WO2014162803A1

WO2014162803A1 - Engine-driven tool

Info

Publication number: WO2014162803A1
Application number: PCT/JP2014/055093
Authority: WO
Inventors: 健太郎金谷; 石田　茂敏
Original assignee: 日立工機株式会社
Priority date: 2013-03-30
Filing date: 2014-02-28
Publication date: 2014-10-09

Abstract

Provided is a braking device for an engine-driven tool, capable of stopping a cutting blade that is rotating by inertia, and also being lightweight and capable of maintaining long-term reliability. The engine-driven tool allows transmission of engine output through a centrifugal clutch to an implement such as a cutting blade, wherein the engine-driven tool is configured so that an eddy-current non-contact braking mechanism (40) is operated when a throttle is in a closed state. In the braking mechanism (40), a disc (35) is provided to the clutch drum (34) of the centrifugal clutch (30), and a permanent magnet is disposed so as to face a rotating body in a non-contact state in a positional relationship such that the magnetic field generated by the permanent magnet intersects the disc (35), whereby an eddy current produces a braking force in the rotating body, stopping the rotary motion of the cutting blade. When a throttle wire is pulled, the braking mechanism (40) is moved and the permanent magnet is moved away from the disc (35), whereby the brake is released.

Description

Engine working machine

The present invention relates to an engine working machine having a centrifugal clutch such as a brush cutter, a chain saw, or a hedge trimmer, and more particularly to an engine working machine having a brake device that operates during idling.

In portable engine working machines such as a brush cutter, a chain saw, and a hedge trimmer, a cutting blade, a saw chain, and the like are driven through a centrifugal clutch mechanism in which the output of the engine is directly or indirectly connected to a crankshaft. Centrifugal clutches are clutches that transmit power by the frictional force of a clutch shoe provided on the rotating body side such as a crankshaft and a clutch drum provided on the driven side and provided on the outer peripheral side of the clutch shoe. Since the centrifugal force is small during low speed rotation such as in a state, the clutch shoe is located on the inner peripheral side, and the power of the rotating body is not transmitted to the driven side (clutch disengaged state). When the engine speed rises and exceeds a predetermined speed (clutch connection speed), the clutch shoe moves to the outer peripheral side by centrifugal force and comes into contact with the inner peripheral surface of the drum to be driven from the rotating body. Power is transmitted to the clutch (clutch connected state). The centrifugal clutch mechanism has a simple structure, and transmission and disconnection of power is performed at the engine speed, so no special operation for connecting and disconnecting the clutch is required, and it is widely used in portable engine working machines. ing. *

Since such a centrifugal clutch mechanism is disconnected when the engine speed decreases, the cutting blade or the like may continue to rotate due to inertial force. Moreover, in the portable engine working machine, there has been a demand for more rapidly reducing the engine speed other than in the actual working state. For this reason, it has also been proposed to provide a mechanical brake mechanism along with the adoption of a centrifugal clutch in an engine working machine. As a brake used for a brush cutter, there exists a thing shown by patent document 1, for example. In this brake device, as disclosed in FIG. 6, a brake shoe is disposed in contact with the outer periphery of the brake drum, a brake wire is stretched between the brake shoe and the arm, and the brake wire is attached by a brake spring. It is a structure of a constantly operating type that pulls back and presses the brake shoe against the brake drum. When the arm is not operated, the brake shoe is pressed by the brake spring, and the brake acts on the brake drum.

JP 2002-186327 A

However, in the above structure, when the brake is used for a long period of time, the brake shoe gradually wears out at the position connected to the brake wire, the function of the brake is deteriorated, and the long-term use cannot be endured. In this case, it is necessary to replace the brake shoe. In addition, since an impact is generated by the contact between the brake shoe and the brake drum when the brake is operated, the operability is deteriorated. In addition, the number of parts for the brake mechanism is very large, and therefore the space for accommodating the brake mechanism also becomes large, which increases the weight and size of the portable engine work machine, which increases costs and deteriorates workability. Will be invited. Furthermore, when a large braking force is generated, a large releasing force is required on the contrary, and there is a problem that the usability is poor. *

The present invention has been made in view of the above background, and an object of the present invention is to provide a brake mechanism having a light and simple structure that can guarantee long-term reliability in an engine working machine having a centrifugal clutch mechanism. *

Another object of the present invention is to provide a non-contact type brake mechanism that operates in conjunction with opening and closing of an engine throttle. *

Still another object of the present invention is to provide an engine working machine that is provided with a non-contact type brake mechanism on the drum side of a centrifugal clutch and can quickly reduce the rotation of a cutting blade or the like when the throttle is turned off. There is to do.

The characteristics of representative ones of the inventions disclosed in the present application will be described as follows. *

According to one aspect of the present invention, in an engine working machine that transmits engine power to a working device such as a cutting blade via a centrifugal clutch, when the throttle is closed in conjunction with opening and closing of the engine throttle, The contact type brake mechanism is configured to operate. This brake mechanism is preferably an eddy current type brake. A metal rotating body (for example, a disk or an annular flange) is provided on the rotating part on the work equipment side from the clutch drum of the centrifugal clutch, and a field composed of a permanent magnet. The magnetic means is brought close to (opposed to) the rotating body in a non-contact state so that the magnetic field generated by the field means crosses the rotating body so that the power transmission member as the rotating body is braked by eddy current. Brakes work equipment by generating force. *

According to another feature of the present invention, the brake mechanism includes a slider member that moves so as to approach or separate from the rotating body, and a plurality of brake mechanisms that are provided at a plurality of positions of the slider member and sandwiching the metal portion of the rotating body. When the throttle is fully closed, the slider member is held at a position sandwiching the rotating body, and the magnetic field generated by the field means crosses the rotating body so that the throttle is opened. When in the state, the slider member is moved to the outer region of the rotating body so that the magnetic field generated by the field means does not cross the rotating body. The rotating body is preferably a disk, an annular plate, a flat plate-like rotating member, or a flange member provided on the clutch drum, and the slider member moves in conjunction with the operation of the throttle wire or lockout lever of the carburetor of the engine. To be configured. *

According to still another feature of the present invention, the slider member is moved in a direction parallel to the disk or the annular plate, and the tip portion close to the disk or the annular plate is moved from both sides of the disk or the annular plate. Two arm portions are formed so as to be sandwiched, and a permanent magnet is provided at a position facing the disk or the annular plate of the arm portion. The slider member is an oscillating type whose one end is pivotally supported, has an arm portion on the other end side, and is provided with urging means for urging the arm portion in a direction approaching the rotating body, The slider member is moved against the urging force of the urging means by operating the throttle wire or the lockout lever. The swing shaft of the slider member is arranged so as to be parallel to the direction of the rotation center axis of the centrifugal clutch. In order to assist the braking effect, the slider member may be provided with a brake shoe that contacts the rotating body or the clutch drum, and a contact-type brake configuration may be used in addition to the non-contact type brake.

According to the first aspect of the invention, the non-contact type brake mechanism is operated when the throttle is closed in conjunction with the opening / closing of the throttle of the engine. It is possible to effectively brake a working device such as a cutting blade. Further, since the brake mechanism is a non-contact type, it is possible to suppress an impact generated during braking, and no wear or the like occurs, so that it can withstand long-term use. According to the invention of claim 2, the brake mechanism is an eddy current type brake and brakes on the work equipment side from the clutch drum of the centrifugal clutch. Therefore, the brake mechanism works extremely effectively on the work equipment rotated or driven by inertia. Can be made. According to the invention of claim 3, the brake mechanism is a permanent magnet that is provided on the slider member and acts on the rotating body. Therefore, unlike the field means such as an electromagnet, no electric power is required. A brake mechanism with less fear of Further, since the brake is always operated when the throttle is completely closed, and the brake is turned off when the throttle is opened, the brake can be operated in conjunction with the operator's intention and operation. Also, if the operator releases the lockout lever for some reason during the work, the engine speed returns to idling and the centrifugal clutch mechanism also works, so the work equipment can be rotated in a short time. And the operation can be stopped. According to the fourth aspect of the present invention, since the positional relationship is such that the metal portion of the rotating body is sandwiched between the plurality of permanent magnets during braking, a sufficient braking force can be realized using the permanent magnets. According to the invention of claim 5, the rotating body is a disk or an annular plate provided on the clutch drum, and the slider member moves in conjunction with the operation of the throttle wire or lockout lever of the carburetor of the engine. In conjunction with the operator's intention, a brake mechanism that operates reliably when the throttle is released or when the lockout lever is released can be realized. In addition, since the brake mechanism moves in a non-contact state with respect to the power transmission member and is an eddy current brake, the brake mechanism is not applied as rapidly as the contact type brake, so the engine working machine is smooth and easy to use. Can be realized. According to the invention of claim 6, since the two arm portions are formed so as to be sandwiched from both sides of the disk or the annular plate in the slider member, and the permanent magnet is provided at a position facing the plate surface of the arm portion, the structure It is a simple brake mechanism and can realize a highly reliable engine working machine with little risk of failure. According to the seventh aspect of the present invention, the slider member is a swinging type whose one end is pivotally supported, has an arm portion on the other end side, and the urging force of the urging means by operating the throttle wire or the lockout lever. Since the slider member moves against this, a highly reliable brake mechanism that operates reliably in conjunction with the operation of the throttle wire or the lockout lever can be realized. According to the eighth aspect of the present invention, since the swing shaft of the slider member is disposed so as to be parallel to the direction of the rotation center axis of the centrifugal clutch, the brake mechanism can be disposed on the outer peripheral portion of the centrifugal clutch mechanism, and the compact engine A work machine can be realized. According to the ninth aspect of the present invention, the slider member is provided with the brake shoe that comes into contact with the rotating body or the clutch drum, so that a strong braking effect can be realized by both the non-contact type brake and the contact type brake. *

The above and other objects and novel features of the present invention will become apparent from the following description and drawings.

It is a perspective view which shows the whole shape of the brush cutter 100 which is an example of an engine working machine. It is a longitudinal section showing the internal structure of engine working machine 1 concerning the example of the present invention. It is a rear view of the engine working machine 1 which concerns on the Example of this invention. FIG. 3 is a diagram illustrating a brake mechanism 40 according to an embodiment of the present invention, as viewed from a cross-sectional position of the AA portion in FIG. 2 (when the throttle lever is not operated, the brake is on). FIG. 5 is a partial view of the brake mechanism 40 shown in FIG. 4 (a state where the brake is turned off by operating the throttle lever). FIG. 5 is a cross-sectional view taken along a line BB in FIG. FIG. 6 is a cross-sectional view showing the positional relationship between a slider member 71 and a disk 35 according to a first modification of the embodiment of the present invention, and is a view corresponding to the cross-sectional position of the BB part of FIG. FIG. 6 is a cross-sectional view showing the positional relationship between a slider member 81 and a disk 35 according to a second modification of the embodiment of the present invention, and is a view corresponding to the cross-sectional position of the BB part of FIG. It is sectional drawing which shows the brake mechanism which concerns on the 2nd Example of this invention. FIG. 6 is a view showing a brake mechanism 240 according to a second embodiment of the present invention, as seen from a position conceived in the cross section of the AA portion of FIG. 2 (the brake lever is operated and the brake is turned off); Status).

Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same portions are denoted by the same reference numerals, and repeated description is omitted. Further, in this specification, description will be made assuming that the front, rear, left, right, and up and down directions are directions shown in the drawing.

FIG. 1 is a perspective view showing the overall shape of a brush cutter 100 as an example of an engine working machine. The engine working machine 1 is attached to an engine main body 10 (driving unit) attached to one end of a main pipe 101, a gear unit 102 attached to the other end of the main pipe 101, and a spindle (not shown) in the gear unit 102. The rotating cutting blade (rotating blade) 103 is provided. The cutting blade 103 is attachable to and detachable from a spindle (not shown) provided on the gear unit 102, and a scattering protection cover 105 for preventing scattering of the cut grass is provided in the vicinity of the cutting blade 103. . A handle 106 is assembled by a mounting member 108 at a substantially middle portion of the main pipe 101 in the longitudinal direction. The handle 106 is a metal pipe having a substantially U-shape when viewed from the front, and

resin grips

107a and 107b are provided at the tip portion. A throttle lever 109 and a throttle lever lockout 112 are provided near the root of the grip 107a on the side that the operator grips with the right hand, and the operator adjusts the engine speed by operating the throttle lever 109 and trims the engine. The rotational operation speed of the blade 103 is adjusted. An engine 10 is provided on the rear end side of the main pipe 101. Using a general-purpose engine that is small and lightweight and can obtain a large output, fuel can be replenished to enable long-term work. For example, a manual starter is widely used to start the engine. *

When the operator works with the throttle lever lockout 112 held, and when the throttle lever lockout 112 is released for some reason, the throttle lever 109 immediately returns to the closed position, and the engine speed is idling. It is configured to drop to the rotational speed. The throttle cable 110 has a wire disposed on the inner side (inner) and the outer side (outer) covered with a resin cover. The cable 110 is a throttle of a carburetor 29 (see FIG. 2) described later. Connected to the mechanism. When the throttle lever 109 is pulled, a wire (described later) disposed inside the cable 110 is pulled toward the handle, and the throttle of the carburetor 29 is opened. The cable 110 of this embodiment branches near the arrow 111, one cable 110a is connected to the carburetor 29, and the other cable 110b is connected to a brake mechanism described later.

FIG. 2 is a longitudinal sectional view showing the internal structure of the engine working machine 1 according to this embodiment. The engine (main body) 10 is a two-cycle small engine, the crankshaft 13 is arranged coaxially with the main pipe 101 (see FIG. 1), and the cylinder 11 extends from the crankcase 14 substantially upward in the vertical direction. The piston 12 is reciprocated up and down in the cylinder 11. The high-voltage current generated by the ignition coil 23 is transmitted to the spark plug 25 through the ignition cord 24 and the plug cap 26. A fuel tank 27 is provided below the crankcase 14 of the engine 10. The fuel tank 27 contains a mixed oil of gasoline and oil for two cycles and is sent to a vaporizer described later. *

An end portion of a drive shaft (not shown) is connected to the front side (output side) of the crankshaft 13 via a clutch shaft 36 via a centrifugal clutch 30. An engine cooling fan is integrally formed with the magnet rotor 22 to which the centrifugal clutch 30 is attached. The centrifugal clutch 30 is a known centrifugal clutch in which a clutch shoe (oscillator) 31 is connected to a clutch drum 34 by centrifugal force when the rotation speed of the crankshaft 13 becomes a certain value or more. On the front side of the clutch drum 34, a flat disk 35 having a circular outer shape is provided. The clutch drum 34 and the disk 35 are also fixed to the clutch shaft 36, and the clutch shaft 36 is rotatably held on the fan case 5 by a bearing 33. When the driving force supplied by the rotation of the engine 10 is provided on the magnet rotor 22 attached to the crankshaft 13, it is transmitted to the clutch drum 34 via the centrifugal clutch 30, and further provided in the main pipe 101 therefrom. This is transmitted to the gear unit 102 and the cutting blade 103 via a shaft (not shown). *

As a starting device of the present embodiment, a manual recoil starter 50 is provided on the rear end side of the crankshaft 13. The recoil starter 50 is rotated at a high speed by pulling a starter rope 52 wound around a reel 51 with a starter handle described later, and the one-way clutch 56 protrudes radially outward by centrifugal force and comes into close contact with the drum 57. Rotate. Since the drum 57 is fixed to the crankshaft 13, when the drum 57 rotates, the crankshaft 13 also rotates and the engine can be started. The released starter rope 52 is wound around the reel 51 by the restoring force of the spiral spring 53. *

FIG. 3 is a rear view of the engine working machine 1 according to the embodiment of the present invention. A carburetor 29 is provided on the left side of the engine 10 via an insulator 19 connected to the intake port of the engine 10, and a storage space for an air cleaner that filters the intake air is formed outside (left side) of the carburetor 29. An air cleaner cover 61 is provided. A muffler 16 is provided on the side (right side) of the engine 10, and an exhaust port 16 a serving as an exhaust gas outlet is provided on the rear surface side of the muffler 16. The muffler 16 is covered with a resin muffler cover 8 to prevent the operator from touching it directly. The upper part of the engine 10 is covered with a cylinder cover 7. A recoil starter 50 (see FIG. 2) is provided coaxially with the crankshaft 13 and at the rear end thereof, and the recoil starter 50 is covered with a starter case 9. A starter handle 54 is provided on the left side of the starter case 9. A fuel tank 27 is provided below the crankcase 14. The fuel tank 27 is a container formed of a translucent polymer resin, and a mixed fuel in which gasoline and a predetermined ratio of oil are mixed can be put in by removing the cap 28 attached to the opening. When starting the engine 10, the operator pulls a choke lever (not shown) and then pulls the starter handle 54 vigorously to start the engine 10. *

4 is a cross-sectional view of the cross-sectional position of the AA portion of FIG. The AA portion in FIG. 2 has a shape when the fan case 5 is viewed from the back side. Since the fan case 5 is manufactured by integral molding of synthetic resin such as plastic, a plurality of ribs for increasing the strength are formed on the inner portion. Further, since the fan case 5 is fixed to the engine 10 by bolts (not shown) at three locations on the outer peripheral side, three screw holes 5c are formed. In the present embodiment, the centrifugal clutch 30 is accommodated in the inner portion of the fan case 5, and the brake mechanism 40 is provided in the vicinity thereof. The brake mechanism 40 is pivotally supported by the rotating shaft 45 with respect to the fan case 5, and is disposed on the radially outer side when viewed from the centrifugal clutch 30. The brake mechanism 40 is configured by a slider member 41 that moves so as to approach or leave the disk 35 that is a rotating body, and a wire 113 branched by a cable 110b is connected to the slider member. An engaging element 114 is formed at the tip of the wire 113 on the slider member side, and the engaging element 114 is attached so as to be fitted into the recess of the slider member 41. A metal cylindrical cap 111 d is provided at the end of the resin cover outside the cable 110 b and is held by a cable attachment portion 5 b provided in the fan case 5. *

A well-known centrifugal clutch 30 can be used. The clutch clutch 31 is fixed to the crankshaft 13 with two bolts 32 via a mounting member (not shown), and these are axially connected. A tension spring 33 that is biased toward the center is included. In this embodiment, there is provided a disk 35 that forms an annular plane region that protrudes to the outer peripheral side of the clutch drum 34. Normally, the clutch drum 34 is made of an iron-based or aluminum-based metal material, but the disk 35 is a member for generating eddy currents, so it is important to be made of a metal-based member. In this embodiment, the disk 35 is made of an aluminum-based material because of the ease of generating eddy currents. The slider member 41 can swing about 60 degrees around the rotation shaft 45. FIG. 4 shows a state in which the throttle lever 109 is returned (idling state). At this time, the wire 113 rotates the slider member 41. The state is extended by the biasing force of the torsion spring 46 provided coaxially with the shaft 45, that is, the engagement element 114 is pulled to the disk 35 side. *

FIG. 5 is a partial view of the brake mechanism 40 shown in FIG. 4 and omits the description of the surrounding fan case 5 portion. Here, a state where the brake lever 40 is turned off by operating the throttle lever 109 (a state where the brake is not applied) is shown. The slider member 41 is a substantially L-shaped member when viewed as shown in FIG. 5, and the arm portion 42 is divided into one side (front side) and the other side (rear side) of the disk 35. A permanent magnet 43 is disposed on a portion of the arm portion 42 that faces the disk 35. When the operator pulls the throttle lever 109, the wire 113 moves to the throttle lever 109 side. Then, the slider member 41 swings against the spring force of the torsion spring 46, and the permanent magnet 43 provided on the arm portion 42 moves radially outward (outer peripheral side) from the outer edge of the rotating region of the disk 35. To do. Due to this movement, the positional relationship such that the disk 35 crosses the magnetic field formed by the permanent magnet 43 is released and no eddy current is generated, so that the brake operation is released. One end 46 a of the torsion spring 46 is held by a rib 5 d provided on the fan case 5, and the other end 46 b is engaged with a part of the main body portion of the slider member 41. When the operator returns the throttle lever 109 or returns the throttle lever lockout 112, the tension state of the wire 113 is released, and the slider member 41 is moved to the position shown in FIG. 5 (brake release position) by the restoring force of the torsion spring 46. 4 returns to the initial position (brake operating position) shown in FIG. 4, and the brake is automatically applied. At this time, because of the eddy current type brake, the braking effect is reduced when the rotation of the disk 35 as the rotating body is slow. In other words, since the braking force is suppressed when the blade is stopped, the occurrence of an impact when the blade is stopped can be reduced by rapid braking. Since the distance between the permanent magnet and the disk can be adjusted according to the release amount of the throttle lever lockout 112, the operator can arbitrarily adjust the braking effect due to the eddy current. *

As described above, the slider member 41 rotates at a certain angle around the rotation shaft 45 provided on the outer periphery of the clutch drum 34. The slider member 41 is constantly urged by a torsion spring 46 toward the center of the disk 35. The slider member 41 is connected by a wire 113 so as to interlock with the operation of the throttle lever 109 or the throttle lever lockout 112 provided on the handle 106. When the throttle lever 109 or the throttle lever lockout 112 is not operated, the

permanent magnets

43a and 43b of the slider member 41 are positioned on the disk 35 by being biased by the spring 17 so that the

permanent magnets

43a and 43b As a result, an eddy current is generated on the disk 35, and a braking force is generated on the clutch drum 34. When the throttle lever 109 or the throttle lever lockout 112 is operated, the

permanent magnets

43a and 43b are pulled from the disk 35 by being pulled by the wire 113 in the direction against the bias of the spring 46 as shown in FIG. It moves to a distant position and no braking force due to eddy current is generated.

6 is a cross-sectional view taken along the line BB in FIG. 4 and shows the positional relationship between the slider member 41 and the disk 35. As shown in FIG. Two arm portions 42 extending so as to protrude on both sides of the disk 35 are formed at the tip of the slider member 41.

Permanent magnets

43 a and 43 b are provided on the side of the arm portion 42 facing the disk 35. For example, the

permanent magnets

43a and 43b are arranged such that the front side has an N-pole and the rear side has an S-pole polarity, and a magnetic field is formed as indicated by a magnetic field line from the permanent magnet 43b toward the 43a side. The arm portion 42 including the permanent magnet 43 a is disposed on the outer periphery of the clutch drum 34, and the two permanent magnets 43 a are provided with a gap larger than the thickness of the disk of the clutch drum 34. The slider member 41 is located at a position where the disk 35 does not face (face to face) between the

permanent magnets

43a and 43b that are spaced apart from each other around a rotation shaft 45 provided on the outer periphery of the clutch drum 34. Rotate up to. At this time, in the region where the slider member 41 rotates, there is a gap between the disk 35 and the

permanent magnets

43a and 43b, so that they do not contact each other. As described above, a plurality (two) of

permanent magnets

43a and 43b are provided to form a magnetic field from one permanent magnet side to the other permanent magnet side, and move relative to the magnetic field inside the magnetic field. By exposing a metal object (rotating body) to be generated, an eddy current is generated in the disk 35, so that a braking force can be obtained on the rotating body. The disk 35 is provided on the front side of the substantially cup-shaped clutch drum 34, and how the disk 35 is attached to the clutch drum 34 is arbitrary. Further, even if a flange-like member (annular flat plate portion) is formed integrally with the clutch drum 34, the same function is achieved. *

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, For example, the following modifications are included. FIG. 7 shows the slider member 71 according to the first modification, and is a view corresponding to the cross-sectional position of the BB portion in FIG. The basic part of the slider member 71 can be manufactured in the same shape and size as the slider member 41. In the configuration of FIG. 6, only the

permanent magnets

43 a and 43 b are provided on the slider member 41, and the slider member 41 and the

permanent magnets

43 a and 43 b are completely in non-contact with the disk 35. On the other hand, in the first modified example, in addition to the

permanent magnets

73a and 73b, a brake shoe 76 is provided on the crotch portion of the two arm portions 72 of the slider member 71 in order to enhance the braking force, and the brake caused by the eddy current is applied. The brake shoe 76 is configured to come into contact with the outer peripheral portion of the disk 35 when the is applied. With this configuration, both a braking effect due to eddy current and a braking effect due to the frictional force between the brake shoe 76 and the disk 35 can be obtained, so that a strong braking force can be obtained. *

FIG. 8 shows a slider member 81 according to a second modification, and is a view corresponding to the cross-sectional position of the BB portion of FIG. The basic part of the slider member 81 can be manufactured in the same shape and size as the slider member 41. In FIG. 8, a part of the clutch drum 34, which is omitted in FIGS. 6 and 7, is also illustrated. In the slider member 81 of FIG. 8, the mounting positions of the slider member 71 and the brake shoe 86 shown in FIG. 7 are different. Here, the brake shoe 86 is attached to the tip of the arm portion 82 on the rear side so that the brake shoe 86 comes into contact with the clutch drum 34. Thus, even if the brake shoe 86 is configured at a position in contact with the clutch drum 34, both a braking effect due to eddy current and a braking effect due to the frictional force between the brake shoe 86 and the clutch drum 34 can be obtained. You can gain power. *

According to the present embodiment, the brake mechanism 40 is automatically operated in conjunction with the operation of the throttle lever and / or the lockout lever. The movable member (the cutting blade 103) can be stopped. Further, when the engine 10 is idling and the centrifugal clutch 30 is in a disconnected state, a braking effect can be obtained even when the movable member (the cutting blade 103) moves for some reason. Further, since a completely non-contact brake mechanism can be realized if no brake shoe is used for the brake mechanism 40, an engine working machine with further improved safety can be realized without adversely affecting the operation on the engine 10 side. In addition, although the brake mechanism 40 of the present embodiment is provided in the vicinity of the centrifugal clutch 30, the brake mechanism 40 is not limited only to that portion, but is arbitrary between the clutch drum 34 and the rotating portion (the cutting blade 103) of the work equipment. You may comprise so that it may provide in a location. For example, in the brush cutter 100 as shown in FIG. 1, an eddy current type non-contact brake mechanism acting on the cutting blade 103 may be provided.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, it is the same principle as in the first embodiment described above that an eddy current type brake is made by bringing a field means such as a permanent magnet close to a metal rotating body in a non-contact state. . However, the configuration of the rotating body, which is a metal medium for causing eddy current, is different. FIG. 9 (1) is a diagram showing the arrangement position of the brake mechanism according to the second embodiment. In the second embodiment, the disk 35 and the clutch drum 34 shown in FIG. 2 are manufactured in an integrated configuration, and a metal rotor that generates eddy currents is formed on the outer peripheral side of the cup-shaped clutch drum 94. And an annular portion 94a extending radially outward. The brake mechanism 40 moves in the radial direction with respect to the annular portion 94a as indicated by an arrow 68. What is necessary is just to comprise the specific structure of the brake mechanism 40 similarly to the structure demonstrated in the 1st Example. In the example of FIG. 9 (1), the position in the axial direction (front-rear direction) for forming the annular portion 94a is set at the substantially center of the outer peripheral surface, but the position where the axial position is formed is arbitrary. It is. *

FIG. 9 (2) is a view showing a brake mechanism showing a modification of the second embodiment. In this modification, a cylindrical portion 96a extending to the front side of the clutch drum 96 is formed, and a brake mechanism 90 that moves in the axial direction as shown by an arrow 69 with respect to the cylindrical portion 96a is provided. Here, the brake mechanism 90 does not swing with the slider member 41 pivotally supported unlike the brake mechanism 40, but may be a type in which the slider member moves linearly in the axial direction as indicated by an arrow 69. This is because the eddy current is generated not by the disk-shaped member but by the cylindrical member. Even in this configuration, it is configured to move in conjunction with the operation of the throttle wire or lockout lever of the carburetor, and the permanent magnet is cylindrical when the throttle wire is not pulled or when the lockout lever is released. It may be configured such that the permanent magnet is retracted forward from the cylindrical portion 96a in the axial direction when the throttle wire is pulled when the throttle wire is pulled. *

As described above, as in the second embodiment, the brake means can be realized by forming the metal rotating body at an arbitrary position of the clutch drum of the centrifugal clutch. It should be noted that the place where the metal rotating body is provided is not only provided directly on the clutch drum, but the same effect can be obtained by providing it on the clutch shaft 36, a rotating shaft (not shown), or in the vicinity of the spindle of the gear unit 102. . According to the brake mechanism for an engine working machine of the present invention, a slider including a centrifugal clutch that transmits power and a permanent magnet that rotates so as to be engaged without contacting a flange provided on the clutch drum is operated by a throttle or the like. By providing a structure that operates in conjunction with the brake mechanism, it is possible to provide a brake mechanism that exhibits a highly reliable braking force over a long period of time with a light and simple structure.

Next, a third embodiment of the present invention will be described with reference to FIG. Parts having the same structure as in the first embodiment are given the same reference numerals. In the third embodiment, the axial rotation direction of the slider member is set upside down with respect to the first embodiment. In FIG. 10, the structure in which the slider member 241 is biased toward the center of the disk 35 is left as it is, and the position of the rotation shaft 245 with respect to the rotation direction 234 is configured to be opposite to the slider member 241. That is, in the first embodiment described with reference to FIGS. 4 and 5, the slider member 41 is located on the downstream side (arrow a side) with respect to the rotational direction from the imaginary line 220 connecting the rotational axis to the central axis of the centrifugal clutch 30. The slider member 41 is located downstream of the rotation shaft 45 in the rotation direction. On the other hand, in the third embodiment, as shown in FIG. 10, the slider member 241 is located on the upstream side (arrow b side) with respect to the rotational direction from the imaginary line 220 connecting the rotational shaft 245 to the central axis of the centrifugal clutch 30. The slider member 241 is positioned upstream of the rotation shaft 245 in the rotation direction. At this time, the positional relationship of the cable 210b is changed, and the arrangement of the springs 246 may be changed as appropriate. As described above, in the configuration in which the permanent magnet moves close to the disk 35 while being pulled by the wire 213 in a direction against the urging of the spring 246, the slider member 241 is urged toward the center of the disk 35. The structure of the rotary shaft 245 with respect to the rotational direction is left on the opposite side of the configuration of FIGS. The shape of the slider 241 can be the same as that of the slider 41 used in the first embodiment, and the positions and shapes of the two permanent magnets attached thereto can be the same.

With this arrangement, when the slider member 241 moves, the two permanent magnets are positioned so as to sandwich the disk 35, and an eddy current is generated in the disk. At this time, the movement path of the permanent magnet viewed from the direction of FIG. At this time, the tangential direction of the movement trajectory when approaching the disk 35 of the permanent magnet and the tangential direction of the circumferential direction of the disk 35 are the same direction, and the angle formed by them is about 50 degrees. The moving direction of the slider member 241 is set so that the moving direction when the slider member 241 approaches the disk and the rotating direction of the disk 35 are the same, and the angle formed by the tangent is less than 60 degrees, preferably as small as possible. To do. As a result, a force that pulls the slider member 241 in the direction of the central axis is generated by the rotation of the disk 35 due to the action due to the eddy current, and the brake mechanism 240 is quickly operated. In the third embodiment, since the tangential direction of the movement locus when approaching the disk 35 of the permanent magnet and the tangential direction of the circumferential direction of the disk 35 should be the same direction, the slider member is not oscillating. The same effect can be obtained by using a linear system and a similar positional relationship. *

As mentioned above, although this invention was demonstrated based on the Example, this invention is not limited to the above-mentioned Example, A various change is possible within the range which does not deviate from the meaning. For example, in the above-described example, a hand-held type brush cutter is used as an example of an engine working machine. However, other engine working machines such as a chain saw, a hedge trimmer, etc., or a backpack that carries the engine on the back. The present invention may be applied to a working machine of a type. The engine is not limited to a two-cycle engine, and may be a four-cycle engine. Furthermore, the drive source of the work equipment is not limited to the engine but may be an electric type or an air type.

DESCRIPTION OF SYMBOLS 1 Engine working machine 5 Fan case 5a Leg part 5b Cable attaching part 5c Screw hole 5d Rib 7 Cylinder cover 8 Muffler cover 9 Starter case 10 Engine (main-body part)
11 Cylinder 12 Piston 13 Crankshaft 14 Crankcase 15 Bolt 16 Muffler 16a Exhaust Port 19 Insulator 22 Magnet Rotor 23 Ignition Coil 24 Ignition Cord 25 Spark Plug 26 Plug Cap 27 Fuel Tank 28 Cap 29 Vaporizer 30 Centrifugal Clutch 31 Clutch Shoe 32 Bolt 33 Bearing 34 Clutch drum 35 Disk 36 Clutch shaft 40 Brake mechanism 41 Slider member 42

Arm part

43, 43a, 43b Permanent magnet 45 Rotary shaft 46 Spring 46a (Spring) one end 46b (Spring) other end 50 Recoil starter 51 Reel 52 Star Rope 53 Spiral spring 54 Starter handle 56 One-way clutch 57 Drum 61 Air

cleaner cover

71, 81

Slider member

72, 82

Arm parts

73a, 73b, 83a,

83b Permanent magnet

76, 86 Brake shoe 90

Brake mechanism

94, 96 Clutch drum 94a Ring Part 96a Cylindrical part 100 Brush cutter 101 Main pipe 102 Gear unit 103 Cutting blade 105 Scatter protection cover 106

Handle

107a, 107b Grip 108 Mounting member 109

Throttle lever

110, 110a, 110b Cable 111d Cylindrical cap 112 Throttle lever lockout 113 Wire 114 Engagement element 210b Cable 213 Wire 220 Virtual line 234 Rotation direction 240 Brake mechanism 241 Slider member 245 Rotating shaft 246 Spring
250 Bold line (movement trajectory of permanent magnet)

Claims

An engine working machine that transmits engine power to a working device via a centrifugal clutch, wherein a non-contact type brake mechanism is operated when the throttle is closed in conjunction with opening and closing of the throttle of the engine. Engine working machine.
The brake mechanism is an eddy current brake, and a metal rotating body is provided from the clutch drum of the centrifugal clutch to the rotating portion on the work equipment side, and a field means is brought close to the rotating body in a non-contact state. The engine working machine according to claim 1, wherein the rotating body is braked.
The brake mechanism has a slider member that can move toward or away from the rotating body, and a permanent magnet that is provided on the slider member and acts on the rotating body, and when the throttle is in a completely closed state. The engine working machine according to claim 2, wherein the slider member is held at a position adjacent to the rotating body, and the slider member is moved to an outer region of the rotating body when the throttle is in an open state.
4. The engine working machine according to claim 3, wherein a plurality of the permanent magnets are used, and the plurality of permanent magnets have a positional relationship so as to sandwich a metal portion of the rotating body during braking.
The rotary body is a disk or an annular plate provided on the clutch drum, and the slider member moves in conjunction with an operation of a throttle wire or a lockout lever of the carburetor of the engine. Item 5. The engine working machine according to Item 4.
The slider member is moved in a direction parallel to the disk or the annular plate, and has two arm portions so as to be sandwiched from both sides of the disk or the annular plate at a tip portion close to the disk or the annular plate. The engine working machine according to claim 5, wherein the permanent magnet is provided at a position facing the disk or the annular plate of the arm portion.
The slider member is an oscillating type whose one end is pivotally supported, has the arm portion on the other end side, and includes an urging means for urging the arm portion in a direction approaching the rotating body. The engine working machine according to claim 6, wherein the slider working member is provided on a slider member, and the slider member is moved against an urging force of the urging means by an operation of the throttle wire or a lockout lever.
The engine working machine according to claim 7, wherein the swing shaft of the slider member is disposed so as to be parallel to the direction of the rotation center axis of the centrifugal clutch.
The engine working machine according to any one of claims 1 to 8, wherein the slider member is provided with a brake shoe that comes into contact with the rotating body or the clutch drum.