JP2001174284A - Rotation sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation sensor capable of detecting a rotor, regardless of the rotation direction. SOLUTION: In a rotation sensor in which a hole IC consisting of at least 2 hole elements detects the projections of a rotor, magnets having different surfaces showing polarity on the left and right of the hole IC are arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a crank angle of an internal combustion engine, a cam angle of the internal combustion engine, and a drive system in a control device for a rotating body of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a detection device is well known in the above-mentioned industrial application field by a combination of a differential Hall IC, which is a package of Hall elements integrated into an IC, and a magnet.
In addition, Japanese Patent Application Laid-Open No. 10-2930,
4 (hereinafter referred to as Patent 1) 1 as described.

[0003] Among them, Patent Document 1 features a magnetic circuit configuration in which a magnet concentrates magnetic flux on one Hall element in a Hall IC. A change has been detected.

[0004]

As described above, in the combination of the differential Hall IC and one magnet, the magnetic flux distributed to one Hall element in the Hall IC is not increased when the rotating body enters and leaves. Therefore, the magnetic flux may not change depending on the rotation direction of the rotating body. Or the change is so small that it cannot be shaped into a pulse. For this reason, the apparatus according to the above-described prior art cannot detect a rotating body having a different rotating direction.

[0005]

In order to solve the above-mentioned problems, in a rotation position detecting device in which a Hall IC composed of at least two Hall elements detects a projection of a rotating body, at both ends located at the two Hall elements, Magnets whose opposite polarities are the same as the sensor detecting surface are arranged, and magnetic fluxes having different polarities are distributed to the Hall elements.

Further, in a function of performing pulse shaping by a comparator on the output difference due to the Hall element and the value obtained by adding the capacitor to the output difference, by providing a resistor in parallel with the capacitor, the value input to the comparator is obtained. Potential of 100
Lower within the range of mV.

Further, the magnet used has a residual magnetic flux density of 1.5 T or less.

Further, by setting the capacitance value of the capacitor within the range of 0.047 μF to 1 μF, the IC
The value input to the comparator inside can be stabilized.

Further, by providing the tip of the sensor made of stainless steel, the strength of the tip can be improved and the thickness of the tip can be made thinner than resin molding, so that the distance between the sensor and the projection of the rotating body can be shortened. And the detection accuracy can be improved.

[0010]

FIG. 1 shows the configuration of the present invention. First, Hall I
At both ends of C, magnets having different polarities on the same plane as the detection surface of the sensor are arranged.

FIG. 2 shows the relationship between the rotation direction of the rotator and the sensor, and shows that the rotator enters the sensor from all directions from 0 to 360 degrees.

A description will be given by taking a certain rotation as an example when the rotation direction of the rotating body is 0 degrees. When there is no protrusion of the rotating body, the Hall element 1 and the Hall element 2 are balanced by the magnetic flux distribution of the magnets disposed at both ends thereof, and the differential amplifier is kept at a constant output. As a result, the comparator outputs LOW shown in FIG. Further, as the rotating body enters, the magnetic flux of the magnet 21 of the Hall element 1 reacts with the protrusion of the rotating body. As a result, the magnetic flux detected by the Hall element 1 also changes, the output of the differential amplifier in the circuit shown in FIG. 3 decreases, and the comparator outputs HIGH shown in FIG. Further, while the projection of the rotating body is passing, a change in magnetic flux is also detected in the Hall element 2, the output of the differential amplifier is slightly increased or decreased, and the comparator maintains the above output. Further, when the protrusion of the rotating body has passed, the Hall element 1 does not detect a change in magnetic flux, only the Hall element 2 detects a change in magnetic flux, the output of the differential amplifier increases, and the comparator sets LOW shown in FIG. Output.

The same operation is explained except that the rotation direction of the rotating body is around 90 degrees or around 270 degrees, and the position facing the 0 degree so that the rotating direction of the rotating body is 180 degrees is the operation from the Hall element 1. The form of the output shown in FIG. 4 does not change at all, only starting from the Hall element 2.

On the other hand, a case will be described where the rotation direction of the rotating body is around 90 degrees or 270 degrees, and the rotation direction of the inner rotating body is 90 degrees. If there is no protrusion on the rotating body,
The Hall element 1 and the Hall element 2 are balanced by the magnetic flux distribution of the magnets arranged at both ends thereof, and the differential amplifier is maintained at a constant output. by this,
The comparator outputs LOW shown in FIG. When the projection of the rotating body further enters, the magnetic flux distributed to the magnets disposed at both ends of the Hall IC reacts with the projection, and the Hall element 1 and the Hall element 2 detect the change. As a result, the output of the differential amplifier decreases, and the comparator outputs HIGH shown in FIG. Further, while the projection of the rotating body is passing, the Hall element 2
The change in the magnetic flux is also detected, the output of the differential amplifier increases and decreases slightly, and the comparator maintains the above output. Further, when the protrusion of the rotating body has passed, the magnetic flux distributed to the magnets disposed at both ends of the Hall IC does not react to the protrusion, and the Hall element 1 and the Hall element 2 do not change. As a result, the output of the differential amplifier increases, and the comparator outputs LOW shown in FIG.

The same operation is described when the direction of rotation of the rotator is 270 degrees. The operation described above when the direction of rotation of the rotator is 90 degrees starts from the end of the passage, further passes through the protrusion of the rotator, and further rotates. It is deployed in a manner called body protrusion entry.

These operations show waveforms which are outputs (hereinafter, referred to as delta B) of the differential amplifier shown in FIG.
This waveform is substantially the same in any direction from 0 to 360 degrees of the rotation direction of the rotating body. This is as explained above. When the rotating body is rotating at a constant rotation speed and a protrusion is periodically detected, the output of the differential amplifier is the non-inverting side of the comparator (corresponding to “+” in FIG. 3). As it is, the inverting side (corresponding to "-" in FIG. 3) is set to 0.
A capacitor having a capacitance value of 047 micro F to 1 micro F and a resistor R1 in parallel with the output from the differential amplifier have a time constant CR. Further, the voltage is divided by about 100 mV by the resistor R2 in parallel with the capacitor. As a result, the value “non-inverting side input” in FIG. 5 is input to the inverting side of the comparator. With these developments, the above-described protrusion detection of the rotating body is executed.

Although the sensor operation has been described above, by providing a stainless steel cover at the tip of the sensor,
As the strength is increased and the tip of the sensor can be made thinner than the resin molded cover, the distance between the Hall element and the magnet and the projection of the rotating body can be shortened. In addition to having a margin, a change in magnetic flux also has a margin, thereby improving the detectability.

[0018]

According to the above configuration, the rotation sensor can produce a constant output regardless of the rotation direction of the projection of the rotating body.

[Brief description of the drawings]

FIG. 1 shows a configuration diagram of a rotation sensor of the present invention.

FIG. 2 is a configuration diagram illustrating a relationship between a rotation direction of a rotating body and a sensor.

FIG. 3 shows a circuit diagram of FIG. 1;

FIG. 4 shows an output waveform diagram from the comparison note shown in FIG.

5 shows an output waveform diagram of the operation amplifier shown in FIG.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. 1, 2 Hall element 10 Sensor 21 Magnet

Claims (6)

[Claims] 1. A rotating position detecting device in which a Hall IC composed of at least two Hall elements detects a projection of a rotating body, opposite surfaces having opposite polarities at both ends located at the two Hall elements are the same as a sensor detecting surface. A rotation sensor, wherein a magnetic flux having different polarities is distributed to each of the Hall elements. 2. A function in which a resistor is provided in parallel with the capacitor in the function of pulse-shaping the output difference due to the Hall element and the value obtained by adding the capacitor by using a comparator. A rotation sensor for lowering the potential of the value input to the comparator within a range of 100 mV or less. 3. A rotation sensor according to claim 2, wherein an output is obtained irrespective of the direction of rotation of the rotating body. 4. A rotation sensor according to claim 3, wherein the magnet has a residual magnetic flux density of 1.5 T or less. 5. The rotation sensor according to claim 4, wherein the capacitance value of the capacitor is set within a range from 0.047 μF to 1 μF. 6. A rotation sensor according to claim 5, further comprising a tip portion of a stainless steel sensor.