JPS5858402A - Position detector for rotating body - Google Patents

Abstract

PURPOSE:To detect the position of a rotating body by forming the pulse signals corresponding to the notches of equal intervals provided on the periphery of a rotary disc to the voltage signals corresponding to frequencies, dividing the voltages and converting the same to corresponding frequencies thereby discriminating the sizes of the notch widths. CONSTITUTION:Notches are provided at equal intervals on the periphery of a magnetic disc RD, and the max. width of arbitrary one piece of the notches is formed to, for example 3mm., and that of the others to 1.8mm.. The disc RD is mounted to the revolving shaft of an internal combustion engine, and when the piston is at the top dead point, the notch of 3mm. width and an electromagnetic sensor EMS are positioned diametrically. The outputs of the sensors EMS are counted with a pulse counter CNT 1 via a waveform shaping circuit WSC. These outputs are subjected to frequency-to-voltage conversion FV and after the voltages are passed through a voltage dividing circuit PD, the voltages are again subjected to voltage-to-frequency conversion FV. The converted frequencies are introduced together with the outputs of a circuit WSC to an AND gate AND. The outputs of the gate AND are counted with a pulse counter CN and are compared with the reference value of a setting circuit DSW for the reference value, whereby the top dead point is detected.

Description

[Detailed description of the invention] The present invention relates to a position detection device for a rotating body.

For example, when detecting the top dead center of a piston in an internal combustion engine, conventionally a disk made of magnetic material is attached to a rotating shaft directly connected to the crankshaft, and a cut is made around the disk at a location corresponding to the top dead center. Alternatively, a protrusion is provided and a top dead center signal is taken out from an electromagnetic sensor provided opposite to the periphery of the disk. Although it is possible to use this disc and electromagnetic sensor as is to determine the rotational speed of the rotating shaft, it is possible to use a notch or protrusion around this disc at the location corresponding to the top dead center. Therefore, in order to improve measurement accuracy, it is necessary to lengthen the measurement time.

(A) For the second reason, a rotary disk dedicated to top dead center detection is attached to the rotating shaft of the conventional 11 internal combustion engine, an electromagnetic sensor is placed opposite to this disk, and multiple notches or protrusions are provided at equal intervals around the circumference. A disk dedicated to measuring the rotational speed is attached, and an electromagnetic sensor is placed opposite this disk as well, but the drawback is that the overall structure is complicated and large.

The present invention simplifies and downsizes the overall configuration by making it possible for one disc to be used both for detecting a specific position such as the top dead center of a piston in an internal combustion engine and for measuring rotational speed. It is an object of the present invention to realize a position detection device for a rotating body that can measure the rotational speed within a short time and with high accuracy.

Conventional discs for measuring rotational speed are generally of the following structure in consideration of the time required for measurement. In other words, if the measurement time is 1 second, 6
Disc with 0 notches or protrusions, measurement time 0
．． If the measurement time is 5 seconds, the number of notches (5) or protrusions is 120, and if the measurement time is 0.2 seconds, the number of incisions or protrusions is 300, and the measurement time is Q.
, 1 second, each disk with 600 notches or protrusions is used.

Figure 1 is a plan view showing the main parts of a conventional disc for measuring rotational speed, and shows the electromagnetic sensor when one electromagnetic sensor is installed facing around the periphery of this disc and one disc is rotated. As shown in Fig. 2 (horizontal axis is time opening t1 vertical axis is voltage V), the detection pulse signal of , 120, 300, or 600 pulse signals are sent, but in any case, the circumferential width of the notches or protrusions provided around the disk is equal to ↑. Therefore, when the rotation speed of the disk is constant, the intervals between each pulse signal are all equal, and the waveforms of each pulse signal are also equal, so it is impossible to identify the pulse signal corresponding to a specific position. It is.

(6) Therefore, in the present invention, among the notches provided around the disk, the circumferential width of any one notch is made larger than other notches, and the detection pulse corresponding to this notch is The time width of the signal is formed to be larger than the time widths of other detection pulse signals.

Now, the diameter of the disc is 10 Oram, and 60 notches are made at equal intervals in the circumferential direction around it, and the maximum width in the circumferential direction of any one notch (at the periphery of the disc) If the opening width of the notch is 3 mm and the maximum circumferential width of the other 59 notches is 1.8 m + r +, then 1.8 mm
The center angle above the maximum width of the cut is approximately 2.06'
% The central angle above the maximum width of the 3 mm cut is approximately 3.43', and if each central angle is measured in units of 0.1', that is, how many times the central angle is 0.1'? When the central angle is 2.06', it is 20, and the central angle is 3.4.
In the case of 3°, it becomes 34. Therefore, for example 20 and 3
Based on the average value 27 of 4, the center angle above the maximum width of the cut is measured in 0.1' increments (7) If the value is smaller than 27, it is a narrow cut, and if the measured value is larger than 27, it is a narrow cut. can be determined to be a wide cut.

The size of the central angle above the maximum width of each cut is 0.1'
To measure in units, there is some method (specifically, the embodiment of the present invention will be explained).If one pulse signal is taken out for every central angle of 0.1a, then the 360 to
0 pulse signals are taken.

The maximum rotation speed of the disc is 10,000 rotations per minute, and the pulse signal extracted at this maximum rotation speed is 3 rotations per minute.
600XIO', and the frequency of this pulse signal is 60
0KH2, but if it is formed so that this frequency can be changed in proportion to the rotational speed of the disk, one per 0.1" of central angle of the disk, regardless of changes in the rotational speed of the disk. Since the pulse signal can be extracted, by counting how many pulse signals corresponding to a center angle of 0.1'' are included within the time width of the pulse signal corresponding to each notch, the maximum width of each notch can be calculated. Center standing above (8) The size of the angle is 0.1” regardless of the change in the rotational speed of the disk.
It can be measured in units.

FIG. 3 is a diagram showing an embodiment of the present invention based on the above-described construction principle, in which RD has a diameter of, for example, 100 mm.
It is a disc made of a magnetic material with a diameter of 60 mm, and has, for example, 60 notches at equal intervals in the circumferential direction, and the maximum width of any one of these notches in the circumferential direction is, for example, 3 mm. mm, and the maximum width of the other cuts in the circumferential direction is, for example, 1.8 m+++. EMs is an electromagnetic sensor, consisting of a voltage induction coil wound around a magnetic core, and is fixedly provided so as to face the periphery of the disk RD at an appropriate interval. When the disc of the present invention is used to measure the rotational speed of an internal combustion engine and detect the top dead center of a piston, for example, when the disc is attached to the rotating shaft of the internal combustion engine, the piston must be at the top dead center. At the time of alignment, the opening of the notch with a width of 3 tnrn provided in the disk is aligned so that it directly faces the electromagnetic sensor EMS. WSC is a waveform (9) shaping circuit, CNTl is a pulse counter, Pv is a frequency voltage conversion circuit, PD is a voltage dividing circuit, vF is a voltage frequency R detection circuit, AND is an AND gate circuit, PH is a phase inversion circuit,
CNT2 is a pulse counter, OMP is a digital comparison circuit, and DSW is a reference value setting circuit, which is composed of, for example, a digital switch. Tol is an output terminal.

Now, assuming that the rotation speed of the disc RD is 10,000 revolutions per minute, the frequency of the pulse signal detected by the electromagnetic sensor EMS is 10 KHz. When the conversion rate of the frequency voltage conversion circuit FV is applied in advance to the signal of 10KH2, the IQ
Select so that a voltage signal of V is sent out, and connect the voltage divider circuit PD.
If the voltage division ratio is set to 10:6 and the conversion rate of the voltage frequency conversion circuit VF is set so that when the voltage signal of IOV is applied, the frequency of the output signal will be ・IMHz, it will be detected by the electromagnetic sensor EMS. The pulse signal of l0KH2 is passed through the waveform shaping circuit wsc to the frequency voltage conversion circuit F.
'V and is converted into a (10) voltage signal of IOV, then divided in the voltage dividing circuit PD, and the divided voltage of 6V is sent to the voltage frequency conversion circuit VP.
It is converted into a 00KH2 pulse signal. The frequency of this pulse signal changes in proportion to the rotation speed of the disc RD,
Voltage frequency conversion circuit VP regardless of the rotation speed of disk RD
The number of pulse signals sent out is 3600 per rotation of the disk RD.

That is, one pulse signal is sent out at each center angle of 0.1° of the circle [RD.

The output pulse signal of the voltage frequency conversion circuit VF and the output pulse signal of the waveform shaping port 118w5c are output from the AND gate circuit A.
ND, the AND gate circuit AND becomes conductive only during the time width of the output pulse signal of the waveform shaping circuit NSC, and the output pulse signal of the voltage frequency conversion circuit VF is introduced into the pulse counter CNT2 via the AND gate circuit AND for counting. The counting output is applied to the comparison circuit OMP. When the part without the notch around the periphery of the disk RD directly faces the electromagnetic sensor EMS and the output of the waveform shaping port u wsc is interrupted and disappears, the pulse counter CNT2 is incremented by the inverted output of the phase inverting circuit PH and the next ' Prepare for counting. Pulse counter CNT when the pulse signal applied from the waveform shaping circuit WSC to the AND gate circuit AND corresponds to a notch with a width of 1.8m+n provided around the disk RD
The count value of 2 is 20, which is the value measured at the center angle of 2.06° standing on the 1.8 mm wide cut at the 0.1# vehicle position.
Since the reference value is smaller than the reference value 27 given to the comparison circuit CMP by the reference value setting circuit DSW, no output is sent from the comparison port g80MP, but the pulse signal applied from the waveform shaping circuit WSC to the AND gate circuit AND is circular. The count value of pulse counter 0NT2 when dealing with a cut of 3 mto width made around plate RD is 3 mto.
The center angle standing on the notch of +++ width is 3.43@0. l
Since the value measured in degrees is 34, which is Q larger than the reference value 27, the output from the comparison corridor cMp is sent out via the terminal To. Therefore, it can be seen that the piston is at the top dead center when this output is delivered.

FIG. 4 is a waveform diagram for explaining the above operation, where (a) is the output pulse signal waveform of the waveform shaping circuit WSC, and (b) the count value of the universal counter CNT2 (however, it is shown as an analog value). , (8) is the output waveform of the comparator circuit (MP), (
A) or (C) In the figure, the horizontal axis is time t1 (A)
and (c) the vertical axis Ji zero voltage 1 in the figure 2; and (b) the vertical axis in the figure is the count value C.

Simultaneously with the above operation, the output pulse signal of the waveform shaping circuit WBC is introduced into the pulse counter CNTl and counted, so that the rotational speed of the disc RD can be determined from the counted value within a suitable unit time. There are 60 notches around the disk RD, and the number of pulse signals sent from the waveform shaping circuit WSC is 60 per 10 rotations of the disk RD, so the rotation speed can be adjusted in a short time and with high precision. It can be measured.

FIG. 5 is a diagram showing another embodiment of the present invention, in which PCNT is a subtraction type preset pulse counter (positive (13) formula name is programmable dependent pi N-4 and cut counter), and other symbols are It is similar to FIG.

In this embodiment, the reference value setting circuit DsW gives the subtraction type preset pulse counter PCNT a reference value of 27, and each time the pulse signal from the AND gate circuit AND is added to the counter P (3NT), the preset value 27 is subtracted. When the pulse signal applied from the waveform shaping circuit wSc to the AND gate circuit AND corresponds to the notch with a width of 1 and 8 north provided around the periphery of the disk RD, the pulse signal is applied to the counter PCNT via the AND gate circuit AND. The number of pulse signals added is 20, and since the subtraction result is not zero, no output is sent from the counter PCNT, but the waveform shaping circuit WSC is connected to the AND gate circuit AND.
When the second pulse signal applied corresponds to a 3 mm width cut, the number of pulse signals applied to the counter PCNT is 34, so the 27th pulse signal is (14
) When added to the counter PCNT, the subtraction result becomes zero, and at the same time, an output is sent from the counter PCNT to indicate that the piston is at the top dead center. When the pulse signal from the waveform shaping circuit WBC is interrupted, the counter PCNT increases by seven due to the inverted output from the phase inverting circuit PH, and the reference value is again preset from the reference value setting circuit DIJ in preparation for the next subtraction count.

In this embodiment, a subtractive preset counter PC! is used instead of the pulse counter CNT2 and comparison circuit CMP in the previous embodiment. Since it is sufficient to provide only the NT, the circuit configuration can be made simpler compared to the previous embodiment.

The above explanation is based on the case where 60 cuts are made around the periphery of the disc RD, but for example, a large disc with a diameter of 200 mm may be used and 120 cuts are made around the periphery. In this case, the partial pressure ratio of the partial pressure port 118PD is set to 1.
By selecting a ratio of 0 to 3, the present invention can be implemented in the same manner as in each of the above embodiments. In addition to the above, the number of notches provided around the disk RD may be arbitrarily selected, and a pulse signal can be used to identify the size of the notch width by selecting the voltage dividing ratio of the voltage dividing circuit PD according to the number of notches. can be made into 3600 pulse signals for each rotation of the disk RD, that is, f pulse signals for every 0.1 m of the center angle of the disk RD.

In this way, in the present invention, when forming a pulse signal for identifying the size of the cut width from the pulse signal corresponding to the cut provided around the periphery of the disk RD, the frequency of the pulse signal corresponding to the cut is adjusted. It is configured to form a corresponding voltage signal, divide it, and convert this divided voltage back into a pulse signal with a frequency corresponding to the divided voltage.
By appropriately selecting the voltage dividing ratio of the voltage dividing circuit, it is possible to always obtain the required notch identification pulse signal regardless of the number of notches in the disc RD. Comparing this to the case where a frequency multiplication circuit is used, it is extremely difficult to configure a frequency multiplication circuit so that the frequency multiplication ratio can be changed arbitrarily, but it is extremely easy to change the voltage division ratio freely. Therefore, the present invention has the advantage that the number of cuts in the disc RD can be arbitrarily selected.

In addition, although the above example shows the case where cuts with widths of 1.8 mm and 3 mm are provided around the periphery of the disc RD, the length of the width can be selected appropriately as long as the size of the cut width can be easily and reliably identified. There is no problem, and the pulse signal for identifying the size of the cutting width according to the width may be set at a rate of one pulse signal for every 0.1' central angle of the disc RD, for example, one pulse signal for every 0.2'' central angle. In addition, the standard value for identifying the size of the cutting width may be arbitrarily selected without being limited to the average value as described above, as long as it can ensure the identification. .

Furthermore, instead of making a notch around the periphery of the disc RD, protrusions are provided protruding from the periphery of the disc, and if the width of one of the protrusions in the circumferential direction is appropriately larger than the width of the other protrusions, then (17) You can do it like this.

Instead of obtaining the desired pulse signal by combining an electromagnetic sensor and a magnetic disk with cuts or protrusions around the periphery as described above, multiple slits are formed around the periphery of a rotating disk made of an opaque material in the circumferential direction. The slits are bored radially at equal intervals, and the width of any one slit in the circumferential direction is made appropriately larger than the width of the other slits, and the light source and photoelectric conversion element are connected through this slit portion. They may be configured to face each other and generate a required pulse signal.

In either an electromagnetic pulse generator or a photoelectric pulse generator, instead of making the width of any one notch, protrusion or slit appropriately larger than the others, Of course, the present invention can also be practiced by making the width of the cutout smaller than that of other notches, protrusions, or slits.

As is clear from the above description, the device of the present invention (18) can reliably adjust the lateral ratio of a specific position of the rotating body by using one common rotating disk, and can quickly and accurately adjust the rotational speed of the rotating body. It can be performed at a high level, the overall structure is simple, and the effects are enormous.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the main parts of a conventional disc for measuring rotational speed, FIG. 2 is a waveform diagram showing a conventional pulse signal for measuring rotational speed, and FIG. 3 is an embodiment of the present invention. , FIG. 4 is a waveform diagram for explaining its operation, and FIG. 5 is a diagram showing another embodiment of the present invention, where RD: rotating disk, EMS: electromagnetic sensor, WSC: waveform shaping. Circuit, CNT I and CN
T2: Pulse counter, FV: Frequency voltage conversion circuit,
PD: voltage divider circuit, vr: voltage frequency conversion circuit, AND:
AND gate circuit, PH two-phase inversion circuit, CMP: digital comparison circuit, OSW: reference value addition circuit, TO: output terminal, PONT: subtraction type preset counter. (19) Figure 1 Figure 2

Claims (2)

[Claims] (1) A plurality of notches or protrusions are provided around the periphery at equal intervals in the circumferential direction, and the circumferential width of any one of these notches or protrusions is equal to that of the other notches or protrusions. A pulse signal generator consisting of a rotating disk made of a magnetic material with different widths in the circumferential direction and an electromagnetic sensor opposed to the periphery of this disk, or a pulse signal generator with a plurality of slits arranged at equal intervals in the circumferential direction. A rotating disk made of an opaque body with radially bored holes and the circumferential width of any two slits in these slits being different from the circumferential width of the other slits, and a rotating disk of this disk. a photoelectric pulse generator comprising a light source and a photoelectric conversion element facing each other through a slit; a first pulse counter into which a pulse signal (1) corresponding to the output of the electromagnetic sensor or photoelectric conversion element is introduced; , a frequency-voltage converter circuit into which a pulse signal corresponding to the output of the electromagnetic sensor or photoelectric conversion element is introduced, a voltage divider circuit that divides the converted output voltage of the frequency-voltage converter circuit, and a divided voltage of the voltage divider circuit. a voltage frequency conversion circuit to which is applied, an AND gate circuit to which a pulse signal corresponding to the converted output pulse signal of this voltage frequency conversion circuit and the output of the electromagnetic sensor or photoelectric conversion element is introduced, and an output pulse of this AND gate circuit. a second pulse counter into which the signal is introduced;
A position detection device for a rotating body, comprising a comparison circuit that compares the count value of the pulse counter with a reference value. (2) A plurality of notches or protrusions are provided around the periphery at equal intervals in the circumferential direction, and the circumferential width of any one of these notches or protrusions is equal to that of the other notches or protrusions. A rotating disk made of a magnetic material with different widths in the circumferential direction, and a pulse signal generator consisting of an electromagnetic sensor facing the umbrella or several slits in the wall around the circumference of this disk (2). An opaque body with slits radially spaced at equal intervals in the circumferential direction, and in which the width of any one slit in the circumferential direction among these slits is different from the width of the other slits in the circumferential direction. a photoelectric pulse generator comprising a rotating disk, a light source and a charge conversion element facing each other through a slit portion of the disk;
a first pulse counter into which a pulse signal corresponding to the output of the electromagnetic sensor or photoelectric conversion element is introduced; a frequency-voltage conversion circuit into which a pulse signal corresponding to the output of the electromagnetic sensor or photoelectric conversion element is introduced; A voltage dividing circuit that divides the converted output voltage of the frequency voltage converting circuit, a voltage frequency converting circuit to which the divided voltage of the voltage dividing circuit is applied, a converted output pulse signal of the voltage frequency converting circuit, and the electromagnetic sensor or photoelectric conversion element. and a subtractive preset counter into which a reference value is blizzeted (3) and the output pulse signal of the AND gate circuit is introduced as a subtraction input. Features: A rotating body position detection device.