JP2014190320A - Air-cooling engine and engine work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-cooling engine and an engine work machine capable of providing high cooling efficiency, in the engine in which a governor controlled by cooling air is used.SOLUTION: When the number of rotation of an engine is increased, a throttle valve shaft 82 rotates according to the operation and, therefore, an air-cooling engine comes to a state of fig. 3(b). In such a state, the uppermost part of a wind receiving plate 21 is moved to the left side in the figure (air channel 13 side). When a load becomes large during the operation and the number of rotation decreases, wind power of cooling air C is lowered and, therefore, the power received by the wind receiving plate 21 from the cooling air C is weakened. In such a case, the wind receiving plate 21 is turned counterclockwise by reaction force of a governor spring 83, the uppermost part of the wind receiving plate 21 moves toward a second position so as to be exhibited in fig. 3(c). In such a case, the throttle valve shaft 82 is turned counterclockwise and, therefore, the throttle is opened. During the operation, a carburetor 8 is controlled between the state of fig.3(b) and the state of fig.3(c) by using a wind power governor 20.

Description

The present invention relates to a structure of a small air-cooled engine and an engine working machine using the same.

  A small working engine is used as a power source for portable working machines such as brush cutters, blowers, chainsaws, power cutters, and the like that are carried and used by workers. FIG. 10 is a perspective view showing a configuration of a brush cutter 300 which is an example of such an engine working machine. In this brush cutter 300, an engine 320 is mounted on one end side of the operation shaft 310, and a cutting blade 330 that is driven by the engine 320 to perform rotational motion is provided on the other end side. An operator can hold a handle 340 provided on the operation shaft 310 and use this cutting blade 330 to cut a plant or the like.

  At this time, in order to control the rotational speed of the cutting blade 330 (the number of revolutions of the engine 320), the engine 320 uses a carburetor that controls the amount of air-fuel mixture supplied, and a throttle provided in the carburetor. The number of revolutions of the engine 320 can be controlled by opening and closing. For this purpose, the handle 340 is provided with a throttle lever 350. For example, when the operator pulls the throttle lever 350, the throttle wire 360 connected between the carburetor used in the engine 320 and the throttle lever 350 is pulled toward the throttle lever, thereby the throttle of the carburetor. Is opened, and the operation of increasing the rotational speed of the engine 320 is performed. In this case, the throttle of the carburetor is provided with a throttle spring, and when the operator does not touch the throttle lever 350, the throttle spring of the carburetor is closed by the throttle spring (the engine 320 is in an idling state). It is energized. Thereby, the user can use this brush cutter 300 safely.

  Among the above-described components, the engine 320 is particularly heavy, but the operator needs to hold and move the brush cutter 300 when working, so the engine 320 used here is small, It is required to be lightweight. For this reason, the engine 320 is often an air-cooled type that can be easily reduced in weight. In this case, a cooling fan is fixed to the crankshaft of the engine 320, and the cooling fan continuously rotates during operation of the engine 320 to generate cooling air. In the engine 320, a particularly high-temperature cylinder is covered with a cylinder cover, and the cooling air flows through the cylinder cover to forcibly cool the cylinder and the like.

  At this time, a governor that automatically controls the engine 320 in accordance with the number of revolutions is used for the safety of the worker, the optimization of the operation, and the efficiency of the work. As an example of a governor, the structure is designed to prevent engine overspeeding or stabilize the rotational speed by detecting the strength (air volume) of cooling air and automatically controlling the throttle according to the air volume. Things are used.

  The configuration of such a governor (wind governor) is described in Patent Document 1, for example. In this configuration, the governor plate is provided in the cooling air flow path. The governor plate is installed so as to be biased toward the inside of the cylinder cover so as to receive the cooling air, and is configured to move outward by the wind of the cooling air. The governor plate and a throttle valve shaft for controlling the opening / closing operation of the throttle are connected so that the movement of the governor plate is interlocked with the throttle of the carburetor. Thus, for example, when the engine speed is too high, the wind power increases and the governor plate moves outward to close the throttle, reducing the amount of air-fuel mixture supplied to the engine, and automatically increasing the engine speed. Control to lower is performed. Thereby, it is possible to prevent the engine from over-rotating. On the other hand, when the engine speed decreases because the load during work increases, the throttle opens when the governor plate returns to the inside due to the biasing, contrary to the above case. Recover (increase) the rotational speed. That is, using such a governor plate, the engine speed can be stabilized within an appropriate range.

  Such a configuration can be realized by providing a governor plate on the cylinder cover and connecting the governor plate to a throttle valve shaft in the carburetor. For this reason, since the configuration of the governor can be simplified without increasing the size of the entire engine, this configuration is particularly effective in an engine working machine that requires the entire engine to be small and light. .

JP-A-6-123243

  However, in the above configuration, it is clear that the governor plate provided in the air passage becomes an obstacle to the cooling air. In particular, when the engine speed is the highest, it is necessary to maximize the air volume and increase the cooling efficiency. In the above configuration, the cooling air is blocked by the governor plate in this state. For this reason, when the governor having the above configuration is used, there arises a problem that the cooling efficiency of the engine decreases. For example, it is possible to maintain high cooling efficiency in such a case by increasing the size of the cooling fins, cooling fans, etc. provided in the cylinder of the engine, but in this case, the overall size of the engine is increased. Therefore, such a configuration is not preferable particularly for an air-cooled engine mounted on an engine working machine.

  That is, it has been difficult to obtain high cooling efficiency in an engine in which a governor controlled by cooling air is used.

  The present invention has been made in view of such problems, and an object thereof is to provide an invention that solves the above problems.

In order to solve the above problems, the present invention has the following configurations.
The air-cooled engine of the present invention includes a cylinder, a crankshaft to which a cooling fan is attached, and output control means for controlling the rotational speed of the crankshaft, and cooling air generated by the cooling fan cools the cylinder. An air-cooled engine in which a cover is provided so as to form an air path that operates, and a wind governor that operates the output control means by wind power of the cooling wind is provided in the air path, and the wind governor includes the air path The one end in the direction in which the cooling air flows is provided to move between a first position spaced from the air passage and a second position located on the air passage side with respect to the first position. A wind receiving plate is provided.
In the air-cooled engine of the present invention, in the output control means, when the one end is at the second position, the rotation speed of the crankshaft is higher than when the one end is at the first position. Control is performed.
In the air-cooled engine of the present invention, the wind receiving plate is configured to rotate about a rotation shaft provided on the other end side in the direction in which the cooling air flows.
In the air-cooled engine of the present invention, the rotation shaft is the same as the rotation speed control shaft provided in the output control means.
In the air-cooled engine of the present invention, the rotation shaft is configured to be interlocked with a rotation speed control shaft provided in the output control means.
The air-cooled engine of the present invention is characterized in that, in the wind governor, an arm fixed to the wind receiving plate rotates a rotation speed control shaft provided in the output control means.
In the air-cooled engine of the present invention, the rotating shaft is provided on the cover.
The air-cooled engine of the present invention is characterized in that the angular fluctuation of the rotational speed control shaft linked to the angular fluctuation of the rotary shaft is set to be larger than the angular fluctuation of the rotary shaft.
The air-cooled engine of the present invention is characterized in that, in the wind governor, the surface of the wind receiving plate has a shape in which a plurality of different planes are combined or a shape including a curved surface.
In the air-cooled engine of the present invention, the cover is formed with a notch, and the wind receiving plate in the wind governor is installed in the notch.
In the air-cooled engine of the present invention, the second position is closer to the air path than the inner surface of the cover, and the wind receiving plate has the wind receiving plate in a state where one end of the wind receiving plate is in the second position. The distance between one end of the receiving plate and the inner surface of the cover is set to 15 mm or less, or the angle between the wind receiving plate and the inner surface of the cover is set to 45 ° or less. .
The air-cooled engine of the present invention is characterized in that a part of one end of the wind receiving plate is in contact with the cover when one end of the wind receiving plate is in the second position.
In the air-cooled engine of the present invention, the wind receiving plate is covered with the cover together with the cylinder.
The engine working machine of the present invention is characterized in that the air-cooled engine is used.

  Since the present invention is configured as described above, high cooling efficiency can be obtained in an engine using a governor controlled by cooling air.

1 is a side view showing a configuration of an engine (air-cooled engine) according to an embodiment of the present invention. It is the fragmentary sectional view (a) of the AA direction of the engine used as embodiment of this invention, and sectional drawing (b) of a carburetor. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a configuration around a wind governor when an engine is stopped or idling (a) and during operation (b) and (c) in an engine according to an embodiment of the present invention. It is sectional drawing which shows the structure of the 1st modification of the air cooling engine used as embodiment of this invention. It is sectional drawing which shows the structure of the 2nd modification of the air cooling engine used as embodiment of this invention. It is sectional drawing which shows the structure of the 3rd modification of the air cooling engine used as embodiment of this invention. It is sectional drawing which shows the structure of the 4th modification of the air cooling engine used as embodiment of this invention. It is sectional drawing which shows the structure of the 5th modification of the air cooling engine used as embodiment of this invention. It is sectional drawing which shows the structure of the 6th modification of the air-cooled engine used as embodiment of this invention. It is a perspective view which shows an example of a structure of the engine working machine in which a small air cooling engine is used.

  A configuration of an air-cooled engine (engine) according to an embodiment of the present invention will be described. Here, the air-cooled engine includes an engine body including a cylinder, a crankcase, and the like. In particular, a high temperature cylinder is covered with a cylinder cover, and cooling air generated by a cooling fan fixed to the crankshaft flows through the inside of the cylinder cover, thereby cooling the cylinder. The rotation speed of the crankshaft is controlled by the rotation angle of a rotation speed control shaft (a throttle valve shaft in the carburetor) of an output control means (for example, a carburetor). The cylinder cover is provided with a wind governor that is operated by cooling air, and the throttle of the carburetor is controlled in conjunction with the operation of the wind governor. However, this wind governor is set so as not to obstruct the flow of cooling air.

  This engine is used, for example, in a portable working machine carried by an operator, such as a brush cutter, a blower, a chain saw, or a power cutter, or in an engine working machine such as a generator. Mounted on. For this reason, in reality, mechanisms for connecting the engine and the engine work machine main body are also provided on the engine side. However, these mechanisms are not directly related to the present invention, and these have been conventionally used. Since it is the same as that known, description thereof will be omitted below, and only the part related to the operation of the wind governor will be described.

  FIG. 1 is a side view showing the configuration of the engine (air-cooled engine) 1. FIG. 2 (a) is a partial cross-sectional view in the AA direction, and FIG. 2 (b) is a cross-sectional view of a carburetor therein. It is. The engine 1 is provided with a cylinder 2 that extends in the vertical direction in FIGS. 1 and 2A and has cooling fins 201 provided on the surface thereof. In the crankcase provided on the lower side of the cylinder 2, a crankshaft 3 having a central axis in the left-right direction in FIG. 1 and in a direction perpendicular to the paper surface in FIG. 2A is provided. The cooling fan 4 is fixed to one end side (left side in FIG. 1) of the crankshaft 3, and the engine starter 5 is connected to the other end side (right side in FIG. 1). FIG. 2 is a partial cross-sectional view showing a cross section perpendicular to the crankshaft 3 at a location where the cooling fan 4 is provided. The cylinder 2 is covered with a cylinder cover 6 and the cooling fan is covered with a fan case 7, respectively. FIG. 1 shows the covered shape. Further, intake is performed on one side of the cylinder 2 (the front side in FIG. 1), and exhaust is performed on the other side (the other side in FIG. 1). For this reason, on one side, a carburetor 8 and an air filter 9 as output control means are connected to the cylinder 2, and in FIG. 1, a filter cover 91 outside the air filter 9 is shown. A fuel tank 10 is provided at the lower part of the crankcase. The fuel in the fuel tank 10 is introduced into the carburetor 8, and in the carburetor 8, an air-fuel mixture is formed by mixing the air introduced through the air filter 9 and the fuel, and this air-fuel mixture is introduced into the cylinder 2. Is done. The air-fuel mixture compressed in the combustion chamber in the cylinder 2 is ignited by an electric current generated by the ignition coil 11 being passed through a spark plug (not shown), and the crankshaft 3 is rotated. The engine starter 5 is operated only when the crankshaft 3 is forcibly rotated when the engine 1 is started. After the start, the crankshaft 3 rotates stably, and cooling air is constantly generated by the cooling fan 4. The

  As shown in FIG. 2A, the vaporizer 8 is attached to the cylinder 2 through the cylinder cover 6 from the outside. The cylinder cover 6 and the fan case 7 cover the cylinder 6 and the cooling fan 4 and are installed so that the cooling air C flows smoothly through the air passage 13 formed in the crankcase involute portion 12 from the cooling fan 4. The Therefore, when the crankshaft 3 rotates counterclockwise in FIG. 2A, the cooling air C flows through the internal air passage 13 covered with the cylinder cover 6 as shown in the figure. As the cooling air C flows through the gaps between the cooling fins 201, the cylinder 2 is cooled, and the air path 13 is a path of the cooling air C from the cooling fan 4 to the cylinder 2. A cutout portion 61 (opening portion) is formed in a part of the cylinder cover 6 that forms the air passage 13, and the wind governor 20 is provided at a location where the cutout portion 61 exists.

  The wind governor 20 is connected to a throttle valve shaft 82 that opens and closes the throttle 81 in the carburetor 8 in FIG. In the carburetor 8, the set angle of the throttle 81 is controlled by the rotation angle of the throttle valve shaft (rotational speed control shaft) 82, and the aperture of the intake passage formed inside the carburetor 8 is changed. The amount of air-fuel mixture introduced into the cylinder 2 is controlled. As a result, the rotational speed of the engine 1 (the rotational speed of the crankshaft 3) is controlled.

  The wind governor 20 includes a wind receiving plate 21 and a connection portion 22, and the wind receiving plate 21 having a planar shape is connected to the throttle valve shaft 82 via the connection portion 22. The valve shaft 82 is rotated around the rotation shaft. That is, the rotational axis of the wind governor 20 is the same as the throttle valve shaft 82. For this reason, the rotation of the wind receiving plate 21 is interlocked with the opening / closing operation of the throttle 81. The wind receiving plate 21 is made of a material having heat resistance and sufficient mechanical strength, such as a metal or a resin material. About the above point, it is the same as that of the conventional wind governor.

  However, the wind governor 20 is disposed so as not to disturb the flow of the cooling wind C. FIG. 3 is a cross-sectional view showing the configuration in the vicinity of the wind governor 20 in three states. Here, FIG. 3A corresponds to when the engine is stopped or idling (when the engine work machine is stopped). 3 (b) and 3 (c) show the configuration when this engine is used, but FIG. 3 (b) shows the case where the rotational speed of the engine 1 increases because the load during use is light. FIG. 3C shows a case where the rotational speed of the engine 1 is reduced due to an increase in load during use. Here, the positional relationship between the carburetor 8 and the cylinder cover 6 is unchanged, and the installation angle of the wind governor 20 with respect to these changes. The installation angle of the wind governor 20 (wind receiving plate 21) varies between the state shown in FIG. 3A and the state shown in FIG. Here, one end on the downstream side of the wind receiving plate 21 (the uppermost portion of the wind receiving plate 21 in FIG. 3) is located at the outermost position (the first position in the state of FIG. 3A) from the air passage 13. In the state of FIG. 3C, the position is closer to the air passage 13 than the first position (second position).

  In the carburetor 8, when the throttle valve shaft 82 rotates counterclockwise in FIGS. 2 and 3, an operation of opening the throttle 81 (increasing the rotational speed of the engine 1) is performed. The throttle valve shaft 82 is also connected to, for example, a throttle wire 360 in the brush cutter 300 shown in FIG. In this case, the throttle valve shaft 82 is urged clockwise (in the direction to close the throttle 81) by a throttle spring provided on the throttle wire 360 (throttle lever 350) side. Thus, when the operator does not touch the throttle lever 350, the engine 1 is automatically set to the idling state or the stopped state. On the other hand, the wind governor 20 is biased counterclockwise (opening the throttle 81) about the throttle valve shaft 82 by a governor spring 83 provided on the throttle valve shaft 82. That is, the throttle valve shaft 82 is biased in different directions from the throttle wire 360 side and the wind governor 20 side.

  Here, as shown in FIG. 3A, when the engine 1 is stopped or idling (the operator does not touch the throttle lever 350), one end on the downstream side of the wind receiving plate 21 is the first end. In position. For this reason, the notch 61 is not blocked by the wind receiving plate 21 and is in a large open state. The cooling wind C does not flow when the engine 1 is stopped, and the wind receiving plate 21 is hardly affected by the cooling wind C because the wind force of the cooling wind C is very weak in the idling state.

  When the operator operates the throttle lever 350 to increase the rotational speed of the engine 1 in order to use the brush cutter 300 from the idling state, the throttle valve shaft 82 rotates in response to this operation. It will be in the state of (b). In this state, the uppermost portion of the wind receiving plate 21 moves to the left side (wind passage 13 side) in the figure, and the wind receiving plate 21 (wind governor 20) is arranged in a direction in which the cutout portion 61 is blocked by the wind receiving plate 21. Rotate. In this state, if the rotational speed of the engine 1 is increased more than necessary (when the engine 1 is excessively rotated), the wind force of the cooling air C in the air passage 13 is increased, so that the wind receiving plate 21 is in the air passage 13. In response to the force from the side toward the outside of the cylinder cover 6, a force is applied to rotate the wind governor 20 and the throttle valve shaft 82 clockwise. As a result, the control for closing the throttle 81 (reducing the rotational speed) is automatically performed.

  On the other hand, when the load on the cutting blade 330 is increased during the operation and the rotational speed is decreased, the wind force of the cooling air C is reduced, and thus the force received by the wind receiving plate 21 from the cooling air C is weakened. In this case, the wind receiving plate 21 is rotated counterclockwise by the reaction force of the governor spring 83, and the uppermost portion of the wind receiving plate 21 moves toward the second position as shown in FIG. To do. In the example of FIG. 3C, this second position overlaps with the notch 61, so that the notch 61 is closed by the wind receiving plate 21. However, when the wind receiving plate 21 rotates to this position and its uppermost portion approaches the second position, the throttle valve shaft 82 rotates counterclockwise, so that the throttle 81 opens. Thereby, the reduced engine speed increases again. Thereby, the state of FIG. 3B is again approached.

  Thus, during operation, the carburetor 8 is controlled between the state of FIG. 3B and the state of FIG. 3C using the wind governor 20 described above. As a result, the rotational speed of the engine 1 is automatically maintained within an appropriate range. At this time, the wind governor 20 (throttle valve shaft 82) is moved so that the uppermost portion of the wind receiving plate 21 moves between the first position in FIG. 3 (b) and the second position in FIG. 3 (c). ) Rotate.

  In this configuration, as shown in FIG. 3C, the wind governor 20 is set so that the top of the wind receiving plate 21 is in the second position when the opening of the throttle 81 is maximized. The In this state, the wind receiving plate 21 constitutes substantially the same surface as the surface constituting the inner surface of the cylinder cover 6, and the notch 61 is substantially closed by the wind receiving plate 21. That is, in the above configuration, the cylinder cover 6 is provided with an opening (notch 61), and the degree of closing of the opening by the wind receiving plate 21 is adjusted together with the opening of the throttle 81. At this time, the state of the wind receiving plate 21 changes within the range of FIGS. When moving to the side (FIG. 3C), the surface constituting the wind receiving plate 21 is parallel to the direction in which the cooling air C flows in the air passage 13. There is no hindrance.

  Further, in the state of FIG. 3B, the cooling air C may leak from the notch 61 to the outside of the cylinder cover 6, whereas FIG. ), The cutout portion 61 is substantially blocked by the wind receiving plate 21, so that the amount of cooling air C leaking from the cutout portion 61 is small. For this reason, in the case of FIG.3 (c), cooling efficiency also increases most. For this reason, even in an engine using a governor (wind governor) controlled by cooling air, high cooling efficiency can be obtained.

  In the above example, when the uppermost portion of the wind receiving plate 21 is in the second position (FIG. 3C), the wind receiving plate 21 and the cutout portion 61 overlap, and the wind receiving plate 21 is overlapped. However, as long as the wind receiving plate 21 does not become an obstacle to the cooling air C and the leakage amount of the cooling air C can be reduced, this configuration can be arbitrarily set. FIG. 4 shows a case where the wind receiving plate 21 protrudes by a distance D toward the air passage 13 in this case (first modification). Even in this case, if the surface constituting the wind receiving plate 21 is parallel to the flow of the cooling air C in this state, the air receiving plate 21 does not become an obstacle to the cooling air C, and the cooling air C Leakage is also small. In this case, for example, D is preferably 15 mm or less, that is, the wind receiving plate 21 is preferably provided at a position close to the inner surface of the cylinder cover 6.

  Alternatively, as shown in FIG. 5, when the uppermost portion of the wind receiving plate 21 is in the second position, the lowermost portion (the other end) of the wind receiving plate 21 overlaps with the notch portion 61 (cylinder cover 6). However, the angle of the wind receiving plate 21 can be set so that the uppermost part (one end) is separated from the inner surface of the cylinder cover 6 (second modification). In this case, when the angle formed between the inner surface of the cylinder cover 6 and the wind receiving plate 21 is θ, the smaller the θ is, the more the wind receiving plate 21 does not become an obstacle to the cooling air C. It is clear that the amount of leakage of C is small. Specifically, it is preferable that θ be 45 ° or less.

  Further, since the cylinder cover 6 is formed so as to cover the cylinder 2, the inner surface of the cylinder cover 6 is not actually a flat surface, and in the vicinity of the wind receiving plate 21 or the notch 61 in FIGS. Only a narrow region is shown, and the inner surface of the cylinder cover 6 is approximated in a planar shape in this narrow region. Actually, bent or curved portions are formed on the inner surface of the cylinder cover 6, and the cooling air C flows along these portions. By matching the shape of the wind receiving plate with these shapes, the flow of the cooling air C can be made smooth particularly when the uppermost portion of the wind receiving plate is in the second position (FIG. 3C). .

  FIG. 6 shows a case where the wind receiving plate 31 is used in which the first flat surface portion 311 and the second flat surface portion 312 are combined with each other so as to correspond to the bent portion of the inner surface of the cylinder cover 6. It is sectional drawing which shows an example (3rd modification). Here, the case where the uppermost part of the wind receiving plate 31 is in the second position is shown. In this example, a first plane portion 311 is provided on the downstream side, and a second plane portion 312 is provided on the upstream side, and the first plane portion 311 is set at an angle inclined with respect to the second plane portion 312 in the drawing. In such a configuration, the force received from the cooling air C by the first flat surface portion 311 on the downstream side and the far side from the rotating shaft (throttle valve shaft 82) is increased. Wind governor works more sensitively. Alternatively, this makes it possible to obtain the same sensitivity using the wind receiving plate 31 having a smaller total area, so that the entire wind governor can be reduced in size. Alternatively, even if a wind governor is provided in a place where the wind of the cooling air C is weak, the same control can be performed, so that the degree of freedom in engine design is increased.

  Thus, the shape of the wind receiving plate can be set as appropriate so as to generate an efficient flow of cooling air C for cooling in accordance with the shape of the cylinder cover at the location where the notch is provided. Is possible. In the above example, the wind receiving plate is formed by combining two different planes in the flow direction. However, it is also possible to combine more planes. Or the surface of a wind-receiving plate can also be made into the shape containing the curved surface which becomes concave shape seeing from the left side in FIG.

  Further, when the wind receiving plate is bent or curved in this way, the wind receiving plate functions as a part of the inner surface of the bent or curved cylinder cover, and the cooling air is bent along the wind receiving plate. Flowing. In order to generate such a flow of cooling air using the wind receiving plate of this shape, when the uppermost portion of the wind receiving plate is at the second position, the notch is blocked by the wind receiving plate. This configuration is particularly preferable.

  When the uppermost portion of the wind receiving plate is at the second position, the wind receiving plate and the cylinder cover may be in contact with each other so that the cooling air leakage amount is reduced. FIG. 7 is a cross-sectional view showing an example (fourth modification) in such a case. Here, the overall shape is the same as in FIG. 6, and similarly, the first flat surface portion 411 and the second flat surface portion 412 are provided. (Protrusion part) 413 is provided. In the upper right of FIG. 7, an enlarged view of the shape of the portion where the wind receiving plate 41 (first flat portion 411) and the cylinder cover 6 are in contact (the portion surrounded by the broken line in FIG. 7) is shown. The first flat surface projection 413 is provided on the upper outer side of the first flat surface portion 411. In this configuration, when the uppermost portion of the wind receiving plate 41 is in the second position, the space between the cylinder cover 6 and the wind receiving plate 21 is sealed by the first flat surface projection 413. For this reason, it is suppressed that the cooling air C leaks to the outer side of the air path 13 (cylinder cover 6). For this reason, higher cooling efficiency can be obtained. Further, in this case, when the wind governor rotates counterclockwise, the first flat surface projection 413 serves as a stopper, and this movement is restricted by the first flat surface projection 413.

  The first flat surface projection 413 does not need to be made of the same material as the first flat surface portion 411 and the second flat surface portion 412 (a material having sufficient mechanical strength such as a metal or a resin material). For example, silicon rubber It can also be comprised with elastic materials, such as. In this case, the sealing performance by the first flat surface projection 413 can be further improved. However, the uppermost portion (one end) of the wind receiving plate does not need to be in contact with the cylinder cover 6 over the entire area, and at least a part of the uppermost portion of the wind receiving plate may be in contact with the cylinder cover 6.

  In the example of FIG. 7, unlike the case of FIGS. 4 and 5, the notch 61 is closed by the wind receiving plate 41, and the wind receiving plate 41 is substantially the inner surface of the cylinder cover 6. Was functioning as a part of. However, when the uppermost portion of the wind receiving plate 41 is in the second position, even when the upper end portion is separated from the cylinder cover as shown in FIGS. It is possible to reduce the leakage amount of the cooling air C by forming a protrusion similar to the protrusion 413.

  Further, the leakage amount of the cooling air C can be further reduced by changing the shape of the cylinder cover 6 near the wind receiving plate. FIG. 8 is a sectional view showing an example (fifth modification) in such a case. In this configuration, the notch portion is not provided in the cylinder cover 6, and instead, the wind receiving plate storage portion 62 that protrudes from the air passage 13 side toward the carburetor 8 side so as to cover the wind receiving plate 31. Is provided on the cylinder cover 6. In the interior covered with the wind receiving plate storage portion 62, the shape of the wind receiving plate storage portion 62 is such that the uppermost portion of the wind receiving plate 21 can be rotated from the first position to the second position. Is set. In FIG. 8, the wind receiving plate 31 corresponding to the second position is indicated by a solid line, and the wind receiving plate 31 corresponding to the first position is indicated by a broken line. The wind receiving plate storage portion 62 can be formed as a part of the cylinder cover 6. That is, in this configuration, the wind receiving plate 31 is provided in the cylinder cover 6 together with the cylinder 2.

  In this configuration, since the notch portion is not provided in the cylinder cover 6, the leakage amount of the cooling air C can be reduced regardless of the rotation angle of the wind receiving plate 31. Strictly speaking, since it is necessary to provide the cylinder cover 6 with an opening through which the connecting portion 22 penetrates, the cooling air C leaks from this opening. The opening is provided with the wind receiving plate 31 inside. Compared with the formed notch 61, the size can be made negligible.

  In the fifth modification, it is obvious that the shape of the wind receiving plate can be appropriately set as in the case of the third modification.

  Further, the connection method between the wind governor and the throttle valve shaft 82 is arbitrary as long as the same control as in FIG. 3 can be performed. For example, in the above example, the wind governor (connection portion) is directly connected to the throttle valve shaft 82, but it is not necessary to directly connect the wind governor and the throttle valve shaft 82, and these are connected via a link mechanism. You can also FIG. 9 is a sectional view showing an example (sixth modification) of such a configuration. The wind receiving plate 51 in the wind governor 50 used in this configuration rotates around a governor rotating shaft 52 separately provided on the upstream side of the throttle valve shaft 82 in the cylinder cover 6. The wind receiving plate 51 is integrated with an arm 53 on the right side of the wind receiving plate 51, and the governor rotating shaft 52 is provided on the lower end side of the wind receiving plate 51 and the arm 53. A throttle arm 84 is fixed to the throttle valve shaft 82, and the upper end of the arm 53 is connected to the throttle arm 84 via a link bar 85. As a result, the throttle valve shaft 82 is rotated by moving the upper end of the arm 53 to the left and right during rotation about the governor rotation shaft 52. Here, in the case of FIG. 3, etc., when the throttle valve shaft 82 rotates counterclockwise, the operation of opening the throttle 81 (increasing the rotational speed of the engine 1) is performed. On the other hand, when the throttle valve shaft 82 rotates clockwise, the operation of opening the throttle 81 (increasing the rotational speed of the engine 1) is performed.

  Thus, it is not necessary that the rotation axis of the wind governor be the same as that of the throttle valve shaft 82. It is also possible to newly provide a rotating shaft (governor rotating shaft 52) and rotate the throttle valve shaft 82 via a link mechanism. The newly provided governor rotating shaft 52 is provided in the cylinder cover 6 in the above example, but may be provided in other constituent elements such as the vaporizer 8 as appropriate. For example, a screw boss used for connecting the cylinder cover 6 and the fan case 7 can also be used as the governor rotating shaft 52.

  In the case of the configuration of FIGS. 2 to 8, the rotation axis of the wind governor is the same as that of the throttle valve shaft 82, so that the overall configuration can be simplified. The turn angle of the governor was always the same. 9 is the same in that the rotation of the throttle valve shaft 82 is synchronized with the rotation of the wind governor, but the position of the governor rotation shaft 52, the arm 53, the throttle arm 84, and the link. Depending on the setting of the bar 85, the angle change rate of the wind governor and the throttle valve shaft 82 can be varied. Thereby, for example, the fluctuation range of the rotation angle of the throttle valve shaft 82 can be made larger than the fluctuation range of the rotation angle of the wind governor. In this case, the throttle valve shaft 82 can be rotated at a larger angle change by a small angle change of the wind governor. That is, the degree of freedom of control of the vaporizer 8 is increased by such setting.

  Further, the governor rotating shaft 52 in FIG. 9 is located below the throttle valve shaft 82. Thus, the rotating shaft of the wind governor can be provided at a location away from the vaporizer 8. Further, for example, the wind governor can be installed in a place where the movable range cannot be increased, and the throttle valve shaft 82 can be appropriately controlled. For this reason, the freedom degree of engine design increases.

  In the sixth modification, it is obvious that the position of the wind receiving plate can be made the same as in the first and second modifications. Similarly, it is obvious that the shape of the wind receiving plate can be made the same as in the third and fourth modified examples, and the shape of the cylinder cover can be made the same as in the fifth modified example.

  In all the above examples, the wind governor is provided adjacent to the cylinder cover 6, and the carburetor 8 is controlled by this. However, it is obvious that the same effect can be obtained even if the above-described wind governor is provided adjacent to the fan case 7 constituting the air passage through which the cooling air flows. Further, in the configuration of FIG. 2, since the cooling air C also flows through the crankcase involute portion 12, the above-described wind governor may be provided in the crankcase involute portion 12. That is, if the above-described wind governor is provided adjacent to the wind path, it is effective regardless of the installation location. In the above example, the notch is provided in the cylinder cover. However, the notch constitutes a cover that forms an air path other than the cylinder cover 6, for example, the fan case 7 and the crankcase involute 12. You may provide in a cover etc. The wind receiving plate storage portion in the fifth modification can also be provided in these covers as appropriate.

The wind governor 20 is configured to be connected to the throttle 81 and the throttle valve shaft 82 of the carburetor 8, but various configurations are possible depending on the configuration of the output control means and the rotational speed control shaft used. is there. For example, a separate throttle may be provided in the intake passage and connected thereto. Further, not only the throttle of the intake passage but also the energization state to the spark plug may be controlled in accordance with the rotation angle, thereby controlling the output of the engine. Also in this case, when the wind governor 20 is in the second position, the engine output is decreased by controlling the current to the spark plug when the second position is in the second position, for example. Can be controlled.

  Moreover, in said structure, the rotating shaft of the wind governor (wind receiving plate) shall be provided in the upstream (the other end side of a wind receiving plate) in the direction through which cooling air flows. However, as long as the same control as described above can be performed, the location of the rotating shaft is also arbitrary.

  In the air-cooled engine having the above-described configuration, the rotation speed is automatically controlled using a wind governor having a simple configuration, and the cooling efficiency is increased. For this reason, the reliability of the air-cooled engine is enhanced in a state of being small and light. Such an air-cooled engine is effective in all engine working machines that are carried and used by workers.

1,320 Engine 2 Cylinder 3 Crankshaft 4 Cooling fan 5 Engine starter 6 Cylinder cover (cover)
7 Fan case (cover)
8 Vaporizer (output control means)
DESCRIPTION OF SYMBOLS 9 Air filter 10 Fuel tank 11 Ignition coil 12 Crankcase involute part 13 Air path 20, 50 Wind governor 21, 31, 41, 51 Wind receiving plate 22 Connection part 52 Governor rotating shaft 53 Arm 61 Notch part 62 Wind receiving plate accommodation Part 81 Throttle 82 Throttle valve shaft (rotational speed control shaft)
83 Governor spring 84 Throttle arm 85 Link bar 91 Filter cover 201 Cooling fin 300 Brush cutter (engine working machine)
310 Operation shaft 311, 411 First plane part 312, 412 Second plane part 330 Cutting blade 340 Handle 350 Throttle lever 360 Throttle wire 413 First plane part projection (projection part)
C Cooling air

Claims (14)

A cylinder, a crankshaft to which a cooling fan is attached, and output control means for controlling the rotation speed of the crankshaft are provided, so that the cooling air generated by the cooling fan forms an air passage for cooling the cylinder. A wind governor for operating the output control means by the wind of the cooling air is provided in the air path,
The wind governor is
One end of the air passage in the direction in which the cooling air flows is moved between a first position that is separated from the air passage and a second position that is located closer to the air passage than the first position. An air-cooled engine comprising a wind receiving plate provided. In the output control means,
The control is performed so that the rotation speed of the crankshaft is higher when the one end is set to the second position than when the one end is set to the first position. The air-cooled engine described.   The air cooling engine according to claim 1 or 2, wherein the wind receiving plate is configured to rotate around a rotation shaft provided on the other end side in a direction in which the cooling air flows.   The air-cooled engine according to claim 3, wherein the rotation shaft is the same as a rotation speed control shaft provided in the output control means.   The air-cooled engine according to claim 3, wherein the rotation shaft is configured to be interlocked with a rotation speed control shaft provided in the output control means. In the wind governor,
The air-cooled engine according to claim 5, wherein an arm fixed to the wind receiving plate is configured to rotate a rotation speed control shaft provided in the output control means.   The air-cooled engine according to claim 6, wherein the rotation shaft is provided on the cover.   The air-cooled engine according to claim 6 or 7, wherein the angular variation of the rotational speed control shaft linked to the angular variation of the rotational shaft is set to be larger than the angular variation of the rotational shaft. In the wind governor,
The air cooling engine according to any one of claims 1 to 8, wherein a surface of the wind receiving plate is formed into a shape in which a plurality of different planes are combined or a shape including a curved surface. The cover is formed with a notch,
The air cooling engine according to any one of claims 1 to 9, wherein the wind receiving plate in the wind governor is installed in the notch. The second position is closer to the air path than the inner surface of the cover;
The wind receiving plate is
When one end of the wind receiving plate is in the second position, a distance between the one end of the wind receiving plate and the inner surface of the cover is 15 mm or less, or between the wind receiving plate and the inner surface of the cover. The air-cooled engine according to any one of claims 1 to 10, wherein the angle is set to be 45 ° or less.   The air-cooled engine according to claim 10, wherein a part of one end of the wind receiving plate and the cover are in contact with each other when one end of the wind receiving plate is in the second position. .   The air cooling engine according to any one of claims 1 to 8, wherein the wind receiving plate is covered with the cover together with the cylinder.   An engine working machine using the air-cooled engine according to any one of claims 1 to 13.

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