JPH0668270B2 - Electromagnetic rotation sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic rotation sensor including a plurality of magneto coils, and particularly to noise reduction due to magnetic interference thereof.

[Prior Art] In an electronic ignition advance control system of an engine, a signal generator in which a signal rotor having a protrusion in a magnetic field and a generator coil are arranged is used as an electromagnetic rotation sensor.
Usually, this system is provided in a housing of a cam position detecting device which is a combination of two signal generators and does not include an ignition generator or a power distribution unit. These two signal generators detect the engine speed (N _E ) on the one hand and the crank position (G) on the other hand, and generate the engine speed signal (hereinafter N _E signal) generated by them. And a crank position signal (hereinafter abbreviated as G signal) are sent to a computer, and the computer determines the optimum ignition timing.

As an ignition distributor of this system, as shown in FIG. 10, conventionally, an ignition distributor in which signal rotors 111 and 121 are attached to a rotor shuff 101 connected to a camshaft of an engine at a distance is used. This ignition distributor includes a signal rotor 111, a generator coil 112, a permanent magnet 113.
The N _E generator 110 is composed of a magnetic path forming iron plate. Further, in this ignition distributor, a G signal generator 120 is composed of a signal rotor 121, a generator coil 122, a permanent magnet 123 and a magnetic path forming iron plate.

And N _E signal generator 110, the distance between the G signal generator 120 (in particular the distance between the two generating coils 111 and 121) A in the ignition distributor, the relationship between the noise voltage generated by the G signal generator 120 first It is shown in the graph of Figure 11. From this graph, it can be confirmed that the noise voltage of the G signal increases as the distance A decreases and the overlapping width increases.

[Problems to be Solved by the Invention] In recent years, however, an electromagnetic rotation sensor of this type has been downsized in order to improve the mountability of an ignition distributor to a vehicle. There is an increasing need to install the coils 112 and 122 on the same plane in the axial direction of the rotor shaft 101.

Therefore, it is necessary to reduce the level of the noise voltage in the electromagnetic rotation sensor having the above configuration. For this reason,
Japanese Patent No. 811 proposes a device that mixes the outputs of two signal generators with each other using resistors, diodes, etc. at an appropriate ratio. However, this device becomes expensive due to an increase in the number of parts and man-hours.

The present invention does not require the addition of electrical components such as resistors and diodes, and the addition of a small configuration reduces the level of noise voltage generated due to magnetic interference between at least two rotation sensors. For the purpose of providing.

[Means for Solving the Problems] In order to achieve the above object, an electromagnetic rotation sensor of the present invention includes a rotating rotor shaft, a signal rotor provided on the rotor shaft, and different rotation positions of the signal rotor. At least two magnetic circuits in which the interlinkage magnetic flux changes are provided, and each of these magnetic circuits is provided with a generating coil to generate at least two independent rotational position signals in response to changes in the magnetic flux at each rotational position. And a first coil portion for generating a voltage signal as the rotation position signal at the one rotation position, and a number of turns from the first coil portion. The noise voltage level generated in the magneto coil of the other rotation sensor due to the change in the magnetic flux of the one magnetic circuit is reduced. A partial voltage signal to employing the technical means having a second coil portion for generating the rotational position of said one.

[Operation] According to the electromagnetic rotation sensor of the present invention, the rotation of the rotor shaft causes the signal rotor to rotate, whereby the magnetic flux of the magnetic circuit of one rotation sensor changes periodically and the magnetic circuit of the other rotation sensor. Since the magnetic flux of is also changed periodically, a voltage signal as a rotational position signal is generated in each of the magneto coils of at least two rotation sensors.

At this time, interference noise is generated in the rotation position signal of the other rotation sensor due to the change in the magnetic flux of the magnetic circuit of the other rotation sensor due to the change of magnetic flux of the magnetic circuit of one rotation sensor,
By canceling the interference noise in the partial voltage signal generated in the second coil portion of the power generation coil of the one rotation sensor, the level of the noise voltage generated in the power generation coil of the other rotation sensor is reduced.

[Effects of the Invention] The electromagnetic rotation sensor of the present invention does not require addition of electric parts such as a resistor and a diode, but a small configuration is added to the other rotation sensor according to a change in magnetic flux of the magnetic circuit of one rotation sensor. It is possible to reduce the level of the noise voltage generated in the power generation coil and to prevent the generation of an erroneous signal.

[Embodiment] Embodiments of the electromagnetic rotation sensor of the present invention are shown in FIGS.
A description will be given based on the figure.

1 to 8 show the first embodiment of the electromagnetic rotation sensor of the present invention.
An example is shown.

FIG. 1 shows an ignition distributor of an internal combustion engine ignition device in which the electromagnetic rotation sensor of the present invention is incorporated into an electronic ignition advance control system for an engine.

The distributor 1 includes a rotor shaft 2, a housing 3 that rotatably holds the rotor shaft 2, an electromagnetic rotation sensor 4 provided in the housing 3, and a power distribution unit provided above the rotor shaft 2 in the figure. 7 and.

Rotation of the camshaft or crankshaft of the engine is transmitted to the rotor shaft 2 by the coupling 22. In addition, the rotor shaft 2 is coupled with the coupling 22 so that the rotational speed of the cam shaft or
Driven at a rotational speed of 2.

The housing 3 includes a tubular portion 31 and a storage portion 32 that stores the electromagnetic rotation sensor 4. The tubular portion 31 is the bearing 3
3. The rotor shaft 2 is rotatably held via the oil seal 34, and the O-ring 37 is fitted in the circumferential groove 36 of the outer circumference 35.

The electromagnetic rotation sensor 4 includes a rotating body 41 fixed to the upper end portion 21 of the rotor shaft 2, an annular plate-shaped bracket 45 coaxially provided on the rotating body 41, and an engine rotation speed (N _E ). It comprises an N _E signal generator 5 for detecting and a G signal generator 6 for detecting a crank position (G).

The rotating body 41 is the signal rotor of the present invention, and has a fixed portion 46 to be fixed to the rotor shaft 2 and a circular recess 48 on the upper surface 47. As shown in FIG. 2, the bracket 45 has a circular hole 42 formed at the center thereof through which the rotor shaft 2 is inserted, and recesses 43 and 44 formed at symmetrical positions on the outer peripheral portion.

The N _E signal generator 5 includes a bracket 45, an N _E signal signal rotor 52 provided on the rotating body 41, an N _E signal generating coil 53 provided corresponding to the N _E signal signal rotor 42, and a bracket It is composed of a permanent magnet 54 for fixing 45 on the upper surface and a plate-shaped iron core 55 forming a magnetic path. The signal rotor
52, bracket 45, N _E signal generating coil 53, permanent magnet 54
And the iron core 55 constitutes one rotation sensor of the present invention.

The signal rotor 52 for the N _E signal is, as shown in FIG.
24 protrusions as the first feature on the outer periphery of the upper part of the rotating body 41
Forming 51. Iron core 55 is L-shaped and bracket 45
It is provided so as to pass through the recess 43. Also iron core 55
The lower part is fixed to the housing 2 and faces the magnetic pole portion 55a of the illustrated upper right portion through a front end surface and the minute gaps of the projection 51 of the N _E signal signal rotor 5.

The G signal generator 6 includes a bracket 45, a G signal signal rotor 62 provided on the rotating body 41, a G signal generating coil 63 provided corresponding to the G signal signal rotor 62, and the bracket 45 on the upper surface. It is composed of a permanent magnet 64 to be fixed and a plate-shaped iron core 65 forming a magnetic path. The signal rotor
62, bracket 45, G signal generating coil 63, permanent magnet 64
The iron core 65 constitutes the other rotation sensor of the present invention.

The signal rotor 62 for the G signal, as shown in FIG.
One protrusion as the second feature on the outer periphery of the lower part of the rotating body 41
Forming 61. Iron core 65 is L-shaped and bracket 45
It is provided so as to pass through the recess 44. Also iron core 65
The lower part is fixed to the housing 2, and the magnetic pole part 65a at the upper left part of the drawing faces the tip end surface of the protrusion 61 of the G signal signal rotor 62 with a minute gap.

In this embodiment, in order to improve the assemblability, the N _E signal generator coil is used.
Reference numeral 53 is a power generation coil of one rotation sensor of the present invention, and as shown in FIGS. 2 and 3, a first coil portion 531 and a second coil portion having a smaller number of turns than the first coil portion 531. A coil portion 532 is provided.

In the N _E signal generator coil 53, the N _E − side terminal 53 a is connected to the ground connection line 56, and the N _E + side terminal 53 b is the N _E signal generation connection line 5.
7 and the intermediate point 53c of the N _E signal generator coil 53 is connected 66
Is a coil connected to the G-side terminal 63a of the G signal power generation coil 63 via the first coil portion 531 and is a coil portion between the N _E − side terminal 53a and the N _E + side terminal 53b. , Generates an N _E voltage signal as a rotational position signal at one rotational position. In this embodiment, the N _E voltage signal (hereinafter referred to as the voltage of the N _E signal) is generated every time the protrusion 51 of the N _E signal signal rotor 52 passes through the position of the magnetic pole portion 55a of the iron core 55.

The second coil portion 532 is provided so as to overlap with the first coil portion 531 and is a coil portion between the N _E − side terminal 53a and the intermediate point 53c, which changes with the magnetic flux of the magnetic circuit 50. A partial voltage signal for reducing the level of the noise voltage generated in the G signal generating coil 63 is generated at one rotational position. In this embodiment, projections 51 of the N _E signal signal rotor 52 to generate a partial voltage signal (hereinafter partial voltage hereinafter) each passing through the position of the magnetic pole portion 55a of the core 55.

The G signal power generation coil 63 is the power generation coil of the other rotation sensor of the present invention, and the G + side terminal 63b is connected to the G signal generation connection line 67. This G signal generating coil 63 is
At the other rotational position, a G signal voltage signal as a rotational position signal is generated. In this embodiment, a G signal voltage signal (hereinafter referred to as a G signal voltage) is generated each time the protrusion 61 of the G signal signal rotor 62 passes through the position of the magnetic pole portion 65a of the iron core 65.

50 As shown in FIG. 1 and FIG. 4, N _E signal generator 5
And 60 shows the magnetic circuit of the G signal generator 6, as shown in FIGS.

The power distribution unit 7 includes a cap 71, a rotor 72, a center electrode 73 of the cap 71, a side electrode 74 of the cap 71, a carbon brush 7
5, consisting of rotor brush 76.

The cap 71 is fastened to the upper portion of the housing 2 in the figure by bolts 77. The rotor 72 is a connecting member fixed to the circular recess 48 of the rotating body 41 so as to rotate together with the rotating body 41.
Mounted via 78.

In the power distribution unit 7, the high voltage generated on the secondary side of the ignition coil (not shown) is transferred from the high voltage terminal of the secondary coil to the center electrode 73 of the cap 71, the carbon brush 75, and the rotor brush 76.
After that, a spark gap is discharged through a discharge gap 79 of about 0.7 mm, reaches the side electrode 74 of the cap 71, and is distributed to the spark plugs of each cylinder of the engine according to a prescribed ignition order as the rotor 72 rotates.

The operation of the distributor 1 adopted in this embodiment will be described with reference to the drawings.

When the distributor 1 is started, the rotation of the engine camshaft or crankshaft is transmitted to the rotor shaft 2 by the coupling 22. Then, the rotor shaft 2 starts rotating at the rotational speed of the camshaft or half the rotational speed of the crankshaft.

The electromagnetic rotation sensor 4, by the rotation of the rotor shaft 2, the permanent magnets 5 → bracket 45 → the rotor shaft 2 → rotating body 41 of the fixing unit 46 → N _E signal signal rotor 52 →
The magnetic flux of the electromagnetic circuit 50 flowing in the path from the iron core 55 to the permanent magnet 54 changes periodically. Further, the electromagnetic rotation sensor 4 is rotated by the rotor shaft 2 so that the permanent magnet 64 → the bracket 45 →
The magnetic flux of the magnetic circuit 60 flowing in the route of the rotor shaft 2 → the fixed portion 46 of the rotating body 41 → the G signal signal rotor 62 → the iron core 65 → the permanent magnet 64 changes periodically.

At this time, the protrusion 51 of the N _E signal signal rotor 52 is
Flux for each lowering the position of the magnetic pole portion 55a of 55 suddenly decreases, the periodic changes in the magnetic flux, electromotive force, i.e. N _E signal generator 5 of the N _E signal voltage of the N _E signal generating coil 53 Occurs.

Further, the protrusion 61 of the signal rotor 62 for G signal is the iron core 65.
Each time the magnetic flux passes through the position of the magnetic pole portion 65a, the magnetic flux sharply decreases, and due to the periodical change of the magnetic flux, an electromotive force, that is, a G signal voltage is generated in the G signal generating coil 63 of the G signal generator 6.

The voltage of the N _E signal and the voltage of the G signal generated as described above are sent to a computer, and the computer determines the optimum ignition timing.

Here, when the distance A between the N _E signal generator 5 and the G signal generator 6 is 0 mm as in the electromagnetic rotation sensor 4 of the present embodiment, the G signal generator 6 is used in the case of the conventional distributor. As for the noise voltage generated at 1, the noise of the G signal of 0.59 V is generated due to the mutual interference between the N _E signal and the G signal from the graph of FIG. This interference noise causes the ignition timing of the spark plug attached to each cylinder of the engine to be disturbed.

Here, from the graph of FIG. 6 showing the relationship between the noise voltage of the G signal and the voltage of the N _E signal, the noise voltage of the G signal is determined by the magnetic pole portion 55a of the iron core 55 and the protrusion of the signal rotor 52 for the N _E signal. Thing 5
It can be confirmed that a proportional relationship is always maintained with respect to the minute gap between the tip surface of 1 and the output change due to the rotation speed of the rotor shaft 2. Further, from the graph of FIG. 7 showing the phase (waveform) of the G signal size voltage and the N _E signal voltage,
It can be confirmed that the voltage of the N _E signal has an inverse waveform of the noise voltage of the G signal.

Due to these two properties, N _E signal generator 5 and G signal generator 6
Interference noise To counteract, the electromagnetic rotation sensor 4 of this embodiment, G-side terminals 63a of the G signal for the generator coil 63 intermediate point 53c via a connection 66 of the N _E signal generation coil 53 of the
To generate a voltage of the N _E signal and a voltage of the G signal by adding the generated voltage of the second coil portion 532 which is a partial voltage of the voltage of the N _E signal to the noise voltage of the G signal. ing. Therefore, the noise voltage of the G signal generated in the G signal generating coil 63 is canceled by the output voltage of the reverse waveform generated in the N _E signal generating coil 53, so that the level of the noise voltage of the G signal is reduced. .

From FIG. 8 showing the relationship between the noise voltage of the G signal and the rotation speed of the rotor shaft 2, when the conventional one is 260 rpm, 14
It is 950 mV at 0 mV and 3500 rpm, whereas it is 38 mV at the electromagnetic rotation sensor 4 of the present embodiment at 260 rpm and 180 mV at 3500 rpm, and the noise reduction effect of the electromagnetic rotation sensor 4 of the present embodiment is It can be confirmed that it is very large.

Therefore, the electromagnetic rotation sensor 4, N _E signal generator 5 and G
The voltage of the N _E signal generated by the signal generator 6 and the voltage of the G signal with the reduced noise voltage level are sent to the computer, and the optimal ignition timing is calculated by the computer without the ignition timing being changed. It is determined.

FIG. 9 shows a second embodiment of the electromagnetic rotation sensor of the present invention.

(Functions having the same functions as those in the first embodiment are designated by the same reference numerals.) In the present embodiment, a plurality of magneto coils are provided with an N _E signal magneto coil 8 and a G signal magneto coil 8 which are electromagnetic coils. The rotation sensor 4 is configured. The N _E signal generating coil 8 is the generating coil of the one rotation sensor of the present invention, and is provided independently of the first coil portion 81 and the first coil portion 81 in parallel. Coil part 81
A second coil portion 82 with less number of turns, the N _E voltage signal of the first coil portion 81 as a rotational position signal in one rotational position (hereinafter referred to as the voltage of the N _E signal), a N _E signal It is generated every time the protrusion 51 of the signal rotor 52 passes through the position of the magnetic pole portion 55a of the iron core 55.

The first coil portion 81, N _E - side terminal 81a is connected to the ground connection line 83, N _E + side terminal 81b is N _E signal generating connection line 84
Connected to.

The second coil portion 82 is a coil portion independently provided in parallel with the first coil portion 81, and is the N _E − side terminal 82a.
Is connected to the ground connection line 83, and the N _E + side terminal 82b is connected 91
It is connected to the G-side terminal 9a of the G signal generating coil 9 via. The second coil portion 82 outputs a partial voltage signal (hereinafter, referred to as a partial voltage) for reducing the level of the noise voltage generated in the G signal generating coil 9 in accordance with the change in the magnetic flux of the magnetic circuit 50, N _E Protrusion 51 of signal signal rotor 52
Occurs each time the position of the magnetic pole portion 55a of the iron core 55 is passed.

The G signal power generation coil 9 is the power generation coil of the rotation sensor according to the other aspect of the present invention, and the G + side terminal 9b is connected to the G signal generation connection line 92. The G signal generating coil 9 outputs a G signal voltage signal (hereinafter referred to as a G signal voltage) as a rotational position signal each time the protrusion 61 of the G signal signal rotor 62 passes through the position of the magnetic pole portion 65a. Occurs in.

The electromagnetic rotation sensor 4 and the G signal generating coil 9 of this embodiment
The voltage of the G signal generated in the second coil portion is a partial voltage of the voltage of the N _E signals generated by N _E signal generator coil 8
82 generated voltage is added. Therefore, the noise voltage of the G signal generated in the G signal generating coil 9 due to the change in the magnetic flux of the magnetic circuit 50 is canceled by the output of the inverse waveform generated in the N _E signal generating coil 8, so that the G signal noise is reduced. The voltage level can be reduced.

In the case of the present embodiment, it is necessary to provide the first coil portion 81 and the second coil portion 82 in the N _E signal generating coil 8, which results in higher cost compared to the first embodiment.

A) In the present embodiment, the _NE signal generating coil 53 and the G signal generating coil 63 are wound in the longitudinal direction (rotation of the rotating body 41) of the iron cores 55 and 65 in order to improve the assembling property. The _NE signal generating coil 53 and the G signal generating coil 63 may be wound in the lateral direction (perpendicular to the rotating direction of the rotating body 41) of the iron cores 55 and 65.

B) In the present embodiment, the plurality of magneto coils of the present invention are applied to the N _E signal magneto coil 53 and the G signal magneto coil 63, but other signal magneto coils may be used, and three or more magneto coils may be used. Also good.

C) In this embodiment, the protrusion of the signal rotor 52 for the N _E signal
Although the number of 51 is 24, the number is not limited to this embodiment.

D) In this embodiment, the protrusion of the G signal signal rotor 62
The number of 61 is one, but it may be two or four.

In e) embodiment, in order to change the magnetic flux in the magnetic circuit 50 is provided with the projections 51 on the N _E signal signal rotor 52,
Instead of the protrusion 51, the signal rotor 52 for N _E signal may be provided with a recess.

F) In this embodiment, the protrusion 61 is provided on the G signal signal rotor 62 in order to change the magnetic flux of the magnetic circuit 60.
Instead of the protrusion 61, the G signal signal rotor 62 may be provided with a recess.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a distributor of an internal combustion engine ignition device incorporating an electromagnetic rotation sensor of the present invention.
FIG. 4 is a front view of a bracket used in the first embodiment of the electromagnetic rotation sensor of the present invention. FIG. 3 is a wiring diagram of a plurality of magneto coils of the first embodiment of the electromagnetic rotation sensor of the present invention. FIG. 5 is a partial view of a magnetic circuit used in the first embodiment of the electromagnetic rotation sensor of the present invention, and FIG. 5 is a partial view of a magnetic circuit used in the first embodiment of the electromagnetic rotation sensor of the present invention. FIG. 6 is a graph showing the relationship between the noise voltage of the G signal and the voltage of the N _E signal, FIG. 7 is a graph showing the noise voltage of the G signal and the phase of the voltage of the N _E signal, and FIG. FIG. 9 is a graph showing the relationship between the noise voltage of the signal and the rotation speed of the rotor shaft, FIG. 9 is a wiring diagram of a plurality of magneto coils in the second embodiment of the electromagnetic rotation sensor of the present invention, and FIG. Sectional view of an ignition distributor using a rotary sensor, Fig. 11 shows two signals of a conventional electromagnetic rotary sensor It is a graph which shows the relationship between the distance A of a generator and the noise voltage of a G signal. 1 in the figure: Distributor, 2 ... Rotor shaft, 3
...... Housing, 4 ... Electromagnetic rotation sensor, 5 ... N _E signal generator, 6 ... G signal generator, 7 ... Distribution unit, 8,53
...... N _E signal generator coil (generator coil of one rotation sensor), 9, 63 …… G signal generator coil (generator coil of the other rotation sensor), 41 …… Rotating body (signal rotor),
45 …… Bracket, 51 …… Protrusion (first feature), 52…
… Signal rotor for N _E signal (first signal rotor), 5
4, 64 ... Permanent magnet, 55, 65 ... Iron core, 61 ... Projection (second feature), 62 ... Signal rotor for G signal (Second)
Signal rotor), 81, 531 ... first coil portion, 8
2,532 …… Second coil part

Claims (5)

[Claims] 1. A rotating rotor shaft, a signal rotor provided on the rotor shaft, and at least two magnetic circuits whose interlinking magnetic flux changes at different rotational positions of the signal rotor, and these magnetic circuits are formed. And at least two rotation sensors that respectively generate independent rotation position signals in accordance with changes in magnetic flux at each rotation position, and the generation coil of one of the rotation sensors has a rotation position of the one rotation position. A first coil portion for generating a voltage signal as the rotational position signal, and a number of turns smaller than that of the first coil portion, and power generation of the other rotation sensor according to a change in magnetic flux of the one magnetic circuit. A second partial voltage signal for reducing the level of the noise voltage generated in the coil at the one rotational position; Electromagnetic rotation sensor characterized by having a coil portion. 2. The electromagnetic type according to claim 1, wherein the second coil portion is a coil portion between one end portion and an intermediate portion of the first coil portion. Rotation sensor. 3. The electromagnetic rotation sensor according to claim 2, wherein the second coil portion is a coil portion provided independently of the first coil portion. . 4. The signal rotor includes a first signal rotor and a second signal rotor, the one rotation sensor is provided corresponding to the first signal rotor, and the other rotation sensor is the second rotation sensor. The electromagnetic rotation sensor according to claim 1, wherein the electromagnetic rotation sensor is provided so as to correspond to the signal rotor. 5. The first characteristic portion for changing the magnetic flux provided in the first signal rotor is more than the second characteristic portion for changing the magnetic flux provided in the second signal rotor, and the first characteristic portion is provided. The electromagnetic rotation sensor according to claim 4, wherein the portion is also provided in a rotation range where the second characteristic portion is not provided.