JPS5947541B2 - ignition signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition signal generator, and particularly to an ignition signal generator suitable for use in an ignition device for an internal combustion engine.

The ignition signal generator, which determines the ignition timing of the ignition system for internal combustion engines, generates a pulse voltage that is precisely synchronized with a predetermined rotation angle of the rotor in order to operate the ignition system normally, and is unnecessary at other rotation angles. It is desirable not to generate any voltage.

However, in conventional ignition signal generators, the magnet that excites the pulsar coil provided in the stator is provided only on a part of the outer circumferential surface of the rotor boss. The noise magnetic flux flows through the pulsar core and the pulsar magnet to the rotor boss,
It has the disadvantage that unnecessary voltage is likely to be generated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ignition signal generator that eliminates the above-described drawbacks of the prior art and does not generate unnecessary voltage except at a predetermined rotation angle of the rotor.

In the present invention, a magnet for exciting a pulsar coil is divided into a plurality of adjacent magnets with different polarities and formed into a ring shape, and the magnets are disposed in a ring shape on the outer periphery of a rotor boss portion, thereby achieving a predetermined rotation of the rotor. At angles other than the rotation angle, the iron core of the pulsar coil is placed in a magnetically saturated state to prevent unnecessary voltage from being generated.

The invention will now be explained with reference to the illustrated embodiments.

In FIGS. 1 and 2, a stepped cylindrical magnet holder 3 made of a magnetic material is fitted onto the outer periphery of the boss portion 2 of the rotor 1, which is formed into a bowl shape, by press-fitting its large diameter portion 3A. There is.

As shown in FIG. 2, on the outer periphery of the small diameter portion 3B of the magnet holder 3, there are two semicircular arc-shaped magnets 4A and 4B having different polarities.
are arranged and fixed in a ring shape.

These magnets 4A, 4B are arranged with a slight distance G from the stepped portion 5 of the magnet holder 3, as shown in FIG.

Further, a presser ring 6 made of a non-magnetic material is fitted to the outer periphery of the magnets 4A, 4B, and are integrally bonded with an adhesive.

Of course, it may also be fixed by the clamping pressure of the presser ring itself without using adhesive.

The stator 7 arranged on the open side of the bowl-shaped rotor 1 is made of a non-magnetic material, and has a pulsar coil 9 extending in the axial direction on its upper surface.
An iron core 8 wound with is fixedly installed, and the base of the iron core is opposed to the magnet 4A, and the pulser coil 9 is opposed to the boss portion 2 with a gap therebetween.

Note that a plurality of main magnets 10 are also attached to the inner peripheral surface of the rotor 1, and although these are not shown, they are arranged in a space other than the position where the pulse coil is located and excite the ignition coil fixed to the stator 7. It is something to do.

Next, the operation of the above configuration will be explained with reference to FIG.

When the rotor 1 rotates, the magnet 4A provided on the boss portion 2
, 4B, and the magnetic flux changes from N to S.

When changing from S to N, rectangular magnetic flux alternates in the iron core 8 as shown by φ in FIG. 3A.

In the pulser coil 9 interlinked with this magnetic flux φ, one positive and one negative pulse voltage is generated every rotation as shown by e in FIG.

At this time, the magnetic flux of the pulser magnet is constantly flowing through the iron core 8 even at positions other than the position where the pulse voltage is generated, and this iron core 8
Since the magnetic flux density is set high and brought close to the magnetic saturation state, the amount of magnetic flux becomes almost constant, and for example, noise magnetic flux from the main magnet 10 does not pass through.

Therefore, good signal pulses can be obtained without generating unnecessary voltage, which is generally likely to occur in this type of device.

In addition, the magnets 4A and 4B are connected to the small diameter portion 3B of the stepped magnet holder 3.
Since it is fixed to the rotor boss portion 2, the size in the radial direction can be suppressed and the entire structure can be made compact.

Note that, when the rotor rotational speed is low, the presser ring 6 is preferably formed of a thin magnetic material to improve magnetic efficiency.

As described above, according to the present invention, outside the predetermined rotation angle of the rotor, the iron core of the pulsar coil is brought into magnetic saturation, suppressing the generation of unnecessary voltage in the pulsar, and igniting the engine accurately and reliably. .

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the ignition signal generator according to the present invention, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is an explanatory diagram of the operation of the same embodiment. It is. 1...Rotor, 2...Boss part, 4A,
4B...Magnet, 7...Stake, 9
...Pulsa coil.

Claims (1)

[Claims] 1. A bowl-shaped rotor with magnets fixed to its inner circumferential surface, a boss located at the center of the rotor that connects the engine side output shaft and the rotor, and a rotor that rotates in synchronization with the boss and In an ignition signal generator comprising a magnet that excites a pulsar coil fixedly arranged in a space, the pulsar coil magnet is arranged in a ring shape with divided pieces having different polarities adjacent to each other. An ignition signal generator characterized by allowing magnetic flux to constantly flow through the pulsar coil iron core.