JP3779099B2 - Small engine intake system for portable working machines - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air-cooled small engine intake device used for portable working machines such as a chain saw, a brush cutter, and a blower.
[0002]
[Prior art]
Conventionally, operations on portable work machines generally generate dust such as chips, chips, sand dust, etc. Therefore, they are provided at the suction port of the vaporizer of an air-cooled small engine used for portable work machines. There was a problem that filter clogging was likely to occur, the cleaning interval was short, and work efficiency was poor. As a countermeasure, for example, there is one disclosed in JP-A-6-1773797.
[0003]
The prior art will be described below based on the engine intake device disclosed in Japanese Patent Application Laid-Open No. Hei 6-1773797. In order to easily explain the content described in the same publication, the engine disclosed in the same publication is disclosed. This will be described with reference to the same configuration drawing as that of the intake device. FIG. 4 is a side view of the chain saw 1a according to the prior art, and shows a state where the fan case is removed. FIG. 5 is a plan view, and a part thereof shows a cross-sectional view taken along the line CC of FIG.
[0004]
4 and 5, the air-cooled engine 2 is installed in an engine case 4 having a handle 3 for carrying at the top, and a side cover 4a attached to the right side surface of the engine case 4 facing forward. A saw chain 9 is rotatably engaged with an outer periphery of a guide bar 9a fixed to a front portion between the engine case 4 and the engine case 4. A fan 10 for blowing cooling air is attached to an end of a crankshaft (not shown) of the engine 2 so that when the engine 2 is driven, it rotates in the direction of arrow Y shown in FIG. The fan 10 is provided with a plurality of blades 12, 12... Radially on the outer periphery of the side surface of the circular rotating body 11. A sealed intake chamber 5 is provided at the rear end of the engine case 4, and a filter 7 attached to a suction port 6 of a carburetor (not shown) is provided in the intake chamber 5. Further, an intake port 8 is provided in the lower portion of the intake chamber 5.
[0005]
In FIG. 5, a fan case 20 a having an outer cover 21 a and an inner cover 31 a is attached to the side surface of the engine case 4 on the side where the fan 10 is disposed so as to cover the fan 10. 6 is a DD arrow view of FIG. 5 and 6, a recoil starter pulley 13 is provided at a portion corresponding to the rotation center portion of the fan 10 of the outer cover 21a. The recoil starter pulley 13 and the recoil starter handle 14 are formed of a wire having a predetermined length or the like. It is connected with. An outside air inlet 22 for sucking outside air is provided in the vicinity of the outer peripheral portion of the fan 10 of the outer cover 21a, and the outer cover 21a and the inner cover 31a are provided with a spiral-type air guide along the outer peripheral portion of the fan 10. Grooves 23 and 32 are formed. An air guide plate 33 is provided on the inner surface of the inner cover 31 a, and an air guide portion 34 for guiding the cooling air to the engine 2 is formed by the air guide plate 33. Further, an air supply port for sending combustion air to the engine 2 at a position corresponding to the intake port 8 of the intake chamber 5 of the inner cover 31a on the other end side (rear side) with respect to the outside air intake port 22. 35 is provided. Furthermore, two partition walls 24a and 24a are provided on the inner surface of the outer cover 21a, and combustion is provided along the outer periphery of the recoil starter pulley 13 by the partition walls 24a and 24a, the outer cover 21a, and the inner cover 31a. An air intake port 25a and an intake passage 26 communicating between the intake port 25a and the air supply port 35 are formed. As shown by the thin two-dot chain line in FIG. 4 and as shown in FIGS. 5 and 6, the suction port 25 a is located near the rotation center of the blade 12 of the fan 10 and is located on the outer periphery of the recoil starter pulley 13. It is provided along. As shown in FIG. 5, the height of the partition wall 24a standing direction of the end surface 28a of the partition wall 24a forming the suction port 25a is such that the end surface 37 of the inner peripheral wall 36 of the spiral-type air guide groove 32 of the inner cover 31a stands. It is set lower by t than the installation direction height. The air supply port 35 and the air intake port 8 are connected by a connection pipe 29 as shown in FIG.
[0006]
Next, the operation will be described. When working, the operator drives the engine 2 to rotate the saw chain 9, grips the handle 3, and performs a pruning operation or the like with the saw chain 9. When the engine 2 is driven, the fan 10 rotates in the direction of the arrow Y shown in FIG. 4, whereby the outside air is sucked from the outside air intake port 22 of the outside cover 21 a and pressurized by the spiral type air guide grooves 23 and 32 and guided. The air reaches the wind portion 34 and is guided to the outer peripheral portion of the engine 2 by the air guide plate 33 to cool the engine 2. Further, a part of the outside air sucked from the outside air inlet 22 is sent to the intake chamber 5 through the intake passage 25, the air supply port 35 and the intake port 8 in order from the intake port 25a, and then filtered by the filter 7. Enter the vaporizer. When the engine 2 rotates at a high speed, a large amount of air in the intake chamber 5 is sucked into the engine 2. Therefore, the pressures in the intake chamber 5 and the intake passage 26 are reduced, and the air sucked from the outside air inlet 22 is sucked from the suction port 25a. A large amount of dust such as chips and chips gathers on the outer periphery of the spiral air guide grooves 23 and 32 due to centrifugal force, and air with relatively little dust is sucked from the suction port 25a. Therefore, clogging of the filter 7 is reduced and the cleaning interval is also increased.
[0007]
[Problems to be solved by the invention]
However, in the configuration of the air intake device as disclosed in the above-mentioned JP-A-6-1773797, it is difficult to sufficiently perform the above-described dust removing function during upward pruning work for the following reason. is there. That is, since a high tree pruning operation is an upward operation, a large amount of chips and chips are sprinkled on the chain saw body, and a large amount of chips and the like are mixed into the combustion air, so that the eyes of the filter 7 can be quickly observed. Cause clogging. In particular, the cuttings of straw and cedar bark are very fine. When the upward pruning operation of the straw and cedar is performed, the fine chips are clogged in the filter 7 and must be cleaned every short time. For example, the cleaning interval is about 30 hours in the normal operation, whereas the upward pruning operation of the reeds and cedars must be cleaned every 2 hours, which causes a problem that the work efficiency is extremely poor.
[0008]
The present invention has been made paying attention to the above-mentioned problems, and even in upward work when fine dust is generated, the filter is not easily clogged, and a small engine used for a portable work machine that can improve work efficiency. It aims to provide an intake device .
[0009]
[Means, actions and effects for solving the problems]
In order to achieve the above object, a first invention of a small engine intake device for use in a portable work machine according to the present invention provides a fan having a plurality of blades arranged radially on an outer peripheral portion, and an outside air intake port. A swirl that is rotatably arranged in a fan case having a cover and an inner cover provided in the outer cover, and guides air from the outside air intake along the outer peripheral portion of the fan by the outer cover and the inner cover. Forming a wind guide passage groove and a wind guide portion for sending the guided air to the engine, opening near the rotational center in the radial direction of the wing plate, and guiding by the spiral wind guide passage groove. The partition wall that forms an intake port for sucking a part of the air and an intake passage that communicates the intake port and an intake chamber in which a filter attached to the suction port of the carburetor of the engine is connected is removed. portable working machine which is provided on the cover or the inner cover An intake system for a small engine to be used,
A wall surface is provided along the radial direction at the part of the partition wall that forms the suction port so as to face the rotation direction of the fan, and an outer wall that is close to the rotation center of the fan is provided on the partition wall. A dust-proof wall having a substantially triangular shape is provided on the wall surface so that one apex side formed by the triangular outer wall (27) and the dust-proof wall (41) faces the direction of rotation of the fan. A part of the air directed from the intake port along the spiral-type air guide passage groove toward the suction port is guided to the air guide portion.
[0010]
According to the above configuration, the passage from the vicinity of the dust-proof wall of the outer periphery of the fan sucked from the outside air inlet of the outer cover to the wind guide portion is formed in a smooth shape by the substantially triangular dust-proof wall (41). Is done. For this reason, air containing dust such as chips, chips, and sand sucked in from the outside air inlet does not directly collide with the substantially radial wall surface of the suction port to generate turbulent flow. Therefore, the air on the outer periphery of the fan containing a large amount of dust is smoothly guided from the vicinity of the dust-proof wall of the spiral type air guide passage groove to the air guide, so that the air on the inner periphery of the fan with less dust is It is inhaled from the inlet through the gap. As a result, clogging of the filter is less likely to occur and the time until clogging is extended, so that the cleaning interval time is increased and work efficiency can be improved.
[0011]
The second aspect of the invention is based on the first aspect of the invention and has a configuration in which a notch is formed in a portion near the dust-proof wall on the inner peripheral wall of the spiral-type air guide passage groove on the inner peripheral side.
[0012]
According to the second invention, the passage from the vicinity of the dust-proof wall of the air at the outer periphery of the fan to the air guide portion is formed widely. For this reason, the air in the outer peripheral portion of the fan containing a large amount of dust has almost no resistance and is smoothly guided to the air guide portion, so that the dust contained in the air sucked from the suction port can be further reduced.
[0013]
The third invention is based on the first invention, and the height of the outer wall of the partition wall that forms the suction port of the partition wall and the dust-proof wall near the rotation center of the fan is set to the inner peripheral side of the spiral-type air guide passage groove. It is set as the structure made higher than the inner peripheral wall which has.
[0014]
According to the third aspect of the present invention, the height of the outer wall of the partition wall that forms the suction port and the dust-proof wall near the fan rotation center is higher than the inner peripheral wall of the spiral-type air guide passage groove. Higher than the ones. Therefore, the dust in the air at the inner periphery of the fan directly gets over the outer wall and is difficult to enter from the suction port, so that the amount of dust sucked from the suction port is further reduced.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an intake device for a small engine used in a portable work machine according to the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 is a side view of the chain saw 1 with a fan case removed, FIG. 2 is a cross-sectional view of the main part of the chain saw 1 according to the present invention, taken along line AA in FIG. 1, and FIG. It is a BB arrow line view. In the following, the same components as those shown in FIGS. 4, 5, and 6 are denoted by the same reference numerals, and description thereof is omitted, and only different portions are described.
[0017]
As shown in FIG. 3, the suction port 25 is formed by a partition wall 24 and an inner cover 31. A wall surface 40 (see FIG. 7) along the radial direction of the fan 10 is provided at a portion of the partition wall 24 that faces the rotation direction (arrow X direction) of the fan 10. The wall 40, in a side view, the outer wall 27 (described later) the length K of the wall 40 in the radial direction of the fan 10 as one side dust-proof walls having a substantially triangular shape (see FIG. 3) in conjunction with (see Fig. 7) 41 ( refer to FIG. 7 ) is provided along the recoil starter pulley 13 with the one apex side of the triangle facing the direction of rotation of the fan 10 (arrow X direction) . The height in the standing direction of the dust-proof wall 41 with respect to the outer cover 21 is set to be the same as the height in the standing direction of the partition wall 24. A notch 42 having a predetermined width L is provided on the inner peripheral wall 36 of the spiral wind guide groove 32 in the vicinity of the dust-proof wall 41. That is, the dust-proof wall 41 and the notch 42 form a passage for introducing the air sucked from the outside air inlet 22 into the air guide portion 34. Further, the outer wall 27 close to the rotation center of the fan 10 between the part of the partition wall 24 forming the suction port 25 and the dustproof wall 41, that is, the end face 28 of the arc length R portion along the outer periphery of the recoil starter pulley 13 As shown in FIG. 2, the height in the direction is set higher by a predetermined length S than the height in the same direction of the end surface 37 of the inner peripheral wall 36 of the spiral air guide groove 32 of the inner cover 31.
[0018]
Next, functions and effects will be described with reference to FIG.
When the engine 2 is driven, the fan 10 rotates, the outside air is sucked from the outside air inlet 22, and is introduced into the air guide portion 34 through the spiral air guide grooves 23 and 32 provided on the outer peripheral portion of the fan 10. . At this time, dusts such as chips, chips, and sand dust flow along the outer peripheral wall surfaces of the spiral air guide grooves 23 and 32 by centrifugal force. Further, the air inside the inner peripheral wall 36 of the spiral type air guide grooves 23 and 32 also rotates in the direction of the arrow X by the rotation of the fan 10, and passes through the passage formed by the dust-proof wall 41 and the notch portion 42. 34 flows smoothly. Therefore, the outside air does not collide with the wall surface 40 provided along the radial direction of the fan 10 and the flow is not disturbed, and a comparison of chips passing through the gap between the fan 10 and the dust-proof wall 41 and the partition wall 24. A relatively small amount of air is sucked into the suction port 25. Further, the height of the outer wall 27 in the partition wall 24 forming the suction port 25 near the rotation center of the fan 10 is increased in height, so that chips and the like are difficult to get over the outer wall 27 directly from the rotation center side of the fan 10. The amount of chips and the like sucked into the intake chamber 5 from the intake port 25 through the intake passage 26, the air supply port 35, and the intake port 8 can be reduced.
As a result, clogging of the filter can be prevented and the cleaning interval can be increased several times.
[0019]
The intake device for a small engine used in the portable working machine of the present invention can be used for purposes other than a chain saw.
[Brief description of the drawings]
FIG. 1 is a side view showing a state in which a fan case of a chain saw provided with an intake device of the present invention is removed.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a view taken along arrow BB in FIG. 2;
FIG. 4 is a side view showing a state where a fan case of a chain saw provided with a conventional air intake device is removed.
5 is a plan view of the chain saw and is a cross-sectional view taken along the line CC in FIG.
6 is a view taken along the line DD in FIG. 5;
7 is a perspective view of the chain saw shown in FIG. 3; FIG.
[Explanation of symbols]
2: engine, 10: fan, 12: vane plate, 20: fan case, 21: outer cover, 22: outside air intake, 23, 32: spiral-type air guide groove, 24: partition wall, 25: suction port, 26 : Intake passage, 27: outer wall, 28, 37: end face, 31: inner cover, 33 air guide plate, 34: air guide part, 36: inner peripheral wall, 40: wall surface, 41: dustproof wall, 42: notch part.

Claims (3)

A fan (10) having a plurality of blades (12, 12 ...) arranged radially on the outer periphery is provided in an outer cover (21) having an outside air inlet (22) and an outer cover (21). The fan case (20) having the inner cover (31) formed therein is rotatably arranged, and the air from the outside air inlet (22) is supplied to the fan (22) by the outer cover (21) and the inner cover (31). And 10) a spiral-type air guide passage groove (23, 32) guided along the outer peripheral portion and an air guide portion (34) for sending the guided air to the engine (2). An inlet (25) that opens near the radial center of (12,12 ...) and sucks a part of the air guided by the spiral air guide passage groove (23,32); An intake passage (26) is formed which communicates the suction port (25) with an intake chamber (5) in which a filter (7) attached to the suction port (6) of the carburetor of the engine (2) is installed. with partition walls (24) to the outer cover (21) or inner cover (31) formed by providing a portable working machine to An intake system for a small engine,
A wall surface (40) is provided substantially along the radial direction at the part of the partition wall (24) forming the suction port (25) so as to oppose the rotation direction of the fan (10), and the fan is provided on the partition wall (24). The outer wall (27) close to the rotation center of (10) is provided, and the dust-proof wall (41) having a substantially triangular shape by the wall surface (40) and the outer wall (27) in a side view is provided with the triangular outer wall (27 ) and provided one corner side forming with the dust-proof wall (41) to the fan (direction of rotation of 10) (the wall in the direction opposite to the arrow X) (40), spiral wound from the outside air inlet (22) Intake of a small engine used in a portable working machine characterized in that a part of the air directed to the inlet (25) along the air guide passage groove (23, 32) is guided to the air guide (34) Equipment . The intake device for a small engine used in the portable work machine according to claim 1, wherein the inner peripheral wall (36) provided on the inner peripheral side of the spiral wind guide passage groove (32) is disposed near the dust-proof wall (41). An intake device for a small engine used in a portable working machine, characterized in that a notch (42) is formed. The small engine intake device used in the portable work machine according to claim 1, wherein the part of the partition wall (24) forming the inlet (25) and the dustproof wall (41) are close to the rotation center of the fan (10). The height of the outer wall (27) in the standing direction is higher than that of the inner peripheral wall (36) on the inner peripheral side of the spiral-type air guide passage groove (32) . Intake device .

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