JP3428173B2 - Signal rotor for rotation speed detection - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational speed which is arranged on a rotary shaft of an internal combustion engine or the like and is opposed to a magnetic sensor of an electromagnetic rotational speed detecting device for detecting the rotational angle and a reference angular position thereof. The present invention relates to a signal rotor for detection.

[0002]

2. Description of the Related Art Conventionally, in an electromagnetic type rotational speed detecting device for detecting the rotational speed of an internal combustion engine or the like, the rotational speed is such that a large number of teeth, which are arranged on a rotary shaft facing a magnetic sensor and are rotated, are provided on the circumference. A signal rotor for detection is used.

In recent years, in order to detect the rotation angle signal and the reference angle position signal of the rotation shaft of an internal combustion engine and the like by one rotation speed detection signal rotor, a plurality of teeth among a plurality of teeth are made to be toothless portions. There is something. As a prior art document relating to such a signal rotor for detecting the number of revolutions, one disclosed in Japanese Patent Publication No. 5-3883 is known, and in this specification, the following contents are provided. Stated.

The magnetic flux interlinking with the pickup coil of the magnetic sensor affects not only the magnetic flux from the convex portion directly below the pickup coil but also the magnetic flux from the concave and convex portions before and after the magnetic flux. Therefore, the interlinkage magnetic flux is smaller on the convex portion adjacent to the missing portion than on the convex portion other than the missing portion having convex portions on both sides. That is, the peak value of the mountain-shaped waveform of the interlinkage magnetic flux on the convex portion adjacent to the missing portion is smaller than the peak value of the mountain-shaped waveform on the convex portion other than the missing portion having the convex portions on both sides. Therefore, the maximum slope of the chevron waveform also becomes smaller, and the peak value of the chevron waveform before and after the missing part of the output voltage waveform of the pickup coil due to the change rate (time derivative) of the interlinkage magnetic flux becomes smaller than the other parts. Occurs.

In order to deal with such a problem, in Japanese Patent Publication No. 5-3883, the depth of the recess of the missing portion which gives the reference angular position signal of the signal rotor for detecting the rotational speed is formed shallower than the other recesses. By doing so, it is possible to suppress fluctuations in the peak value of the mountain-shaped waveform before and after the missing part of the output voltage waveform from the magnetic sensor in the part adjacent to the missing part, making it easy to distinguish noise from a normal signal. The technique to do is shown.

[0006]

By the way, as described above, when a signal is generated by the signal rotor for detecting the rotational speed, which is opposed to the magnetic sensor of the electromagnetic rotational speed detecting device, the magnetic sensor is generated in the vicinity of the concave portion of the missing portion. It includes a factor that the output characteristics fluctuate greatly when passing just below.
In addition to this, there is a tendency for downsizing of the signal rotor for rotation speed detection, that is, for the outer diameter of the rotor to be reduced in response to the demand for downsizing of internal combustion engines and the like.

For this reason, even if the depth of the recessed portion of the rotational speed detecting signal rotor from the convex portion is shallower than the other concave portions by a predetermined amount, the outer diameter of the rotor is reduced. , The maximum usable rotor speed of the rotation speed detection signal rotor is lowered, that is, the output voltage waveform does not reach the threshold voltage before and after the missing portion of the rotation speed detection signal rotor, and the pulse signal is dropped. There was a new defect.

Therefore, the present invention has been made in order to solve such a new inconvenience, and it is possible to detect an accurate rotation angle and reference angle position without dropping a pulse signal up to a required maximum rotor rotation speed. An object of the present invention is to provide a signal rotor for detecting the rotation speed of an electromagnetic rotation speed detecting device.

[0009]

According to a first aspect of the present invention, there is provided a signal rotor for detecting the number of revolutions, which is made of a magnetic material having a large number of protrusions and depressions continuously formed on the circumference thereof. A magnetic sensor is arranged so as to face each other, which constitutes an electromagnetic rotation speed detecting device for detecting a change in magnetic flux by the convex portion and the concave portion to detect a rotation angle and a reference angle position, The width of the concave portion forming the interval between the convex portions is widened only at one place or a plurality of places, and the other convex portions and the concave portions are provided at equal intervals, and the depth of the wide concave portion from the convex portion is The outer diameter of the rotor and the maximum number of rotations of the rotor are set so as to be shallower than the concave portions between the convex portions provided at equal intervals.

According to a second aspect of the present invention, in the configuration of the first aspect, when the rotor outer diameters are the same, the signal rotor for detecting the number of revolutions has the above-mentioned recessed portion which is wider as the maximum rotor revolution number is higher. The depth from the convex portion is set to be shallow.

According to a third aspect of the present invention, there is provided a signal rotor for detecting the number of revolutions according to the first aspect, wherein, when the maximum number of revolutions of the rotor is the same, the width of the concave portion is increased as the outer diameter of the rotor is reduced. The depth from the convex portion is set to be shallow.

[0012]

According to the first aspect of the present invention, in the signal rotor for detecting the rotation speed of the electromagnetic rotation speed detecting device, the width of the concave portion which forms the interval between the convex portions on the circumference is widened at only one location or at a plurality of locations. The protrusions and the recesses of the are provided at equal intervals, and the depth from the protrusions of the widely provided recesses corresponds to the outer diameter of the rotor and the maximum rotor rotational speed between the protrusions provided at equal intervals. By setting it shallower than the concave portion, the magnetic resistance between the magnetic sensor and the wide concave portion facing the magnetic sensor becomes small and becomes almost the same as the magnetic resistance between the adjacent convex portions, and the voltage waveform shape output from the magnetic sensor Can be stabilized.

In the signal rotor for detecting the number of revolutions according to the second aspect, in addition to the action of the first aspect, when the rotor outer diameter is the same among the parameters, the concave portion formed wider as the maximum rotor number increases. By setting the depth from the convex portion to be shallow, the voltage waveform shape output from the magnetic sensor can be stabilized.

In addition to the operation of claim 1, in the signal rotor for rotation speed detection of claim 3, when the maximum rotor rotation speed among the parameters is the same, the recessed portion is wider as the rotor outer diameter is smaller. By setting the depth from the convex portion to be shallow, the voltage waveform shape output from the magnetic sensor can be stabilized.

[0015]

EXAMPLES The present invention will be described below based on specific examples.

FIG. 1 is a schematic configuration diagram showing a signal rotor for detecting the number of revolutions and a magnetic sensor according to an embodiment of the present invention.

In FIG. 1, a rotation speed detecting signal rotor 1 is formed of a magnetic material such as iron, and a large number of convex portions 2 and concave portions 3 for giving a rotation angle signal are alternately provided at equal intervals on the circumference. At the required reference angle position, a wide concave portion 4 is provided in which the convex portion 2 is omitted and is shallower than the depth of the concave portion 3. This rotation speed detecting signal rotor 1 has convex portions 2 at equal intervals at an angle of 10 ° obtained by dividing the circumference 360 ° into 36 equal parts.
Is provided, and two adjacent convex portions are omitted, and it is called a 36-2 tooth. In addition, the rotation speed detection signal rotor 1 has a rotor outer diameter of φD [m
m], the depth of the wide concave portion 4 from the convex portion 2 is h [mm],
The width of the convex portion 2 is Wa [mm], and the width of the concave portion 3 is Wb [mm].
And respectively.

A magnetic sensor 5 is arranged at a position facing the convex portion 2 on the circumference of the rotation speed detecting signal rotor 1. The magnetic sensor 5 is an electromagnetic pickup type sensor including a pickup coil 6 and a permanent magnet 7. The magnetic sensor 5 detects that the magnetic flux interlinking with the pickup coil 6 changes due to the concavo-convex portion of the signal rotor 1 for detecting the number of revolutions passing immediately below the magnetic sensor 5,
A voltage waveform corresponding to the rotation angle and the reference angle position is output.

Next, the advantages of this embodiment when performing waveform processing based on the output voltage waveform of the pickup coil 6 of the magnetic sensor 5 will be described.

The inventor has found that the maximum rotor rotational speed RoMAX that can be used decreases when the rotor outer diameter φD of the rotational speed detection signal rotor 1 is small because of the missing portion of the rotational speed detection signal rotor 1. Depth h of a certain wide recess 4
As a result of earnest experimental research, we came to know the relevance as follows.

FIGS. 2, 3 and 4 are timing charts showing output waveforms when the vicinity of the wide recess 4 of the signal rotor 1 for detecting the number of revolutions passes immediately below the magnetic sensor 5, and FIG. 3 (a) and 4 (a) are output voltage waveforms of the pickup coil 6 of the magnetic sensor 5, FIG.
2B, FIG. 3B, and FIG. 4B are respectively shown in FIG.
Waveforms before the output voltage waveforms of (a), FIG. 3 (a), and FIG. 4 (a) are shaped by the comparator of the electromagnetic rotation speed detecting device, FIG. 2 (c), FIG. 3 (c), and FIG. (C) shows the pulse waveform after waveform shaping by the comparator of the electromagnetic type rotation speed detecting device, respectively.

FIG. 2 shows that the rotor outer diameter φD of the signal rotor 1 for detecting the number of revolutions is 70 mm, the depth h of the wide concave portion 4 from the convex portion 2 is 0.8 mm, the width Wa of the convex portion 2 and the width of the concave portion 3 are large. Wb
Is about 1: 1.5 and the actual size is the width Wa of the convex portion 2.
Is about 2.4 mm, the width Wb of the recess 3 is about 3.7 mm, and the rotor speed Ro is 5000 rpm, FIG. 3 has the same external dimensions as FIG. 2 and the rotor speed Ro is 6000 r.
4, when only the depth h from the convex portion 2 of the wide concave portion 4 in the external dimensions of FIG. 2 is reduced to 0.3 mm and the rotor speed Ro is 6000 rpm as in FIG.
And when, respectively. The depth h of the wide concave portion 4 from the convex portion 2 may be a step from the convex portions 2 at both ends of the wide concave portion 4 and may be a linear shape or an arc shape as shown in FIG. The difference does not affect the output waveform. The ratio of the width Wa of the convex portion 2 to the width Wb of the concave portion 3 is not fixed because the peripheral speed changes depending on the rotor outer diameter φD.
When D is 84 mm, about 1: 2.0 is preferable, and according to the experimental results, the width W of the convex portion 2 is irrespective of the rotor outer diameter φD.
It is preferable that a is 2.0 to 3.0 mm.

In FIG. 2A, the output voltage waveform a21 of the pickup coil 6 of the magnetic sensor 5 corresponding to the convex portion 2 following the wide concave portion 4 of the rotation speed detecting signal rotor 1.
However, since it is largely projected, the corrugated a22 due to the recess 3 which follows is lifted up. Therefore, as shown in FIG. 2B, a waveform b corresponding to the waveform a22 of FIG. 2A before the waveform shaping by the threshold voltages VthON and VthOFF having the hysteresis width of the comparator of the electromagnetic rotation speed detecting device.
22 becomes a pointed shape downward and is lifted.
Then, as shown in FIG. 2 (c), the pulse waveform c22 corresponding to the waveform b22 of FIG. 2 (b) after waveform shaping by the threshold voltages VthON and VthOFF of the comparator of the electromagnetic rotation speed detecting device is Although it is narrower and narrower than the corrugated width corresponding to the concave portion 3, it is output somehow.

Next, the rotor rotational speed Ro of the rotational speed detecting signal rotor 1 is changed from 5000 rpm in FIG. 2 to 60 in FIG.
When the speed is increased to 00 rpm, the output voltage waveform a31 of FIG. 3A corresponding to the output voltage waveform a21 of FIG.
Since it becomes larger, the waveform a32 by the subsequent recess 3 is further lifted. Therefore, the waveform b32 of FIG. 3B corresponding to the waveform b22 of FIG. 2B is further lifted. Therefore, at the timing of FIG. 3 (c) corresponding to the output timing of the waveform c22 of FIG. 2 (c), it disappears regardless of the threshold voltage VthON and a waveform omission c32 occurs.

Therefore, when the depth h of the wide concave portion 4 of the rotation speed detecting signal rotor 1 from the convex portion 2 is set to 0.3 mm, FIG. 4 corresponding to the output voltage waveform a31 of FIG.
Since the lifting of the output voltage waveform a41 of (a) is suppressed, the lifting of the waveform a42 corresponding to the next recess 3 is also suppressed, and the shape becomes almost the same as the other recesses 3. Therefore, the waveform b42 of FIG. 4B corresponding to the waveform b32 of FIG. 3B cannot be lifted. Therefore, in FIG. 3C, the waveform omission c32 corresponds to the timing when there is no output in FIG.
At the timing of (c), the pulse waveform c42 due to the threshold voltages VthON and VthOFF is output with a width substantially the same as the waveform width corresponding to the other concave portions 3.

In this way, the maximum rotor rotation speed RoMAX [rpm] that can be used by the rotation speed detection signal rotor 1 is obtained.
Is the rotor outer diameter φD [mm] and the depth h of the wide recess 4
As a result of repeated experiments using [mm] as a parameter, the characteristic diagram shown in FIG. 5 could be obtained. According to FIG. 5, the rotor outer diameter φD [mm] and its maximum rotor rotation speed R
If oMAX is determined, the depth of the wide concave portion 4 from the convex portion 2 can be set. It should be noted that the characteristics of the depth h = 0.8 [mm] of the wide concave portion 4 and h = 0.3 [m] in FIG.
The characteristics between [m] and the characteristics of [m] are obtained by proportional interpolation calculation, assuming that there are parallel characteristic lines dividing 0.3 to 0.8 at equal intervals. From the experimental results of FIG. 5, assuming that the rotor outer diameter is φD [mm] and the required maximum rotor rotation speed is RoMAX [rpm], the depth h is h ≦ (375 ·
It was found that the condition φD-R-10650) / 12000 should be satisfied. The depth of the concave portion 3 from the convex portion 2 may be deeper than the width Wb of the concave portion 3 shown in FIG.

As described above, the rotation speed detecting signal rotor 1 of this embodiment is made of a magnetic material having a large number of convex portions 2 and concave portions 3 continuously provided on the circumference thereof. A magnetic sensor 5 is arranged so as to face each other, and constitutes an electromagnetic rotation speed detection device for detecting a change in the amount of magnetic flux due to the convex portion 2 and the concave portion 3 to detect a rotation angle and a reference angular position. The width of the concave portion 3 forming the interval between the convex portions 2 on the circumference is widened only at two places, and the other convex portions 2 and the concave portions 3 are provided at equal intervals,
The depth h of the wide concave portion 4 from the convex portion 2 is set to be shallower than the concave portion 3 between the convex portions 2 provided at equal intervals corresponding to the rotor outer diameter φD and the maximum rotor rotation speed RoMAX. This can be the embodiment of claim 1.

Therefore, the magnetic resistance between the pickup coil 6 of the magnetic sensor 5 and the wide concave portion 4 facing the magnetic sensor 5 becomes small and becomes almost the same as the magnetic resistance between the adjacent convex portion 2, and at that position. The peak value of the mountain-shaped waveform of the interlinkage magnetic flux amount is almost equal to the peak value of the mountain-shaped waveform at other positions. For this reason, the peak values of the mountain-shaped waveforms of the interlinkage magnetic flux amount are all uniform, and the maximum gradients thereof are also substantially equal. In the present embodiment, as shown in FIG. 5, when the rotor outer diameter φD is 70 mm and the maximum rotor rotation speed RoMAX is up to around 12000 rpm, the depths from the convex portions 2 of the wide concave portions 4 are provided at equal intervals. Shallower than the concave portions 3 between the formed convex portions 2 h = 0.3 mm
By setting to, the voltage waveform shape output from the magnetic sensor can be stabilized.

Therefore, the waveform omission of the pulse waveform generated based on the voltage waveform shape output from the magnetic sensor is eliminated, and the reliability of the electromagnetic rotation speed detecting device can be improved.

Further, in the signal rotor for detecting the rotational speed of the present embodiment, when the rotor outer diameter φD is the same, the depth from the convex portion 2 of the concave portion 4 which is wider as the maximum rotor rotational speed RoMAX is increased. h is set to be shallow, and this can be the embodiment of claim 2.

Therefore, when the rotor outer diameter φD is the same, the depth h from the convex portion 2 of the wider concave portion 4 is set to be smaller as the maximum rotor rotational speed RoMAX is higher, so that the magnetic sensor outputs. The voltage waveform shape can be stabilized.

Therefore, the waveform omission of the pulse waveform generated based on the voltage waveform shape output from the magnetic sensor is eliminated, and the reliability of the electromagnetic rotation speed detecting device can be improved.

In the signal rotor for rotation speed detection of this embodiment, when the maximum rotor rotation speed RoMAX is the same, the depth from the convex portion 2 of the concave portion 4 which is wider as the rotor outer diameter φD is smaller. h is set to be shallow, and this can be the embodiment of claim 3.

Therefore, when the maximum rotor speed RoMAX is the same, the depth h from the convex portion 2 of the wider concave portion 4 is set to be smaller as the rotor outer diameter φD is smaller,
The voltage waveform shape output from the magnetic sensor can be stabilized.

Therefore, the waveform omission of the pulse waveform generated based on the voltage waveform shape output from the magnetic sensor is eliminated, and the reliability of the electromagnetic rotation speed detecting device can be improved.

In the signal rotor 1 for detecting the number of revolutions of the present embodiment, as shown in FIG. 4 (b), since the peak values of the peak waveform of the output voltage are aligned, the threshold voltage VthON having a wider hysteresis width, Even if it is set to VthOFF,
Each pulse signal of the rotation angle signal corresponding to each chevron waveform does not drop out. Therefore, when the analog output voltage waveform from the pickup coil 6 is converted into a digital signal, it can be set to a threshold value having a sufficient hysteresis width, which makes it easy to distinguish noise from a normal signal.

[0037]

As described above, according to the signal rotor for detecting the number of revolutions of the first aspect, the width of the concave portion forming the interval between the convex portions on the circumference is widened at only one place or at a plurality of places. Other convex portions and concave portions are provided at equal intervals, and the depth of the wide concave portions from the convex portions corresponds to the outer diameter of the rotor and the maximum rotor rotation number. By setting it shallower than the concave part of the magnetic sensor, the magnetic resistance between the magnetic sensor and the wide concave part facing the magnetic sensor is reduced to be almost the same as the magnetic resistance between the adjacent convex parts, and the flux linkage at that position is reduced. The peak value of the mountain-shaped waveform can be made almost equal to the peak value of the mountain-shaped waveform at other positions. As a result, the voltage waveform shape output from the magnetic sensor can be stabilized, the waveform omission of the pulse waveform generated based on the voltage waveform shape is eliminated, and the reliability of the electromagnetic rotation speed detection device is improved. You can

According to the signal rotor for detecting the number of revolutions of the second aspect, similarly to the effect of the first aspect, the outer diameter of the rotor is one of the parameters for setting the depth from the convex portion of the concave portion provided in a wide width. When they are the same, the depth of the concave portion formed wider is set to be shallower as the maximum rotor speed is higher, so that the voltage waveform shape output from the magnetic sensor can be stabilized. The waveform omission of the pulse waveform generated based on the voltage waveform shape is eliminated, and the reliability of the electromagnetic rotation speed detection device can be improved.

According to the signal rotor for rotation speed detection of claim 3, the maximum rotor rotation speed is one of the parameters for setting the depth from the convex part of the wide recessed portion, similarly to the effect of claim 1. When the rotors have the same diameter, the smaller the rotor outer diameter is, the shallower the depth from the convex portion of the concave portion is set, so that the voltage waveform shape output from the magnetic sensor can be stabilized, The waveform omission of the pulse waveform generated based on the voltage waveform shape is eliminated, and the reliability of the electromagnetic rotation speed detection device can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a rotation speed detecting signal rotor and a magnetic sensor according to an embodiment of the present invention.

FIG. 2 is a timing chart showing a relationship between an output signal and a rotation angle signal from a magnetic sensor facing a rotation speed detection signal rotor according to an embodiment of the present invention.

FIG. 3 is a timing chart showing a relationship between an output signal and a rotation angle signal from a magnetic sensor facing a rotation speed detection signal rotor according to an embodiment of the present invention.

FIG. 4 is a timing chart showing a relationship between an output signal and a rotation angle signal from a magnetic sensor facing a rotation speed detection signal rotor according to an embodiment of the present invention.

FIG. 5 is a characteristic diagram showing the maximum usable rotor rotational speed of the signal rotor for detecting the rotational speed according to one embodiment of the present invention, with the outer diameter of the rotor and the depth of the wide concave portion as parameters.

[Explanation of symbols]

1 Rotation speed signal rotor 2 convex 3 recess 4 Wide recess 5 Magnetic sensor 6 pickup coil 7 Permanent magnet h Depth (from convex part of wide concave part)

Claims (3)

(57) [Claims] 1. A magnetic body comprising a magnetic body having a large number of convex portions and concave portions continuously provided on a circumference, and a magnetic sensor is arranged so as to face the convex portions and the concave portions, and a magnetic flux generated by the convex portions and the concave portions. In the signal rotor for detecting the rotation speed of the electromagnetic rotation speed detecting device for detecting the change of the rotation angle and the reference angle position, the width of the concave portion which forms the interval of the convex portions on the circumference is one or more places. Only the width is wide and the other convex portions and the concave portions are provided at equal intervals, and the depth of the wide concave portions from the convex portion is made to correspond to the rotor outer diameter and the maximum rotor rotational speed. A signal rotor for rotation speed detection, characterized in that the signal rotor is set to be shallower than the concave portions between the convex portions provided at intervals. 2. When the rotor outer diameters are the same,
The signal rotor for rotation speed detection according to claim 1, wherein the depth from the convex portion of the wide concave portion is set to be shallower as the maximum rotor rotation speed is increased. 3. When the maximum rotor speeds are the same, the smaller the outer diameter of the rotor, the shallower the depth from the convex portion of the concave portion provided with the wider width is set. A signal rotor for detecting the number of rotations according to.