JPH01107644A - Permanent magnet generator for engine - Google Patents

Abstract

PURPOSE:To obtain one ignition signal per rotation of a crankshaft and a large generation capacity with a simple and low-cost constitution, by causing an ignition coil to cross the flux of only one magnet and a magneto coil to cross the flux of all magnets. CONSTITUTION:The fitting positions of a magneto coil 23 and an ignition coil 24 are caused to deviate from each other in the axial direction of a crankshaft 3, and said magneto coil 23 is fitted at a high position and said ignition coil 24, at a low position. The magneto coil 23 cooperates with magnets 14, 15 to have a double-pole generating function. The ignition coil 24 cooperates with said magnet 14 to have the function of generating an ignition signal once during one rotation of said crankshaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnet generator attached to a flywheel of an engine.

For example, in general-purpose engines used as a power source for lawnmowers, etc., there is one in which a magnet generator ff1l is constructed using a flywheel fixed to one end of a crankshaft. - As an example, such a magnet generator is shown in Japanese Utility Model Publication No. 50-14093, but in this magnet generator,
Four magnets are arranged at equal intervals on the inner peripheral wall of the flywheel, and a magnetic pole piece is arranged on the surface of each magnet. On the other hand, a generator coil for ignition power supply, a signal coil (ignition coil) for generating an ignition signal for discharging a capacitor charged by the output of the generator coil, and a signal coil for lighting are provided in a portion surrounded by the inner circumferential wall of the flywheel. Alternatively, a power generating coil for charging the battery is fixedly provided to the engine case.

Each of the above-mentioned coils generates an output in cooperation with the field of each magnet that rotates with the flywheel, so it is desirable for the generator coil to have a large number of magnets in order to increase its output. However, in this case, the signal output from the signal coil occurs twice or more during one revolution of the crankshaft, which is undesirable because unnecessary fire occurs in the ignition system. Therefore, various attempts have been made to generate one ignition signal per revolution of the crankshaft.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to enable an ignition coil to generate one ignition signal per revolution of the crankshaft with a simpler and cheaper structure than the conventional one.

. Therefore, in the present invention, a plurality of magnets are arranged in the circumferential direction on the peripheral wall of a flywheel attached to the crankshaft, and an ignition coil is provided opposite to the peripheral wall of the flywheel. and a power generation coil arranged and fixed, the ignition coil and the power generation coil are arranged offset from each other in the axial direction of the crankshaft, and one of the plurality of magnets The ignition coil is arranged to be shifted from the other magnets toward the ignition coil in the axial direction, and the ignition coil cooperates with only the one magnet, but the power generation coil cooperates with all the magnets. do it like this.

According to the present invention, the power generation coil intersects the magnetic fluxes of all the magnets provided on the flywheel one after another during one revolution of the flywheel, that is, the crankshaft, so that a large power generation capacity can be obtained.

However, since the ignition coil only intersects the magnetic flux of only one magnet, which is installed axially offset from the other magnets, one ignition signal per revolution of the crankshaft is sent to the ignition coil. It is sent from the coil to the ignition system to ignite without waste. Moreover, such an effect can be obtained by an extremely simple means of displacing the ignition coil and the 1 fl magnet in the axial direction.

Tue-51 Hereinafter, the present invention will be described with reference to illustrated embodiments.

FIG. 1 shows an engine 2 equipped with a magnet generator iii according to the present invention.
FIG. The engine 2 is a general-purpose engine used as a power source for a lawnmower, for example, and has a crankshaft 3 oriented vertically, and a lawnmower or the like is connected to its lower end 3a.

4 is a crankcase, 5 is a cylinder, 6 is a cylinder head, 7 is a cylinder head cover, 8 is a piston, and 9 is a camshaft.

The upper end of the crankshaft 3 rotatably penetrates the crankcase 4 and protrudes upward, and a flywheel 10 is fixed to the tip. A cooling fan 11 is attached to the upper surface of the flywheel 10, and a recoil starter 12 is disposed above the cooling fan 11, and the recoil starter 12 rotates the crankshaft 3 and starts the engine 2. . A cover 13 is provided to cover these parts 44101it and 12. The cover 13 is provided with a suitable intake port, and when the engine is running, outside air is drawn into the cover 13 through the intake port by the cooling fan 11, flows downward around the flywheel 10, and cools the engine body. It has become.

Next, a magnet generator 1, which is an embodiment of the present invention, will be described with reference to FIGS. 1 to 3. Magnets 14.15 and magnetic pole pieces 16.11 are respectively attached by screws 18.19 to diametrically opposed positions on the outer surface of the peripheral wall 10a of the flywheel 1G.

The flywheel peripheral wall 10a has a magnet 1 as shown in FIG.
The magnets 14.15 are housed in these recesses 20.20, and the outer peripheral surface of the magnetic pole piece 16.17 is in contact with the outer peripheral surface of the peripheral wall 10a. They form almost the same circumference. Iron cores 21 and 22 are respectively disposed near the outer surface of the peripheral wall 10a and diametrically opposed to each other.
A power generation coil 23 and an ignition coil 24 are arranged, and these coils 23 and 24 are attached to bolts 27 and 28 on a pedestal 25 and 26 that protrude upward from the engine body.
has been fixed through. In this way the magnet 14.1
5 and a stator having coils 23 and 24. The output power from the power generation coil 23 is used for lighting or battery charging, and the output power from the ignition coil 24 is used for lighting or battery charging. The electric power is sent as an ignition signal to the switching element of the non-contact ignition device.

By the way, as can be seen from FIG. 1, the installation positions of the power generation coil 23 and the ignition coil 24 are shifted from each other in the axial direction of the crankshaft 3, with the power generation coil 23 located at a higher position and the ignition coil 24 mounted at a higher position. is installed in a low position.

Further, the mounting positions of the magnets 14 and 15 are also shifted from each other, with the magnet 14 being mounted at a high position and the magnet 15 being mounted at a low position. Therefore, the magnet 15 is connected to the ignition coil 2.
4 and the iron core 21 of the power generating coil 23, and the magnet 14 is installed at a position higher than the iron core 22 and corresponding only to the iron core 21. As a result, the crankshaft and therefore the flywheel 10
As shown in FIG. 1 during rotation, when the magnet 14 passes the power generation coil 23 side and the magnet 15 passes the ignition coil 24 side, the magnetic flux of the magnet 14 crosses the power generation coil 23 and the magnet 15 Since the magnetic flux of crosses the ignition coil 24,
Electric power is generated in both the power generation coil 23 and the ignition coil 24. However, when the flywheel 10 rotates 180 degrees from the state shown in FIG. 1 and the magnet 14 comes to the ignition coil 24 side and the magnet 15 comes to the power generation coil 23 side as shown in FIG. Since the magnetic flux does not intersect with the ignition coil 24, no electric power is generated in the ignition coil 24. On the other hand, since the magnetic flux of the magnet 15 intersects with the power generation coil 23, electric power is generated in the power generation coil 23.

In this way, the power generation coil 23 cooperates with the magnets 14 and 15 to have a two-pole power generation function, so that sufficient power generation capacity can be obtained for lighting or battery charging. On the other hand, electric power is generated in the ignition coil 24 once during one rotation of the crankshaft 3, and this electric power is sent to the ignition device as an ignition signal, so that efficient ignition suitable for engine operation is performed.

In the above embodiment, the peripheral wall 10a of the flywheel 10
Although two magnets 15 and 16 are attached to the magnet, the number of magnets may be two or more, and in this way, the power generation capacity of the power generation coil 23 can be further increased. Needless to say, in this case as well, only one magnet cooperates with the ignition coil 24.

1 As described above, in the present invention, a plurality of magnets are arranged circumferentially on the peripheral wall of the flywheel attached to the crankshaft, and an ignition coil is provided facing the peripheral wall of the flywheel. and a power generation coil arranged and fixed, the ignition coil and the power generation coil are arranged offset from each other in the axial direction of the crankshaft, and one of the plurality of magnets The ignition coil is arranged to be shifted in the axial direction from the other magnets toward the ignition coil, and the ignition coil cooperates with only the one magnet, but the power generation coil cooperates with all the magnets. As a result, it is possible to obtain a magnet generator for an engine that has sufficient power generation capacity for lighting or battery charging, can generate one ignition signal per revolution of the crankshaft, and is simple in structure and inexpensive. It will be done.

Figure 1 is a vertical sectional view of an engine equipped with a magnet generator according to the present invention, Figure 2 is a partial sectional view taken along the line ■-■ in Figure 1, and Figure 3 is a FIG. 2 is a partial view of FIG. 1 showing a state in which the wheel is in a different rotational position from FIG. 1;

1... Magnet generator, 2... Engine, 3... Crankshaft, 4... Crank case, 5... Cylinder,
6... Cylinder head, 7... Cylinder head cover, 8... Piston, 9... Camshaft, 10...
...Flywheel, 11...Cooling fan, 12...
・Recoil starter, 13...Cover, 14.15・
...Magnet, 16.11...Magnetic pole piece, 18.19...
Screw, 20... Recessed part, 21.22... Iron core, 23
... Coil for power generation, 24... Coil for ignition, 25.
26...Pedestal, 21.28...Bolt.

Claims (1)

[Claims] An engine comprising a plurality of magnets arranged circumferentially on the circumferential wall of a flywheel attached to a crankshaft, and an ignition coil and a power generation coil arranged and fixed opposite to the circumferential wall of the flywheel. In the magnet generator, the ignition coil and the power generation coil are arranged offset from each other in the axial direction of the crankshaft, and one of the plurality of magnets is arranged so that the ignition coil and the power generation coil are arranged so as to be offset from each other in the axial direction of the crankshaft. A magnet generator for an engine, wherein the ignition coil cooperates with only one magnet, while the power generation coil cooperates with all magnets.