JP2011190732A - Engine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine tool capable of making sure of the engine condition in detail. <P>SOLUTION: A brush cutter includes an engine having an ignition plug 15 and an ignition device 60 to make electric discharge by impressing voltage on the ignition plug 15, mowing blades to work upon receiving power from the engine, and a light emission part 70 installed visibly from outside. The ignition device 60 is composed of a magneto-rotor 61 to rotate upon receiving power from the engine, a permanent magnet 62 installed fast on the peripheral part of the magneto-rotor 61, a primary coil 63 arranged confronting the peripheral part of the magneto-rotor 61 and generating the primary current owing to the electromagnetic induction effect in interaction with the permanent magnet 62, and a secondary coil 64 generating the secondary voltage owing to the mutual induction effect in interaction with the primary coil 63 and impressing the secondary voltage on the ignition plug 15. The lighting condition of the light emission part 70 varies in compliance with the current flowing through the primary coil 63. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine tool.

  Engine tools such as a brush cutter, a hedge trimmer, and a chain saw are generally driven by a spark ignition engine such as a two-cycle engine. A spark ignition engine (hereinafter referred to as an engine) includes an ignition plug that ignites an air-fuel mixture in a combustion chamber by discharge, and an ignition device that applies a high voltage to the ignition plug in synchronization with the rotation of the engine. In particular, an engine of an engine tool generally includes a magneto ignition device in order to reduce or omit the power source. The magneto ignition device includes a rotor having a magnet and rotating in synchronization with the rotation of the engine, a primary coil, and a secondary coil, as disclosed in, for example, Patent Document 1, and the rotation of the rotor Accordingly, a high voltage is generated by boosting the voltage generated by the electromagnetic induction action of the magnet and the primary coil by the mutual induction action of the primary coil and the secondary coil.

Japanese Utility Model Publication No. 2-50176

  In an engine tool, for example, due to various abnormalities of the spark plug such as fuel adhering to the electrode of the spark plug, the spark plug cannot be normally discharged and the engine may not start. In such a case, the operator needs to perform appropriate maintenance such as removing the spark plug from the engine and wiping off the fuel adhering to the electrode. However, in reality, the operator cannot determine whether or not the spark plug is normally discharged, and the state of the spark plug cannot be confirmed unless the spark plug is removed from the engine. Furthermore, the reason why the engine does not start is not limited to the abnormality of the ignition plug, and there are various reasons such as an abnormality of the ignition device and an on / off state of a switch for stopping the engine. Therefore, it is difficult to quickly identify this. Therefore, conventional engine tools have poor engine startability and maintainability.

  Engine tools generally include a throttle lever for adjusting the engine speed. The engine generally has a characteristic that the maximum output is generated at a rotational speed smaller than the maximum rotational speed, and the fuel efficiency is better as the smaller rotational speed is maintained. However, the operator cannot determine whether or not the engine speed is appropriate with respect to the output and the fuel consumption, based on experience and intuition. Therefore, even if the conventional engine tool performs the same work, the workability and fuel consumption may be deteriorated by the operator.

  That is, the conventional engine tool is not limited to the above example because the operator cannot confirm the state of the engine in detail, and is not convenient.

  In view of the above problems, an object of the present invention is to provide an engine tool that can check the state of the engine in more detail.

In order to achieve the above object, an engine tool according to the present invention provides:
An engine having a spark plug, and an ignition device that applies a voltage to the spark plug to discharge it;
A working tool that operates by receiving the power of the engine;
A light emitting portion provided so as to be visible from the outside,
The ignition device is
A rotor that rotates under the power of the engine;
A permanent magnet fixed to the outer periphery of the rotor;
A primary coil disposed opposite to the outer peripheral portion of the rotor and generating a primary current by electromagnetic induction with the permanent magnet;
A secondary coil that generates a secondary voltage by a mutual induction action with the primary coil and applies the secondary voltage to the spark plug.
The light emitting unit changes its lighting state according to the current flowing through the primary coil.
It is characterized by that.

The above-mentioned engine tool is, for example,
A primary current detection circuit that detects a level of a current flowing through the primary coil and outputs a primary current detection signal;
And a control circuit that controls a lighting state of the light emitting unit based on the primary current detection signal.

  In addition, for example, the light emitting unit may change its lighting state in accordance with a current flowing through the primary coil and a current flowing through the spark plug.

The above-mentioned engine tool is, for example,
A plug current detection circuit for detecting a level of current flowing through the spark plug and outputting a plug current detection signal;
The control circuit may control a lighting state of the light emitting unit based on the primary current detection signal and the plug current detection signal.

Moreover, the above-mentioned engine tool is, for example,
A plug current detection circuit for detecting a level of a current flowing through the spark plug and outputting a plug current detection signal;
And a control circuit that controls a lighting state of the light emitting unit based on the plug current detection signal.

  For example, the control circuit may control the lighting state of the light emitting unit according to whether or not a current flows through the spark plug.

  For example, the control circuit may obtain the engine speed based on the primary current detection signal and control the lighting state of the light emitting unit according to the engine speed.

  For example, the control circuit may obtain the engine speed based on the plug current detection signal and control the lighting state of the light emitting unit according to the engine speed.

  For example, the control circuit compares the rotational speed of the engine with a predetermined rotational speed range, and changes the lighting state of the light emitting unit according to whether or not the rotational speed of the engine is in the predetermined rotational speed range. You may make it control.

  The control circuit preferably includes means for changing the predetermined rotational speed range.

  The light emitting unit is preferably operated by electric power supplied from the ignition device.

  ADVANTAGE OF THE INVENTION According to this invention, the engine tool which can confirm the state of an engine in detail can be provided.

(A) The perspective view which shows the brush cutter which concerns on embodiment of this invention. (B) The perspective view which shows the holding part of the brush cutter shown by (a). FIG. 2 is a schematic block diagram showing an ignition plug, an ignition device, a light emitting unit, and a lighting circuit of the brush cutter shown in FIG. 1. FIG. 3 is a flowchart showing the operation of the control circuit shown in FIG. 2.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  The engine tool according to the embodiment is a brush cutter 1 shown in FIG. The brush cutter 1 includes an engine 10, an operation rod 20, a handle 30, a gear case 40, and a cutting blade (work tool) 50.

  The engine 10 is composed of, for example, a two-cycle engine. Although not shown, the engine 10 includes a cylinder that defines a combustion chamber, a piston that reciprocates within the cylinder, a crankshaft that rotates as the piston reciprocates, and fuel. A tank, a carburetor that creates a mixture of fuel and air, a recoil for starting the engine 10 by rotating a crankshaft, and the like are provided. Further, as will be described later with reference to FIG. 2, the engine 10 includes an ignition plug 15 that ignites an air-fuel mixture in the combustion chamber by discharge, and an ignition that applies a high voltage to the ignition plug 15 in synchronization with the rotation of the engine 10. The apparatus 60, the 1st LED (light emitting diode) 71 which comprises the light emission part 70, and the lighting circuit 80 which controls the lighting state of 1st LED71 and 2nd LED72 mentioned later are provided. Although not shown in FIG. 1A, the first LED 71 is disposed on the outer surface of the engine 10 so that the user can visually recognize the engine 10 when starting the engine 10.

  The operating rod 20 is a hollow tube formed of aluminum alloy, reinforced plastic, or the like, and mechanically connects the engine 10 and the gear case 40. A power transmission member (not shown) that transmits the power of the engine 10 to the gear case 40 is inserted into the operation rod 20.

  The handle 30 is fixed to the operation rod 20, is formed in a substantially U shape when the operation rod 20 is viewed in the longitudinal direction, and includes grip portions 31a and 31b at one end and the other end, respectively. As shown in FIG. 1B, a throttle lever 32, a safety lever 33, and a stop switch 34 are attached to one gripping portion 31a. The throttle lever 32 is a trigger type lever, and controls the amount of air supplied to the carburetor of the engine 10 according to the pulling amount, thereby changing the rotational speed (output) of the engine 10. The safety lever 33 is a retractable lever and mechanically restricts the operation of the throttle lever 32 when the user is not gripping the grip portion 31a. The stop switch 34 is a kind of on / off switch. For example, when the stop switch 34 is turned on while the engine 10 is being driven, the high voltage (secondary voltage) applied from the ignition device 60 to the ignition plug 15 is short-circuited. Then, the discharge of the spark plug 15 is restricted and the engine 10 is stopped. Furthermore, the holding part 31a includes a second LED 72 constituting the light emitting part 70, as will be described later with reference to FIG. The second LED 72 is disposed on the outer surface of the grip portion 31a so that the user can visually recognize when starting the engine 10 and during the work.

  A gear case 40 shown in FIG. 1A includes an unillustrated bevel gear connected to the power transmission member of the operation rod 20 and an unillustrated output shaft connected to the bevel gear.

  The cutting blade 50 is fixed to the output shaft of the gear case 40. Therefore, the cutting blade 50 receives the power of the engine 10 and rotates through the power transmission member of the operating rod 20 and the bevel gear of the gear case 40.

  Next, the ignition plug 15, the ignition device 60, the light emitting unit 70, and the lighting circuit 80 will be described in detail with reference to FIG. In FIG. 2, the above-described stop switch 34 is omitted for easy understanding.

  First, the ignition device 60 will be described. The ignition device 60 includes a magnet rotor 61, a permanent magnet 62, a primary coil 63, a secondary coil 64, and an iron core 65.

  The magnet rotor 61 is formed in a substantially disc shape and is connected to the crankshaft of the engine 10 coaxially.

  The permanent magnet 62 is fixed to the outer periphery of the magnet rotor 61, and the magnetic poles are arranged in the radial direction of the magnet rotor 61.

  One or both ends of the iron core 65 are arranged to face the outer periphery of the magnet rotor 61.

  The primary coil 63 is wound around an iron core 65, one end of which is connected to a control circuit 83 described later, and the other end is connected to the control circuit 83 via a primary current detection circuit 81 described later. .

  The secondary coil 64 is wound around the iron core 65 and is electromagnetically coupled to the primary coil 63. One end of the secondary coil 64 is connected to the center electrode of the spark plug 15 via a secondary current detection circuit 82 described later, and the other end is grounded. Further, the number of turns of the secondary coil 64 is larger than the number of turns of the primary coil 63.

  Here, operations of the ignition device 60 and the ignition plug 15 will be described.

  When the recoil of the engine 10 is pulled, the magnet rotor 61 rotates together with the crankshaft. Thereby, the permanent magnet 62 fixed to the outer periphery of the magnet rotor 61 passes through the vicinity of the primary coil 63 and the iron core 65 and changes the magnetic field around the primary coil 63. Accordingly, a primary current is generated in the primary coil 63 by electromagnetic induction. Then, the control circuit 83 rapidly changes the magnetic field around the primary coil 63 by rapidly interrupting the primary current flowing through the primary coil 63 at a predetermined timing. As a result, a secondary voltage is generated in the secondary coil 64 due to the mutual induction effect of the primary coil 63 and the secondary coil 64. The secondary voltage is greater than the electromotive force generated in the primary coil 63 due to the difference in the number of turns between the primary coil 63 and the secondary coil 64. The spark plug 15 discharges the secondary voltage generated in the secondary coil 64 and ignites the air-fuel mixture in the combustion chamber of the engine 10. Since the permanent magnet 62 fixed to the magnet rotor 61 rotates in synchronization with the rotation of the engine 10, the spark plug 15 is discharged in synchronization with the rotation of the engine 10. As a result, the engine 10 can be started and continuously driven.

  Next, the lighting circuit 80 will be described. The lighting circuit 80 includes a primary current detection circuit 81, a secondary current detection circuit (plug current detection circuit) 82, and a control circuit 83.

  The primary current detection circuit 81 detects a primary current I1 generated in the primary coil 63, and outputs an analog primary current detection signal P1 indicating the level of the detected primary current I1 to the control circuit 83.

  The secondary current detection circuit 82 detects a secondary current (plug current) I2 flowing through the spark plug 15 and outputs an analog secondary current detection signal P2 indicating the level of the detected secondary current I2 to the control circuit 83.

  The control circuit 83 includes, for example, a control unit configured with a microprocessor and a switch circuit.

  The control unit takes in the analog primary current detection signal P1 input from the primary current detection circuit 81 by A / D (analog-digital) conversion, and compares the current value of the primary current I1 with a predetermined threshold value Ir1. The lighting state (lighting, blinking, extinguishing, etc.) of the first LED 71 is controlled according to the comparison result. The threshold value Ir1 is a reference value for determining that the secondary coil 64 can generate a specified secondary voltage when the primary current I1 is equal to or greater than that value. The primary current I1 is an alternating current generated in a pulse shape according to the relative position of the permanent magnet 62 once during one cycle of the engine 10. The control unit compares the value (instantaneous value) of the primary current I1 at a predetermined timing with the threshold value Ir1. For this reason, the threshold value Ir1 is also set as appropriate according to the acquisition timing of the primary current I1. Note that the effective value of one period of the primary current I1 may be used as a comparison target. In this case, the threshold value Ir1 is set as appropriate.

  Further, the control unit performs A / D conversion on the analog secondary current detection signal P2 input from the secondary current detection circuit 82, compares the current value of the secondary current I2 with a predetermined threshold value Ir2, and compares them. The lighting state of the second LED 72 is controlled according to the result. The threshold value Ir2 is a reference value for determining that a current has flown through the spark plug 15 when the secondary current I2 is equal to or greater than that value. The secondary current I2 is a current that changes in a pulse shape only at the discharge timing once during one cycle of the engine 10. For example, the control unit compares the peak value of the secondary current I2 with the threshold value Ir2. Note that the effective value of one period of the secondary current I2 may be used as a comparison target, and in this case, the threshold value Ir2 is appropriately set.

Further, the control unit obtains the rotational speed N of the engine 10 by measuring the discharge cycle of the spark plug 15 by an internal timer based on the analog secondary current detection signal P2 input from the secondary current detection circuit 82. The control unit compares the obtained rotation speed N with the predetermined upper limit threshold value Nru and the lower limit threshold value Nrl, and the rotation speed N controls the lighting state of the second LED 72 according to the comparison result. The upper limit threshold value Nru and the lower limit threshold value Nrl are an upper limit value and a lower limit value of the rotational speed N for determining that the engine 10 is exhibiting a prescribed output, and the rotational speed N is an upper limit threshold value Nru and a lower limit value Nrl. When it is between, it is determined that the specified output is exhibited. For example, when the rotational speed at which the engine 10 exhibits the maximum output is 9000 min ⁻¹ and the engine 10 can exhibit a specified output in the rotational speed range of ± 500 min ⁻¹ around this, the upper limit threshold Nru And the lower threshold Nrl are set to 9500 min ⁻¹ and 8500 min ⁻¹ , respectively. The control circuit 83 is set with a plurality of upper limit threshold values Nru and lower limit threshold values Nrl respectively corresponding to a plurality of engines having different performances, and is provided with a switch (not shown) for switching between them.

  Further, the control unit switches the switch so as to induce a large voltage in the secondary coil 64 by substantially interrupting the primary current flowing through the primary coil 63 at a predetermined ignition timing linked to the movement of the piston. Control the circuit. The switch circuit is connected between both ends of the primary coil 63, and substantially cuts off the primary current at a predetermined ignition timing linked to the movement of the piston according to the control of the control unit. Induces a large voltage.

  The operating power of the control circuit 83 may be supplied from, for example, a battery (not shown), or may be obtained by rectifying and smoothing the electric power generated by the primary coil 63. A generator is connected to the crankshaft, You may make it obtain from a generator.

  Here, the operation of the control circuit 83 for controlling the lighting states of the first and second LEDs 71 and 72 will be described with reference to FIG. For ease of understanding, the control circuit 83 starts operating when the power is turned on and ends when the power is turned off.

  First, the control circuit 83 compares the primary current I1 generated in the primary coil 63 with a predetermined threshold value Ir1 (step S1). As described above, the primary current I <b> 1 is an alternating current that is generated in a pulse shape by the proximity and separation of the permanent magnet 62 once during one cycle of the engine 10. The control circuit 83 compares the value (instantaneous value) of the primary current I1 at a predetermined timing with the threshold value Ir1. In the present embodiment, the control unit of the control circuit 83 samples a value immediately before cutting off the primary current I1, and compares it with the threshold value Ir1. Note that the effective value of one period of the primary current I1 may be a comparison target.

  When the primary current I1 is smaller than the threshold value Ir1 (step S1, NO), the control circuit 83 turns off the first LED 71 (step S2).

  When the primary current I1 is greater than or equal to the threshold value Ir1 (step S1, YES), the control circuit 83 turns on the first LED 71 (step S3).

  Next, the control circuit 83 compares the secondary current I2 flowing through the spark plug 15 with a predetermined threshold value Ir2 (step S4). The secondary current I2 is a current that changes in a pulse shape only at the discharge timing once during one cycle of the engine 10. For example, the control unit of the control circuit 83 samples the peak value of the secondary current I2, and compares the sampled peak value with the threshold value Ir2. Note that the effective value of one period of the secondary current I2 may be a comparison target.

  When the secondary current I2 is smaller than the threshold value Ir2 (step S4, NO), the control circuit 83 turns off the second LED 72 (step S5) and returns to the operation of step S1 described above.

  When the secondary current I2 is equal to or greater than the threshold value Ir2 (step S4, YES), the control circuit 83 rotates the engine 10 based on the period of the secondary current I2 continuously measured by the internal timer of the control unit. The number N is obtained, and the obtained number of revolutions N is compared with the predetermined upper limit threshold value Nru and the lower limit threshold value Nrl (step S6).

  When the rotation speed N is smaller than the lower limit threshold Nrl or larger than the upper limit threshold Nru (step S6, NO), the control circuit 83 blinks the second LED 72 (step S7) and returns to the operation of step S1 described above.

  When the rotational speed N is not less than the lower limit threshold Nrl and not more than the upper limit threshold Nru (step S6, YES), the control circuit 83 turns on the second LED 72 (step S8) and returns to the operation of step S1 described above.

  Next, a method in which the user confirms the state of the engine 10 based on the lighting state of the first and second LEDs 71 and 72 will be described.

(1) Method for confirming the cause of the engine 10 not starting

  When the first LED 71 is turned off when the recoil of the engine 10 is pulled, no primary current exceeding the specified value is generated in the primary coil 63. From this, it is inferred that the cause of the engine 10 not starting is not an abnormality related to the spark plug 15 but an abnormality related to the ignition device 60. As an abnormality of the ignition device 60, for example, the gap between the magnet rotor 61 and the primary coil 63 is not appropriate.

  On the other hand, when the first LED 71 is lit when the recoil of the engine 10 is pulled, a sufficient primary current is generated in the primary coil 63. In this case, as will be described below, the lighting state of the second LED 72 is further confirmed to confirm the cause of the engine 10 not starting.

  When the first LED 71 is turned on and the second LED 72 is turned off when the recoil of the engine 10 is pulled, a primary current exceeding a specified value is generated in the primary coil 63. No secondary current exceeding the specified value flows through the spark plug 15. For this reason, the engine 10 does not start because, for example, the stop switch 34 is operating, the wiring for applying the secondary voltage to the spark plug 15 is broken, or the control circuit 83 is broken. It is presumed that

  Further, when the first LED 71 is lit when the recoil is pulled and the second LED 72 is blinking, a primary current exceeding a specified value is generated in the primary coil 63, and In addition, a secondary current exceeding the specified value flows through the spark plug 15. From this, it is inferred that the cause of the engine 10 not starting is an abnormality related to fuel or an abnormality related to the spark plug 15. Examples of the abnormality of the fuel include a shortage of fuel supply and a deterioration of the fuel. Further, the abnormality of the spark plug 15 includes failure of the spark plug 15, improper distance between the electrodes, or fuel or carbon adhering to the electrode part.

  As described above, when starting the engine 10, the user can narrow down the cause of the engine 10 not starting to some extent by checking the lighting state of the first and second LEDs 71 and 72. The engine 10 can be stopped early and maintenance can be performed quickly and accurately. Further, this can prevent the occurrence of secondary abnormality such as fuel adhering to the electrode portion of the spark plug 15, so that the user can start the engine 10 quickly after maintenance.

(2) Method for confirming the rotational speed of the engine 10

  When the second LED 72 is blinking while the engine 10 is being driven, the rotational speed of the engine 10 is not in the rotational speed range in which the engine 10 exhibits a specified output (near the rotational speed that exhibits the maximum output). . In addition, when the second LED 72 is lit while the engine 10 is being driven, the rotational speed of the engine 10 is a rotational speed range in which the engine 10 exhibits a specified output (near the rotational speed at which the maximum output is exhibited). It is in. Therefore, when the engine 10 is driven, the user can work efficiently by adjusting the pulling amount of the throttle lever 32 so that the second LED 72 is lit while checking the second LED 72. Can be implemented.

  As described above, according to the brush cutter 1 having the above-described configuration, the secondary current (plug current) flowing through the spark plug 15 is detected, and the second light source 70 is configured based on the detected secondary current. By controlling the lighting state of the LED 72, the state of the engine 10 can be confirmed in more detail.

  Specifically, by controlling the lighting state of the second LED 72 according to whether or not a current flows through the spark plug 15, the user can turn on the second LED 72 when starting the engine 10. Based on the above, it can be roughly inferred whether or not the cause of the engine 10 not starting is an abnormality related to the spark plug 15. Therefore, the startability and maintainability of the engine 10 can be improved.

  In addition, the rotation speed of the engine 10 is obtained based on the secondary current, and the lighting state of the second LED 72 is controlled according to the rotation speed of the engine 10, so that the user can drive the engine 10 while the engine 10 is driven. Can check the rotational speed of the engine 10 based on the lighting state of the second LED 72. Further, by controlling the lighting state of the second LED 72 according to whether or not the rotational speed of the engine 10 is within a predetermined rotational speed range so that the engine 10 can exhibit an output exceeding a specified value. The user can confirm whether or not the engine 10 is exhibiting an output exceeding a specified level and whether or not the rotational speed of the engine 10 is maintained substantially constant. Therefore, the output and fuel consumption of the engine 10 can be improved, and efficient work can be realized.

  In addition, the control circuit 83 that controls the lighting state of the second LED 72 is provided with means for changing the predetermined rotation speed range (switch not shown) to control between a plurality of engine tools having different specifications. The circuit 83 can be shared. Therefore, the manufacturing cost of the brush cutter 1 and other engine tools can be suppressed. Note that the above-described means for changing the predetermined rotation speed range may be configured such that the user can set a target rotation speed range in accordance with the work content or the like. Thereby, the convenience of an engine tool can be improved.

  Furthermore, according to the brush cutter 1 having the above-described configuration, the primary current generated in the primary coil 63 of the ignition device 60 is detected, and the first LED 71 constituting the light emitting unit 70 is configured based on the detected primary current. By controlling the lighting state, when the user starts the engine 10, based on the lighting state of the first LED 71, the user can roughly determine whether the cause of the engine 10 not starting is an abnormality related to the ignition device 60. Can be guessed. Therefore, the startability and maintainability of the engine 10 can be further improved. The first LED 71 can also be used to adjust the gap between the permanent magnet 62 fixed to the magnet rotor 61 and the primary coil 63 in the manufacturing process of the ignition device 60.

  Further, by operating the first and second LEDs 71 and 72 with the electric power generated by the ignition device 60, it is not necessary to separately provide a power source for energizing the light emitting unit 70. Therefore, the size and the manufacturing cost of the brush cutter 1 are eliminated. Can be suppressed.

(Modification)
The present invention is not limited to the above-described embodiments, and various modifications within the scope described in the claims are also included in the technical scope of the present invention.

  For example, the lighting circuit 80 of the embodiment inputs the primary current detection signal P1 and the secondary current detection signal P2 from the primary current detection circuit 81 and the secondary current detection circuit 82 to the control circuit 83 configured by a microprocessor. In addition, the lighting state of the first LED 71 and the second LED 72 is controlled according to the result of comparing the primary current and the secondary current with a predetermined threshold. For example, the first LED 71 and the second LED 72 are connected to the primary coil 63 and the secondary coil 64 without using a microprocessor or the like, and the primary current and the secondary current are You may be comprised so that it may light-emit by electricity supply. In this way, the state of the engine 10 can be confirmed with a cheaper and simpler configuration without providing an electronic component such as a microprocessor and its power supply. In this case, as a method for confirming the state of the engine 10, substantially the same determination criteria as in the above-described embodiment can be used. For example, when the first LED 71 connected so that the primary current flows is not lit, it can be inferred that the gap between the magnet rotor 61 and the primary coil 63 is inappropriate. Also, for example, when the first LED 71 is lit but the second LED 72 connected so that the secondary current flows is not lit, the stop switch 34 is operating or the ignition device 60 It can be inferred that there is an abnormality somewhere. Further, for example, when both the first LED 71 and the second LED 72 are lit, it can be inferred that there is an abnormality related to the fuel or the spark plug 15.

  In addition, for example, the light emitting unit 70 of the embodiment includes the first and second LEDs 71 and 72. However, the light emitting unit of the present invention is not limited to this, and can emit light by energization or the like. The configuration itself is arbitrary. For example, you may make it switch a lighting state according to the driving | running state of an engine using three or more LED. For example, you may be comprised from the single or several variable color light emitting element (RGB-LED etc.). In addition, the control circuit 83 of the embodiment controls the lighting state of the first and second LEDs 71 and 72 to be off, blinking, or lighting, but the control circuit of the present invention is not limited thereto. For example, the light emission color of a variable color light emitting element (RGB-LED or the like) may be controlled as a lighting state.

  For example, when it is considered rare that an abnormality occurs in the ignition device 60, the primary current detection circuit 81 and the first LED 71 may be omitted. Further, for example, when it is necessary to check whether or not a current has flowed through the spark plug 15, but it is considered unnecessary to check the rotational speed of the engine 10, the second LED 72 detects the secondary current detection signal. The control circuit 83 may be configured to light up in response to P2. Thereby, the control circuit of the present invention can be further simplified.

  In the above embodiment, the control circuit 83 is configured from a processor and a switch circuit. However, the circuit configuration itself is arbitrary as long as the same function can be realized. For example, the control circuit 83 may be configured with a dedicated logic circuit. It can also be configured with an analog circuit. Furthermore, the value of the primary current to be compared with the threshold value is the value immediately before the interruption, and the value of the secondary current to be compared with the threshold value is the peak value. However, the present invention is not limited to these values. Alternatively, the rising of current may be detected, and the current value after a predetermined time may be used as a comparison target. Furthermore, the effective value may be a comparison target. Further, the rotational speed of the engine 10 may be obtained based on the primary current as well as the secondary current, and is not limited to the method of measuring the current cycle, but counts the number of times the current is generated within the unit time. You may obtain | require by methods, such as doing.

  The present invention is not limited to the brush cutter illustrated in the embodiment, and can be applied to, for example, a hedge trimmer, a chain saw, and other various engine tools.

  In addition, the material, shape, quantity, arrangement, and the like of each component can be appropriately changed as long as the object of the present invention can be achieved.

DESCRIPTION OF SYMBOLS 1 Brush cutter 10 Engine 15 Spark plug 20 Operation rod 30 Handles 31a and 31b Grip part 32 Throttle lever 33 Safety lever 34 Stop switch 40 Gear case 50 Cutting blade (working tool)
60 Ignition Device 61 Magnet Rotor 62 Permanent Magnet 63 Primary Coil 64 Secondary Coil 65 Iron Core 70 Light Emitting Unit 71 First LED
72 Second LED
80 lighting circuit 81 primary current detection circuit 82 secondary current detection circuit (plug current detection circuit)
83 Control circuit

Claims (12)

An engine having a spark plug, and an ignition device that applies a voltage to the spark plug to discharge it;
A working tool that operates by receiving the power of the engine;
A light emitting portion provided so as to be visible from the outside,
The ignition device is
A rotor that rotates under the power of the engine;
A permanent magnet fixed to the outer periphery of the rotor;
A primary coil disposed opposite to the outer peripheral portion of the rotor and generating a primary current by electromagnetic induction with the permanent magnet;
A secondary coil that generates a secondary voltage by a mutual induction action with the primary coil and applies the secondary voltage to the spark plug.
The light emitting unit changes its lighting state according to the current flowing through the primary coil.
An engine tool characterized by that. A primary current detection circuit that detects a level of a current flowing through the primary coil and outputs a primary current detection signal;
A control circuit that controls a lighting state of the light emitting unit based on the primary current detection signal;
The engine tool according to claim 1. The light emitting unit changes a lighting state according to a current flowing through the primary coil and a current flowing through the spark plug.
The engine tool according to claim 2. A plug current detection circuit for detecting a level of current flowing through the spark plug and outputting a plug current detection signal;
The control circuit controls a lighting state of the light emitting unit based on the primary current detection signal and the plug current detection signal.
The engine tool according to claim 3. The light emitting unit changes a lighting state according to a current flowing through the primary coil and a current flowing through the spark plug.
The engine tool according to claim 1. A plug current detection circuit for detecting a level of a current flowing through the spark plug and outputting a plug current detection signal;
A control circuit that controls a lighting state of the light emitting unit based on the plug current detection signal;
The engine tool according to claim 5. The control circuit controls a lighting state of the light emitting unit according to whether or not a current flows through the spark plug;
The engine tool according to claim 4 or 6, wherein the engine tool is provided. The control circuit obtains the rotational speed of the engine based on the primary current detection signal, and controls the lighting state of the light emitting unit according to the rotational speed of the engine.
The engine tool according to any one of claims 2, 3, 4, and 7. The control circuit obtains the engine speed based on the plug current detection signal, and controls the lighting state of the light emitting unit according to the engine speed.
The engine tool according to any one of claims 4, 6, and 7. The control circuit compares the rotational speed of the engine with a predetermined rotational speed range, and controls the lighting state of the light emitting unit according to whether or not the rotational speed of the engine is in the predetermined rotational speed range. ,
The engine tool according to claim 8 or 9, wherein The control circuit includes means for changing the predetermined rotation speed range.
The engine tool according to claim 10. The light emitting unit is operated by electric power supplied from the ignition device.
The engine tool according to any one of claims 1 to 11, wherein:

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