JP3879587B2 - Flywheel magnet generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flywheel magnet generator, and more particularly to a flywheel magnet generator used in an internal combustion engine.
[0002]
[Prior art]
As a generator used in an internal combustion engine, a flywheel magnet generator having an ignition unit on the stator side is widely used. This type of magnet generator is configured as shown in FIGS. 3 and 4, for example. FIG. 3 is a front view of a conventional flywheel magnet generator, and FIG. 4 is a cross-sectional view taken along line BB of FIG.
[0003]
In these drawings, reference numeral 1 denotes a flywheel which is attached to a rotating shaft of an internal combustion engine (not shown) and is driven to rotate by the internal combustion engine. A permanent magnet is provided in a groove provided in the peripheral wall portion 1a of the flywheel. 2 is attached. A large number of blower blades 1c are formed on the outer surface of the bottom wall portion 1b of the flywheel 1 along the peripheral wall portion 1a. A boss 1e is formed in the center of the bottom wall portion of the flywheel 1, and this boss 1e is attached to a rotating shaft of an internal combustion engine (not shown).
[0004]
Reference numeral 5 denotes a stator iron core attached to a fixed member such as an engine case. The stator iron core has a pair of magnetic pole portions 5a and 5b arranged at intervals in the circumferential direction of the flywheel 1. The pair of magnetic pole portions 5 a and 5 b are opposed to the outer peripheral surface of the peripheral wall portion 1 a of the flywheel 1 and the permanent magnet 2.
[0005]
An ignition unit 6 is attached to the stator core 5. The ignition unit 6 includes an ignition coil 6a having a primary coil 6a1 and a secondary coil 6a2, an electronic component (not shown) that forms at least a part of an ignition device for an internal combustion engine together with the ignition coil, an ignition coil 6a and an electronic It is comprised by the exterior part 6c which covers components. The exterior part 6c is usually made of a mold layer of an insulating resin.
[0006]
Recently, in order to purify exhaust gas and to save fuel consumption, control of ignition timing has become complicated. Therefore, as the ignition unit 6, there are many digital control systems using a microcomputer. It has come to be used. For this reason, electronic components arranged in the exterior of the ignition unit 6 often include a microcomputer that is vulnerable to heat in addition to a switch element that controls the primary current of the ignition coil.
[0007]
In this type of ignition unit, heat is generated from the ignition coil 6a and electronic components such as a switch element that controls the primary current of the ignition coil in accordance with the ignition operation, so that the temperature of the unit rises. Therefore, in order to protect the electronic components, it is necessary to cool the ignition unit 6, and for this purpose, the blower blades 1c, 1c,... Are provided on the bottom wall portion 1b of the flywheel.
[0008]
[Problems to be solved by the invention]
3 and 4, when the flywheel 1 rotates in the direction of the arrow shown in FIG. 3 as the engine rotates, the flywheels 1 c, 1 c,. A flow of cooling air sent to the outside is generated. As shown by the arrow W ′ in FIG. 4, the cooling air flows outward in the outer diameter direction along the outer surface of the bottom wall of the flywheel, but most of the cooling air does not directly touch the ignition unit 6. Since the ignition unit 6 is flowed by grazing, there is a problem that it is difficult to cool the ignition unit 6 effectively.
[0009]
In particular, in the case where an electronic component constituting the ignition unit 6 includes a microcomputer that is weak against heat, it is required to keep the temperature of the ignition unit below a limit value lower than the conventional one. Flywheel magnet generators have had difficulty meeting such requirements.
[0010]
It is an object of the present invention to provide a flywheel magnet generator that can increase the cooling effect of an ignition unit by increasing the amount of cooling air that directly touches the ignition unit.
[0011]
[Means for Solving the Problems]
The magnet generator according to the present invention has a substantially cup-like shape having a peripheral wall portion and a bottom wall portion, and a large number of blower blades arranged along the peripheral wall portion are formed on the outer surface of the bottom wall portion to rotate the internal combustion engine. A flywheel mounted on a shaft and driven to rotate by the internal combustion engine, a permanent magnet mounted in a groove formed on the outer peripheral side of the peripheral wall portion of the flywheel, and arranged at intervals in the circumferential direction of the flywheel A stator iron core having a pair of magnetic pole parts that are opposed to the outer peripheral surface of the flywheel and the permanent magnet, an ignition coil wound around the stator iron core, and an internal combustion engine together with the ignition coil An ignition unit having an electronic component constituting at least a part of the ignition device and an exterior part covering the ignition coil and the electronic component and fixed to the stator iron core is provided.
[0012]
In the present invention, the flywheel has an opening in the axial direction that is open on the outer surface side of the bottom wall portion of the flywheel between two adjacent blower blades among a large number of blower blades, and an outer peripheral surface of the peripheral wall portion. At least one recess having a radial opening is provided on the outer surface side of the bottom wall. The recess is provided such that the radial opening thereof faces at least a part of the magnetic pole portion of the stator core.
[0013]
As described above, if the depressions opened in the bottom wall of the flywheel are provided between adjacent blower blades and the outer peripheral surface of the peripheral wall of the flywheel, the inside of the depression is negative when the flywheel rotates. Because of the pressure, the flow of cooling air generated by the blower blades is drawn into the recess. The cooling air drawn into the recess is drawn toward the bottom of the recess (near the center of the ignition unit) and sent out to the ignition unit due to the centrifugal force generated by the rotation of the flywheel. The amount of wind that is blown directly on the air increases. Therefore, the ignition unit can be effectively cooled, and even when it is required to keep the temperature of the ignition unit low, as in the case where a microcomputer is provided in the ignition unit, the request is met. I can respond.
[0014]
Further, as described above, if the recess is provided so that the radial opening thereof faces at least a part of the magnetic pole portion of the stator core, the amount of cooling air blown directly on the stator core increases, and the cooling of the stator core is increased. Therefore, the temperature difference between the ignition unit and the stator iron core can be increased. Therefore, heat conduction from the ignition unit to the stator core can be improved, and a synergistic effect between heat exchange performed between the outer surface of the ignition unit and the cooling air and heat radiation performed from the ignition unit through the stator core. The ignition unit can be cooled more effectively.
[0015]
Each of the large number of blower blades is usually formed in an arcuate shape that protrudes rearward in the rotational direction of the flywheel. In this case, it is preferable to form the inner surface of the dent facing the rotation direction of the flywheel into a shape curved in an arc along the blower blades.
[0016]
Providing the recesses in this way allows the flow of cooling air flowing along the recesses to be generated smoothly, so that the amount of cooling air blown to the ignition unit can be increased .
[0017]
In order to enhance the cooling effect by increasing the amount of cooling air blown to the ignition unit, it is preferable to provide a plurality of the depressions with a gap in the circumferential direction of the flywheel.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention is shown in FIGS. In these drawings, reference numeral 11 denotes a flywheel that is attached to a rotating shaft of an internal combustion engine (not shown) and is rotationally driven by the internal combustion engine in the direction of arrow CL in FIG. This flywheel is made of a ferromagnetic material such as iron, and is formed in a substantially cup shape having a peripheral wall portion 11a and a bottom wall portion 11b. A large number of blower blades 11c are formed on the outer surface of the bottom wall portion 11b of the flywheel along the peripheral wall portion 11a. Each blower blade 11c is formed so as to exhibit a convex arc shape on the rear side in the rotation direction of the flywheel, and when the flywheel 11 rotates, the diameter of the flywheel is increased by the blower blades 11c, 11c,. An air flow is generated from the inside to the outside in the direction.
[0019]
A groove 11d is formed in a part of the outer peripheral portion of the peripheral wall portion 11a of the flywheel 11, and the permanent magnet 12 is disposed at the bottom of the groove. A magnetic pole piece 13 is disposed on the magnetic pole surface outside the magnet 12, and the magnetic pole piece 13 and the magnet 12 are fastened to the peripheral wall portion 11a of the flywheel 11 by screws (not shown). The flywheel 11, the permanent magnet 12, and the magnetic pole piece 13 constitute a flywheel magnet rotor 14.
[0020]
A boss 11e having a tapered hole at its center is formed at the center of the bottom wall 11b of the flywheel 11, and this boss is attached to the tip of the rotating shaft of the internal combustion engine (not shown).
[0021]
In the present invention, a portion located between two adjacent blower blades 11c, 11c of the flywheel 11 is recessed toward the opening side of the flywheel, thereby providing a bottom between the two adjacent blower blades 11c, 11c. A recess 11f having an axial opening 11f1 opened on the outer surface side of the wall 11b and a radial opening 11f2 opened on the outer circumferential surface of the peripheral wall 11a is formed. At least one recess 11f may be provided, but in the illustrated example, three recesses 11f are provided at intervals of 120 °.
[0022]
A stator 17 including a stator core 15 and an ignition unit 16 attached to the stator core is disposed on the side of the outer peripheral side of the flywheel 11.
[0023]
The stator core 15 is formed in a U shape by an I-shaped coil winding portion 15C and leg portions 15A and 15B having rear end portions coupled to both ends of the coil winding portion, and the tips of the leg portions 15A and 15B are formed. Magnetic pole portions 15a and 15b are formed respectively.
[0024]
The ignition unit 16 attached to the stator core 15 includes an ignition coil 16a composed of a primary coil 16a1 and a secondary coil 16a2 wound around a coil winding portion 15C of the stator core, and an ignition device for an internal combustion engine together with the ignition coil. The electronic component (not shown) which comprises at least one part and the exterior part 16c provided so that the ignition coil 16a and an electronic component might be coat | covered are comprised. In the illustrated example, the exterior portion 16c is made of a mold layer formed of an insulating resin, and an electronic component that constitutes an ignition device together with an ignition coil is formed in a rectangular protrusion 16c1 formed on the upper portion of the exterior portion 16c. Has been placed. This electronic component includes a microcomputer chip for controlling the ignition timing. At the end of the exterior portion 16c of the ignition unit 16, a high-voltage cord connection portion 16c2 having a high-voltage terminal connected to the non-grounded terminal of the secondary coil of the ignition coil is formed and connected to the high-voltage cord connection portion 16c2. The high-voltage cord 20 connects the high-voltage terminal to a spark plug attached to a cylinder of an internal combustion engine (not shown).
[0025]
In the illustrated example, lead wires 21 and 22 connected to a pulser for detecting crank angle information used for controlling the ignition timing and a sensor for detecting control conditions are drawn out from the end of the exterior portion 16c of the ignition unit 16. ing.
[0026]
In the illustrated stator 17, the magnetic pole portions 15a and 15b at both ends of the stator core 15 are arranged in a state of being spaced apart in the circumferential direction of the flywheel, and the magnetic pole portions 15a and 5b are permanently connected to the outer peripheral surface of the flywheel 11. It arrange | positions so that it may oppose with the magnet 12 through a gap, and it is fixed to the attaching part provided in fixed members, such as the case of an internal combustion engine which is not shown in figure, by appropriate fixing means, such as a screw.
[0027]
In this embodiment, as shown in FIG. 1, the inner surface of the recess 11f facing the rotation direction of the flywheel 11 exhibits an arcuate shape along the arc-shaped blower blades 11c and 11c on both sides of the recess 11f. It is formed as follows. As shown in FIG. 2, when each recess passes through the position of the magnetic pole portions 15a and 15b of the stator core in the process of rotating the flywheel, the radial opening 11f2 of each recess 11f becomes the stator core 15. The depth of the recess 11f is set so as to face at least a part of each of the magnetic pole portions 15a and 15b.
[0028]
In the magnet generator shown in FIGS. 1 and 2, when the flywheel 11 rotates, a voltage is induced in the primary coil of the ignition coil 16 a of the ignition unit 16. The electronic components that constitute the ignition unit constitute a control circuit that controls the primary current of the ignition coil 16a using the voltage induced in the primary coil as the power supply voltage. This control circuit is, for example, a current interruption type circuit that induces a high voltage in the secondary coil of the ignition coil by interrupting the current flowing through the primary coil of the ignition coil at the ignition timing. Since this high voltage is applied to the ignition plug attached to the cylinder of the internal combustion engine through the high-voltage cord 20, a spark discharge is generated in the ignition plug, and the engine is ignited.
[0029]
As described above, when the depression 11f opened between the adjacent blower blades and the outer peripheral surface of the peripheral wall portion of the flywheel is provided in the bottom wall portion of the flywheel 11, the depression 11f when the flywheel rotates. Since the inside becomes a negative pressure, as indicated by an arrow W in FIG. 2, the flow of the cooling air generated by the blower blades 11c, 11c,... Is drawn into the recess 11f. The cooling air drawn into the recess is drawn toward the bottom of the recess (near the center of the ignition unit 17), and is sent out to the ignition unit 16 due to the centrifugal force generated as the flywheel 11 rotates. The amount of wind directly blown to the ignition unit 16 increases. Therefore, the ignition unit 16 can be effectively cooled, and even when it is required to keep the temperature of the ignition unit low, such as when a microcomputer is provided in the ignition unit, the request It became possible to respond to.
[0030]
In particular, when the recess 11f is provided so that the radial opening 11f2 of the recess 11f faces at least a part of the magnetic pole portion of the stator core 15 as in the present embodiment, the cooling air blown directly onto the stator core. And the cooling of the stator core 15 is promoted, so that the temperature difference between the ignition unit 16 and the stator core 15 can be increased. Therefore, heat conduction from the ignition unit 16 to the stator core 15 can be improved, heat exchange performed between the outer surface of the ignition unit 16 and the cooling air, and heat dissipation performed from the ignition unit 16 through the stator core 15. As a result, the ignition unit 16 can be cooled more effectively.
[0031]
Moreover, when the inner surface of the recess 11f facing the rotation direction of the flywheel 11 is formed in a curved shape along the arc-shaped blower blade as in this embodiment, the blower blade 11c generates the recess 11f. Since the flow of the cooling air flowing along the air can be made smooth, the amount of the cooling air blown to the ignition unit can be increased to enhance the cooling effect.
[0032]
In the above example, three depressions 11f are provided. However, in the present invention, the number of depressions 11f is arbitrary, and in some cases, magnetic flux of magnetic flux flowing from the permanent magnet 12 through the iron core 15 and the peripheral wall portion of the flywheel 11 is obtained. Only one depression 11f may be provided at a position that does not affect the road.
[0033]
In the case where a plurality of recesses 11f are provided, the number of recesses 11f and the positions where the recesses 11f are provided so as not to affect the magnetic path of the magnetic flux flowing from the permanent magnet 12 through the iron core 15 and the peripheral wall portion of the flywheel 11. Is preferably set.
[0034]
【The invention's effect】
As described above, according to the present invention, the bottom wall of the flywheel is provided with the recesses opened between the adjacent blower blades and the outer peripheral surface of the peripheral wall of the flywheel, and the flywheel rotates. Since the inside of the depression is set to a negative pressure, the flow of the cooling air generated by the blower blades can be drawn toward the bottom of the depression (close to the center of the ignition unit) and sent to the ignition unit. Accordingly, it is possible to effectively cool the ignition unit by increasing the amount of wind directly blown to the ignition unit, and the temperature of the ignition unit is as in the case where a microcomputer is provided in the ignition unit. Even when it is required to keep the value low, there is an advantage that the request can be met.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a flywheel magnet generator according to the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a front view showing a configuration of a conventional flywheel magnet generator.
4 is a cross-sectional view taken along line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Flywheel, 11a ... Peripheral wall part of flywheel, 11b ... Bottom wall part of flywheel, 11c ... Blower, 11d ... Groove, 11f ... Depression, 11f1 ... Axial direction opening part, 11f2 ... Radial direction opening part, 12 DESCRIPTION OF SYMBOLS Permanent magnet, 13 ... Magnetic pole piece, 14 ... Flywheel magnet rotor, 15 ... Stator iron core, 16 ... Ignition unit, 17 ... Stator.

Claims (3)

A magnet generator for use in an internal combustion engine,
A large number of blower blades having a substantially cup-like shape having a peripheral wall portion and a bottom wall portion and arranged along the peripheral wall portion are formed on the outer surface of the bottom wall portion and attached to the rotating shaft of the internal combustion engine. A flywheel that is rotationally driven by an internal combustion engine;
A permanent magnet mounted in a groove formed on the outer peripheral side of the peripheral wall of the flywheel;
A stator iron core having a pair of magnetic pole portions arranged at intervals in the circumferential direction of the flywheel, the pair of magnetic pole portions being opposed to the outer peripheral surface of the flywheel and the permanent magnet;
The stator core includes an ignition coil wound around the stator core, an electronic component that forms at least a part of an ignition device for an internal combustion engine together with the ignition coil, and an exterior portion that covers the ignition coil and the electronic component. A fixed ignition unit;
With
An axial opening that opens on the outer surface side of the bottom wall portion between two adjacent air blowing blades among a plurality of air blowing blades provided on the bottom wall portion of the flywheel and an opening on the outer peripheral surface of the peripheral wall portion At least one indentation having a radial opening formed in the bottom wall ,
The flywheel magnet generator in which the depth of the recess is set so that at least a part of the magnetic pole part of the iron core faces a part of the radial opening of the recess . Each of the large number of blower blades is formed in an arc shape that is convex to the rear side in the rotational direction of the flywheel,
2. The flywheel magnet generator according to claim 1, wherein an inner surface of the recess facing the rotation direction of the flywheel is formed in an arcuate shape along the blower blade. 3. The flywheel magnet generator according to claim 1 or 2, wherein a plurality of the recesses are provided at intervals in a circumferential direction of the flywheel.

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