JP2006258090A - Battery pack for driving electric motor of compact engine starting device, engine starting device driven by battery pack and manual working machine equipped with starting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery mounted on a working machine ultimately miniaturized and lightened, capable of driving a compact electric motor for starting a compact engine smoothly and safely for a long period of time. <P>SOLUTION: The battery is packed. A lithium based secondary battery composed of two cells of entire discharge capacity being 500-2,000 mAh and charging voltage per one cell being 3.0-4.2 V, a drive circuit of the electric motor 131 connected to the battery and built in the pack and various kinds of electronic circuits such as a battery protection circuit are built in the battery pack 16. Maximum discharge current of the battery is high rate of 10-60 A. The protection circuit includes an exclusive over discharge suppression circuit A installed at least in the electric motor drive circuit and automatically stopping drive of the electric motor 131 after time required for engine start elapses. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an ultra-compact electric motor for starting a small engine mounted on various working machines such as a portable brush cutter, a chainsaw, a lawn mower, a backpack-type brush cutter, a power spreader, an engine blower, a duster, and a hedge trimmer. The present invention relates to a battery pack having a small and large output battery for driving a motor, an engine starter driven by the pack, and a manual work machine equipped with the starter.

  Most of the engine starters that start small air-cooled gasoline engines installed in hand-operated machines such as brush cutters and chainsaws, which are currently in common use, are recoil-type drive units and engine crankshafts. A driven unit connected via a connecting means such as a clutch, and the drive unit and the driven unit are arranged to buffer the driving force of the drive unit and elastically store power between the driven unit and the driven unit. And a buffering / accumulating part having a spring. The recoil type drive unit is arranged between a recoil reel on which a recoil rope is wound, and a recoil reel and a casing, and the inner and outer ends thereof are fixed to the recoil reel and the casing, respectively. For springs. By pulling out the recoil rope by hand, the recoil reel is rotated in one direction, and at the same time, the recoil spring is wound up to store the spring force. In this state, when the hand is released from the recoil rope, the recoil spring Is released and the recoil rope is automatically rewound onto the recoil reel.

  However, the above-described recoil drive unit requires a pulling operation for pulling out the recoil rope every time the engine is started. This pulling operation of the recoil rope usually needs to be quickly and greatly pulled out, so that the engine cannot be operated by a single pulling operation for people with weak power, elderly people, or in a small work space. There are also many. Thus, many proposals have been made to make it easier to start the engine by pulling the recoil rope, and although it has been put into practical use, the complexity of the pulling operation itself remains. On the other hand, the development of small electric motors and batteries in recent years has been remarkable, and even though they have been extremely miniaturized, they have come to have a large capacity. Recently, in order to avoid the complicated operability of the recoil-type starter described above, helped by these circumstances, the electric engine starter that can easily start the engine by a single switch is reviewed and developed. Has been desired.

  This type of electric small engine starting device is, for example, an engine starting device disclosed in Japanese Utility Model Laid-Open No. 63-110672 (Patent Document 1). According to this starting device, a DC motor powered by a battery, a mainspring spring that is driven and wound up by a worm gear fixed to an output shaft of the motor, and an inner end of the mainspring spring are fixed. An output rotation shaft, an engine rotation shaft connected to the output rotation shaft via a one-way clutch, a rotation lever for stopping or releasing the rotation of the output rotation shaft, and output rotation by the lever An interlocking electrical switch that is turned on only when the rotation stop of the shaft is released, and a motor that is driven when the electrical switch is turned off, and continues to rotate even when the rotational speed of the motor exceeds the set rotational speed. When the spring is wound up and the spring speed is lowered from the set rotational speed at the end of the spring spring, the power supply is cut off and the motor stops rotating. And a armature current control circuit to.

  Further, for example, according to the starter device disclosed in Japanese Patent Application Laid-Open No. 2002-285940 (Patent Document 2), the starter device includes a buffering / accumulating means in the middle of the power transmission system between the driving unit and the driven unit. The drive unit is an electric motor as a drive source, and a speed reduction mechanism is constituted by a worm connected and fixed to an output rotation shaft of the electric motor and a worm wheel provided on the outer periphery of the mainspring barrel. The configuration described above is not substantially different from that of Patent Document 1. The drive side is provided with a recoil type drive unit separately from the electric motor, and the recoil type drive unit is a rope reel wound with a recoil rope and rotated by pulling the recoil rope. A recoil spring for reversing the rope reel to wind the recoil rope, and a recoil ratchet mechanism for transmitting the rotation of the rope reel to the buffering / accumulating means). The spring barrel can be rotated only in one direction by a one-way clutch. From these configurations, it can be said that the starter of Patent Document 4 is merely a combination of Patent Document 1 and a known recoil mechanism.

  Further, for example, according to Japanese Patent No. 2573340 (Patent Document 3), a battery, a DC electric motor driven by the electric power of the battery, a control device for controlling stoppage of the motor, and the power of the motor are transmitted. A high reduction ratio reduction mechanism, a spring-spring type energy storage device driven by the high reduction ratio reduction mechanism, and a power transmission device that unilaterally transmits the force of the energy storage device to the crankshaft. A housed spring spring starter is disclosed. The high reduction ratio reduction mechanism includes a first-stage planetary gear reduction device that is arranged on another axis parallel to the crankshaft and is driven by a DC electric motor, and a spring accumulation chamber of the accumulation device A drive gear provided on the output shaft of the planetary gear type reduction gear is meshed with a driven gear provided integrally with the outer periphery of the planetary gear type reduction gear, and the second reduction gear is configured.

  Further, for example, in Japanese Utility Model Laid-Open No. 2-13171 (Patent Document 4), a mainspring barrel can be rotated in one direction via a support system of a planetary gear speed reducer arranged on the opposite side to the crankshaft side of the engine. Is pivotally supported. The rotation of the spring barrel is reduced and rotated by the planetary gear reducer connected through a pair of reduction gears of a small gear and a large gear fixed to the output shaft of a DC electric motor disposed in the housing. . The one-way rotation at this time is performed by the engagement between the ratchet claw and the tooth portion provided on the outer peripheral portion of the mainspring barrel. A starting ratchet wheel and a starting ratchet pawl are arranged on the crankshaft side of the mainspring barrel, and the ratchet wheel is rotatable when the engagement is released. A starter ratchet wheel is assembled to the starting ratchet wheel, and this starter ratchet wheel engages with a centrifugal clutch pawl provided on a crankshaft.

  A ratchet wheel is integrally formed on the outer periphery of the mainspring barrel, and a small-diameter ratchet wheel meshes with the upper end of the mainspring barrel. The rotating shaft fixed to the small-diameter ratchet wheel can be rotated from the outside using a manual crank. During normal engine operation, the manual crank is not inserted and the small-diameter ratchet wheel runs idle. If the engine fails to start and the mainspring is to be re-wound, a manual crank is inserted into the rotary shaft of the small-diameter ratchet wheel, and the mainspring barrel is rotated to store power in the mainspring. When the engine is started, the start ratchet wheel is operated to release the energy stored in the mainspring spring, thereby rotating the starter ratchet wheel and cranking and starting the engine.

  The batteries used for the power source of the engine starting device disclosed in the above Patent Documents 1 to 4 are so-called nickel cadmium batteries and nickel hydride batteries, and the storage locations of these batteries are designated as described above. Not. However, usually, as described in Patent Documents 3 and 4, it is often arranged inside the starter, otherwise the conventional battery has a large total volume, so a dedicated part in the vicinity of the starter It is often attached to. Further, if the electric power necessary for the electric motor that is arranged between the engine and the starting electric motor, for example, to wind up the spring of the energy storage device, is to be obtained from the aforementioned battery, a large number of NiCd batteries and NiMH batteries are naturally used. A battery called is required. Therefore, there is a limit even if the starter is reduced in size and weight.

  By the way, according to the engine starting device of Patent Document 1, the mainspring barrel is rotated in one direction by meshing the worm gear directly connected to the electric motor and the worm wheel formed on the outer periphery of the mainspring barrel. Although the barrel does not reverse, in the power transmission mechanism by meshing the worm gear and worm wheel, the output shaft direction of the electric motor and the rotation drive shaft of the mainspring barrel are arranged orthogonally, The efficiency is low (about 60%) and there is an unavoidable limit even if it is downsized. Further, in the engine starting device according to Patent Document 1, when the battery runs out or the electric motor fails, the engine starting device itself cannot be operated.

  Further, in Patent Document 2, since the mainspring barrel is manually driven in an emergency by a recoil type drive mechanism, the entire apparatus further incorporates an electric motor and its speed reduction mechanism in a conventional recoil type engine starter. In addition, since the speed reduction mechanism is composed of the worm and the worm wheel of the mainspring barrel, the electric motor shaft and the spindle of the mainspring barrel must be arranged orthogonally, and it is difficult to downsize the entire apparatus.

  On the other hand, according to Patent Document 3, a high reduction ratio reduction mechanism is arranged between the electric motor and the mainspring barrel, and the motor capacity and battery capacity are 1/10 or 1/6 or less of the cell starter system, respectively. Although it is said that the practicality is not lost even if a storage battery is installed, the reduction ratio by the high reduction ratio reduction mechanism is set to 1/250 to 1/300, which is extremely large. For this reason, it takes a long time to rotate the mainspring barrel to obtain a required power accumulation in the mainspring spring. Therefore, in this engine starting device, an automatic winding control device for the spiral spring is installed, and the control circuit of the control device automatically performs the accumulating operation of the accumulating spring for each starting operation, and the timer or the spring spring By detecting the winding of the motor, the power supply to the motor is stopped to reduce the waiting time at the time of restart. This complicates the entire apparatus and inevitably increases the price.

  According to the above-mentioned Patent Document 4, when the electric motor stops operating, the mainspring barrel is rotated through the small-diameter ratchet wheel by operating the manual crank, and the mainspring spring is rewinded to the mainspring spring. After accumulating and removing the manual crank, the start ratchet is operated to release the energy accumulated in the spring and rotate the starter ratchet wheel to start the engine. However, during the engine rotation, the small-diameter ratchet wheel rotates idly. Further, since the shafts of the electric motor, the mainspring barrel, the small-diameter ratchet wheel, and the ratchet pawl are arranged in parallel to each other, the engine starter can be prevented from being downsized.

  In order to solve such a conventional problem, the present applicant, for example, by Japanese Patent Application No. 2004-232139 (Patent Document 5), eliminates unnecessary equipment and achieves the ultimate miniaturization based on a rational design. An electric engine starter that can reduce the weight and weight and can start the engine manually in an emergency has been proposed.

  The basic configuration includes a small electric motor driven by a battery, a power storage unit in which the power of the small electric motor is transmitted in a power storage direction via a high speed reduction mechanism, and the power storage of the power storage unit An engine starter including a power transmission unit for transmitting to a crankshaft of the engine, wherein the power storage unit includes a spring and a rotation support member that supports one end of the spring, and the spring includes a spring or a coil A spring can be used. In the case of a spring, the rotary support member is constituted by a spring barrel, and in the case of a coil spring, a normal gear can be used.

A first gear is formed on the support member, a second gear is fixed to the output shaft of the high speed reduction mechanism, and the first and second gears mesh with each other, and Usually, the rotation of the energy storage unit or the power transmission unit is allowed to rotate in the energy storage release direction, but rotation prevention means is provided to prevent rotation in the energy storage release direction when the electric motor is not operating. A rotation operation mechanism is provided on the output shaft of the high speed reduction mechanism, which can be engaged with and disengaged from the shaft end of the output shaft and can manually rotate the output shaft. The high speed reduction mechanism is a planetary gear type speed reduction mechanism, the rotational axes of the power storage unit and the power transmission unit are arranged on the same axis as the crankshaft, and the rotary shafts of the small electric motor and the high speed reduction mechanism are Spur gears are used for the first and second gears, which are arranged in parallel with the crankshaft.
Japanese Utility Model Publication No. 63-110672 JP 2002-285940 A Japanese Patent No. 2573340 Japanese Utility Model Publication No. 2-13171 Japanese Patent Application No. 2004-232139

  As described above, the above-mentioned mechanical problems of the small engine starting devices disclosed in the above-mentioned Patent Documents 1 to 4 have been solved by the above-mentioned Patent Document 5, but on the other hand, the downsized engine starting mechanism is reduced in size. There remains a problem of how to enable smooth, reliable and safe driving with an integrated battery. That is, in order to reduce the overall size of the work machine and reduce the weight, not only the engine is started, but also the battery itself that controls the engine ignition circuit, the fuel supply control circuit, and the like is required. It is important to achieve a small size and light weight while providing a sufficient discharge capacity.

By the way, not only the engine starter disclosed in the above-mentioned patent documents 1 to 4, but the power source of the starter of the work machine equipped with this kind of small engine is heavily used for all of the nickel-cadmium batteries and nickel-metal hydride batteries as described above. Has been. These small batteries are typically 1.2V per unit, and usually require at least 7.2V to drive a small electric motor for starting, so theoretically using six batteries It should be possible to drive the small electric motor. However, in order to realize an ideal engine start, a larger number is required, and the volume is too large to be accommodated in the switch box arranged on the handle of the work machine, and it is inevitably necessary for the starter or other dedicated use. In order to achieve a small size and light weight, it would be beyond the allowable range. Even if an alkaline battery or an oxyride battery (1.5 V) is used, the internal impedance (internal resistance) is large, and at least six batteries are required to obtain the output voltage.
Accordingly, an object of the present invention is to provide a high-performance battery pack that is applied to a small engine starting device of a work machine, is small and light, enables high output, and at the same time ensures safety.

  The above-described object is achieved by a small electric motor that is a basic configuration of the present invention, a power storage unit in which power of the small electric motor is transmitted in a power storage direction via a high speed reduction mechanism, and the power storage unit is connected to the engine. A battery pack for driving a small electric motor of a small engine starter mounted on a work machine having a power transmission unit for transmitting to a crankshaft, and in the battery pack, a lithium secondary battery and the same battery In addition to the normal self-discharge prevention circuit and overcurrent prevention circuit connected to the circuit, there are built-in protection circuits consisting of electronic circuits such as an overcharge prevention circuit, an overdischarge suppression circuit, and a start switch relay circuit. Effectively achieved by the featured electric motor drive battery pack.

The overdischarge suppression circuit is a timed circuit, and is preferably set to automatically stop after 5 to 15 seconds have elapsed for the continuous discharge time required to drive the electric motor for starting the engine. More preferably, the continuous discharge time by the overdischarge suppression circuit is set to 7 to 12 seconds. The lithium secondary battery in the battery pack has a total discharge capacity of 500 to 2000 mAh and a charge voltage per cell of 3.0 to 4.2V. Further, the lithium secondary battery in the battery pack has a maximum discharge current set to 10 to 60 A, and automatically stops discharge after a predetermined continuous discharge time corresponding to the set maximum discharge current. Good. The battery pack may have a volume of 2.5 × 10 ⁴ to 1.0 × 10 ⁵ mm ³ . Furthermore, it is preferable that the overcharge prevention circuit cuts off charging when a charging voltage per cell of the cells exceeds 4.0 to 4.4V. The protection circuit detects the internal temperature of the battery pack, and the electronic switch is automatically opened when the detected temperature rises to a predetermined temperature regardless of the set discharge time range of the overdischarge suppression circuit. It is desirable to further include a circuit.

A small engine starter mounted on a manual work machine includes a small electric motor driven by the lithium secondary battery of the battery pack, and the power of the small electric motor is driven in the direction of power accumulation through a high speed reduction mechanism. A built-in power storage unit and a power transmission unit that transmits the stored power of the power storage unit to the crankshaft of the engine are incorporated. Here, it is preferable that the battery pack is integrally disposed in a switch box of a handle portion of the manual work machine. The small electric motor has a housing volume of 4.0 × 10 ^{3 to} 8.0 × 10 ⁴ mm ³ , a stationary current of 1 to 100 A, and a stationary torque of 10 to 500 mNm. . Furthermore, a carburetor with an auto choke that is operated by a solenoid valve driven by the lithium secondary battery may be provided, and the drive current of the solenoid valve may be 200 to 800 mA.

  Further, in the manual work machine equipped with the engine starting device, the engine has a generator for charging the lithium secondary battery, the generator is a magnet disposed in the rotating part of the engine, It is preferable to include a power generation coil disposed on the facing portion of the magnet. It is preferable that the rotating part of the engine is a fan fixed to a crankshaft.

Effect

  According to the present invention, in order to keep the components integrated with the starter to the minimum necessary, the battery can be miniaturized most in spite of the difference in performance from other dry cells. A certain lithium secondary battery is adopted. In the present invention, the overall capacity as a power source is at least for driving an electric motor for starting an engine, a battery protection circuit, driving a solenoid valve of a carburetor with an auto choke described later, and for an electronic circuit. Therefore, it is only necessary to satisfy the necessary discharge capacity.

  According to a preferred embodiment, the required discharge capacity is 1000 mAh. The output voltage of one cell is 3.8V. If two cells are used, the output voltage is 7.6V. Even if the discharge current for the electric motor for starting the engine is set to 10 to 60A, the other is driven. As a power source, the capacity is sufficient. As described above, the lithium secondary battery of the present invention, which serves as a power source for a small engine starter mounted on a work machine, has a sufficient capacity for starting the engine and has a very small volume. For example, the starter Even if it is built in, it is possible to achieve downsizing that is not comparable to the conventional one.

  Moreover, the performance of the lithium secondary battery itself is as low as 1/30 of the conventional dry battery as described above, and the weight energy density and volumetric energy density are 2 to 3 times that of the conventional dry battery. Therefore, it is optimal for light weight and downsizing. Furthermore, especially for lithium-ion ion secondary batteries, they do not contain environmentally hazardous materials, and they do not have any memory effect like a nickel-cadmium battery and have little self-discharge. Capacity is maintained. In the present invention, since the safety is ensured by various protection circuits and a high output is obtained, it is desirable to be a manganese-based lithium ion secondary battery.

  Furthermore, in order to drive the electric motor for starting the engine with a predetermined capacity and torque, in addition to reducing the size and weight of the battery, it is necessary to increase the rate of the battery itself more than before. By increasing this rate, a stable discharge with a high current value can be sustained for a long time. Usually, in this type of lithium-based secondary battery, the rate value called high rate is 3-5C, but in the present invention, a lithium-based battery having a rate value of 26C or more that enables discharge of 26A or more with a discharge capacity of 1000 mAh. A secondary battery is used.

  In the present invention, as one of the battery protection circuits, a discharge time required for driving the electric motor for starting the engine is set, and after the set time has elapsed, the electric motor is automatically driven. It includes a dedicated overdischarge suppression circuit that stops automatically. By incorporating this overdischarge suppression circuit, overheating of the electric motor drive circuit with the largest power consumption can be prevented, and at the same time, the battery life can be prolonged. This overdischarge suppression circuit not only prevents overheating of the electric motor drive circuit, but also suppresses overheating of the entire battery, especially elements disposed in various circuits built in the battery. Burnout and ignition can be prevented. A preferred embodiment of this overdischarge suppression circuit is conventionally known in which a time required from the start of the electric motor to the engine start is set in advance, and the drive of the electric motor is automatically stopped after the time has elapsed. A so-called timed circuit and electronic switch may be incorporated in the circuit.

  An appropriate time range required from starting the electric motor to starting the engine is 5 to 15 seconds. To further prevent overheating of the drive circuit of the electric motor, it is preferable to provide an overheat prevention circuit. In this overheat prevention circuit, the temperature inside the battery is detected, and as a matter of course, the electronic switch is closed when the temperature rise exceeds 10 ° C. even within the time range. In addition to the above-described function, this overdischarge suppression circuit stops discharge within the above time range even when the electric motor itself is in a stall state where rotation stops even if current is supplied for some reason. Therefore, the electric motor is not seized and durability is improved.

Incidentally, the volume of the battery pack employed in the present invention is 5.5 × 10 ^{4 to} 1.0 × 10 ⁵ mm ³ and the weight is about 80 g, and it is extremely small and lightweight. Since it is extremely small and light, it can be directly incorporated in the case of the engine starting device, but it can be accommodated in a switch box of the handle portion of the working machine, for example, outside the case. When housed in the switch box, there is an effect of vibration resistance and heat resistance by being far from the engine, and safety is ensured by being away from the gasoline tank, and the battery can be easily replaced. Further, according to the above-mentioned Patent Document 5, coupled with the elimination of the recoil drive mechanism, the external dimensions of the starting device can be extremely reduced, and the weight thereof can be greatly reduced.

  That is, the battery, the start switch, and the like are not provided in the starter, but are arranged in the switch box of the handle portion of the work machine. On the other hand, for example, the first axis of the rotation support shaft of the engine starting device and the power transmission unit and the second axis of the rotation shaft of the electric motor and the high speed reduction mechanism are arranged in parallel, and the first and second axes. A rational design is adopted in which they are arranged on the same plane. In this case, considering the weight balance of the starter, a plane including the second axis and the first axis of the engine is a vertical plane. With this design, the dimensions of the starting device in the axial direction can be shortened, the space for arranging these components can be minimized, and weight balance can be easily achieved. Of course, a significant reduction in weight is realized as the number of devices is reduced.

  In addition, when a planetary gear type reduction mechanism is used as the high reduction mechanism, the mechanism can be easily downsized, and the reduction ratio of the lithium secondary battery having high output as described above is also used as the battery. At the same time, when a small electric motor that can be expected to have high torque is adopted, it is not as large as 1/250 to 1/300 as in the above-mentioned Patent Document 2, and it is possible to cope with even 1/50 at most. Thus, the engine start time, that is, the time until the energy storage unit obtains the required energy storage can be greatly shortened.

If the battery pack has an electronic circuit such as an overcharge prevention circuit or an overcurrent prevention circuit in addition to the overdischarge suppression circuit as its protection circuit, overheating of the battery due to overcharging is prevented, and Prevents ignition of peripheral devices due to electric current. Incidentally, the small electric motor for starting is stored by, for example, a speed reduction mechanism including a planetary gear group regardless of the housing volume being as small as 4.0 × 10 ^{3 to} 8.0 × 10 ⁴ mm ^3. It has sufficient capacity and torque to enable winding of the power spring. Also, if a carburetor with an auto choke is installed, the electric motor for starting is driven when the engine is below a predetermined temperature, and at the same time, the solenoid valve is energized to change the air-fuel ratio and contain fuel. Increase the amount to an appropriate value.

  If a generator is installed in the engine of a work machine equipped with an engine starter having the above-mentioned configuration and characteristics, the battery will not rise and the required discharge can always be performed at the start of the engine for smooth engine start. Connected. However, when the lithium secondary battery employed in the present invention is charged by the generator, when the charging voltage per cell exceeds 4.0 to 4.4 V, the resistance in the battery increases rapidly, The capacity recovery rate tends to drop significantly. Therefore, a dedicated overcharge prevention circuit is provided in the battery pack to prevent overcharge and improve the battery life. If the rotating part of the engine provided with the magnet for the generator is a part of the peripheral surface of a fan fixed to the crankshaft that always rotates as the engine starts, power generation is started from the time of starting the engine. In addition, since only the coil is installed, it is not necessary to increase the size of the conventional engine case itself.

Hereinafter, representative embodiments of the present invention will be specifically described with reference to the accompanying drawings.
FIG. 1 is a starting circuit diagram of a hybrid engine starter for a small engine mounted on a work machine according to the present invention. FIG. 2 is a specific example of the small engine and a battery housed in a switch box attached to the handle of the work machine. It is a perspective view which shows various wiring.
As shown in FIG. 2, the small engine 10 according to this embodiment includes a cylinder 11, a spark plug 12 provided in the combustion chamber of the cylinder 11, a piston (not shown), a crankshaft (not shown), A fan 13 fixed to the shaft and a centrifugal clutch (not shown) arranged on the back side (the front side in FIG. 2) of the fan 13 are provided.

  As shown in FIGS. 1 and 3, the small engine 10 according to the present embodiment is charged with a battery, which will be described later, which is a power source for driving the electric motor 131 for starting the engine in addition to the above-described components. A generator 14 and a carburetor 15 with an auto choke that adjusts the air-fuel ratio when the engine is started are provided. The generator 14 includes a first magnet 13a fixed on a part of the peripheral surface of the fan 13 and a charging coil 14a provided on the rotating surface of the magnet 13a. A solenoid valve (not shown) is mounted on the carburetor 15 with an auto choke. The solenoid valve is not energized to the choke coil 15b when the engine is stopped and is in a closed state, but current flows from the battery pack 16 to the choke coil 15b simultaneously with the start switch operation at the time of engine start, and the valve is opened. Operate in the direction. The air-fuel ratio is controlled by the opening / closing amount of the solenoid valve. According to this embodiment, a temperature sensor (not shown) is disposed in the vicinity of the explosion chamber of the engine, and the opening degree of the valve is controlled based on the detected temperature of the sensor.

  On the other hand, in the present invention, various electric or electronic devices arranged in the engine 10 including the electric motor 131 are driven or operated by a single battery. In the present invention, it is important to use a lithium secondary battery as the battery. Although this lithium secondary battery is small and light as described above, the output voltage of a single small cell (cell) is, for example, slightly more than three times that of a conventional nickel-cadmium battery. Even if shallow charge / discharge is repeated as in such a cell starter system, there is no so-called memory effect in which the capacity decreases, so that the engine can be started smoothly even after being left for a long period of time. In addition, the lithium secondary battery has a small self-discharge amount of 1/5 as compared with the nickel-cadmium battery and is overwhelmingly small, and the internal resistance is particularly low as compared with other dry batteries including the nickel-cadmium battery. In particular, it is desirable to employ a manganese-based lithium ion battery that is highly safe and capable of high output discharge.

In this embodiment, two lithium secondary batteries are used as a set. In this embodiment, the output voltage of one cell is about 4.2 V, the discharge capacity is 1000 mAh, and the rate value is as extremely high as 26C. Moreover, the volume of the packed battery pack 16 is only 2.5 × 10 ⁴ mm ³ and the weight is only about 70 g. On the other hand, the small electric motor 131 used in the present embodiment is also extremely small with a housing volume of 2.0 × 10 ⁴ mm ^3, and its stationary current is 1 to 100 A and the stationary torque is 100 mNm, covering a wide range. . In order to drive the starting electric motor 131, a power source of about 7.6 to 8.0 V or more is required. Therefore, two cells are used as the engine starting battery as described above. For example, if a voltage of about 7.0 V or more is obtained using a 1.2 V NiCd battery, at least six batteries are required. The battery according to the present embodiment is formed into a single package containing a lithium secondary battery composed of two cells and various electronic circuits. The electronic circuit includes a later-described battery protection circuit, a battery charging circuit, and various circuits for driving the engine. The lithium secondary battery has a high rate. In this embodiment, the total discharge capacity is set to 1000 mAh, and the drive current of the starting electric motor 131 is set to 26A.

  Since the packaged battery according to the present embodiment is extremely miniaturized as described above, the battery pack 16 may be built in the case of the starting device. The switch box 17 attached to the handle of the machine is detachably accommodated. Therefore, as shown in FIG. 2, the various electrical devices of the engine 10 and the battery pack 16 are connected through a plurality of lead wires connected to the first and second connectors 19 a and 19 b of the connector 19. . FIG. 3 schematically shows a part of the connection circuit.

  1 to 3, when the start switch 20 is turned on, the electric motor 131 for start is discharged via the overdischarge suppression circuit A which is one of the battery protection circuits, and the electric motor 131 is started. . At the same time, when it is detected by a temperature sensor (not shown) that the temperature around the explosion chamber of the engine is lower than a predetermined temperature, the air / fuel ratio control circuit is activated and current is supplied to the choke coil 15b of the carburetor 15 with an auto choke. A solenoid valve (not shown) disposed in the intake passage of the carburetor 15a is opened, and fuel supplied to the small engine 10 is increased. When the periphery of the explosion chamber of the engine 10 exceeds a predetermined temperature, the current that flows through the choke coil 15b is blocked by a not-shown blocking circuit, and the solenoid valve is kept closed. At this time, the drive current of the solenoid valve is at most 200 to 800 mA. This drive current is also sent from the battery pack 16.

  The overdischarge suppression circuit A is one of the most characteristic features of the present invention, and its basic function is to have sufficient time to start the small engine 10 reliably by driving the electric motor 131. When the electric motor 131 is preset and the preset time has elapsed, the drive circuit of the electric motor 131 is automatically shut off, and the drive of the electric motor 131 is stopped. FIG. 4 shows an example of a typical timing circuit using a capacitor constituting the overdischarge suppression circuit A in the present embodiment. Of course, the present invention is not limited to this overdischarge suppression circuit, and an overdischarge suppression circuit and an overheat prevention circuit can be provided in parallel. As this overheat prevention circuit, for example, the internal temperature of the battery pack 16 is detected, and when the detected value exceeds a preset temperature, the start switch is automatically opened to cut off the discharge, or the starting electric motor The current value flowing through the motor 131 is integrated with the driving time, and the value is converted into a heat amount. When the heat amount exceeds the set value, the discharge is automatically cut off. When it exceeds, discharge is automatically cut off.

  In FIG. 4, when the start switch 20 of the electric motor 131 is turned on, a voltage V1 is generated at the point a, and the voltage V2 continues to increase while the capacitor C is charged at the point b. When the voltages V1 and V2 at this time match, a signal is issued from the AND circuit 29, the electronic switch 30 that has been closed is opened, and the drive of the electric motor 131 is stopped. The time T from the start to the stop of the electric motor 131 at this time is determined by the capacity of the capacitor C.

  In the present embodiment, the driving duration T of the electric motor 131 is set to 10 seconds. When the electric motor 131 is stalled, the start switch 20 is turned on, and a current of 26A is supplied from the battery pack 16 to the motor drive circuit, the internal circuit of the battery pack 16 is overheated, and some circuit elements are burned out. Will be destroyed. Further, when the winding temperature exceeds a certain temperature, the electric motor 131 is also burned out and cannot be smoothly rotated. 5 and 6 show the results of the experiment.

  The electric motor 131 was stalled by the battery pack in the fully charged (8.4 V) state, and a current of 26 A was passed through the electric motor 131 for 15 seconds. As a result, as shown in FIG. 5, both the voltage and current decrease with the passage of time. FIG. 6 shows fluctuations in winding temperature when a current is passed through the electric motor 131 for 12 seconds under the same conditions. Usually, in this type of electric motor, the heat resistance temperature of the insulating film covering the surface of the winding is limited to 180 ° C. As can be understood from the figure, 10 seconds after the current starts to flow, the temperature reaches 187 ° C., which exceeds the heat resistance temperature of the insulating film.

  In the present embodiment, in addition to the overdischarge suppression circuit and the overheat prevention circuit, a relay circuit that is one of the features of the present invention is built in the battery pack. FIG. 7 shows the relay circuit. The relay circuit according to the present invention plays a protective role as a start switch, and the circuit is constituted by a transistor circuit rather than an excitation type and is extremely miniaturized. When this relay circuit is not provided, for example, when a high-rate battery that instantaneously discharges a large current of 30 A as in the present invention is used, the battery directly flows to the electric motor via the start switch, and the start switch 20 As a result, the metal part of the metal is burned and melted, and the switch ON state is maintained, and the electric motor cannot be stopped.

  In the relay circuit according to the present embodiment, as shown in FIG. 7, while the start switch 20 is open, the transistor 29 has an infinite resistance and no current flows through the circuit. Is not in operation. Of course, no drive current flows through the electric motor M. Now, when the start switch is turned on, the current discharged from the battery is divided into a large current on the electric motor M side and a small current on the discharge suppression circuit A side through the transistor 30 and is conducted. At this time, the current used to the overdischarge suppression circuit A is as low as about 5 mA, and the remaining large current flows to the electric motor M. As soon as this current flows, the capacitor C of the overdischarge suppression circuit A starts charging, and when a time determined by the capacity of the capacitor C elapses, a signal is sent to a switching circuit (not shown) and the switching circuit is opened. To stop discharging the battery. In this embodiment, the discharge time is set to 5 to 10 seconds for the reason described later.

  FIG. 8 and Table 1 show the current-time-temperature characteristics in the battery circuit when the same electric motor and battery are used and the above-described various circuits are arranged and the same experiment is performed. According to the figure, it can be seen that there is a linear correlation with the same gradient between the load current and the temperature in the battery circuit as time passes. According to this embodiment, since the discharge current immediately after the start switch 20 is turned on is 26 A, the temperature rise at that time is 8.8 ° C., and the time until the rise temperature is reached is shown in FIGS. . Expected to take 8 seconds.

  On the other hand, for example, in a working machine such as a portable brush cutter, the temperature in the vicinity of the battery box under direct sunlight during summer and hot weather may be about 60 ° C., whereas the heat resistance of the battery circuit is limited to 70 ° C. . Under these constraints, if the temperature rise of the battery circuit is suppressed to 8.8 ° C., 60 ° C. + 8.8 ° C. = 68.8 ° C., which is lower than the heat resistant temperature of 70 ° C. Therefore, in this embodiment, the discharge time is set to 5 to 10 seconds. However, since this discharge time varies depending on the capacity of the electric motor, the discharge capacity of the battery pack, etc., it cannot be uniformly defined.In the present invention, the operator feels uncomfortable with the discharge time in consideration of safety. It is set to 5 to 15 seconds, which is the engine start time you don't feel.

  According to the present embodiment, the battery protection circuit built in the battery pack 16 includes a battery overcharge prevention circuit B and an unillustrated overcurrent prevention circuit in addition to the overdischarge suppression circuit A. Yes. At the same time, the battery pack 16 also includes a charging circuit (not shown) and an engine ignition circuit. Since the overcharge prevention circuit B, the charging circuit from the generator (not shown), and the ignition circuit of the engine are conventionally known circuits, detailed description thereof is omitted here. On the other hand, although not shown, the overcurrent prevention circuit is configured by providing the overcurrent prevention circuit in the middle of necessary wiring among the wiring of each circuit. Incidentally, in the present embodiment, the overcurrent prevention circuit cuts off the current with an upper limit of about 30A.

  While the engine is rotating, the generator 14 continues to generate power through the overcharge prevention circuit B, and the AC power is smoothed through a smoothing circuit (not shown) and sent to the battery pack 16. The battery pack 16 is charged. When the charging voltage at this time exceeds 4.1 V, as shown in FIG. 10, the internal resistivity of the lithium secondary battery increases rapidly and the capacity recovery rate decreases rapidly. For this reason, in the present embodiment, adjustment is made by an overcharge prevention circuit built in the battery pack so that the charging voltage is suppressed to about 8.1V.

  In another embodiment, when the working machine is not used or when the engine is stopped, the battery pack 16 is prevented from being discharged into the internal circuit, and the battery life is improved. FIG. 9 is a block diagram showing a circuit when discharge to the internal circuit of the battery pack 16 is prohibited. In this figure, among the internal circuits of the battery pack 16, the overdischarge suppression circuit A and the overcharge prevention circuit B are illustrated as typical circuit diagrams. In the figure, a right block C indicated by a virtual line indicates external wiring, and a left block D indicates internal wiring of the battery pack 16 of the present invention.

  As shown in the figure, eight external wires on the engine side are connected to the first connector 19a, and the terminals of the internal circuit exposed to the outside from the battery pack 16 are connected to the second via the eight external wires. Connected to the connector 19b, the first and second connectors 19a, 19b are detachable from each other. In the illustrated example, there are eight external wirings and eight input / output terminals of the battery pack 16. The specific wiring of the illustrated example will be described. The closed circuit formed by the input / output terminals 1, 2, 7, and 8 is necessary to avoid the self-discharge of the electric motor driving circuit and the protection circuit of the battery pack 16. The input / output terminals 3 to 6 are terminals for connecting the electric motor drive circuit including the overdischarge suppression circuit A and the filling circuit B to external wiring.

  By attaching the battery pack 16 to the switch box 17 at the time of work, all the internal circuits are electrically connected, and the battery can be driven. Now, when the battery pack 16 is removed from the switch box 17, the discharge from the battery is only the self-discharge of the battery itself, and the battery life can be prolonged.

  FIG. 10 shows an example in which all of the closed circuit and the open circuit built in the battery pack 16 are simultaneously cut off at the same time when the engine stop switch 23 is turned off regardless of whether the operation is performed or not. That is, in the figure, the four input / output terminals 1, 2, 7, and 8 can be connected and disconnected through the switches 31 and 32, and these switches 31 and 32 are connected to the engine stop switch 23. It is configured to be linked to the operation of When the engine stop switch 23 is ON, it is not connected to the spark plug 12, and the start switch 20 and the switches 31, 32 between the input / output terminals 1, 2, 7, and 8 are also open.

  Now, when the start switch 20 and the engine stop switch 23 are closed in this state, the battery 10 is discharged toward the electric motor 131 and the engine 10 is started. At the same time, the battery and the spark plug 12 are connected, and the engine 10 continues to rotate. Here, when it is necessary to stop the rotation of the engine, the engine stop switch 23 is turned off, and the KILL terminal of the coil 12a of the ignition circuit 22 is connected to the ground to stop the engine. By turning off the engine stop switch 23, the switches 31 and 32 arranged between the two sets of input / output terminals 1, 2, 7 and 8 are also disconnected at the same time. When the switches 31 and 32 are opened, all the internal circuits of the battery pack 16 are shut off for each circuit.

  FIG. 12 shows an assembly diagram of the engine starter 100 and the small engine 10 according to an embodiment of the present invention provided with the connection circuit. 12-15 is explanatory drawing which shows arrangement | positioning and structure of each component apparatus of the said engine starting apparatus 100 in the embodiment. The engine starter 100 according to the present embodiment is applied to a small air-cooled gasoline engine or the like, and the starter 100 is disposed close to the input end of the crankshaft 25 of the internal combustion engine 10.

  The engine starter 100 includes a power storage unit 110, a power transmission unit 120, and an electric drive unit 130. The power storage unit 110, the power transmission unit 120, and the electric drive unit 130 are assembled into one unit. And accommodated in a single case 140. The case 140 has a first space A that has a square shape in which the upper half accommodates the accumulator 110 and the power transmission unit 120, and a lower half that gradually narrows toward the lower end that accommodates the drive unit 130. And a second space B having an inverted triangular shape. The second space B has a halved structure of the engine side and the anti-engine side, and includes first and second case bodies 140a and 140b.

  The upper half of the first case body 140a on the engine side is a substantially rectangular window 141, and a high speed reduction mechanism 132, which will be described later, is one of the constituent members of the electric drive unit 130 at the center of the lower half. A speed-reduction mechanism insertion hole 142 for inserting and supporting is formed. Bolt insertion holes 143 for fixing the first case body 140a to the engine 10 are formed inside the four corners of the rectangular window 141, and the upper two corners and the lower two corners of the frame of the rectangular window 141 are formed. Screw holes 144 for coupling to the second case body 140b are formed at four locations below. On the other hand, a shaft portion 145 protrudes in the center of the inner wall surface of the bottom portion forming the first space A of the second case body 140b on the side opposite to the engine and extends vertically below the coaxial portion 145. A wrench insertion hole 146 that communicates with the internal space is formed in a portion of the back wall portion that forms the second space B corresponding to the center of the speed reduction mechanism fitting insertion hole 142. In addition, bolt insertion holes 147 are also formed in portions of the second case body 140b corresponding to the screw holes 144 of the first case body 140a.

  As shown in FIGS. 12 and 13, the power storage unit 110 includes a spring spring 111 and a spring barrel 112, and a spur gear 113 continuous in the circumferential direction is formed on a half of the outer peripheral surface of the spring barrel 112. Yes. A through hole 112a is formed at the center of the mainspring barrel 112, and an outer ring of a bearing-like one-way clutch 114 is tightly fitted into the through-hole 112a, and the second case body is fitted to the inner ring of the one-way clutch 114. The shaft portion 145 of 140b is press-fitted and fixed. Further, a spring spring housing space (not shown) is formed on the engine side of the mainspring barrel 112, and the outer end 111a of the spring spring 111 is fixedly fixed to a part of the peripheral wall of the spring spring housing space. An outer end fixing groove (not shown) is formed.

  According to this embodiment, the mainspring barrel 112 is allowed to rotate only in one direction with the bearing type one-way clutch 114 as described above, but instead of the one-way clutch 114, for example, as shown in FIG. A ratchet tooth 115 different from the spur gear 113 is formed on the outer peripheral surface of the mainspring barrel 112, and a ratchet claw 116 engaging with the ratchet tooth 115 is rotatably supported on a part of the second case body 140b. Even in this case, the mainspring barrel 112 can be allowed to rotate only in one direction. At this time, the ratchet pawl 116 is always urged in a direction to engage with the ratchet teeth 115 by a spring member 117 similarly attached to the second case body 140b. In this case, the mainspring barrel 112 is rotatably supported on the shaft portion 145 via a normal flat bearing 118.

  The power transmission unit 120 includes an activation pulley 121 and an engagement / disengagement member 122 that engages and disengages with the activation pulley 121, as shown in FIGS. In the center of the starting pulley 121, a loose insertion hole 121a is formed in which the shaft portion 145 protruding from the second case body 140b can be loosely inserted. The central portion of the starting pulley 121 on the non-engine side is shown in FIG. As described above, a spring spring end fixing portion 121b is formed to project toward the mainspring barrel 112 so as to surround the loose insertion hole 121a. The spring spring end fixing portion 121b is formed with an inner end fixing groove 121b 'for engaging and fixing the inner end portion 111b of the spring spring 111. A screw hole (not shown) is formed at the distal end portion of the shaft portion 145. When the assembly is completed, a set screw 148 is screwed into the screw hole, and the power storage portion 110 and the start pulley 121 are connected to the second case body. It is accommodated and fixed to 140b.

  Further, the engine-side central portion of the start pulley 121 is engaged with an engaging claw 26 that is an element of a centrifugal clutch mechanism mounted on the crankshaft 25 of the engine 10 and has a circumferential surface as shown in FIG. An engaging protrusion 121c having ratchet teeth 121d is provided. The engaging protrusion 121c is attached to the crankshaft 25 until the maximum load of the engine is exceeded while receiving the energy in the releasing direction generated when the spring barrel 112 rotates and the spring force is stored in the spring 111. When the accumulated force stored in the mainspring spring 111 exceeds the maximum load of the engine, the engine engages with the engagement claw 26 and starts rotating together. Start. When the engine rotation enters a steady state, the engagement claw 26 is disengaged from the engagement protrusion 121c of the start pulley 121 by the centrifugal force, and the engine rotation is continued.

  Further, ratchet teeth 123 are formed on the outer periphery of the start pulley 121 at a predetermined interval, and the start pulley 121 as a whole constitutes a ratchet wheel. One end 122b of the engagement / disengagement member 122 is rotatably supported by the boss portion 140a-1 of the first case body 140a, and the distal end 122a is rotated by the push button 149 to rotate the outer ratchet teeth of the start pulley 121. 123, the start pulley 121 is allowed to rotate or cannot be rotated. The distal end 122a of the engagement / disengagement member 122 is urged by a torsion spring 150 in a direction away from the ratchet teeth 123 during normal engine start, and the one end 122b is resisted against the urging of the torsion spring 150. Then, the tip 122a can be engaged with the ratchet teeth 123 for the first time by rotating. Here, the engagement / disengagement member 122 and the ratchet teeth 123 of the start pulley 121 correspond to the rotation preventing means in the present invention.

  According to the present embodiment, in order to rotate the front end 122a of the engagement / disengagement member 122 against urging, it is attached to a part of the peripheral wall portion of the first case body 140a as shown in FIGS. Further, the ball portion 149 a at the tip of the pin of the push button 149 is fitted to the tip 122 a of the engagement / disengagement member 122, and the engagement / disengagement member 122 resists the bias of the torsion spring 150 by pushing the push button 149. And rotate toward the ratchet teeth 123. By this pushing operation, the push button 149 is locked by a locking means (not shown). Next, when the push button 149 is pulled to the front side, the lock is released and the engagement / disengagement member 122 is disengaged from the ratchet teeth 123. To turn. Further, the engagement / disengagement member 122 is fixed to the peripheral wall portion of the first case body 140 a by the bias of the torsion spring 150.

  The electric drive unit 130 includes the starter electric motor 131 described above and the high speed reduction mechanism 132 coupled to the output shaft of the electric motor 131, and the high speed rotation of the electric motor 131 causes the high speed reduction mechanism 132. And is transmitted to the mainspring barrel 112. The high speed reduction mechanism 132 includes a small planetary gear mechanism 132a and a spur gear 132b fixed to the output shaft of the planetary gear mechanism 132a. Since the planetary gear mechanism 132a and the spur gear 132b are used in combination as the speed reduction mechanism 132, the input portion and the output shaft can be arranged on the same axis, and the axis is the second case body. It is possible to arrange in parallel with the shaft portion 145 protruding from the engine 140b toward the engine. Moreover, in the present embodiment, the axis of the electric drive unit 130 is disposed substantially vertically below the shaft unit 145. This is because the present invention eliminates the recoil mechanism and attaches the battery, which is conventionally arranged below the power storage unit 110 and the power transmission unit 120, to the operation handle (not shown) of the work machine, for example, outside the case 140. The switch 140 is arranged in the switch box 17 (see FIG. 3), and the electric drive unit 130 is arranged in the empty space, so that the length of the case 140 in the axial direction is shortened. The left and right width can be shortened to the minimum.

  The planetary gear mechanism 132a according to the present embodiment includes first to third internal gears 132a-1 to 132a-3, which are ring-shaped sun gears, and the planetary gear mechanism 132a is the above-described electric part housing case. 134 is accommodated and fixed together with the electric motor 131. That is, a plurality of protrusions 132a'-1 and 132a'-3 extending in parallel with the rotation shaft are provided on the outer peripheral surfaces of the first and third internal gears 132a-1 and 132a-3. In addition, on the inner circumferential surface of the electric part housing case 134, the protrusions 132a'-1, 132a'-3 extend parallel to the axis at the corresponding positions of the protrusions 132a'-1, 132a'-3, and the protrusions 132a'-1, 132a'-3 are fitted. The same number of fitting grooves 134a-1 to be worn are formed.

  In the present embodiment, the electric part housing case 134 is formed of a bottomed cylindrical body that opens on the side opposite to the engine side, and is divided into a cylindrical main body 134a and a bottom part 134b. Protrusions 134c and 134d extending in parallel with the axis project from the outer peripheral surface portion of the cylindrical main body 134a and the bottom 134b where the fitting groove 134a-1 is formed, and the protrusion 134d of the bottom 134b. Is formed with a screw hole, and a protrusion 134c of the cylindrical body 134a is formed with a bolt insertion hole. The protrusions 132a′-1 and 132a′-3 of the planetary gear mechanism 132a are fitted into the fitting grooves 134a of the electric part housing case 134 having such a configuration, and the electric motor 131 and the planetary gear mechanism 132a are fitted. Is fixed. The electric part accommodating case 134 that accommodates the electric motor 131 and the planetary gear mechanism 132a is tightly fitted and supported in the electric part close fitting hole 142 formed in the first case body 140a. At this time, the electric motor 131 and the planetary gear mechanism 132a accommodated in the electric part accommodating case 134 expose the output shaft of the planetary gear mechanism 132a to the outside and the fixing frame 135 via bolts and nuts (not shown). And fastened. Thus, the spur gear 132a is fixed to the tip of the output shaft of the planetary gear mechanism 132a housed and fixed in the electric part housing case 134.

  According to the present embodiment, the reduction ratio between the small electric motor 131 and the mainspring barrel 112 is set to 1/50. The reduction ratio between the spur gear 132b fixed to the output shaft of the planetary gear mechanism 132a and the spur gear 113 formed on the outer periphery of the mainspring barrel 112 is set to 1 / 2.5. Therefore, the reduction ratio of the planetary gear mechanism 132a is set to 1/20. An engagement portion 133a that can be engaged with, for example, a hexagon wrench (not shown) is formed at the output shaft 133 of the planetary gear mechanism 132a, that is, the end of the support shaft of the spur gear 132b, and the second case is formed on the axis. The center of the wrench insertion hole 146 formed in the back wall portion of the body 140b is positioned.

  Now, in order to house and assemble the constituent members according to the present embodiment configured as described above in the case 140, the shaft portion 145 of the second case body 140a is penetrated through the mainspring barrel 112 in which the one-way clutch 114 is closely fitted. This is done by press-fitting and fixing to the holes 112a. At this time, the outer end of the mainspring spring 111 is fixedly engaged with an outer end fixing groove (not shown) formed in the peripheral wall of the mainspring spring accommodating space of the mainspring barrel 112. Next, the inner end portion of the mainspring spring 111 is fixedly engaged with an inner end fixing groove 121b ′ of the mainspring spring end fixing portion 121b formed at the center of the starting pulley 121. Subsequently, after the shaft portion 145 of the second case body 140b is loosely inserted into the loose insertion hole 121a that penetrates the spring spring end fixing portion 121b, the screw is fixed to the screw hole at the distal end portion of the shaft portion 145. 147 is screwed in, and the assembly of the mainspring barrel 1 and the starting pulley 121 into the second case body 140b is completed.

  On the other hand, when the electric drive unit 130 is assembled to the case 140, the DC electric motor 131 and the planetary gear mechanism 132a and the spur gear 132b of the reduction mechanism 132 are assembled in advance to form an assembly. The protrusions 132a'-1 and 132a'-3 formed on the outer peripheral surface of the planetary gear mechanism 132a of this assembly are fitted into the inner surface of the speed reduction mechanism fitting insertion hole 142 formed in the first case body 140a. The groove 142a is fitted and fixedly supported. Thereafter, the bolt 28 is fastened to the crankcase 29 through four bolt insertion holes 143 formed at the four corners of the rectangular window portion 141 of the first case body 140a. At the same time, the electric motor 131 is positioned and fixed at a predetermined position of the crankcase 29.

  Thus, after fixing the first case body 140a to the crankcase 29 together with the electric drive unit 130, the bolt 28 is screwed into the screw hole 144 of the first case body 140a via the screw insertion hole 147 of the second case body 140b. As described above, the second case body 140b in which the power storage unit 110 and the power transmission unit 120 are assembled is fixedly integrated with the first case body 140a. When the second case body 140b is fixed to the first case body 140a, the rotating other end 122c of the engagement / disengagement member 122 is engaged with the outer peripheral ratchet teeth 123 of the start pulley 121. When the engagement / disengagement member 122 is pivotally supported by the boss portion 140 a-1, unless the end portion 122 b of the engagement / disengagement member 122 is operated by the torsion spring 150, the front end 122 c is not engaged with the ratchet teeth 123. Energize.

  The electric engine starter 100 according to the present embodiment having the above-described configuration is, as described above, the case 140 excludes the conventional recoil-type drive unit and battery, and the spring of the energy storage unit 110. The mainspring barrel 112 containing the spring 111 and the start pulley 121 of the power transmission unit 120 are supported by the same shaft portion 145, and are electrically driven on the axis parallel to the coaxial portion 145 and vertically below the shaft portion 145. The planetary gear mechanism 132a and the spur gear 132b which comprise the electric motor 131 which is the part 130, and the deceleration mechanism 132 are only arranged. In addition, since the electric motor 131 and the planetary gear mechanism 132a are also very small, they can be accommodated in the case 140 very compactly. As a result, the case 140 itself, that is, the entire starting device is extremely miniaturized. .

  In order to start the engine 10 by the starter 100, for example, when a start switch 131 provided in the handle portion is turned on, the electric motor 131 is started, and a high speed reduction mechanism comprising a planetary gear mechanism 132a and a spur gear 132b. By 132, the mainspring barrel 112 is rotated in the accumulating direction of the mainspring spring 111 at a reduction ratio of 1/50. At this time, the engagement / disengagement member 122 is not engaged with the activation pulley 121 of the power transmission unit 120, and the engagement claw 26 attached to the crankshaft 25 is engaged with the engagement protrusion 121c of the activation pulley 121. It ’s just that.

  Now, in the process in which the mainspring barrel 112 is rotated and accumulating force is applied to the mainspring spring 111, a force to release the accumulating force acts on the mainspring spring 111, and the crankshaft 25 is rotated via the engaging claw 26. While the engine 10 starts to be compressed, the crankshaft 25 cannot be rotated any more while the stored force of the mainspring spring 111 is not sufficiently stored to exceed the maximum load in the compression stroke. When the mainspring spring 111 has accumulated force exceeding the maximum load in the compression stroke of the engine 10, the force in the direction of releasing the accumulated force of the mainspring spring 111 is won, and the starting pulley 121 is connected to the crankshaft 25 via the engaging claw 26. And the engine 10 is ignited and the operation is started. It takes only 1 to 5 seconds from the start of the electric motor 131 to the start of the engine 10. In this embodiment, when the discharge time to the electric motor exceeds 10 seconds to start the engine 10, the overdischarge suppression circuit A which is one of the protection circuits inside the battery pack 16 is activated. Shut off the discharge from the battery. When the rotation of the engine 10 enters a steady state, the engagement between the engagement claw 26 and the engagement protrusion 121c of the start pulley 121 is released by the centrifugal force, and the rotation of the engine is continued. The time required for starting the engine 10 at this time is small because the speed reduction ratio of the speed reduction mechanism is set to be relatively small, such as 1/50, in combination with the battery of the present invention. There is almost no difference from the start time.

  As is clear from the above description, according to the electric engine starter of the present invention, since the lithium secondary battery is adopted as the battery, the quality of the battery is high, while the reliability is high and the output is small. Weight reduction can be achieved. Furthermore, this battery pack with a built-in battery is not housed in the case of the engine starter, but can be placed in a switch box attached to the handle of the work machine outside the device. In combination with the adoption of a motor and a high speed reduction mechanism and the elimination of the recoil drive mechanism from the starter, the starter itself can be made extremely compact. Furthermore, in the present invention, a protection circuit such as an overdischarge suppression circuit, an overheat prevention circuit, or a relay circuit connected to the overdischarge suppression circuit is arranged in the electric motor drive circuit built in the battery pack. The internal circuit of the battery pack and the electric motor will not burn out due to overheating. In addition, since the overcharge prevention circuit B is arranged in the battery pack, the battery can be charged using the engine rotation, and at the same time, if equipped with a carburetor with an auto choke, it is always in a cold region. Enables smooth engine start. Furthermore, the components of the engine starter have been rationally arranged to the ultimate to achieve further miniaturization. Moreover, like the conventional electric engine starting device, when the electric motor cannot be driven, the engine can be started easily and safely by manual operation.

It is a wiring diagram between the small engine starting device of this invention and a battery pack. It is a three-dimensional view schematically showing a specific wiring example based on the connection circuit. It is a circuit diagram between the small engine starting device which is embodiment of this invention, and a battery pack. It is a circuit diagram which shows the typical example of the overcharge suppression circuit which is one of the protection circuits provided in the battery pack of this invention. It is a voltage-current characteristic view at the time of motor stall. It is a temperature characteristic figure which shows an example of the temperature characteristic of the winding line at the time of a motor stall. It is a circuit diagram which shows an example of the relay circuit which is one of the protection circuits provided in the battery pack of this invention. It is a current-time-temperature characteristic figure in the internal circuit of a battery pack. It is a shut-off mechanism figure of the internal circuit of a battery pack. It is the interruption | blocking mechanism figure which shows the modification. It is a characteristic view which shows the capacity | capacitance maintenance factor and internal resistance increase rate of a lithium secondary battery. It is an assembly drawing of the small engine starting device carrying the battery pack of the present invention. It is a disassembled perspective view which expands and shows the accumulator part, the power transmission part, and one part electric drive part of the engine starting device. It is the front view seen from the back side when an engagement / disengagement means exists in the said power transmission part. It is the front view seen from the back side when an engagement / disengagement means exists in the said power transmission part in a non-engagement state. It is the perspective view which looked at the drive wheel of a power transmission part from the front side. It is a disassembled perspective view which expands and shows a principal part in the modification of the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 11 Cylinder 12 Spark plug 12a Ignition coil 13 Fan 13a, 13b Magnet 14 Generator 14a Charging coil 15 Carburetor with auto choke 15a Carburetor 15b Choke coil 16 Battery 17 Switch box 19a, 19b First and second connector 20 Starter switch 21 Relay 22 Ignition circuit 23 Engine stop switch 24 Centrifugal clutch 24a Engagement claw 25 Crankshaft 26 Engagement claw 27 Crankcase 28 Bolt 29 Crankcase 30 Transistor 100 Engine starter 110 Power storage unit 111 Spring spring 111a Outer end 111b Inner end Portion 112 Spring barrel 112a Through hole 113 Outer spur gear 114 One-way clutch 115 Ratchet tooth 116 Ratchet claw 117 Spring 1 8 Plain bearing 120 Power transmission part 121 Starting pulley 121a Shaft free insertion hole 121b Spring spring end fixing part 121b 'Inner end fixing groove 121c Engaging protrusion 122 Engaging / disengaging member 122a Tip 122b One end 123 Ratchet teeth 130 Electric starting part 131 Small electric motor 132 High speed reduction mechanism 132a Planetary gear mechanism 132b Spur gears 132a-1 to 132a-3 First to third internal gears
132a'-1, 132a'-3 ridge 133 output shaft 133a engaging portion 134 electric portion accommodating case 134a-1 fitting groove 134a cylindrical portion main body 134b bottom portion 134c, 134d ridge 135 fixed frame 140 case 140a (on the engine side) ) First case body 140b (opposite engine side) second case body 141 Window portion 142 Electric portion close fitting holes 143, 147 Bolt insertion hole 144 Screw hole 145 Shaft portion 146 Wrench insertion hole 149 Push button 149a Ball portion 150 Torsion spring A Overdischarge suppression circuit B Overcharge prevention circuit C Capacitor

Claims (14)

A small electric motor, a power storage unit in which the power of the small electric motor is transmitted in the direction of power storage via a high speed reduction mechanism, and a power transmission unit that transmits the power storage unit to the crankshaft of the engine A battery pack for driving a small electric motor of a small engine starting device mounted on a work machine,
In the battery pack, in addition to a lithium secondary battery composed of at least two cells and a normal self-discharge prevention circuit and an overcurrent prevention circuit connected to the battery, an overcharge prevention circuit and an overdischarge suppression A battery pack for driving an electric motor comprising a protection circuit comprising an electronic circuit such as a circuit and a relay circuit for a start switch.   The overdischarge suppression circuit is a timed circuit, and is set to automatically stop after 5 to 15 seconds have elapsed for a continuous discharge time required to drive the electric motor for starting the engine. Item 6. The battery pack according to item 1.   The battery according to claim 1, wherein the lithium secondary battery in the battery pack has a total discharge capacity of 500 to 2000 mAh and a charge voltage per cell of 3.0 to 4.2V. pack.   The lithium secondary battery in the battery pack has a maximum discharge current set to 10 to 60 A, and discharge is automatically stopped after a predetermined continuous discharge time corresponding to the set maximum discharge current. The battery pack according to claim 1. The battery pack according to claim 1, wherein the battery pack has a volume of 2.5 × 10 ^{4 to} 1.0 × 10 ⁵ mm ³ .   2. The battery pack according to claim 1, wherein the overcharge prevention circuit cuts off charging when a charge voltage per cell of the cells exceeds 4.0 to 4.4V. The protection circuit detects the internal temperature of the battery pack, and the electronic switch is automatically opened when the detected temperature rises to a predetermined temperature regardless of the set discharge time range of the overdischarge suppression circuit. The battery pack according to claim 1, further comprising a circuit.   A small electric motor driven by the lithium secondary battery of the battery pack according to any one of claims 1 to 7, and an accumulator in which power of the small electric motor is driven and transmitted in a power accumulation direction via a high speed reduction mechanism. A starter for a small engine mounted on a manual work machine, wherein a power unit and a power transmission unit that transmits the stored energy of the energy storage unit to a crankshaft of the engine are incorporated.   The starter according to claim 8, wherein the battery pack is integrally disposed in a switch box of a handle portion of the manual work machine. The small electric motor has a housing volume of 4.0 × 10 ^{3 to} 8.0 × 10 ⁴ mm ³ , a stationary current of 1 to 100 A, and a stationary torque of 10 to 500 mNm. The starting device as described.   The starter according to claim 8, further comprising a carburetor with an auto choke operated by a solenoid valve driven by the lithium secondary battery, wherein the solenoid valve has a drive current of 200 to 800 mA.   A manual work machine comprising the starter according to any one of claims 8 to 11. The engine has a generator for charging the lithium secondary battery;
13. The manual work machine according to claim 12, wherein the power generator includes a magnet disposed in a rotating portion of the engine and a power generating coil disposed in a facing portion of the magnet.   The manual work machine according to claim 13, wherein the rotating portion of the engine is a fan fixed to a crankshaft.

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