JP2016065464A - Engine work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine work machine capable of restricting electromagnetic radiation noise under a low cost by using general purpose component and simplifying assembly step.SOLUTION: This invention relates to a work machine for performing a work under utilization of force power of an engine in which a noise removing ferrite core 28 is inserted in an electric current path 25 for performing a jump spark ignition at an ignition device of an engine 6. It is possible that electromagnetic noise is absorbed and reduced by the ferrite core. The ferrite core is a general line filter component capable of being added afterward at a low cost and its mere insertion at an electric wiring is satisfactory, so that its assembly step can be simplified. Additionally, it is satisfactory that a mere installation of a holding part of the ferrite core is set and the present structure is not needed to be substantially changed, so that it is possible to restrict electromagnetic radiation noise under a low cost.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an engine working machine that performs work using the power of an engine.

  Regarding measures against EMI (Electro Magnetic Interference) in engine working machines, for example, a shield is provided around the spark plug as described in Patent Documents 1 and 2, and a plug as described in Patent Documents 3 and 4. A device in which a ferrite member or the like is arranged on a cap or connector is known.

JP 2011-52581 A JP 2014-15865 A Japanese Patent No. 4005385 JP 2000-145603 A

  However, in both cases, there is a problem that the cost of EMI countermeasures becomes high, such as the structure of the periphery of the spark plug and the connector is complicated, and the assembly process is increased by hand and dedicated parts are required. .

  The present invention has been made in view of the circumstances as described above, and its object is to use engine parts that can reduce electromagnetic radiation noise at low cost by using general-purpose parts and simplifying the assembly process. Is to provide a machine.

  The engine working machine according to the present invention is a working machine that performs work using the power of the engine, and a ferrite core for noise removal is inserted in a current path for spark ignition in an ignition device of the engine. It is characterized by.

  According to the present invention, the ferrite core, which is a general-purpose line filter component that can be retrofitted at a low cost, is inserted into the current path for spark ignition in the ignition device of the engine working machine, thereby simplifying the assembly process. However, electromagnetic radiation noise can be suppressed at a low cost.

It is a perspective view showing a backpack type engine blower as an example of an engine working machine concerning an embodiment of the present invention. It is sectional drawing which cut | disconnected the engine blower shown in FIG. 1 into right and left, and was seen from the left side. It is sectional drawing which cut | disconnected the engine blower shown in FIG. 1 back and forth, and was seen from the flame | frame side. FIG. 2 is a front view showing in detail a mounting example of a ferrite core by removing a part of a casing and parts from the engine blower shown in FIG. 1. It is a figure which shows typically arrangement | positioning of the ferrite core in the engine blower shown in FIG. 1 thru | or FIG. FIG. 4 is a perspective view illustrating a configuration example of a ferrite core and a protection member, showing a state before mounting and a state where the ferrite core and the protection member are mounted on wiring.

Embodiments of the present invention will be described below with reference to the drawings.
FIGS. 1 to 4 each show an engine working machine according to an embodiment of the present invention, taking a backpack type engine blower as an example. Here, although it demonstrates with an engine blower, this invention is applicable to various engine working machines, such as a dust collector, a brush cutter, a mower, a sprayer, and a spreader.

  As shown in FIG. 1, the engine blower 1 has a blower unit 3 attached to a frame 2 for an operator to carry on the back, and a blower pipe (ventilation pipe) 5 that discharges air to an ejection duct (ventilation duct) 4 of the blower unit 3. Is a communication. The blower unit 3 ejects air sucked by rotation of a blower fan 7 driven by an engine (see FIGS. 2 and 3) 6. The base end portion of the blower pipe 5 is supported by the frame 2 and assembled to the opening end portion of the ejection duct 4.

  The frame 2 is for the operator to carry the blower unit 3 on his / her back, and is composed of a backrest portion 2a extending vertically and hitting the operator's back, and a pedestal portion 2b extending rearward from the lower portion of the backrest portion 2a. It is L-shaped. A pair of shoulder straps 8-1 and 8-2 are attached to the backrest portion 2 a of the frame 2 for the operator to carry on his back.

  The blower unit 3 is mounted on the frame 2 via a vibration suppression mechanism. Coil springs 10-1 and 10-2 constituting a vibration suppression mechanism are interposed between the lower part of the blower unit 3 and the base 2 b of the frame 2, and the vibration suppression mechanism is provided above the blower unit 3. The constituting coil springs 10-3 and 10-4 are interposed between the backrest portion 2a.

  Further, as shown in FIG. 2, the blower unit 3 ejects the air sucked by the rotation of the blower fan 7 driven by the engine 6. The blower fan 7 is accommodated in the volute case 9, and the engine 6 for rotating the blower fan 7 is integrally assembled to the volute case 9. The volute case 9 is provided with an air suction port 9a on the backrest 2a side, and a cylindrical air ejection duct 4 is integrally provided on the right side.

  An enlarged diameter portion 4a having a large diameter is provided at the distal end portion of the ejection duct 4, and the proximal end portion of the blower pipe 5 supported by the frame 2 is inserted into the enlarged diameter portion 4a of the ejection duct 4 in a floating manner. Are assembled. The blower pipe 5 is for releasing air ejected from the blower unit 3 held by an operator. The blower pipe 5 includes an elbow part 5a floatingly connected to the jet duct 4 of the blower unit 3, a flexible bellows pipe part 5b connected to the tip of the elbow part 5a, and a tip of the bellows pipe part 5b. The rotating pipe portion 5c is connected, the short pipe portion 5d is connected to the rotating pipe portion 5c, and the end nozzle portion (blowing port) 5e is connected to the short pipe portion 5d.

  A control handle 11 for holding the blower pipe 5 is attached in the vicinity of the connecting portion between the rotating pipe portion 5c and the bellows pipe portion 5b. The control handle 11 is provided with a trigger lever 12 for operating the blower unit 3.

  A fuel tank 13 for storing liquid fuel such as gasoline is mounted between the lower part of the blower unit 3 and the pedestal part 2b, and a fuel tank cap 14 is provided on the upper part of the fuel tank 13. The blower unit 3 is provided with a recoil starter unit 15 for starting the engine 6.

  As shown in FIG. 3, the fuel in the fuel tank 13 is supplied to the carburetor 20 via the fuel pipe 13 a, and the vaporized fuel is sent to the engine 6 together with air, and is sparked by the spark plug 19. The exhaust gas after combustion is supplied to the muffler 17 to be silenced and exhausted to the outside.

  As shown in FIGS. 2 to 4, a net for suppressing inhalation of dust and the like from an air suction port is attached to the bottom surface of the engine blower 1 (the bottom surface of the base portion 2 b of the frame 2). This net is mounted so as to cover the air inlet provided on the bottom surface of the base 2b. In this example, the net is made of metal, and also functions as the ground plate 21 by being electrically connected to the engine 6 via wiring (lead wire).

  The ground plate 21 includes a plate-like portion 21a and a grounding portion 21b that extends downward from the plate-like portion 21a and grounds the plate-like portion 21a when the engine blower 1 is placed on the ground. A large number of openings are formed in the plate-like portion 21a, and air is sucked from the suction port through these openings. The grounding portion 21b slightly projects downward from the bottom surface of the pedestal portion 2b, and is grounded when the engine blower 1 is placed on the ground.

  In FIG. 4, reference numeral 16 denotes an arm type throttle lever. The throttle lever 16 moves the arm up and down around the rotation shaft 16a and can be freely expanded outward by the rotation shaft 16b. It has become. The rotary shaft 16b is provided with a spring and urges it to return to the inside when the arm is expanded outward. This makes it possible to adjust the throttle at a position that matches the working posture.

  Next, EMI countermeasures in the engine blower 1 configured as described above will be described. As shown in FIG. 3, a line filter, for example, a ferrite core 28 is inserted in the current path (wiring 25) between the spark plug 19 and the ignition coil 24. The ferrite core 28 functions as an EMI filter that removes noise generated from the spark plug 19. The ferrite core 28 is preferably disposed in the vicinity of the spark plug 19 which is a noise generation source in order to suppress the radiation of noise to the outside.

  In addition, as shown in FIG. 4, a ferrite core 29 is also inserted in a wiring 27 that connects the ignition coil 24 and a stop switch (a switch that disconnects the ignition coil from the current path) 26. The ferrite core 29 functions as an EMI filter. Further, the earth plate 21 has a function of grounding the engine 6 when the engine blower 1 is placed on the ground and releasing the static electricity accumulated in the engine 6, but when working with the engine blower 1 on the back, Noise may be radiated using the ground plate 21 as an antenna. Therefore, a ferrite core 23 is also inserted in the wiring 22 that connects the engine 6 and the ground plate 21.

  5A and 5B schematically show the arrangement of the ferrite cores 23, 28, and 29 described above. As shown in FIG. 5A, the ferrite core 28 is inserted into the wiring 25 between the ignition plug 19 and the ignition coil 24, and the ferrite core 29 is connected to the wiring 27 between the ignition coil 24 and the stop switch 26. Is inserted. Further, as shown in FIG. 5B, the ferrite core 23 is inserted into the wiring 22 between the engine (body earth) 6 and the earth plate 21.

  As described above, impedance is given to the wirings 22, 25, and 27 to which the ferrite cores 23, 28, and 29 are attached by the ferrite cores 23, 28, and 29, and a noise current flowing in the wirings 22, 25, and 27 is given. In addition to being suppressed by the impedance, it is attenuated by being converted into heat by the resistance component. In the high frequency band, most of the ferrite cores 23, 28, and 29 have a resistance component, so that the noise attenuation effect is greater than that in the low frequency band.

  Further, in this example, as shown in FIG. 4, the ferrite core 23 is attached to a resin casing (only the mounting base is shown in a detached state) 3 a provided so as to cover the engine 6. A holding portion 33 for holding is provided. The ground plate 21 is fixed to one end of the wiring 22 with a screw 35 or the like using a metal sleeve 34, and the other end of the wiring 22 is fixed to the engine 6 with a bolt 36 or the like. A ferrite core 23 is inserted in the wiring 22, and the ferrite core 23 is held by a holding portion 33 provided in the housing 3a.

  Although not shown, the ferrite core 29 is similarly held by the housing 3a or a holding portion provided on the mounting base of the housing 3a. The ferrite core 29 is preferably arranged in the vicinity of the high-voltage wiring of the ignition system, more preferably in the vicinity of the ignition coil 24. The ferrite core 28 floats when placed in the vicinity of the plug cap of the spark plug 19, but is slightly shifted to the ignition coil 24 side to form a holding portion on the housing 3 a or the mounting base of the housing 3 a and hold it. May be. On the other hand, the wiring 22 is not directly involved in engine ignition, but the ferrite core 23 is preferably arranged in the vicinity of the engine 6 when it is connected to a metal part or the like as a ground wire.

  Each of the ferrite cores 23, 28, and 29 has a shape obtained by dividing a hollow cylinder into two along the central axis as shown in FIG. 6A, for example. Here, the ferrite core 23 (23-1, 23-2) is illustrated, but the ferrite cores 28, 29 have the same configuration. The ferrite core 23 is accommodated in a protective member 31 made of, for example, resin for protecting from an external impact or high temperature.

  The protective member 31 has a cylindrical shape divided into two, has hinge portions 32a and 32a at the connecting portions of the semi-cylindrical portions 31-1 and 31-2, and claw portions 32b and 32b and engaging portions 32c and 32c at both ends. And have. The claw portions 32a and 32a correspond to the engaging portions 32c and 32c. The ferrite cores 23-1 and 23-2 are accommodated in the semi-cylindrical portions 31-1 and 31-2 of the protective member 31, respectively, and the wiring 22 is disposed in the hollow portions of the ferrite cores 23-1 and 23-2. The claws 31a and 31a are engaged with the engaging portions 31b and 31b so as to be sandwiched between the wires 22 as shown in FIG. 6B.

  Here, in the semi-cylindrical portions 31-1 and 31-2 of the protective member 31, a sheet-like elastic member such as rubber, urethane foam, and a porous material is accommodated, and the ferrite cores 23-1 and 23-2 By interposing between them, the protective effect can be further enhanced.

  The operation of the engine blower 1 configured as described above is performed as follows. An operator pulls the starter handle of the recoil starter unit 15 to start the engine 6 of the blower unit 3, and supports the frame 2 with shoulder straps 8-1 and 8-2. Then, holding the grip 11 of the blower pipe 5 with the right hand and operating the throttle with the arm type throttle lever 16 with the left hand, the sucked air is blown out from the end nozzle portion 5e of the blower pipe 5, thereby providing fallen leaves, cut grass, etc. To blow.

  According to such a configuration, since the ferrite core for noise removal is inserted in the current path for spark ignition in the ignition device of the engine blower, electromagnetic radiation noise can be absorbed and reduced. Further, by inserting a ferrite core in the wiring connecting the engine and the ground plate, it is possible to suppress noise from being emitted using the ground plate as an antenna. The ferrite core is a general-purpose line filter component that can be retrofitted at a low cost and can be simply inserted into the wiring, so that the assembly process can be simplified. Moreover, the engine blower only needs to be provided with a ferrite core holding portion in the casing, and there is no need to greatly change the current structure, so that electromagnetic radiation noise can be suppressed at low cost.

<Modification 1>
In the above-described embodiment, the holding portion that holds the ferrite core accommodated in the protective member attached to the resin housing is provided, but the accommodating portion that accommodates the ferrite core and protects it from vibration and high temperature is provided. Of course, it may be provided. If an elastic member or a heat insulating member is interposed between the housing portion and the ferrite core, the same function as that of the protective member described above can be provided.

<Modification 2>
When holding the ferrite core in the holding part or receiving it in the receiving part, the longitudinal direction along the central axis of the hollow cylinder of the ferrite core is the same direction as the piston movement direction in the engine (or the direction in which it can drop) In the same direction). By holding or accommodating the engine vibration direction (vertical direction in this example) and the longitudinal direction along the central axis of the hollow cylinder where the strength of the ferrite core is high, the impact caused by engine vibration or dropping Can prevent the ferrite core from cracking.

<Modification 3>
The ferrite core is installed in a place lower than the Curie temperature (for example, 120 ° C.) of the ferrite core. If a ferrite core is installed near the heat source (engine) exceeding the Curie temperature and the ferrite core exceeds the Curie temperature, the effect of attenuating noise is lost. Therefore, for example, a ferrite core holding portion or accommodation portion is provided in a resin member that insulates heat from the engine to the vaporizer. Moreover, it is good to arrange | position an ignition coil in the position where temperature is low, and to arrange | position a ferrite core in the vicinity of this ignition coil.

<Modification 4>
An example in which the ferrite core is inserted into the wiring connecting the engine and the ground plate, the wiring connecting the ignition plug and the ignition coil, and the wiring connecting the ignition coil and the stop switch has been shown. One or two may be selectively provided. In addition to these, a line filter may be inserted in a wiring that may cause noise. Moreover, although the example of the ferrite core was shown as a line filter, a choke coil etc. may be sufficient and other various EMI filters are applicable. When a choke coil is used, the choke coil generates heat in a high-voltage wiring. Therefore, a ferrite core is preferably used between the spark plug and the ignition coil.

<Modification 5>
When metal is used for the housing, the housing is also close to the spark plug that is a noise source, so a ferrite core is inserted into the wiring (lead wire) connected to this housing or the wiring for body grounding. To do. Since the metal casing serves as a path for noise propagation, electromagnetic radiation noise can be suppressed by inserting a ferrite core in each lead wire connected thereto.

<Modification 6>
In the above embodiment, the example in which the ferrite core is installed in the resin casing has been described. Resin material is preferable to metal material from the viewpoint of temperature and vibration, but if the place is lower than Curie temperature and vibration is relatively small, a holding part or a housing part is formed in the engine or its vicinity to form a ferrite. A core can also be installed. Specifically, a recess is provided in an engine crankcase or the like to accommodate the ferrite core. At this time, the influence of the temperature rise and vibration can be suppressed by interposing a heat insulating material or a vibration absorbing material between the recess of the crankcase and the ferrite core, or by setting the cooling air to the engine.

<Modification 7>
Further, since the blower unit is mounted on the frame via the vibration suppressing mechanism, the influence of vibration can be further reduced by providing the frame with a holding portion or a holding portion and holding or holding the ferrite core. In this way, a holding part or a housing part may be provided in a part other than the blower unit, and the ferrite core may be attached.

<Modification 8>
In the embodiment described above, the case where the ferrite core is divided into two along the central axis on the assumption that the ferrite core is attached later to the wiring has been described as an example. However, as a matter of course, a non-divided core (hollow cylindrical shape) may be used, and the ferrite core may be inserted into the wiring and then connected.

  DESCRIPTION OF SYMBOLS 1 ... Engine blower, 2 ... Frame, 3 ... Blower unit, 3a ... Housing, 4 ... Jet duct, 5 ... Blower pipe, 6 ... Engine, 7 ... Blower fan, 11 ... Control handle, 19 ... Spark plug, 21 ... Ground plate, 22, 25, 27 ... wiring, 23, 28, 29 ... ferrite core, 24 ... ignition coil, 26 ... stop switch, 31 ... protective member, 33 ... holding part

Claims (6)

A working machine that uses the power of the engine to perform work.
An engine working machine, characterized in that a noise removal ferrite core is inserted in a current path for spark ignition in an engine ignition device.   The current path through which the ferrite core is inserted includes at least one of a spark plug and an ignition coil, between the ignition coil and a switch for disconnecting the ignition coil from the current path, and between a body ground and a ground plate. The engine working machine according to claim 1.   The engine working machine according to claim 1, further comprising a holding portion that is provided in a resin casing attached to the engine and holds the ferrite core.   The engine work machine according to any one of claims 1 to 3, further comprising a protection member that accommodates the ferrite core and protects the ferrite core from an external impact.   The said ferrite core is a hollow cylinder shape, and the longitudinal direction along a central axis is arrange | positioned in the same direction as the moving direction of the piston in the said engine, The Claim 1 thru | or 4 characterized by the above-mentioned. Engine work machine.   The engine work machine according to any one of claims 1 to 5, wherein the ferrite core is installed in a place where a temperature is lower than a Curie temperature of the ferrite core.