CN108138661B

CN108138661B - Engine type working machine

Info

Publication number: CN108138661B
Application number: CN201680058732.3A
Authority: CN
Inventors: 一桥直人
Original assignee: Hitachi Koki Co Ltd
Current assignee: Koki Holdings Co Ltd
Priority date: 2015-10-16
Filing date: 2016-09-30
Publication date: 2020-10-30
Anticipated expiration: 2036-09-30
Also published as: WO2017065024A1; CN108138661A; DE112016004711T5; JP6544436B2; JPWO2017065024A1

Abstract

The invention provides an engine type working machine which can reliably control the rotation number of a crankshaft through cooling air of a cooling fan. The engine-driven working machine includes: a cylinder that enables the piston to reciprocate in the vertical direction; a crankcase provided below the cylinder; a crankshaft that extends orthogonally to a reciprocating direction of the piston and rotates in accordance with the reciprocating movement of the piston; a throttle valve that controls an intake air amount of the cylinder and controls a rotation number of the crankshaft; a throttle shaft that rotates to control an opening degree of the throttle valve; a cooling fan fixed to the crankshaft on an outer side of the crankcase, the cooling fan being rotated by rotation of the crankshaft to generate cooling air for cooling the cylinder; and an air receiving portion that receives the cooling air and moves by the cooling air to rotate the throttle shaft, wherein a component in an axial direction of the crankshaft is included in a moving direction of the air receiving portion, and an opening degree of the throttle valve decreases as the air receiving portion moves toward the cylinder side in the crankshaft direction.

Description

Engine type working machine

Technical Field

The present invention relates to a structure of an engine-driven working machine using a small engine, for example, a brush cutter.

Background

Portable working machines and generators, such as brush cutters, blowers, chain saws, and power cutters, which are carried by operators, use small engines as power sources.

In these engines, an operator needs to set an optimum engine speed according to a work condition. For example, the lower the number of revolutions, the less fuel consumption, noise, and vibration, and therefore, the minimum required number of engine revolutions is preferable.

For example, as described in patent document 1, an air flow regulator is used which performs such engine speed control in an operating state with a simple configuration by feeding back the intensity of cooling air. Such a configuration can be easily realized by using a small-sized governor plate (air regulator) having an air receiving portion connected to a throttle valve shaft of the carburetor, and is therefore particularly effective in a portable engine-driven working machine using a small-sized engine. Therefore, such a configuration is effective also in an engine-type working machine other than the brush cutter.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-037390

Disclosure of Invention

Problems to be solved by the invention

The conventional air conditioner is configured such that, upon receiving an external load, the air receiving portion of the conditioner plate operates to open the throttle valve, and the air receiving portion is more likely to receive air as the maximum output position is approached. The damper plate operates to close the throttle as it receives wind, and therefore, when a load is applied, the throttle is not sufficiently opened, and a sufficient output cannot be obtained. Further, since the regulator plate easily receives the cooling air when a load is applied, the volume of the cooling air decreases, and the cooling performance of the cylinder cannot be maintained.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an invention for solving the above problems.

Means for solving the problems

In order to solve the above problems, the present invention has the following configurations.

An engine-type working machine according to the present invention includes: a cylinder that enables the piston to reciprocate in the vertical direction; a crankcase provided below the cylinder; a crankshaft that extends orthogonally to a reciprocating direction of the piston and rotates in accordance with the reciprocating movement of the piston; a throttle valve that controls an intake air amount of the cylinder and controls a rotation number of the crankshaft; a throttle shaft that rotates to control an opening degree of the throttle valve; a cooling fan fixed to the crankshaft on an outer side of the crankcase, the cooling fan being rotated by rotation of the crankshaft to generate cooling air for cooling the cylinder; and an air receiving portion that receives the cooling air and moves by the cooling air to thereby rotate the throttle shaft, wherein the engine-driven working machine has a component in an axial direction of the crankshaft in a moving direction of the air receiving portion, and an opening degree of the throttle valve decreases as the air receiving portion moves toward the cylinder side in the crankshaft direction.

Further, the movement of the air receiving portion may be a rotation.

The rotation shaft of the air receiving portion may be inclined with respect to the crankshaft in a direction in which the longitudinal direction of the rotation shaft is located on the cylinder side as it goes toward the fan.

The rotation shaft of the air receiving portion may be the throttle shaft.

Further, the wind receiving portion may have a larger projected area as viewed in the reciprocating direction of the piston as the wind receiving portion moves toward the cylinder side.

In addition, the wind receiving portion may be provided with a hole.

Effects of the invention

According to the present invention, it is possible to realize an engine-driven working machine in which the number of revolutions of a crankshaft can be reliably controlled by cooling air of a cooling fan.

Drawings

Fig. 1 is a sectional view a-a of an idle state of the embodiment of the present invention.

Fig. 2 is a sectional view a-a of the maximum output state of the embodiment of the present invention.

Fig. 3 is a B-B sectional view of the idle state of the embodiment of the present invention.

Fig. 4 is a B-B sectional view of the maximum output state of the embodiment of the present invention.

FIG. 5 is a C-C cross-sectional view of an idle state of an embodiment of the present invention.

Fig. 6 is a C-C sectional view of a maximum output state of the embodiment of the present invention.

FIG. 7 is a front view of an idle state gasifier in accordance with an embodiment of the present invention.

FIG. 8 is a front view of a gasifier in a maximum output state according to an embodiment of the present invention.

Fig. 9 is a perspective view of an adjuster plate of an embodiment of the invention.

Fig. 10 is a cross-sectional view showing the position of the air receiving portion and the flow of the cooling air in the embodiment of the present invention.

Fig. 11 is an explanatory diagram of the relationship between the wind torque and the throttle opening degree of the embodiment of the invention.

FIG. 12 is a perspective view of a brush cutter of an embodiment of the present invention

Detailed Description

(basic Structure and basic operation of wind regulator)

The structure of an engine-driven working machine (brush cutter) according to an embodiment of the present invention will be described. Here, an air conditioner is used for control in which a small air-cooled engine is used and the number of revolutions is kept substantially constant in an operating state.

Fig. 12 is an external perspective view of a brush cutter 101 to which the present invention is applied. The illustrated brush cutter 101 has: a tubular operating lever 103; a rotary knife 104 provided at one end of the operating lever 103; an engine 102 as a driving source provided at the other end of the operation lever 103; and a grip 105 provided at substantially the center of the operation lever 103. In the brush cutter 101 shown in fig. 12, the operator who holds the handle 105 swings the operating lever 103 to the left and right, thereby cutting the brush with the rotary blade 104.

In fig. 1, an engine 102 includes a cylinder 13 that allows a piston 26 to reciprocate in the vertical direction, and a crankcase 25 provided below the cylinder 13, and is connected to an air intake port to which a carburetor 19 and an air cleaner 18 are connected, and to an exhaust port to which a muffler 14 is connected. Further, a spark coil 20 is fixed to the outer periphery of the cylinder 13. A throttle shaft 52A is disposed in the carburetor 19, and the throttle valve 63 changes its opening degree in the intake passage in conjunction with the throttle shaft 52A to control the intake air amount of the cylinder 13 and control the rotation number or output of the crankshaft 60 of the engine 102. An adjuster plate 50 having an air receiving portion 65 is attached to the throttle shaft 52A, and the adjuster plate 50 is inserted into the cylinder head 11 through the opening portion 51. Therefore, the air receiving portion 65 can be rotated about the throttle shaft 52A as a rotation shaft, and the throttle shaft 52A is also rotated by the rotation of the air receiving portion 65. On the other hand, the cooling fan 17 is fixed to the crankshaft 60 of the engine 102 outside the crankcase 25, and is accommodated by the outer surface of the crankcase 25, the fan case 16, and the cylinder head 11. The cooling fan 17 rotates to supply cooling air CA1 to the cylinder 11, thereby cooling the cylinder. At this time, the air receiving portion 65 of the governor plate 50 receives the cooling air CA1, transmits the rotational torque to the throttle shaft 52A, and rotates the throttle shaft 52A, thereby adjusting the rotational speed or the output of the engine 102.

In fig. 7, a throttle lever 53 linked to a throttle shaft 52A is disposed, and the throttle lever 53 is housed in an opening degree stopper 54. An opening degree restricting portion 59 is formed in the opening degree restricting member 54. The opening degree limiter 54 is connected to the throttle wire 61. The opening degree limiter 54 limits the throttle lever 53 to an idle position (a position where the opening degree of the throttle valve 63 is minimum) by the return spring 55. Further, a torsion spring 63 is attached to the throttle shaft 52A, and always biases the throttle shaft 52A to rotate in a direction to increase the rotation speed or output. On the other hand, the regulator plate 50 receives the cooling air CA1, and generates torque that rotates the throttle shaft 52A in a direction to decrease the rotation speed or the output. In the situation of fig. 5, since the throttle lever 53 is biased to the idle position by the return spring 55, the throttle shaft 52A is fixed to the idle position regardless of the governor plate 50.

In fig. 2, when the rotation speed is reduced by the external load and the volume of the cooling air CA1 is reduced, the wind force acting on the governor plate 50 is reduced, and the rotational torque acting on the throttle shaft 52A in the direction of reducing the rotation speed is reduced. Since the throttle shaft 52A is constantly biased by the torsion spring 63 in a direction to increase the rotation speed, when the torque of the torsion spring 63 is set to be a condition for increasing the torque with respect to the wind force, the throttle shaft 52A rotates in a direction to increase the rotation speed or the output, and finally reaches the maximum output position (the position where the opening degree of the throttle valve 63 is maximized). Further, at the maximum output position, as shown in fig. 8, the throttle stopper 56 abuts against a collision portion 57 formed in the carburetor 19, thereby positioning the throttle shaft 52A.

(operation of tilting throttle shaft 52A)

As shown in fig. 3, 4, 7, and 8, the throttle shaft 52A and the throttle axis 52B are inclined with respect to the fan rotating shaft 100 (crankshaft 60). Specifically, the gasifier 19 is inclined at the following angles: the cooling fan 17 side is farther from the fan rotation shaft 100, and the opposite side to the cooling fan 17 is closer to the fan rotation shaft 100, that is, the longitudinal direction of the throttle shaft 52A is inclined toward the cylinder 13 side as it goes toward the cooling fan 17. Therefore, the air receiving portion 65 has a component in the axial direction of the crankshaft 60 in the moving direction, and rotates about the throttle shaft 52A in the direction of the crankshaft 60 so that the opening degree of the throttle valve 63 becomes smaller (closer to the idle position) as the air receiving portion 65 moves toward the cylinder 13 and the opening degree of the throttle valve 63 becomes larger (closer to the maximum output position) as it moves away from the cylinder 13. Further, the wind receiving portion 65 is formed so that the projected area viewed in the reciprocating direction of the piston 26 increases as it moves toward the cylinder 13. Since the airflow of the cooling air CA1 generated by the cooling fan 17 is guided to the cylinder 13 side by the cylinder head 11 and the fan case 16, the flow velocity is smaller on the side opposite to the cylinder 13 and larger on the side of the cylinder 13 with respect to the fan rotating shaft 100. Therefore, when the throttle shaft 52A is at the idle position (or a position where the rotation speed is low) with no load, the cooling air CA1 flowing from the cooling fan 17 toward the cylinder 13 is reliably blocked by the air receiving portion 65, and the rotation torque in the direction of reducing the rotation speed can be obtained at the throttle shaft 52A, so that the rotation speed can be reliably suppressed. Further, since the flow velocity of the cooling air CA1 near the cylinder 13 is large, the torque of the wind force becomes larger, and the rotational speed is more easily suppressed.

As shown in fig. 2, 4, and 6, when the rotation speed is reduced by the external load and the volume of the cooling air CA1 is reduced, the wind force acting on the wind receiving portion 65 is reduced, and the rotational torque acting on the throttle shaft 52A in the direction of reducing the rotation speed is reduced. Since the throttle shaft 52A is constantly biased by the torsion spring 63 in a direction to increase the rotational speed (or increase the output), the torsion torque of the torsion spring 63 increases with respect to the rotational torque of the wind force, and the throttle shaft 52A rotates in a direction to increase the rotational speed or the output. At this time, since the wind receiving portion 65 rotates in a direction away from the cylinder 13 with respect to the fan rotation shaft 100, the flow of the cooling air CA1 heading from the cooling fan 17 to the cylinder 13 is separated, and the cooling air CA1 is hardly received. Therefore, the turning torque in the direction of decreasing the rotation speed due to the wind force can be reliably decreased, and the throttle shaft 52A can be reliably turned in the direction of increasing the rotation speed or the output, thereby increasing the rotation speed or the output. Further, the flow velocity is smaller on the side opposite to the cylinder 13, and therefore, the torque of the wind force can be further reduced, and the rotational speed and the output can be easily further increased. As a result of the above operation, the following control of the engine 102 can be reliably performed by the governor plate 50: when no load is applied, the rotational speed is suppressed, and when a load is applied, the rotational speed or the output is increased.

(Cooling based on the attitude of the regulator plate 50)

As shown in fig. 1 and 2, an air passage from the cooling fan 17 to the cylinder 13 is formed by the cylinder head 11, the fan case 16, and the ignition coil 20, and the air receiver 65 of the regulator plate 50 is disposed in the air passage. With this configuration, since the cooling air CA1 flows intensively to the air receiving portion 65, the air receiving portion 65 reliably receives the cooling air CA 1. Further, a gap 67A is formed between the wind receiving portion 65 and the ignition coil, and a second gap 67B is formed between the wind receiving portion 65 and the cylinder head 11. As shown in fig. 5, when the wind receiving portion 65 is in the idle position, the interval 67A is small relative to the second interval 67B. As shown in fig. 6, the interval 67A becomes wider and the second interval 67B becomes smaller toward the maximum output position where the interval 67A is narrowed with respect to the second interval 67B. Therefore, as the opening degree of the throttle valve 63 becomes smaller, the interval 67A becomes narrower, and the wind receiving portion 65 can reliably receive the cooling wind CA1 heading from the cooling fan 17 to the cylinder 13, and therefore the rotation speed of the engine 102 can be suppressed. Further, since the interval 67A is wide and the air passage area from the cooling fan 17 to the cylinder 13 is secured near the maximum output position, the air receiver 65 is less likely to receive the cooling air CA1, the rotational torque in the direction of decreasing the rotation speed can be reduced, the air volume of the cooling air CA1 to the cylinder 13 can be maintained, and the cooling performance of the cylinder can be maintained. Further, as shown in fig. 1, when the wind receiver 65 is at the maximum output position, the gap 67A is formed to be wider than the third gap 67C between the wind receiver 65 and the cooling fan 17, and therefore the cooling air CA1 having passed through the third gap 67C flows toward the gap 67A while increasing the duct area, and therefore the air volume of the cooling air CA1 is not reduced by the gap 67A.

(Effect of voids 66)

As shown in fig. 9, a hole 66 as a ventilation portion of the present invention is formed in the area of the air receiving portion 65 of the regulator plate 50. As shown in fig. 10(a) to (F), the air receiving portion 65 assumes the following posture: in the idling position (state 1), the cooling fan 17 is distant from the cooling fan 17 and is substantially horizontal to the cooling air CA1, and in the maximum output position (state 3), the cooling fan 17 is close to the cooling fan 17 and substantially coincides with the radiation direction with respect to the cooling fan 17. That is, the wind receiving portion 65 is provided so that the angle with respect to the radial direction of the cooling fan 17 changes by the rotation, and the angle with respect to the radial direction becomes larger as the opening degree of the throttle valve 63 becomes smaller. As a result, the angle θ formed by the cylinder axis 58 and the wind receiving portion 65 is made smaller as the output position from the idling position becomes the maximum output position. Fig. 11 is a graph conceptually showing the positional relationship between the air receiving portion 65 and the cooling fan 17, the flow of the cooling air CA1, and the torque characteristics of the wind force at that time.

In the conventional characteristic, since the wind receiving portion 65 is substantially horizontal to the cooling air CA1 in a state close to the idle position and receives the cooling air CA1 from the directly opposite surface, the pressure of the surface on the cooling fan 17 side with respect to the cylinder axis 58 is greatly increased, and the pressure difference from the opposite side to the cooling fan 17 is increased. Thereby, a large wind torque is generated. On the other hand, when the rotation speed decreases due to the external load and the air volume of the cooling air CA1 decreases, the wind receiving portion 65 gradually approaches the maximum output position. At this time, the wind receiving portion 65 approaches the cooling fan 17, and is oriented along the flow of the cooling air CA1 and the radiation direction of the cooling fan 17, and the wind receiving portion 65 itself functions as a wind deflector for the cooling air CA 1. Therefore, the cooling air CA1 flows along the wind receiving portion 65 within a certain state (state 2), and therefore the pressure difference between the front surface and the rear surface of the wind receiving portion 65 is eliminated, and the wind torque may suddenly decrease. When the wind torque decreases, the torque of the torsion spring 63 increases relative to the wind torque, and the wind receiving portion 65 abruptly operates in a direction to increase the rotation speed or the output. As a result, the rotation speed and the air volume of the cooling air CA1 sharply increase, and the wind receiving portion 65 operates in the direction of decreasing the rotation speed this time with the increase in the cooling air CA 1. Therefore, the wind receiving portion 65 may be in an unstable vibration state in which the rotation speed is repeatedly decreased and increased within a certain state (state 2). In the characteristic of the present invention, since the air hole 66 as the ventilation portion is provided in the air receiving portion 65, the wind torque obtained by the cooling wind CA1 is reduced in the idle position (state 1). From this state, when the rotation speed is reduced by the external load and the air volume of the cooling air CA1 is decreased, the wind receiving portion 65 gradually approaches the maximum output position. At this time, since the cooling air CA2 passing through the hole 66 is always present in the direction in which the wind receiving portion 65 turns so as to reduce the opening degree of the throttle valve 63, the cooling air CA1 does not form a flow along the wind receiving portion 65 even when the wind receiving portion 65 approaches state 2 in fig. 10. Therefore, the wind torque does not change abruptly due to the posture of the wind receiving portion 65 (i.e., the throttle opening degree), and a characteristic with strong linearity can be obtained, so that the wind torque can be operated stably before the maximum output position (state 3), and the controllability of the engine 102 can be improved. Further, since the portion of the hole 66 does not receive the cooling air CA1, the air receiving portion 65 can be formed to have a relatively large area, and even if the shape of the air receiving portion 65 is uneven, the flow is difficult to change, and robustness with respect to controllability of the engine 102 can be improved. Further, since the maximum output position is operated so that the opening direction of the hole 66 faces the cylinder 13 or the cylinder axis 58, the cooling air CA2 passing through the hole 66 can be smoothly supplied to the cylinder 13 at the maximum output position where the heat generation of the cylinder 13 increases, and the cooling performance of the cylinder 13 can be maintained.

Further, a plurality of mounting portions 68 of the torsion spring 63 may be formed on the adjuster plate 50, and mounted in such a manner as to convert the torque of the torsion spring 63 into a plurality of stages. Therefore, even when the torque converter is applied to the engine 102 having different exhaust gas amounts, fan diameters, and the like, the torque converter can easily reset to the optimum torque. Therefore, the regulator plate 50 can be easily shared among the different engines 102, and cost reduction can be achieved.

While the present invention has been described with reference to the embodiments, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims. For example, the air receiving portion 65 is configured to rotate about the throttle shaft 52A, but may be configured to rotate about a different shaft from the throttle shaft 52A and rotate the throttle shaft 52A via a link or the like. The ventilation portion provided in the region of the air receiving portion 65 may have any shape as long as it has the following functions: the cooling air passes through the region of the air receiving portion 65 in the direction in which the air receiving portion 65 rotates so as to reduce the opening degree of the throttle valve 63, and the pressure difference between the cooling fan 17 side and the opposite side to the cooling fan 17 is reduced, and the air receiving portion may be a hole 66 other than a circular hole, for example, a quadrangular hole, a notch, or the like.

Description of the symbols

11-a cylinder head, 12-a spark plug cap, 13-a cylinder, 14-a muffler, 15-a fuel tank, 16-a fan housing, 17-a cooling fan, 18-an air cleaner, 19-a carburetor, 20-an ignition coil, 21-a fuel tank cap, 22-a recoil starter, 23-a grip portion, 25-a crankcase, 26-a piston, 50-a regulator plate, 51-an opening portion, 52A-a throttle shaft, 52B-a throttle axis, 53-a throttle lever, 54-an opening degree limiter, 55-a return spring, 56-a throttle limiter, 57-a collision portion, 58-a cylinder axis, 59-a limiting portion, 60-a crankshaft, 61-a throttle wire, 63-a torsion spring, 64-a throttle valve, 65-an air receiving portion, 66-a hollow hole, 67A-a first interval, 67B-a second interval, 67C-a third interval, 68-a mounting portion, 100-a fan rotating shaft, 101-a brush cutter, 102-an engine, 103-operating rod, 104-cutting knife, 105-handle, CA1, 2-cooling wind.

Claims

1. An engine-type working machine comprising: a cylinder that enables the piston to reciprocate in the vertical direction; a crankcase provided below the cylinder; a crankshaft that extends orthogonally to a reciprocating direction of the piston and rotates in accordance with the reciprocating movement of the piston; a throttle valve that controls an intake air amount of the cylinder and controls a rotation number of the crankshaft; a throttle shaft that rotates to control an opening degree of the throttle valve; a cooling fan fixed to the crankshaft on an outer side of the crankcase, the cooling fan being rotated by rotation of the crankshaft to generate cooling air for cooling the cylinder; and an air receiving portion that receives the cooling air and rotates by the cooling air to rotate the throttle shaft,

the engine-driven working machine is characterized in that,

a rotating shaft of the air receiving portion is disposed obliquely with respect to the crankshaft such that a side thereof closer to the cooling fan is positioned on the cylinder side in the view of the crankshaft direction,

in the view in the crankshaft direction, as the air receiving portion moves toward the cylinder side, the air receiving portion moves in the crankshaft direction, and the opening degree of the throttle valve decreases.

2. The engine-driven working machine according to claim 1,

the rotation shaft of the air receiving part is the throttle shaft.

3. The engine-driven working machine according to claim 1 or 2,

the air receiving portion has a larger projected area as viewed in the reciprocating direction of the piston as it rotates toward the cylinder side.

4. The engine-driven working machine according to claim 1 or 2,

the air receiving portion is provided so that an angle with respect to a radial direction of the cooling fan changes by the rotation, and the angle with respect to the radial direction increases as an opening degree of the throttle valve decreases, and a ventilation portion that passes the cooling air in a direction in which the air receiving portion rotates so that the opening degree of the throttle valve decreases is provided in a region of the air receiving portion.

5. An engine-type working machine comprising: a cylinder that enables the piston to reciprocate in the vertical direction; a crankcase provided below the cylinder; a crankshaft that extends orthogonally to a reciprocating direction of the piston and rotates in accordance with the reciprocating movement of the piston; a throttle valve that controls an intake air amount of the cylinder and controls a rotation number of the crankshaft; a throttle shaft that rotates to control an opening degree of the throttle valve; a cooling fan fixed to the crankshaft on an outer side of the crankcase, the cooling fan being rotated by rotation of the crankshaft to generate cooling air for cooling the cylinder; an ignition coil fixed to an outer periphery of the cylinder so as to be positioned outside the cooling fan; and an air receiving portion that receives the cooling air and moves by the cooling air to rotate the throttle shaft,

the engine-driven working machine is characterized in that,

the air receiving portion is configured to move by rotating, and the air receiving portion rotates so that an interval between the air receiving portion and the ignition coil becomes narrower as an opening degree of the throttle valve becomes smaller.