art of an engine cooling structure for a working machine, a system in which a negative pressure generating part of a fan case of a working blower and a cooling air outlet of a cylinder cover of an air-cooled internal combustion engine are communicated with each other through a communication path has been proposed. (Patent Document 2). According to this proposal, since the cylinder cooling air blown by the engine cooling fan is sucked into the fan case through the communication path, the flow of the cylinder cooling air is greatly improved and the cooling efficiency is improved. It is supposed to improve.
JP 2006-307690 A Utility Model Registration No. 2570247

  However, as shown in FIG. 1 of the above-mentioned Patent Document 2, since the communication path is formed on the surface of the fan case opposite to the air inlet, the engine cooling air is not supplied. The negative pressure for inhalation is only small. Therefore, if the air outlet is throttled to increase the air speed of the air outlet of the blower, the opening of the communication path becomes positive pressure, and the engine cooling air is not discharged from the cylinder cover. Problems arise.

  For example, in the power blower, the air outlet is often narrowed to a flat shape or the like so that the wind speed from the air outlet can be increased to quickly collect fallen leaves and the like. For this reason, when the configuration described in Patent Document 2 is applied to the power blower as it is, a disadvantage such as that engine cooling air is not discharged from the cylinder cover as described above is expected.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a blower working machine capable of reliably improving the cooling efficiency of an air-cooled internal combustion engine.

  In order to solve the above-mentioned problems, a blower working machine according to the present invention includes an air-cooled internal combustion engine, a blower for supplying cooling air to a high temperature portion of the internal combustion engine, and a centrifugal type for work driven by the internal combustion engine A blower working machine including a blower, wherein the blower is integrated with a fan case having an intake port only on one side, a centrifugal fan rotatably supported in the fan case, and an outside of the fan case. And the hot air side of the high-temperature part is communicated with each other via the hot air intake passage (Claim 1).

  According to the present invention, since the intake port is opened only on one side surface of the fan case, a large negative pressure is generated at the intake port by the rotation of the centrifugal fan. Further, even when the air outlet is throttled to increase the outlet wind speed of the working machine and the air pressure is increased, the outside air is continuously sucked from the air inlet, so that the negative pressure is maintained. For this reason, the cooling air (hot air) that has been blown by the air blowing means and has cooled the high-temperature portion to a high temperature is reliably sucked into the fan case through the hot air intake passage.

  The hot air sucked through the hot air sucking path is mixed with the outside air sucked from the air intake port in the fan case, so that there is no problem that the inside of the fan case becomes high temperature. Moreover, since the hot air intake passage communicates with the intake port through the outside of the fan case, the intake efficiency of the blower is not adversely affected. Furthermore, since the hot air suction path is formed integrally with the fan case, the contour of the entire work machine becomes compact.

  According to the present invention, since the flow of the cooling air in the high temperature part is promoted, the cooling efficiency of the internal combustion engine is improved. And since the ventilation means, such as a cooling fan, is not added, the increase in the weight of the whole working machine is also suppressed.

  In addition, the said ventilation means in this invention may be a cooling fan, and may divert some ventilation by the said air blower.

  As a preferred embodiment, the hot air intake passage may be opened in the vicinity of a fan blade of the intake port of the centrifugal fan (Claim 2). In this manner, the cooling efficiency of the internal combustion engine is further improved because the efficiency of sucking the cooling air heated to a high temperature by cooling the high temperature portion into the fan case is further improved.

  As one preferred embodiment, the end of the hot air intake passage on the high temperature side is the hot air side of the cylinder of the internal combustion engine, and the cylinder is more than the exhaust port of the exhaust muffler connected to the cylinder. It can also be set as the aspect located in the side (Claim 3). In this way, the flowability of the cooling air around the cylinder is improved, and the exhaust from the exhaust muffler is not sucked into the fan case.

  On the other hand, a blower casing according to the present invention is a blower casing driven by an air-cooled internal combustion engine, and the intake port and the high-temperature portion of the internal combustion engine are provided outside the fan case having the intake port only on one side surface. At least a portion of a hot air intake passage that communicates with the hot air side of each other (claim 4).

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  Here, a handheld power blower will be described as an embodiment of the present invention. The power blower is a blower working machine suitable for use in, for example, a falling leaf blowing operation. However, it goes without saying that the present invention can be implemented as a stationary air blower as well as a portable air blower such as a handheld type or a backpack type.

  1 is an overall perspective view showing a use state of a hand-held power blower according to the present embodiment, FIG. 2 is a perspective view of the power blower of FIG. 1 as viewed from the reverse side, and FIG. 3 is a power blower of FIG. FIG.

  As shown in FIGS. 1 and 2, a hand-held power blower 1 according to an embodiment of the present invention includes a small air-cooled internal combustion engine 2 and a working centrifugal blower 3 driven by the internal combustion engine 2. The air discharge pipe 5 connected to the air discharge opening 4 of the blower 3 is provided. Further, the power blower 1 can be operated with a handle 6 for an operator to hold the body 8, which is a combined body of the internal combustion engine 2 and the blower 3, with one hand, and with a finger of the hand holding the handle 6. Throttle trigger 7 is attached. As shown in FIG. 1, the operator holds the handle 6 with one hand and controls the output of the internal combustion engine 2 with the throttle trigger 7, and the fallen leaves L are generated by the high-speed airflow W blown out from the discharge pipe 5. And so on.

  As shown in FIG. 3, the blower 3 covers a fan case 10 having an intake port 9 only on one side surface 13, a centrifugal fan 11 rotatably supported in the fan case 10, and the intake port 9. A grid 12 is provided as a breathable cover. The air inlet 9 is formed in a circular shape concentrically with the centrifugal fan 11 at the center of the one side surface 13 of the fan case 10. The centrifugal fan 11 is fixed to one end portion 14 a of the crankshaft 14 of the internal combustion engine 2. The other end 14b of the crankshaft 14 is operatively connected to a recoil starter device 15 known per se.

  A cooling fan 17 is fixed to the crankshaft 14 as a blowing means for supplying cooling air A1 around a cylinder 16 that is a high temperature portion of the internal combustion engine 2. Although not limited, the cooling fan 17 is disposed between a crankcase (not shown) and the blower 3 and is integrated with a well-known magnet rotor 18. The cooling fan 17 sucks outside air from a cooling air inlet 19 formed in the lower part of the machine case by the rotation of the crankshaft 14, and sends cooling air A <b> 1 around the cylinder 16. This cooling air A1 is guided by the inner surface of the airframe cover 20 (see FIG. 1) covering the internal combustion engine 2 and contacts the numerous cooling fins 21 formed on the outer peripheral surface of the cylinder 16 so that the exhaust muffler 22 The cylinder 16 is cooled.

  The exhaust muffler 22 connected to the cylinder 16 is covered with a muffler cover 23. The muffler cover 23 includes an exhaust outlet 25 on the downstream side of the exhaust E of the exhaust port 24 of the exhaust muffler 22. The muffler cover 23 includes a hot air inlet 27 on one side surface 26 on the fan case 10 side. The hot air inlet 27 is disposed on the hot air side of the cylinder 16 and on the cylinder 16 side of the exhaust port 24 of the exhaust muffler 22. Except for a portion 28 between the exhaust outlet 25 and the hot air inlet 27, the muffler cover 23 is formed with a large number of vent holes 29. Through these vent holes 29, radiant heat from the exhaust muffler 22 is released and outside air for cooling the muffler is taken in.

  The blower 3 is integrally provided with a hot air suction passage 30 outside the fan case 10. The hot air intake passage 30 allows the intake port 9 and the hot air side of the cylinder 16 to communicate with each other via the hot air intake port 27. The hot air intake passage 30 is opened at a radially outward position of the intake port 9 so as to face the centrifugal fan 11.

  As shown in FIG. 2, in the present embodiment, at least a part (30a, 30b) of the hot air intake passage 30 is formed by the casing 31 of the blower 3. That is, the casing 31 includes a first casing half 32 fixed to the body cover 20 (see FIG. 1) side and a second casing half 33 fixed to the first casing half 32. Prepare.

  As shown in FIG. 3, the first casing half 32 is disposed between a first fan case half 34 corresponding to substantially half of the fan case 10 and the first fan case half 34. An upstream defining wall 35 a that defines the upstream portion 30 a of the hot air suction passage 30 is provided. The second casing half 33 is disposed between the second fan case half 36 corresponding to the remaining half of the fan case 10 and the second fan case half 36. The middle stream defining wall 35b that defines the middle stream portion 30b is provided. When the first casing half 32 and the second casing half 33 are joined together, the fan case 10 is formed by the first fan case half 34 and the second fan case half 36. In addition, the upstream portion 30a and the midstream portion 30b of the hot air intake passage 30 communicate with each other.

  In the present embodiment, the downstream portion 30 c of the hot air suction passage 30 is formed between the second casing half 33 and the grid 12. That is, a non-porous downstream defining wall 35 c is formed in a part of the grid 12. When the grid 12 is fixed to the second casing half 33, the downstream portion 30c is formed between the outer surface of the second fan case half 36 and the downstream defining wall 35c. A hot air guide 37 is formed on the inner surface of the grid 12. The hot air guide 37 extends at a right angle toward the rotating surface of the centrifugal fan 11. By providing the hot air guide 37, the hot air A 2 can be reliably sucked from around the cylinder 16 through the hot air suction passage 30 by effectively utilizing the negative suction pressure generated by the rotation of the centrifugal fan 11. .

  The fan case 10 includes a short intake cylinder 38 that defines the intake port 9, but a portion 39 of the intake cylinder 38 that faces the hot air guide 37 is cut. This is because the hot air A2 is smoothly taken into the fan case 10.

  In the above configuration, when the blower 3 is activated, the intake port 9 is opened only on the one side surface 13 of the fan case 10, so that a large negative pressure is generated at the intake port 9 by the rotation of the centrifugal fan 11. To do. Moreover, as shown in FIG. 1, even when the front-end | tip part 5a of the said discharge pipe 5 is restrict | squeezed by the flat shape etc. so that it may be suitable for ventilation work, the said inlet 9 is maintained at a negative pressure. For this reason, the cooling air (hot air A1) that is blown by the cooling fan 17 and cools the cylinder 16 to become high temperature (hot air A1) passes from the periphery of the cylinder 16 through the hot air inlet 27 and the hot air intake passage 30. The air is reliably sucked into the fan case 10. As a result, the flow of the cooling air A1 around the cylinder 16 is promoted, so that the cooling efficiency of the internal combustion engine 2 is improved.

  The hot air A2 sucked into the fan case 10 through the hot air intake passage 30 is mixed with the outside air A3 sucked from the intake port 9 in the fan case 10, so that the inside of the fan case 10 has a high temperature. There is no problem such as becoming. Moreover, since the hot air intake passage 30 communicates with the intake port 9 through the outside of the fan case 10, the intake efficiency of the blower 3 is not adversely affected. Further, since the hot air intake passage 30 is formed integrally with the fan case 10, the contour of the entire working machine is also compact.

  In addition, when forming the hot air suction passage 30, it is only necessary to add the defining walls 35a, 35b, and 35c to the fan case 10 and the grid 12 that are generally formed of plastic and lightweight, so that the manufacture is easy. Therefore, an increase in the weight of the entire work machine is also suppressed.

  Further, since the hot air intake passage 30 is opened in the vicinity of the fan blade 11a of the air inlet 9 of the centrifugal fan 11, the hot air A2 that has been heated to a high temperature by cooling the cylinder 16 enters the fan case 10. Is further improved, and the cooling efficiency of the internal combustion engine 2 is further improved.

  Furthermore, since the end of the hot air intake passage 30 on the cylinder 16 side (the hot air intake port 27) is located closer to the cylinder 16 than the exhaust port 24 of the exhaust muffler 22, the exhaust muffler. The exhaust E from 22 is not sucked into the fan case 10.

It is a whole perspective view which shows the use condition of the hand-held power blower which concerns on one Embodiment of the ventilation working machine of this invention. It is the perspective view which looked at the power blower of FIG. 1 from the reverse side. It is a principal part cross-sectional plan view of the power blower of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air blower 2 Air-cooled internal combustion engine 3 Centrifugal blower 9 Air inlet 10 Fan case 11 Centrifugal fan 11a Fan blade 13 One side 16 High temperature part (cylinder)
17 Blowing means (cooling fan)
22 Exhaust muffler 24 Exhaust port 27 End of hot air intake passage (hot air intake port)
30 Hot air intake passage 30a Part of the hot air intake passage (upstream part)
30b Part of hot air intake passage (middle stream)
30c Part of the hot air intake passage (downstream part)
31 Casing

Claims (4)

  An air-cooled internal combustion engine (2), a blower means (17) for supplying cooling air (A1) to the high temperature portion (16) of the internal combustion engine (2), and a work for driving by the internal combustion engine (2) A blower working machine (1) provided with a centrifugal blower (3), wherein the blower (3) has a fan case (10) having an intake port (9) only on one side surface (13), and the fan A centrifugal fan (11) rotatably supported in the case (10), and a hot air intake passage (30) integrally formed outside the fan case (10), the intake port (9) and the A blower working machine in which hot air sides of the high temperature section (16) are communicated with each other via the hot air suction passage (30).   The blower working machine according to claim 1, wherein the hot air intake passage (30) is opened near the fan blade (11a) of the air inlet (9) of the centrifugal fan (11).   An end (27) of the hot air intake passage (30) on the high temperature portion (16) side is a hot air side of the cylinder (16) of the internal combustion engine (2) and is connected to the cylinder (16). The blower working machine according to claim 1 or 2, wherein the blower working machine is located closer to the cylinder (16) than the exhaust port (24) of the exhaust muffler (22).   In the casing (31) of the blower (3) driven by the air-cooled internal combustion engine (2), the intake port is provided outside the fan case (10) having the intake port (9) only on one side surface (13). A blower casing comprising (9) and at least a part (30a, 30b) of a hot air intake passage (30) communicating with the hot air side of the high temperature section (16) of the internal combustion engine (2).

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